| 2021 | Acceptance and completion of rifapentine-based TB preventive therapy (3HP) among people living with HIV (PLHIV) in Kampala, Uganda-patient and health worker perspectives. | Implement Sci Commun | A 12-dose, once-weekly regimen of isoniazid and Rifapentine (3HP) is effective in preventing tuberculosis (TB) among people living with HIV (PLHIV). We sought to identify potential barriers to and facilitators of acceptance and completion of 3HP treatment from the perspective of people living with HIV (PLHIV) and health workers in a routine HIV care setting in Kampala, Uganda.We conducted semi-structured interviews with 25 PLHIV and 10 health workers at an HIV/AIDS clinic in Kampala, Uganda. For both groups, we explored their understanding and interpretations of TB and TB preventive therapy (TPT), and perceptions about social and contextual factors that might influence the willingness of PLHIV to initiate and complete 3HP. We analyzed the data using an inductive thematic approach and aligned the emergent themes to the Behavior Change Wheel framework to identify sources of behavior and targeted behavior change interventions.Facilitators of acceptance and completion of 3HP treatment among PLHIV were fear of contracting TB, awareness of being at risk of getting TB, willingness to take TPT, trust in health workers, and the perceived benefits of directly observed therapy (DOT) and self-administered therapy (SAT) 3HP delivery strategies. Barriers included inadequate understanding of TPT, fear of potential side effects, concerns about the effectiveness of 3HP, and the perceived challenges of DOT or SAT. Among health workers, perceived facilitators included knowledge that TB is a common cause of mortality for PLHIV, fear of getting TB, and trust in the health workers by PLHIV, the advantages of once-weekly 3HP dosing, and the benefits of DOT and SAT 3HP delivery strategies. Health worker-reported barriers for PLHIV included inadequate understanding of TB and benefits of TPT, TB-associated stigma, potential side effects pill burden, and challenges of DOT and SAT 3HP delivery strategies. Lack of experience in the use of digital technology to monitor patient care was identified as a health worker-specific barrier. Identified intervention functions to address the facilitators or barriers included education, persuasion, environmental restructuring, enablement, and training.Using a formative qualitative and comprehensive theoretical approach, we identified key barriers, facilitators, and appropriate interventions, including patient education, enhancing trust, and patient-centered treatment support that could be used to optimize the delivery of 3HP to PLHIV in our setting. These interventions are likely generalizable to other clinical interventions in similar populations in sub-Saharan Africa and other TB high-burden settings. |
| 2021 | High rate of completion for weekly rifapentine plus isoniazid treatment in Chinese children with latent tuberculosis infection-A single center study. | PLoS One | Three months of weekly Rifapentine plus isoniazid (3HP) is a short course regimen for latent tuberculosis infection treatment with satisfied safety and efficacy. However, research on its use in children is limited. In this study, we evaluated the completion rate and safety of the 3HP regimen among children in China. Participants aged 1-14 years receiving 3HP for TB prevention at Shanghai Public Health Clinical Center were followed from December 2019 to November 2020 to evaluate the safety and completion rate of the treatment. Thirty-one children were eligible for inclusion, but five were excluded from the analysis (three were treated with a lower than recommended dose, and two were lost to follow-up). Of the 26 children included in the analysis, the treatment completion rate was 100%. Adverse drug reactions (ADRs) were reported in 38.5% (10/26) of the patients. The most common ADRs were gastrointestinal symptoms (19.2%,5/26), and all ADRs were rated as Grade 1. The 3HP regimen has a high completion rate, and it seems well tolerated in our study population. However, further randomized controlled clinical trial with larger sample size are warranted. |
| 2021 | An observational study on prevalence of latent tuberculosis infection and outcome of 3HP treatment in patients under hemodialysis in Taiwan. | J Formos Med Assoc | Identification and treatment for latent tuberculosis infection (LTBI) are of great epidemiological importance of controlling tuberculosis (TB) worldwide. Identification in high-risk population on dialysis and treatment with 12-week weekly Rifapentine plus isoniazid (3HP) help improve prevention outcomes effectively.We conducted a single-center, nonrandomized follow-up study on end-stage renal disease patients on hemodialysis. The interferon-gamma release assay (IGRA) was used for the diagnosis of LTBI. Participants were treated with 3HP, and treatment responses were recorded and analyzed.A total of 123 of the 641 patients showed positive IGRA results. The male sex, age >60 years, low serum albumin level (<4.0 g/dL), and hypercalcemia (serum calcium level > 10.2 mg/dL) were associated with IGRA positivity. Seventy-five patients were treated with 3HP, with a completion rate of 66.67%. The male sex, albumin level >4.0 g/dL, and absence of adverse drug reaction were associated with increased completion rates. Adverse drug reactions included dizziness, fatigue, nausea and vomiting, fever, and hypertension.Risk factors for LTBI in dialysis patients were identified to prioritize LTBI screening and initiate early treatment. The completion rate in dialysis patients were approximately 2 of 3 patients with mild adverse drug reaction, leading to discontinuation of the treatment. |
| 2021 | Rifapentine Polylactic Acid Sustained-Release Microsphere Complex for Spinal Tuberculosis Therapy: Preparation, in vitro and in vivo Studies. | Infect Drug Resist | Spinal tuberculosis has been a common clinical extrapulmonary tuberculosis in recent years. The general anti-tuberculosis drug treatment cycle is long, with unsatisfactory efficacy. This study focused on the preparation and evaluation of Rifapentine polylactic acid sustained-release microsphere complex for spinal tuberculosis therapy.Rifapentine polylactic acid sustained-release microspheres (RPSMs) were prepared through the double emulsion solvent evaporation method, and RPSMs were combined with hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) composite material to obtain drug-loaded, sustained-release complex. We evaluated the complex for dynamics of drug release and osteogenic ability using in vitro release test, alkaline phosphatase and alizarin red staining, real-time PCR and Western blot. A rabbit model of a spinal tuberculosis defect was established and repaired using HA/β-TCP or complex. The ability of anti-tuberculosis and tissue repair effects of the complex were evaluated through in vivo experiments.The complex constructed of RPSMs and HA/β-TCP demonstrated a long drug release time, with no significant inhibition of cell osteogenic differentiation in vitro experiments. Postoperative macroscopic observation, immunohistochemical staining and Nilsson histological scores showed that the complex has good effects on the tissue repair. Moreover, the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), important indexes of inflammation, decreased to normal levels in the complex group.In vitro and in vivo experiments demonstrated that the complex constructed of RPSMs and HA/β-TCP effectively treated spinal tuberculosis. Therefore, the complex represents a promising approach for the treatment of spinal tuberculosis. |
| 2021 | Cost-effectiveness analysis of 3 months of weekly rifapentine and isoniazid compared to isoniazid monotherapy in a Canadian arctic setting. | BMJ Open | To assess the cost effectiveness of once weekly Rifapentine and isoniazid for 12 weeks (3HP) to the current standard care for latent tuberculosis (TB) infection (LTBI) in Iqaluit, Nunavut.A cost-effectiveness analysis using a Markov model reflecting local practices for LTBI treatment.A remote Canadian arctic community with a high incidence of TB.Hypothetical patients with LTBI.The cost effectiveness of 3HP was compared with the existing standard of care in the study region which consists of 9 months of twice weekly isoniazid (9H) given by directly observed therapy.Effectiveness was measured in quality-adjusted life years (QALYs) with model parameters were derived from historical programmatic data, a local implementation study of 3HP and published literature. Costs from the perspective of the Nunavut healthcare system were measured in 2019 US dollars and were obtained primarily from local, empirically collected data. Secondary health outcomes included estimated TB cases and TB deaths averted using 3HP versus 9H. One way and probabilistic sensitivity analyses were performed.The 3HP regimen was dominant over 9H: costs were lower (US$628 vs US$924/person) and health outcomes slightly improved (20.14 vs 20.13 QALYs/person). In comparison to 9H, 3HP treatment resulted in fewer TB cases (27.89 vs 30.16/1000 persons) and TB deaths (2.29 vs 2.48/1000 persons). 3HP completion, initiation and risk of fatal adverse events were the primary drivers of cost effectiveness.In a remote Canadian arctic setting, using 3HP instead of 9H for LTBI treatment may result in cost savings and similar or improved health outcomes. |
| 2021 | Urgent need to address the slow scale-up of TB preventive treatment in the WHO South-East Asia Region. | Int J Tuberc Lung Dis | In September 2018, all countries made a commitment at the first ever United Nations High-Level Meeting (UNHLM) on TB, to provide TB preventive treatment (TPT) to at least 30 million people at high-risk of TB disease between 2018 and 2022. In the WHO South-East Asia Region (SEA Region), which accounts for 44% of the global TB burden, only 1.2 million high-risk individuals (household contacts and people living with HIV) were provided TPT (11% of the 10.8 million regional UNHLM TPT target) in 2018 and 2019. By 2020, almost all 11 countries of the SEA Region had revised their policies on TPT target groups and criteria to assess TPT eligibility, and had adopted at least one shorter TPT regimen recommended in the latest WHO TPT guidelines. The major challenges for TPT scale-up in the SEA Region are resource shortages, knowledge and service delivery/uptake gaps among providers and service recipients, and the lack of adequate quantities of Rifapentine for use in shorter TPT regimens. There are several regional opportunities to address these gaps and countries of the SEA Region must make use of these opportunities to scale up TPT services rapidly to reduce the TB burden in the SEA Region. |
| 2021 | Adverse events associated with weekly short course isoniazid and rifapentine therapy in pediatric patients with latent tuberculosis: A chart and literature review. | Pediatr Pulmonol | Effective yet safe treatment of latent tuberculosis is important for preventing the spread of tuberculosis and the progression to active disease in pediatric patients. As of 2017, the short course combination regimen of weekly isoniazid and Rifapentine (3HP) administered by directly observed therapy (DOT) has replaced 9 months of isoniazid as the standard of treatment for latent tuberculosis in pediatric patients. The literature, limited in size, has established the 3HP regimen's superior safety and adherence.We completed a retrospective chart review (n = 22) of pediatric patients at our institution receiving the 3HP regimen via DOT between 2017 and 2019. Frequencies of selected outcomes were compared to previously published data collected in a literature review.In this retrospective chart review, pediatric patients ages 2-20 years receiving 3HP with DOT for latent tuberculosis experienced frequent adverse events, more severe adverse events such as anaphylaxis, and higher treatment discontinuation than that which has been previously reported in the literature. Of note, our cohort's race/ethnicity differed from the cohorts described in the literature.Our data suggests that the short course combination regimen for pediatric latent tuberculosis patients may have a higher adverse event rate than previously established. Although this sample size is small, this study urges further investigation of more diverse cohorts to better establish the 3HP regimen's safety and tolerability. |
| 2021 | Comparison of Rifamycins for Efficacy Against Complex and Resistance Emergence in the Hollow Fiber Model System. | Front Pharmacol | Rifamycins are integral part of the combination regimen for treatment of pulmonary [MAC] infection, but different practitioners prefer different rifamycins. The objective of the study was to compare microbial kill and resistance emergence of rifamycins using principles of pharmacokinetics/pharmacodynamics. First, we identified rifamycin MICs in 20 MAC isolates from patients followed by concentration-response studies in test-tubes. Next, we examined efficacy and resistance suppression of three doses of each rifamycin in the hollow fiber system model of pulmonary MAC [HFS-MAC], mimicking human like concentration-time profile of the drugs. HFS-MAC units were repetitively sampled for total and drug-resistant MAC burden and for drug concentration measurements. Inhibitory sigmoid E model, linear regression, and analysis of variance was used for data analysis. For rifabutin 90% of isolates had MIC ≤ 0.125 mg/L while for both rifampin and Rifapentine this was ≤2.0 mg/L. There was no statistically significant difference ( > 0.05) in maximal kill and effective concentration mediating 50% of the bacterial kill among three rifamycins in the static concentration experiment. In the HFS-MAC, the bactericidal kill (day 0-4) for rifampin was 0.89 (95% Confidence Interval (CI): 0.43-1.35), for Rifapentine was 1.05 (95% CI: 0.08-1.23), and for rifabutin was 0.92 (95% CI: 0.61-1.24) log CFU/ml, respectively. Rifamycins monotherapy failed after just 4-days of treatment and entire MAC population was drug resistant on day 26 of the study. There was no dose dependent difference in MAC kill or resistance suppression among the three rifamycins tested in the HFS-MAC. Therefore, replacing one rifamycin, due to emergence of drug-resistance, with other may not be beneficial in clinical setting. |
| 2021 | The Enzymes of the Rifamycin Antibiotic Resistome. | Acc Chem Res | Rifamycin antibiotics include the WHO essential medicines rifampin, rifabutin, and Rifapentine. These are semisynthetic derivatives of the natural product rifamycins, originally isolated from the soil bacterium . These antibiotics are primarily used to treat mycobacterial infections, including tuberculosis. Rifamycins act by binding to the β-subunit of bacterial RNA polymerase, inhibiting transcription, which results in cell death. These antibiotics consist of a naphthalene core spanned by a polyketide bridge. This structure presents a unique 3D configuration that engages RNA polymerase through a series of hydrogen bonds between hydroxyl groups linked to the naphthalene core and C21 and C23 of the bridge. This binding occurs not in the enzyme active site where template-directed RNA synthesis occurs but instead in the RNA exit tunnel, thereby blocking productive formation of full-length RNA. In their clinical use to treat tuberculosis, resistance to rifamycin antibiotics arises principally from point mutations in RNA polymerase that decrease the antibiotic's affinity for the binding site in the RNA exit tunnel. In contrast, the rifamycin resistome of environmental mycobacteria and actinomycetes is much richer and diverse. In these organisms, rifamycin resistance includes many different enzymatic mechanisms that modify and alter the antibiotic directly, thereby inactivating it. These enzymes include ADP ribosyltransferases, glycosyltransferases, phosphotransferases, and monooxygenases.ADP ribosyltransferases catalyze group transfer of ADP ribose from the cofactor NAD, which is more commonly deployed for metabolic redox reactions. ADP ribose is transferred to the hydroxyl linked to C23 of the antibiotic, thereby sterically blocking productive interaction with RNA polymerase. Like ADP ribosyltransferases, rifamycin glycosyl transferases also modify the hydroxyl of position C23 of rifamycins, transferring a glucose moiety from the donor molecule UDP-glucose. Unlike other antibiotic resistance kinases that transfer the γ-phosphate of ATP to inactivate antibiotics such as aminoglycosides or macrolides, rifamycin phosphotransferases are ATP-dependent dikinases. These enzymes transfer the β-phosphate of ATP to the C21 hydroxyl of the rifamycin bridge. The result is modification of a critical RNA polymerase binding group that blocks productive complex formation. On the other hand, rifamycin monooxygenases are FAD-dependent enzymes that hydroxylate the naphthoquinone core. The result of this modification is untethering of the chain from the naphthyl moiety, disrupting the essential 3D shape necessary for productive RNA polymerase binding and inhibition that leads to cell death.All of these enzymes have homologues in bacterial metabolism that either are their direct precursors or share common ancestors to the resistance enzyme. The diversity of these resistance mechanisms, often redundant in individual bacterial isolates, speaks to the importance of protecting RNA polymerase from these compounds and validates this enzyme as a critical antibiotic target. |
| 2021 | Safety and feasibility of 1 month of daily rifapentine plus isoniazid to prevent tuberculosis in children and adolescents: a prospective cohort study. | Lancet Child Adolesc Health | Shorter regimens for tuberculosis prevention can improve completion rates and protection against developing active tuberculosis disease after tuberculosis exposure. We aimed to assess the safety and feasibility of 1 month of daily isoniazid and Rifapentine (1HP) in children and adolescents in a low-resource setting in south Asia with low prevalence of HIV.This prospective cohort study was done in eight tuberculosis facilities in Karachi, Pakistan. Eligible participants were aged 2-19 years and were household contacts of patients with drug-susceptible tuberculosis infection. After clinical, radiological, and laboratory evaluation to rule out tuberculosis disease, participants were prescribed 1HP as a preventive regimen. Isoniazid was administered as 100 mg or 300 mg oral tablets and Rifapentine was administered as 150 mg oral tablets. Dosing was according to participant bodyweight. The primary endpoints were the cumulative probability of a household contact completing all stages of the preventive care cascade, assessed in all eligible participants, and the proportion of household contacts completing 1HP, assessed among all those who initiated the regimen. Safety was assessed in all household contacts who initiated the 1HP regimen.Between Dec 21, 2019, and March 20, 2020, 1395 household contacts of 253 patients with tuberculosis were identified, including 678 household contacts who were eligible to participate. 628 (93%) completed evaluation, of whom ten (2%) had active tuberculosis disease. Of the 618 individuals eligible for tuberculosis prevention, 408 (66%) initiated 1HP, 385 (94%) of whom completed the regimen. The median duration of 1HP was 31 days (IQR 30-32) in those who completed the regimen. The cumulative probability of completing all steps of the tuberculosis prevention cascade was 58%. A girl aged 11 years developed tuberculosis disease within 6 months of completing 1HP. A boy aged 14 years developed a burning sensation during 1HP therapy and discontinued the regimen. No other adverse events were observed.1HP can be safely and feasibly implemented as tuberculosis prevention in children and adolescents in programmatic settings.The Global Fund to Fight AIDS, Tuberculosis and Malaria. |
| 2021 | Determinants of Drug-Induced Hepatotoxicity Among Patients with Human Immunodeficiency Virus Taking a High Dose of Rifapentine Plus Isoniazid Drugs at the All Africa Leprosy Tuberculosis Rehabilitation and Training Center in Addis Ababa, Ethiopia. | HIV AIDS (Auckl) | The drugs for the treatment of latent Tuberculosis are potentially hepatotoxic and can lead to drug-induced hepatotoxicity. The current study aimed at identifying the determinants of anti-tuberculosis drug-induced hepatotoxicity among patients living with Human Immunodeficiency Virus taking Isoniazid and Rifapentine at All Africa Leprosy Tuberculosis Rehabilitation and Training Center in Addis Ababa, Ethiopia.An unmatched case-control study was conducted from March, 21, to April 21, 2020, at All Africa Leprosy Tuberculosis Rehabilitation and Training Center. A total of 65 cases and 130 controls were interviewed. Data were collected using a data extraction tool from clinical reporting forms, follow-up charts, and patients' logbooks. Binary and multiple logistic regressions were conducted to check the association between independent and dependent variables. Adjusted odds ratios and the corresponding 95% confidence intervals were estimated to assess the strength of association. P-values <0.05 were used to declare statistical significance.The prevalence of anti-TB drug-induced hepatotoxicity was 8%. Body mass index <18.5 Kg/m2 (AOR = 5.8 [95% CI: 2.2-8.9]), low CD4 count (AOR = 4.9 [95% CI: 1.6-15.8]), and the presence of comorbid illnesses (AOR = 3.9 [95% CI: 1.7-8.9]) were identified as independent predictors of drugs-induced hepatotoxicity among Human Immunodeficiency Virus positive patients taking Isoniazid and Rifapentine.The prevalence of anti-TB drug-induced hepatotoxicity was higher compared to standard references. BMI<18 kg/m2, low CD4 count, and comorbid illness were positively associated with anti-tuberculosis drug-induced hepatotoxicity among patients with HIV. |
| 2021 | Activity of Rifamycin Derivatives against Nontuberculous Mycobacteria, including Macrolide-/Amikacin-Resistant Clinical Isolates. | Antimicrob Agents Chemother | We evaluated the activity of rifamycin derivatives, including rifampin, Rifapentine, rifaximin, and rifabutin, against clinical nontuberculous mycobacteria (NTM) isolates. Of the rifamycin derivatives, rifabutin showed the lowest MICs against all NTM species, including complex, , and Rifabutin also had effective activity against macrolide- and aminoglycoside-resistant NTM isolates. Rifabutin could be worth considering as a therapeutic option for NTM disease, particularly drug-resistant disease. |
| 2021 | Completion Rate and Safety of Programmatic Screening and Treatment for Latent Tuberculosis Infection in Elderly Patients with Poorly Controlled Diabetic Mellitus: A Prospective Multicenter Study. | Clin Infect Dis | Poor control of diabetes mellitus (DM) increases active tuberculosis (TB) risk. Understanding risk factors for latent TB infection (LTBI) in this population and intervention completion rates is crucial for policy making.Under a collaborative multidisciplinary team consisting of public health professionals, endocrinologists, and pulmonologists, patients aged >45 years with poorly controlled DM (pDM), defined as having a glycated hemoglobin level of ≥9% within the preceding year, were enrolled by endocrinologists from 2 hospitals; these patients underwent LTBI screening by using QuantiFERON (QFT). Once-weekly isoniazid and Rifapentine for 12 weeks (3HP) or daily isoniazid for 9 months (9H) was administered by pulmonologists. QFT-positivity predictors were evaluated using logistic regression. Completion rates and safety were also investigated.Among 980 patients with pDM (age: 64.2 ± 9.7 years), 261 (26.6%) were QFT-positive. Age, DM duration, chronic kidney disease stage ≥3, and dipeptidyl peptidase-4 inhibitor use, not using metformin, were associated with QFT-positivity. Preventive therapy (3HP: 138; 9H: 62) was administered in 200 (76.6%) QFT-positive patients. The completion rates of 3HP and 9H were 84.1% and 79.0%, respectively (p=0.494). Nine (6.5%) and zero patients in the 3HP and 9H groups, respectively, developed systemic drug reactions (p=0.059); 78.3% and 45.2% had ≥1 adverse drug reactions (p<0.001); and post-treatment QFT conversion rates were 32% and 20%, respectively (p=0.228).LTBI prevalence exceeds 25% in elderly patients with pDM. Under care from a collaborative multidisciplinary team, the completion rate of preventive therapy, regardless of regimen could approach, or even exceed 80% in this population. |
| 2021 | HIV-associated tuberculosis. | Int J STD AIDS | Tuberculosis (TB) remains a leading cause of morbidity and mortality among people living with HIV. HIV-associated TB disproportionally affects African countries, particularly vulnerable groups at risk for both TB and HIV. Currently available TB diagnostics perform poorly in people living with HIV; however, new diagnostics such as Xpert Ultra and lateral flow urine lipoarabinomannan assays can greatly facilitate diagnosis of TB in people living with HIV. TB preventive treatment has been underutilized despite its proven benefits independent of antiretroviral therapy (ART). Shorter regimens using Rifapentine can support increased availability and scale-up. Mortality is high in people with HIV-associated TB, and timely initiation of ART is critical. Programs should provide decentralized and integrated TB and HIV care in settings with high burden of both diseases to improve access to services that diagnose TB and HIV as early as possible. The new prevention and diagnosis tools recently recommended by WHO offer an immense opportunity to advance our fight against HIV-associated TB. They should be made widely available and scaled up rapidly supported by adequate funding with robust monitoring of the uptake to advance global TB elimination. |
| 2021 | Higher Dosing of Rifamycins Does Not Increase Activity against Mycobacterium tuberculosis in the Hollow-Fiber Infection Model. | Antimicrob Agents Chemother | Improvements in the translational value of preclinical models can allow more-successful and more-focused research on shortening the duration of tuberculosis treatment. Although the hollow-fiber infection model (HFIM) is considered a valuable addition to the drug development pipeline, its exact role has not been fully determined yet. Since the strategy of increasing the dose of rifamycins is being evaluated for its treatment-shortening potential, additional modeling is important. Therefore, we assessed increased dosing of rifampin and Rifapentine in our HFIM in order to gain more insight into the place of the HFIM in the drug development pipeline. Total and free-fraction concentrations corresponding to daily dosing of 2.7, 10, and 50 mg of rifampin/kg of body weight, as well as 600 mg and 1,500 mg Rifapentine, were assessed in our HFIM using the H37Rv strain. Drug activity and the emergence of drug resistance were assessed by CFU counting and subsequent mathematical modeling over 14 days, and pharmacokinetic exposures were checked. We found that increasing rifampin exposure above what is expected with the standard dose did not result in higher antimycobacterial activity. For Rifapentine, only the highest concentration showed increased activity, but the clinical relevance of this observation is questionable. Moreover, for both drugs, the emergence of resistance was unrelated to exposure. In conclusion, in the simplest experimental setup, the results of the HFIM did not fully correspond to preexisting clinical data. The inclusion of additional parameters and readouts in this preclinical model could be of interest for proper assessment of the translational value of the HFIM. |
| 2021 | Patient choice improves self-efficacy and intention to complete tuberculosis preventive therapy in a routine HIV program setting in Uganda. | PLoS One | A 12-dose weekly regimen of Rifapentine plus isoniazid (3HP) is recommended for the prevention of active tuberculosis (TB); however, it is unclear whether 3HP should be provided by directly observed therapy (DOT) or self-administered therapy (SAT). In addition, the introduction of patient informed choice between delivery modalities may have a positive impact on factors leading to treatment completion. The authors randomized 252 participants with HIV to a hypothetical scenario of providing preventive therapy by either DOT or an informed choice between DOT and SAT. Out of 104 participants who were randomized to a choice between DOT and SAT, 103 chose therapy by SAT. Participants rated their level of confidence and intention to complete therapy. Compared to those assigned to the DOT scenario, patients assigned to the choice scenario expressed greater confidence and intention to complete preventive therapy. Convenience and travel required to complete 3HP therapy were important factors in deciding between delivery modalities. Those assigned to DOT identified more barriers to completing therapy than those given a choice. Empowering patients to make informed decisions about how they receive TB preventive therapy may improve completion rates. |
| 2021 | Biomarker-guided tuberculosis preventive therapy (CORTIS): a randomised controlled trial. | Lancet Infect Dis | Targeted preventive therapy for individuals at highest risk of incident tuberculosis might impact the epidemic by interrupting transmission. We tested performance of a transcriptomic signature of tuberculosis (RISK11) and efficacy of signature-guided preventive therapy in parallel, using a hybrid three-group study design.Adult volunteers aged 18-59 years were recruited at five geographically distinct communities in South Africa. Whole blood was sampled for RISK11 by quantitative RT-PCR assay from eligible volunteers without HIV, recent previous tuberculosis (ie, <3 years before screening), or comorbidities at screening. RISK11-positive participants were block randomised (1:2; block size 15) to once-weekly, directly-observed, open-label isoniazid and Rifapentine for 12 weeks (ie, RISK11 positive and 3HP positive), or no treatment (ie, RISK11 positive and 3HP negative). A subset of eligible RISK11-negative volunteers were randomly assigned to no treatment (ie, RISK11 negative and 3HP negative). Diagnostic discrimination of prevalent tuberculosis was tested in all participants at baseline. Thereafter, prognostic discrimination of incident tuberculosis was tested in the untreated RISK11-positive versus RISK11-negative groups, and treatment efficacy in the 3HP-treated versus untreated RISK11-positive groups, during active surveillance through 15 months. The primary endpoint was microbiologically confirmed pulmonary tuberculosis. The primary outcome measures were risk ratio [RR] for tuberculosis of RISK11-positive to RISK11-negative participants, and treatment efficacy. This trial is registered with ClinicalTrials.gov, NCT02735590.20 207 volunteers were screened, and 2923 participants were enrolled, including RISK11-positive participants randomly assigned to 3HP (n=375) or no 3HP (n=764), and 1784 RISK11-negative participants. Cumulative probability of prevalent or incident tuberculosis disease was 0·066 (95% CI 0·049 to 0·084) in RISK11-positive (3HP negative) participants and 0·018 (0·011 to 0·025) in RISK11-negative participants (RR 3·69, 95% CI 2·25-6·05) over 15 months. Tuberculosis prevalence was 47 (4·1%) of 1139 versus 14 (0·78%) of 1984 in RISK11-positive compared with RISK11-negative participants, respectively (diagnostic RR 5·13, 95% CI 2·93 to 9·43). Tuberculosis incidence over 15 months was 2·09 (95% CI 0·97 to 3·19) vs 0·80 (0·30 to 1·30) per 100 person years in RISK11-positive (3HP-negative) participants compared with RISK11-negative participants (cumulative incidence ratio 2·6, 95% CI 1·2 to 5·9). Serious adverse events related to 3HP included one hospitalisation for seizures (unintentional isoniazid overdose) and one death of unknown cause (possibly temporally related). Tuberculosis incidence over 15 months was 1·94 (95% CI 0·35 to 3·50) versus 2·09 (95% CI 0·97 to 3·19) per 100 person-years in 3HP-treated RISK11-positive participants compared with untreated RISK11-positive participants (efficacy 7·0%, 95% CI -145 to 65).The RISK11 signature discriminated between individuals with prevalent tuberculosis, or progression to incident tuberculosis, and individuals who remained healthy, but provision of 3HP to signature-positive individuals after exclusion of baseline disease did not reduce progression to tuberculosis over 15 months.Bill and Melinda Gates Foundation, South African Medical Research Council. |
| 2021 | Tele-TB: Using TeleMedicine to Increase Access to Directly Observed Therapy for Latent Tuberculosis Infection. | Mil Med | Treatment of latent tuberculosis infection (LTBI) decreases risk of progression to active tuberculosis. Traditional treatment regimens required either daily isoniazid for 9 months, with historically poor compliance, or 12-week directly observed therapy (DOT) with isoniazid and Rifapentine, with improved compliance but additional challenges of coordinating weekly clinic visits, further complicated if patients must travel a great distance for care.Our referral area is complicated by congested traffic often resulting in one-way commutes, which can exceed 2 hours. These travel times would be prohibitive for conducting weekly in-clinic DOT. In an effort to improve access to DOT, we implemented TeleMedicine LTBI DOT (vDOT) within a military pediatric infectious diseases clinic. Patients aged 24 months or older diagnosed with LTBI were referred for possible enrollment into our vDOT clinic. All patients without contraindications for receiving isoniazid and/or Rifapentine were offered LTBI treatment via weekly vDOT or daily treatment with isoniazid or rifampin. The first visit for vDOT patients was performed in person to discuss treatment options, demonstrate use of TeleMedicine software, and ensure the patient was able to take the medications. Baseline information about patients and travel time to our facility was determined.To date, 16 patients have completed LTBI therapy using vDOT. Average one-way travel time to our facility for patients was 51 minutes. Actual time spent in most vDOT encounters was less than 10 minutes. Appointments were arranged to take place outside usual school and work hours so patients could complete vDOT with minimal interruptions to daily life, resulting in 100% treatment compliance and completion.Conducting LTBI DOT using TeleMedicine is a viable and time-saving measure that still allows for high levels of patient compliance and treatment completion while minimizing interruptions to academic and work schedules. |
| 2021 | An open label, randomised controlled trial of rifapentine versus rifampicin based short course regimens for the treatment of latent tuberculosis in England: the HALT LTBI pilot study. | BMC Infect Dis | Ending the global tuberculosis (TB) epidemic requires a focus on treating individuals with latent TB infection (LTBI) to prevent future cases. Promising trials of shorter regimens have shown them to be effective as preventative TB treatment, however there is a paucity of data on self-administered treatment completion rates. This pilot trial assessed treatment completion, adherence, safety and the feasibility of treating LTBI in the UK using a weekly Rifapentine and isoniazid regimen versus daily rifampicin and isoniazid, both self-administered for 12 weeks.An open label, randomised, multi-site pilot trial was conducted in London, UK, between March 2015 and January 2017. Adults between 16 and 65 years with LTBI at two TB clinics who were eligible for and agreed to preventative therapy were consented and randomised 1:1 to receive either a weekly combination of Rifapentine/isoniazid ('intervention') or a daily combination of rifampicin/isoniazid ('standard'), with both regimens taken for twelve weeks; treatment was self-administered in both arms. The primary outcome, completion of treatment, was self-reported, defined as taking more than 90% of prescribed doses and corroborated by pill counts and urine testing. Adverse events were recorded.Fifty-two patients were successfully enrolled. In the intervention arm 21 of 27 patients completed treatment (77.8, 95% confidence interval [CI] 57.7-91.4), compared with 19 of 25 (76.0%, CI 54.9-90.6) in the standard of care arm. There was a similar adverse effect profile between the two arms.In this pilot trial, treatment completion was comparable between the weekly Rifapentine/isoniazid and the daily rifampicin/isoniazid regimens. Additionally, the adverse event profile was similar between the two arms. We conclude that it is safe and feasible to undertake a fully powered trial to determine whether self-administered weekly treatment is superior/non-inferior compared to current treatment.The trial was funded by the NIHR, UK and registered with ISRCTN ( 26/02/2013-No.04379941 ). |
| 2021 | Toward patient-centered tuberculosis preventive treatment: preferences for regimens and formulations in Lima, Peru. | BMC Public Health | To ensure patient-centered tuberculosis preventive treatment, it is important to consider factors that make it easier for patients to complete treatment. However, there is little published literature about patient preferences for different preventive treatment regimen options, particularly from countries with high tuberculosis burdens.We conducted a qualitative research study using a framework analysis approach to understand tuberculosis preventive treatment preferences among household contacts. We conducted three focus group discussions with 16 members of families affected by tuberculosis in Lima, Peru. Participants were asked to vote for preferred preventive treatment regimens and discuss the reasons behind their choices. Coding followed a deductive approach based on prior research, with data-driven codes added.In total, 7 (44%) participants voted for 3 months isoniazid and Rifapentine, 4 (25%) chose 3 months isoniazid and rifampicin, 3 (19%) chose 4 months rifampicin, and 2 (13%) chose 6 months isoniazid. Preferences for shorter regimens over 6 months of isoniazid were driven by concerns over "getting tired" or "getting bored" of taking medications, the difficulty of remembering to take medications, side effects, and interference with daily life. For some, weekly dosing was perceived as being easier to remember and less disruptive, leading to a preference for 3 months isoniazid and Rifapentine, which is dosed weekly. However, among caregivers, having a child-friendly formulation was more important than regimen duration. Caregivers reported difficulty in administering pills to children, and preferred treatments available as syrup or dispersible formulations.There is demand for shorter regimens and child-friendly formulations for tuberculosis preventive treatment in high-burden settings. Individual preferences differ, suggesting that patient-centered care would best be supported by having multiple shorter regimens available. |
| 2021 | Decreased plasma rifapentine concentrations associated with AADAC single nucleotide polymorphism in adults with tuberculosis. | J Antimicrob Chemother | Rifapentine exposure is associated with bactericidal activity against Mycobacterium tuberculosis, but high interindividual variation in plasma concentrations is encountered.To investigate a genomic association with interindividual variation of Rifapentine exposure, SNPs of six human genes involving rifamycin metabolism (AADAC, CES2), drug transport (SLCO1B1, SLCO1B3) and gene regulation (HNF4A, PXR) were evaluated.We characterized these genes in 173 adult participants in treatment trials of the Tuberculosis Trials Consortium. Participants were stratified by self-identified race (black or non-black), and Rifapentine AUC from 0 to 24 h (AUC0-24) was adjusted by analysis of covariance for SNPs, Rifapentine dose, sex, food and HIV coinfection. This study was registered at ClinicalTrials.gov under identifier NCT01043575.The effect on Rifapentine least squares mean AUC0-24 in black participants overall decreased by -10.2% for AADAC rs1803155 G versus A allele (Wald test: P = 0.03; false discovery rate, 0.10). Black participants with one G allele in AADAC rs1803155 were three times as likely to have below target bactericidal Rifapentine exposure than black participants with the A allele (OR, 2.97; 95% CI: 1.16, 7.58). With two G alleles, the OR was greater. In non-black participants, AADAC rs1803155 SNP was not associated with Rifapentine exposure. In both black and non-black participants, other evaluated genes were not associated with Rifapentine exposure (P > 0.05; false discovery rate > 0.10).Rifapentine exposure in black participants varied with AADAC rs1803155 genotype and the G allele was more likely to be associated with below bactericidal target Rifapentine exposure. Further pharmacogenomic study is needed to characterize the association of the AADAC rs1803155 with inadequate Rifapentine exposure in different patient groups. |
| 2021 | Completion and Adverse Drug Events of Latent Tuberculosis Infection Treatment in Patients Receiving Dialysis: Predictors and Impacts of Different Regimens in a Prospective Cohort Study. | Antimicrob Agents Chemother | Although patients with end-stage renal disease receiving maintenance hemodialysis are at high risk for tuberculosis, the optimal treatment regimen for latent tuberculosis infection (LTBI) in this group has scarcely been studied for predictors of completion rate and adverse drug events (ADE). We prospectively enrolled dialysis patients for LTBI intervention from three medical centers in Taiwan. LTBI treatments were 3 months of weekly Rifapentine plus isoniazid (3HP) and 9 months of daily isoniazid (9H). Completion rate, ADE, and reasons for treatment termination were recorded. Factors associated with treatment termination and ADE were analyzed using multivariate logistic regression. In all, 91 treatment courses (41 9H and 50 3HP) were surveyed. The completion rates were 61% for 9H and 82% for 3HP ( = 0.046). Use of 9H and development of ADE with a grade of ≥2 (≥grade 2 ADE) were associated with treatment termination. Hypersensitivity occurred in 29.2% of subjects in the 3HP group and 10.8% in the 9H group ( = 0.035) and independently correlated with 3HP regimen, diabetes mellitus (DM), and peritoneal dialysis (PD). Similarly, the independent predictors of ≥grade 2 ADE were use of 3HP regimen, presence of DM, and use of PD, whereas ≥grade 3 ADE were associated with eosinophil counts of >700/mm after 2 weeks of LTBI treatment even after adjustment for age and gender. In conclusion, for patients on dialysis, 3HP showed a higher rate of completion but also a higher rate of ≥grade 2 ADE than 9H. In addition, DM and PD were risk factors for ≥grade 2 ADE. Eosinophilia after 2-week treatment might be an alert for severe ADE. |
| 2020 | Cost of delivering 12-dose isoniazid and rifapentine versus 6 months of isoniazid for tuberculosis infection in a high-burden setting. | Clin Infect Dis | Successful delivery and completion of tuberculosis preventive treatment delivery is necessary for tuberculosis elimination. Shorter preventive treatment regimens currently have higher medication costs, but patients spend less time in care and are more likely to complete treatment. It is unknown how economic costs of successful delivery differ between longer and shorter regimens in high-tuberculosis-burden settings.We developed survey instruments to collect costs from program and patient sources, considering costs incurred from when household contacts first entered the health system. We compared the cost per completed course of preventive treatment with either 6 months of daily isoniazid (6H) or 3 months of weekly isoniazid and Rifapentine (3HP), delivered by the Indus tuberculosis program in Karachi, Pakistan, between October 2016 and February 2018.During this period, 459 individuals initiated 6H, and 643 initiated 3HP; 39% and 61% completed treatment, respectively. Considering costs to both the program and care recipients, the cost per completed course was 394 USD for 6H and 333 USD for 3HP. Using a new 2020 price for Rifapentine reduced the cost per completed course of 3HP to 290 USD. Under varying assumptions about drug prices and costs incurred by care recipients, the cost per completed course was lower for 3HP in all scenarios, and the largest cost drivers were the salaries of clinical staff.In a high-burden setting, the cost of successful delivery of 3HP was lower than that of 6H, driven by higher completion. |
| 2021 | Nevirapine pharmacokinetics in HIV-infected persons receiving rifapentine and isoniazid for TB prevention. | J Antimicrob Chemother | The use of rifamycin antibiotics for TB prevention carries a risk of detrimental drug-drug interactions with concomitantly used ART.To evaluate the interaction of the antiretroviral drug nevirapine in combination with 4 weeks of daily Rifapentine and isoniazid for TB prevention in people living with HIV.Participants were individuals enrolled in the BRIEF-TB study receiving nevirapine and randomized to the Rifapentine/isoniazid arm of the study. Participants provided sparse pharmacokinetic (PK) sampling at baseline and weeks 2 and 4 for trough nevirapine determination. Nevirapine apparent oral clearance (CL/F) was estimated and the geometric mean ratio (GMR) of CL/F prior to and during Rifapentine/isoniazid was calculated.Seventy-eight participants had evaluable PK data: 61 (78%) female, 51 (65%) black non-Hispanic and median (range) age of 40 (13-66) years. Median (IQR) nevirapine trough concentrations were: week 0, 7322 (5266-9302) ng/mL; week 2, 5537 (3552-8462) ng/mL; and week 4, 5388 (3516-8243) ng/mL. Sixty out of 78 participants (77%) had nevirapine concentrations ≥3000 ng/mL at both week 2 and 4. Median (IQR) nevirapine CL/F values were: week 0 pre-Rifapentine/isoniazid, 2.03 (1.58-2.58) L/h; and during Rifapentine/isoniazid, 2.62 (1.81-3.42) L/h. The GMR (90% CI) for nevirapine CL/F was 1.30 (1.26-1.33).The CL/F of nevirapine significantly increased with concomitant Rifapentine/isoniazid. The decrease in nevirapine trough concentrations during Rifapentine/isoniazid therapy suggests induction of nevirapine metabolism, consistent with known Rifapentine effects. The magnitude of this drug-drug interaction suggests daily Rifapentine/isoniazid for TB prevention should not be co-administered with nevirapine-containing ART. |
| 2020 | Impact of age on outcome of rifapentine-based weekly therapy for latent tuberculosis infection. | Clin Infect Dis | Weekly Rifapentine and isoniazid (3HP) is gaining popularity for latent tuberculosis infection treatment because of its short course and high completion rate. Prior to widespread use, comprehensive 3HP treatment assessment covering an all-age population is essential.Participants receiving ≥1 3HP dose from September 2014 to December 2019 were stratified into elderly (≥65 years), middle-aged (35-65 years), and younger (≤35 years) groups. This study investigated the impact of age on treatment outcome, particularly systemic drug reaction (SDR) and 3HP discontinuation.Overall, 134 (23.1%) of 579 participants were elderly. The completion rate was 83.1% in overall and was highest and lowest in the younger group (94.5%) and elderly (73.9%) groups, respectively. However, the 3HP discontinuation rate was not significantly different among the three groups in multivariate logistic regression analysis. In total, 362 (62.5%) participants experienced ≥1 adverse drug reactions (ADRs), of which 38 (10.5%) and 98 (27.1%) required temporary and permanent treatment interruption, respectively. The SDR risk was 11.2% in overall and 17.1% in the middle-aged group, 3.04-fold higher than that in the elderly group (p=0.025). This finding was consistently observed in different clinical settings. Hypertensive event accompanied with flu-like symptoms occurred in 11.2% of elderly participants, and accounted for 50% of grade ≥3 ADRs.With proper medical support and programmatic follow-up, the 3HP completion rate is higher than 70% even in elderly participants. In middle-aged and elderly individuals, 3HP should be employed with caution because of risk of SDR and hypertensive event, respectively. |
| 2021 | Rifampin, Rifapentine, and Rifabutin Are Active against Intracellular Periprosthetic Joint Infection-Associated Staphylococcus epidermidis. | Antimicrob Agents Chemother | is a major cause of periprosthetic joint infection (PJI); its intracellular persistence within osteoblasts may compromise therapy if that therapy is not intracellularly active. The intracellular activity of rifampin, Rifapentine, and rifabutin was assessed against five rifampin-susceptible and two rifampin-resistant isolates. Compared to no treatment, treatment resulted in a ≥2-fold log reduction of intracellular rifampin-susceptible, but not rifampin-resistant, These findings show activity of rifampin, Rifapentine, and rifabutin against intraosteoblast PJI-associated . |
| 2020 | Development of Rifapentine-Loaded PLGA-Based Nanoparticles: In vitro Characterisation and in vivo Study in Mice. | Int J Nanomedicine | Tuberculosis (TB) is a leading cause of death amongst infectious diseases. The poor response to antitubercular agents necessitates the long-term use of high drug doses, resulting in low patient compliance, which is the main reason for chemotherapy failure and contributes to the development of multidrug-resistant TB. Patient non-compliance has been a major obstacle in the successful management of TB. The aim of this work was to develop and characterise Rifapentine (RPT)-loaded PLGA-based nanoparticles (NPs) for reducing dosing frequency.RPT-loaded PLGA and PLGA-PEG NPs were prepared using premix membrane homogenisation combined with solvent evaporation method. The resulting NPs were characterised in terms of physicochemical characteristics, toxicity, cellular uptake and antitubercular activity. NPs were further evaluated for pharmacokinetic and biodistribution studies in mice.The resulting NPs showed suitable and safe physicochemical characteristics and could be taken up by macrophages. RPT-loaded NPs were more effective against than free RPT. In vivo studies revealed that NPs could improve pharmacokinetic parameters, particularly for RPT/PLGA-PEG NPs. Moreover, both formulations had no toxicity to the organs of mice and could reduce hepatotoxicity.The application of PLGA-based NPs as sustained-release delivery vehicles for RPT could prolong drug release, modify pharmacokinetics, increase antitubercular activity and diminish toxicity, thereby allowing low dosage and frequency. |
| 2020 | Cost-effectiveness of one month of daily isoniazid and rifapentine versus three months of weekly isoniazid and rifapentine for prevention of tuberculosis among people receiving antiretroviral therapy in Uganda. | J Int AIDS Soc | Preventive therapy is essential for reducing tuberculosis (TB) burden among people living with HIV (PLWH) in high-burden settings. Short-course preventive therapy regimens, such as three-month weekly Rifapentine and isoniazid (3HP) and one-month daily Rifapentine and isoniazid (1HP), may help facilitate uptake of preventive therapy for latently infected patients, but the comparative cost-effectiveness of these regimens under different conditions is uncertain.We used a Markov state-transition model to estimate the incremental costs and effectiveness of 1HP versus 3HP in a simulated cohort of patients attending an HIV clinic in Uganda, as an example of a low-income, high-burden setting in which TB preventive therapy might be prescribed to PLWH. Our primary outcome was the incremental cost-effectiveness ratio, expressed as 2019 US dollars per disability-adjusted life year (DALY) averted. We estimated cost-effectiveness under different conditions of treatment completion and efficacy of 1HP versus 3HP, latent TB prevalence and Rifapentine price.Assuming equivalent clinical outcomes using 1HP and 3HP and a Rifapentine price of $0.21 per 150 mg, 1HP would cost an additional $4.66 per patient treated. Assuming equivalent efficacy but 20% higher completion with 1HP versus 3HP, 1HP would cost $1,221 per DALY averted relative to 3HP. This could be reduced to $18 per DALY averted if 1HP had 5% greater efficacy than 3HP and the price of Rifapentine were 50% lower. At a Rifapentine price of $0.06 per 150 mg, 1HP would become cost-neutral relative to 3HP.1HP has the potential to be cost-effective under many realistic circumstances. Cost-effectiveness depends on Rifapentine price, relative completion and efficacy, prevalence of latent TB and local willingness-to-pay. |
| 2020 | Abnormal Dexamethasone Suppression Tests in a Rifapentine-Treated Patient With Primary Aldosteronism. | Front Endocrinol (Lausanne) | Aldosterone-producing adenoma (APA) is a main cause of primary aldosteronism (PA). Given that a large benign-appearing unilateral masse (>1 cm in diameter) may represent an aldosterone and cortisol-co-secreting adenoma, dexamethasone suppression testing is required in such patients to exclude or confirm the diagnosis of hypercortisolism. Tuberculosis is highly prevalent in China, and rifamycins are often used in these patients. Rifapentine belongs to the rifamycin family, and we herein for the first time report a case of misdiagnosis of hypercortisolism due to Rifapentine use in a patient with APA. Thus, in patients treated with Rifapentine, diagnosis of hypercortisolism based on dexamethasone suppression tests can be very misleading. |
| 2020 | Prediction of potential inhibitors for RNA-dependent RNA polymerase of SARS-CoV-2 using comprehensive drug repurposing and molecular docking approach. | Int J Biol Macromol | The pandemic prevalence of COVID-19 has become a very serious global health issue. Scientists all over the world have been seriously attempting in the discovery of a drug to combat SARS-CoV-2. It has been found that RNA-dependent RNA polymerase (RdRp) plays a crucial role in SARS-CoV-2 replication, and thus could be a potential drug target. Here, comprehensive computational approaches including drug repurposing and molecular docking were employed to predict an effective drug candidate targeting RdRp of SARS-CoV-2. This study revealed that Rifabutin, Rifapentine, Fidaxomicin, 7-methyl-guanosine-5'-triphosphate-5'-guanosine and Ivermectin have a potential inhibitory interaction with RdRp of SARS-CoV-2 and could be effective drugs for COVID-19. In addition, virtual screening of the compounds from ZINC database also allowed the prediction of two compounds (ZINC09128258 and ZINC09883305) with pharmacophore features that interact effectively with RdRp of SARS-CoV-2, indicating their potentiality as effective inhibitors of the enzyme. Furthermore, ADME analysis along with analysis of toxicity was also undertaken to check the pharmacokinetics and drug-likeness properties of the two compounds. Comparative structural analysis of protein-inhibitor complexes revealed that the amino acids Y32, K47, Y122, Y129, H133, N138, D140, T141, S709 and N781 are crucial for drug surface hotspot in the RdRp of SARS-CoV-2. |
| 2020 | Post-exposure prophylaxis (PEP) efficacy of rifampin, rifapentine, moxifloxacin, minocycline, and clarithromycin in a susceptible-subclinical model of leprosy. | PLoS Negl Trop Dis | Subclinical infection with Mycobacterium leprae is one potential source of leprosy transmission, and post-exposure prophylaxis (PEP) regimens have been proposed to control this source. Because PEP trials require considerable investment, we applied a sensitive variation of the kinetic mouse footpad (MFP) screening assay to aid in the choice of drugs and regimens for clinical trials.Athymic nude mice were inoculated in the footpad (FP) with 6 x 103 viable M. leprae and treated by gastric gavage with a single dose of Rifampin (SDR), Rifampin + Ofloxacin + Minocycline (SD-ROM), or Rifapentine + Minocycline + Moxifloxacin (SD-PMM) or with the proposed PEP++ regimen of three once-monthly doses of Rifampin + Moxifloxacin (RM), Rifampin + Clarithromycin (RC), Rifapentine + Moxifloxacin (PM), or Rifapentine + Clarithromycin (PC). At various times post-treatment, DNA was purified from the FP, and M. leprae were enumerated by RLEP quantitative PCR. A regression analysis was calculated to determine the expected RLEP value if 99.9% of the bacilli were killed after the administration of each regimen. SDR and SD-ROM induced little growth delay in this highly susceptible murine model of subclinical infection. In contrast, SD-PMM delayed measurable M. leprae growth above the inoculum by 8 months. The four multi-dose regimens delayed bacterial growth for >9months post-treatment cessation.The delay in discernable M. leprae growth post-treatment was an excellent indicator of drug efficacy for both early (3-4 months) and late (8-9 months) drug efficacy. Our data indicates that multi-dose PEP may be required to control infection in highly susceptible individuals with subclinical leprosy to prevent disease and decrease transmission. |
| 2020 | Novel Use of Rifabutin and Rifapentine to Treat Methicillin-Resistant Staphylococcus aureus in a Rat Model of Foreign Body Osteomyelitis. | J Infect Dis | Owing to patient intolerance or drug interactions, alternative agents to rifampin are needed for management of staphylococcal periprosthetic joint infection. In the current study, we evaluated rifabutin, Rifapentine and rifampin, with and without vancomycin, in a rat model of foreign body osteomyelitis.Proximal tibiae were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and a Kirschner wire (K-wire) implanted in each. After 4 weeks of infection, rifampin, rifabutin, or Rifapentine were administered, alone or with vancomycin. Tibiae and K-wires were cultured, and medians were reported as log10 colony-forming units (CFUs) per gram of bone or log10 CFUs per K-wire, respectively.Rifampin, rifabutin or Rifapentine administered with vancomycin yielded less MRSA from bones (0.10, 3.02, and 0.10 log10 CFUs/g, respectively) than did no treatment (4.36 log10 CFUs/g) or vancomycin alone (4.64 log10 CFUs/g) (both P ≤ .02). The K-wires of animals receiving no treatment or vancomycin monotherapy recovered medians of 1.76 and 2.91 log10 CFUs/g per K-wire, respectively. In contrast, rifampin, rifabutin and Rifapentine administered with vancomycin yielded medians of 0.1 log10 CFUs per K-wire, respectively. Rifampin resistance was detected in a single animal in the rifampin monotherapy group.Rifabutin or Rifapentine with vancomycin were as active as rifampin with vancomycin against MRSA in rat foreign body osteomyelitis, suggesting that rifabutin and/or Rifapentine may be alternatives to rifampin in the clinical management of staphylococcal periprosthetic joint infections. |
| 2020 | Potential inhibitors of SARS-cov-2 RNA dependent RNA polymerase protein: molecular docking, molecular dynamics simulations and MM-PBSA analyses. | J Biomol Struct Dyn | The SARS-cov-2 RNA dependent RNA polymerase (nsp12) is a crucial viral enzyme that catalyzes the replication of RNA from RNA templates. The fixation of some ligands in the active site may alter the viral life cycle. The aim of the present study is to identify the conservation level of nsp12 motifs (A-G), using consurf server, and discover their interactions with rifabutin, rifampicin, rifapentin, sorangicin A, streptolydigin, myxopyronin B, VXR and VRX using AutoDockTools-1.5.6, Gromacs 2018.2 and g-mmpbsa. Thus, the most of amino acids residues located in nsp12 protein Motifs (A-G) were predicted as highly conserved. The binding energies of streptolydigin, VXR, rifabutin, Rifapentine, VRX, sorangicin A, myxopyronin B and rifampicin with nsp12 protein are -8.11, -8.23, -7.14, -6.94, -6.55, -5.46, -5.33 and -5.26 kcal/mol, respectively. In the other hand, the binding energies of ligand in the same order with nsp7-nsp8-nsp12 complex are -7.23, -7.08, -7.21, -7, -6.59, -8.73, -5.52, -5.87 kcal/mol, respectively. All ligands interact with at least two nsp12 motifs. The molecular dynamics simulation of nsp12-streptolydigin and nsp12-VXR complexes shows that these two complexes are stable and the number of hydrogen bonds as a function of time, after 30 ns of simulation, varies between 0 and 6 for nsp12-streptolydigin complex and between 0 and 4 for nsp12-VXR complex. The average of free binding energies obtained using g_mmpbsa, after 30 ns of simulation, is -191.982 Kj/mol for nsp12-streptolydigin complex and -153.583 Kj/mol for nsp12-VXR complex. Our results suggest that these ligands may be used as inhibitors of SARS-cov-2 nsp12 protein.Communicated by Ramaswamy H. Sarma. |
| 2020 | Telacebec (Q203)-containing intermittent oral regimens sterilized mice infected with Mycobacterium ulcerans after only 16 doses. | PLoS Negl Trop Dis | Buruli ulcer (BU), caused by Mycobacterium ulcerans, is currently treated with a daily combination of rifampin and either injectable streptomycin or oral clarithromycin. An intermittent oral regimen would facilitate treatment supervision. We first evaluated the bactericidal activity of newer antimicrobials against M. ulcerans using a BU animal model. The imidazopyridine amine telacebec (Q203) exhibited high bactericidal activity whereas tedizolid (an oxazolidinone closely related to linezolid), selamectin and ivermectin (two avermectine compounds) and the benzothiazinone PBTZ169 were not active. Consequently, telacebec was evaluated for its bactericidal and sterilizing activities in combined intermittent regimens. Telacebec given twice a week in combination with a long-half-life compound, either Rifapentine or bedaquiline, sterilized mouse footpads in 8 weeks, i.e. after a total of only 16 doses, and prevented relapse during a period of 20 weeks after the end of treatment. These results are very promising for future intermittent oral regimens which would greatly simplify BU treatment in the field. |
| 2021 | Pharmacogenetic interactions of rifapentine plus isoniazid with efavirenz or nevirapine. | Pharmacogenet Genomics | The effect of Rifapentine plus isoniazid on efavirenz pharmacokinetics was characterized in AIDS Clinical Trials Group protocol A5279 (NCT01404312). The present analyses characterize pharmacogenetic interactions between these drugs, and with nevirapine.A subset of HIV-positive individuals receiving efavirenz- or nevirapine-containing antiretroviral therapy in A5279 underwent pharmacokinetic evaluations at baseline, and again weeks 2 and 4 after initiating daily Rifapentine plus isoniazid. Associations with polymorphisms relevant to efavirenz, nevirapine, isoniazid, and Rifapentine pharmacokinetics were assessed.Of 128 participants, 101 were evaluable for associations with Rifapentine and its active 25-desacetyl metabolite, 87 with efavirenz, and 38 with nevirapine. In multivariable analyses, NAT2 slow acetylators had greater week 4 plasma concentrations of Rifapentine (P = 2.6 × 10) and 25-desacetyl Rifapentine (P = 7.0 × 10) among all participants, and in efavirenz and nevirapine subgroups. NAT2 slow acetylators also had greater plasma efavirenz and nevirapine concentration increases from baseline to week 4, and greater decreases from baseline in clearance. CYP2B6 poor metabolizers had greater efavirenz concentrations at all weeks and greater nevirapine concentrations at baseline. None of 47 additional polymorphisms in 11 genes were significantly associated with pharmacokinetics.Among HIV-positive individuals receiving efavirenz or nevirapine, and who then initiated Rifapentine plus isoniazid in A5279, NAT2 slow acetylators had greater Rifapentine and 25-desacetyl Rifapentine concentrations, and greater increases from baseline in plasma efavirenz and nevirapine concentrations. These associations are likely mediated by greater isoniazid exposure in NAT2 slow acetylators. |
| 2020 | Protocol for the 3HP Options Trial: a hybrid type 3 implementation-effectiveness randomized trial of delivery strategies for short-course tuberculosis preventive therapy among people living with HIV in Uganda. | Implement Sci | Recently, a 3-month (12-dose) regimen of weekly isoniazid and Rifapentine (3HP) was recommended by the World Health Organization for the prevention of tuberculosis (TB) among people living with HIV (PLHIV) on common antiretroviral therapy regimens. The best approach to delivering 3HP to PLHIV remains uncertain.We developed a three-armed randomized trial assessing optimized strategies for delivering 3HP to PLHIV. The trial will be conducted at the Mulago Immune Suppression Syndrome (i.e., HIV/AIDS) clinic in Kampala, Uganda. We plan to recruit 1656 PLHIV, randomized 1:1 to each of the three arms (552 per arm). Using a hybrid type 3 effectiveness-implementation design, this pragmatic trial aims to (1) compare the acceptance and completion of 3HP among PLHIV under three delivery strategies: directly observed therapy (DOT), self-administered therapy (SAT), and informed patient choice of either DOT or SAT (with the assistance of a decision aid); (2) to identify processes and contextual factors that influence the acceptance and completion of 3HP under each delivery strategy; and (3) to estimate the costs and compare the cost-effectiveness of three strategies for delivering 3HP. The three delivery strategies were each optimized to address key barriers to 3HP completion using a theory-informed approach. We hypothesize that high levels of treatment acceptance and completion can be achieved among PLHIV in sub-Saharan Africa and that offering PLHIV an informed choice between the optimized DOT and SAT delivery strategies will result in greater acceptance and completion of 3HP. The design and planned evaluation of the delivery strategies were guided by the use of implementation science conceptual frameworks.3HP-one of the most promising interventions for TB prevention-will not be scaled up unless it can be delivered in a patient-centered fashion. We highlight shared decision-making as a key element of our trial design and theorize that offering PLHIV an informed choice between optimized delivery strategies will facilitate the highest levels of treatment acceptance and completion.ClinicalTrials.gov: NCT03934931 ; Registered 2 May 2019. |
| 2020 | Design, synthesis and antimycobacterial activity of new benzothiazinones inspired by rifampicin/rifapentine. | Bioorg Chem | A series of novel benzothiazinone derivatives containing a N-((methylene)amino)piperazine moiety, inspired by rifampicin/Rifapentine, were designed and synthesized. Seven compounds 1a and 1e-j show excellent in vitro activity against both drug-sensitive MTB strain H37Rv and drug-resistant clinical isolates (MIC: <0.029-0.110 μM), and accepted selective index (>1100->4000). Compound 1h displays good safety and pharmacokinetic profiles, suggesting its promising potential to be lead compound for future antitubercular drug discovery. |
| Ramadan and Culturally Competent Care: Strengthening Tuberculosis Protections for Recently Resettled Muslim Refugees. | J Public Health Manag Pract | To improve latent tuberculosis infection treatment completion rates, Tarrant County Public Health began providing after-dusk home delivery of a 12-dose latent tuberculosis infection regimen of weekly Rifapentine plus isoniazid administered via directly observed preventive therapy during Ramadan, a month of prayer and daytime fasting observed by Muslims. In unadjusted difference-in-difference logistic regression analyses (n = 148), Muslim patients had lower treatment completion rates than non-Muslim patients during Ramadan prior to program implementation (68.8% vs 95.4%), whereas rates were comparable postimplementation (95.7% vs 96.4%; difference-in-difference P = .011). Similar results were found after adjusting for age and gender (pre: 71.4% vs 94.8%; post: 95.5% vs 96.3%; P = .032). These findings provide evidence of the need for and effectiveness of programmatic innovations tailored to the varying cultural norms of the widely diverse populations served by public health authorities and suggest that culturally competent clinical care may advance population health goals. |
| 2020 | Hepatocytic transcriptional signatures predict comparative drug interaction potential of rifamycin antibiotics. | Sci Rep | Current strategies to treat tuberculosis (TB) and co-morbidities involve multidrug combination therapies. Rifamycin antibiotics are a key component of TB therapy and a common source of drug-drug interactions (DDIs) due to induction of drug metabolizing enzymes (DMEs). Management of rifamycin DDIs are complex, particularly in patients with co-morbidities, and differences in DDI potential between rifamycin antibiotics are not well established. DME profiles induced in response to tuberculosis antibiotics (rifampin, rifabutin and Rifapentine) were compared in primary human hepatocytes. We identified rifamycin induced DMEs, cytochrome P450 (CYP) 2C8/3A4/3A5, SULT2A, and UGT1A4/1A5 and predicted lower DDIs of Rifapentine with 58 clinical drugs used to treat co-morbidities in TB patients. Transcriptional networks and upstream regulator analyses showed FOXA3, HNF4α, NR1I2, NR1I3, NR3C1 and RXRα as key transcriptional regulators of rifamycin induced DMEs. Our study findings are an important resource to design effective medication regimens to treat common co-conditions in TB patients. |
| 2020 | Comparison of a Novel Regimen of Rifapentine, Tedizolid, and Minocycline with Standard Regimens for Treatment of Pulmonary Mycobacterium kansasii. | Antimicrob Agents Chemother | The combination of isoniazid, rifampin, and ethambutol is recommended by the American Thoracic Society (ATS) for treatment of pulmonary , while the British Thoracic Society (BTS) recommends clarithromycin, rifampin and ethambutol. Unfortunately, therapy duration for both regimens lasts for years. In this study, we administered tedizolid, minocycline, clarithromycin, and Rifapentine as monotherapy as well as novel combinations in the intracellular hollow-fiber model system of (HFS-) in a 28-day study. The ATS and BTS regimens were used as comparators. Repetitive sampling was used to validate the intended intrapulmonary pharmacokinetics of each drug and to monitor changes in burden. As monotherapy, tedizolid at an observed area under the concentration-time curve from 0 to 24 h (AUC)/MIC of 5.85 and minocycline at an AUC/MIC of 5.77 failed to kill the bacteria below day 0 (stasis), clarithromycin at an AUC/MIC of 2.4 held the bacterial burden at stasis, but Rifapentine at an AUC/MIC of 140 killed 2 log CFU/ml below stasis. The BTS regimen kill slope was -0.083 ± 0.035 CFU/ml/day, which was significantly superior to the ATS regimen slope of -0.038 ± 0.038 CFU/ml/day. The Rifapentine-tedizolid-minocycline combination kill slope was -0.119 ± 0.031 CFU/ml/day, superior to that of the ATS regimen and comparable to that of the BTS regimen. In conclusion, the BTS regimen and the novel Rifapentine-tedizolid-minocycline regimen showed better kill of intracellular bacteria in the HFS- However, the efficacy of the new combination regimen remains to be tested in clinical settings. |
| 2020 | Rapid and simultaneous determination of ten anti-tuberculosis drugs in human plasma by UPLC-MS/MS with applications in therapeutic drug monitoring. | J Chromatogr B Analyt Technol Biomed Life Sci | Tuberculosis remains a global challenge, particularly with a growing number of resistant cases, which may become an obstacle to eliminating this disease. Standardized short-course therapy composed of first-line anti-tuberculosis drugs isoniazid (INH), rifampicin (RIF), ethambutol (EMB), and pyrazinamide (PZA) is playing vital roles for curbing the rapid spread of tuberculosis. However, some patients have poor responses to standardized short-course therapy. As the number of drug-resistant tuberculosis increase, some other anti-tuberculous drugs are needed to achieve better treatment outcomes. In this study, we established a UPLC-MS/MS method for simultaneous detection of ten anti-tuberculosis drugs in human plasma including INH, EMB, PZA, RIF, rifampin, Rifapentine as well as four second-line antituberculosis drugs, i.e. ethionamide, protionamide, thiosemicarbazone and clofazimine. This study contains almost all the commonly used anti-tuberculosis drugs. The plasma samples were treated with acetonitrile to precipitate proteins, and doped with the isotope internal standard. A Shiseido CAPCELL RAK-ADME (2.1 mm × 50 mm, 3 μm) column was used for chromatographic separation, and acetonitrile-water (containing 0.1% formic acid) was the mobile phase. The separation used gradient elution with a flow rate of 0.4 mL/min. The column temperature was 40 °C, and the sample volume was 1 μL. The electrospray ionization source (ESI) and the positive ion multiple reaction monitoring (MRM) mode were used for the detection. The analysis time was as short as 7 min. The results show a good linear relationship under optimized conditions in the range of 5.00-7.50 × 10, 1.00-1.50 × 10, 5.00-5.00 × 10, 5.00-7.50 × 10, 1.00-3.00 × 10, 1.00 × 10-1.00 × 10, 1.00-3.00 × 10, 1.00-3.00 × 10, 2.00-4.00 × 10, and 1.00 × 10-2.00 × 10 ng/mL for INH, EMB PZA, RIF, rifabutin, Rifapentine, ethionamide, protionamide, thiosemicarbazone, and clofazimine, respectively, with a linear correlation coefficient of R > 0.99. Finally, 34 patients with pulmonary TB were tested for therapeutic drug monitoring. The results showed that the presented method have significant advances in sensitivity, separation efficiency and simplicity. |
| 2020 | Model-Based Cost-Effectiveness of State-level Latent Tuberculosis Interventions in California, Florida, New York and Texas. | Clin Infect Dis | Targeted testing and treatment (TTT) for latent tuberculosis infection (LTBI) is a recommended strategy to accelerate TB reductions and further tuberculosis elimination in the United States (US). Evidence on cost-effectiveness of TTT for key populations can help advance this goal.We used a model of TB transmission to estimate the numbers of individuals who could be tested by interferon-γ release assay (IGRA) and treated for LTBI with three months of self-administered Rifapentine and isoniazid (3HP) under various TTT scenarios. Specifically, we considered rapidly scaling up TTT among people who are non-US-born, diabetic, HIV-positive, homeless or incarcerated in California, Florida, New York, and Texas - states where more than half of US TB cases occur. We projected costs (from the healthcare system perspective, in 2018 dollars), thirty-year reductions in TB incidence, and incremental cost effectiveness (cost per quality-adjusted life year [QALY] gained) for TTT in each modeled population.The projected cost effectiveness of TTT differed substantially by state and population, while the health impact (number of TB cases averted) was consistently greatest among the non-US-born. TTT was most cost-effective among persons living with HIV (from $2,828/QALY gained in Florida to $11,265/QALY gained in New York) and least cost-effective among people with diabetes (from $223,041/QALY gained in California to $817,753 /QALY in New York).The modeled cost-effectiveness of TTT for LTBI varies across states but was consistently greatest among people living with HIV, moderate among people who are non-US-born, incarcerated, or homeless, and least cost-effective among people living with diabetes. |
| 2021 | Efficacy and safety of weekly rifapentine and isoniazid for tuberculosis prevention in Chinese silicosis patients: a randomized controlled trial. | Clin Microbiol Infect | The aim was to evaluate the efficacy, safety and completion rate of 3-month, once-weekly Rifapentine and isoniazid for tuberculosis (TB) prevention among Chinese silicosis patients.Male silicosis patients without human immunodeficiency virus infection, aged 18 years to 65 years, with or without latent TB infection, were randomized 1:1 to receive Rifapentine/isoniazid under direct observation (3RPT/INH group) or were untreated (observation group). Active TB incidence was compared between the two groups with 37 months of follow-up. Safety profile and complete rates were evaluated.A total of 1227 adults with silicosis were screened; 513 eligible participants were enrolled and assigned to 3RPT/INH (n = 254) vs. observation (n = 259). Twenty-eight participants were diagnosed with active TB, and 9 and 19 in the 3RPT/INH group and observation groups, respectively. In the intention-to-treat analysis, the cumulative active TB rate was 3.5% (9/254) in the 3RPT/INH group and 7.3% (19/259) in the observation group (log rank p 0.055). On per protocol analysis, the cumulative active TB rates were 0.7% (1/139) and 7.3% (19/259), respectively (log rank p 0.01). Owing to an unexpected high frequency of adverse events (70.4%) and Grade 3 or 4 AEs (7.9%), the completion rate of the 3RPT/INH regimen was 54.7% (139/254). Twenty-six (10.8%) participants had flu-like systemic drug reactions; five (2.1%) experienced hepatotoxicity.Weekly Rifapentine/isoniazid prophylaxis prevented active TB among Chinese people with silicosis when taken, irrespective of LTBI screening; efficacy was reduced by lack of compliance. The regimen must be used with caution because of the high rates of adverse effects.ClinicalTrials.gov number: NCT02430259. |
| 2020 | Isoniazid Preventive Therapy in Contacts of Multidrug-Resistant Tuberculosis. | Am J Respir Crit Care Med | The World Health Organization recommends the use of isoniazid (INH) alone or in combination with Rifapentine to treat latent tuberculosis infections. The recent rise of drug-resistant tuberculosis has complicated the choice of treatment regimen for latent tuberculosis infection. To evaluate the effects of INH preventive therapy on the contacts of patients with multidrug-resistant tuberculosis. In a prospective cohort study conducted between September 2009 and August 2012, we identified 4,500 index patients with tuberculosis and 14,044 tuberculosis-exposed household contacts who we followed for 1 year for the occurrence of incident tuberculosis disease. Although Peruvian national guidelines specify that INH preventive therapy should be provided to contacts aged 19 years old or younger, only half this group received INH preventive therapy. Among 4,216 contacts under 19 years of age, 2,106 contacts (50%) initiated INH preventive therapy at enrollment. The protective effect of INH was more extreme in contacts exposed to drug-sensitive tuberculosis (adjusted hazard ratio, 0.30; 95% confidence interval, 0.18-0.48) and to multidrug-resistant tuberculosis (adjusted hazard ratio, 0.19; 95% confidence interval, 0.05-0.66) compared with those exposed to mono-INH-resistant tuberculosis (adjusted hazard ratio, 0.80; 95% confidence interval, 0.23-2.80). In the second independent study, tuberculosis occurred in none of the 76 household contacts who received INH preventive therapy compared with 3% (8 of 273) of those who did not. Household contacts who received INH preventive therapy had a lower incidence of tuberculosis disease even when they had been exposed to an index patient with multidrug-resistant tuberculosis. INH may have a role in the management of latent multidrug-resistant tuberculosis infection. |
| 2020 | Seizures in an Immunocompetent Adult From Treatment of Latent Tuberculosis Infection: Is Isoniazid to Blame? | Open Forum Infect Dis | Isoniazid-induced seizures are a rare adverse reaction especially in immunocompetent adults. We report a case of a healthy man with seizures shortly after ingestion of his first therapeutic dose of isoniazid with Rifapentine therapy for treatment of latent tuberculosis infection. Only 6 other similar cases are reported in the literature. |
| 2020 | Safety and treatment completion of latent tuberculosis infection treatment in the elderly population-A prospective observational study in Taiwan. | Int J Infect Dis | The detection and treatment of latent tuberculosis infection (LTBI) is a key step in eliminating tuberculosis (TB), but information on safety and on treatment interruption in elderly LTBI patients remains limited.This multicenter prospective observational study included individuals with LTBI who underwent preventive therapy. Incidents of systemic adverse reactions (SARs) and treatment interruption rates in an elderly group (≥60 years old) and a young group (<60 years old) were analyzed.A total of 406 LTBI patients, comprising 167 elderly and 239 young patients, were included in the analyses. The incidence of SARs was similar in the elderly group (18%) and the young group (15.1%). Being middle-aged (35-59 years), body mass index <23 kg/m, a regimen of 3 months of once-weekly Rifapentine plus isoniazid, and end-stage renal disease were independent factors associated with SARs. The treatment interruption rate was similar between the elderly group (21.6%) and the young group (15.9%). LTBI patients aged ≥80 years with SARs had the highest risk of treatment interruption.The occurrence of SARs was similar in the elderly (≥60 years old) and young (<60 years old) LTBI patients receiving preventive therapy. Extremely old (≥80 years old) LTBI patients had a higher treatment interruption rate, especially when they had SARs. |
| 2020 | Fully weekly antituberculosis regimen: a proof-of-concept study. | Eur Respir J | The World Health Organization recommends supervising the treatment of tuberculosis. Intermittent regimens have the potential to simplify the supervision and improve compliance. Our objective was to analyse the sterilising activity of once-weekly regimens based on drugs with a long half-life, bedaquiline and Rifapentine, in a murine model of tuberculosis.300 Swiss mice were infected intravenously infected with ×10 CFU H37Rv. Mice were treated once weekly with regimens containing: 1) bedaquiline, Rifapentine and pyrazinamide (BPZ); 2) BPZ plus moxifloxacin (BPZM); 3) BPZM plus clofazimine (BPZMC); 4) the standard daily regimen of tuberculosis. All regimens were given for 4 or 6 months. Bactericidal and sterilising activity were assessed.After 2 months of treatment, the mean count in lungs was 0.76±0.60 log CFU in mice treated with the daily control regimen and negative in all mice treated with once-weekly regimens (p<0.05 compared to the daily control). All mice had negative lung cultures on completion of either 4 or 6 months of treatment, whereas 3 months after 4 and 6 months of treatment, respectively, the relapse rate was 64% and 13% in the standard daily regimen, 5% and 0% in BPZ, 0% and 0% in BPMZ and 0% and 5% in BPMZC (p<0.05 for all once-weekly regimens 4-month daily control; p>0.05 for all once-weekly regimens 6-month daily control).BPZ-based once-weekly regimens have higher sterilising activity than the standard daily regimen and could greatly simplify treatment administration and possibly shorten the duration of tuberculosis treatment. |
| 2020 | Rifapentine Population Pharmacokinetics and Dosing Recommendations for Latent Tuberculosis Infection. | Am J Respir Crit Care Med | Rifapentine has been investigated at various doses, frequencies, and dosing algorithms, but clarity on the optimal dosing approach is lacking. To characterize Rifapentine population pharmacokinetics, including autoinduction, and determine optimal dosing strategies for short-course Rifapentine-based regimens for latent tuberculosis infection. Rifapentine pharmacokinetic studies were identified though a systematic review of literature. Individual plasma concentrations were pooled, and nonlinear mixed-effects modeling was performed. A subset of data was reserved for external validation. Simulations were performed under various dosing conditions, including current weight-based methods; and alternative methods driven by identified covariates. We identified nine clinical studies with a total of 863 participants with pharmacokinetic data ( = 4,301 plasma samples). Rifapentine population pharmacokinetics were described successfully with a one-compartment distribution model. Autoinduction of clearance was driven by Rifapentine plasma concentrations. The maximum effect was a 72% increase in clearance and was reached after 21 days. Drug bioavailability decreased by 27% with HIV infection, decreased by 28% with fasting, and increased by 49% with a high-fat meal. Body weight was not a clinically relevant predictor of clearance. Pharmacokinetic simulations showed that current weight-based dosing leads to lower exposures in individuals with low weight, which can be overcome with flat dosing. In HIV-positive patients, 30% higher doses are required to match drug exposure in HIV-negative patients. Weight-based dosing of Rifapentine should be removed from clinical guidelines, and higher doses for HIV-positive patients should be considered to provide equivalent efficacy. |
| 2020 | Twice-Daily Doravirine Overcomes the Interaction Effect from Once-Weekly Rifapentine and Isoniazid in Healthy Volunteers. | Clin Transl Sci | Doravirine (DOR) is a non-nucleoside reverse transcriptase inhibitor indicated for the treatment of HIV-1. Its use in combination with Rifapentine (RPT), an antituberculosis (TB) antibiotic, may reduce the exposure of DOR compromising viral suppression in those living with HIV-1 co-infected with TB. We conducted a prospective, phase I, open label, two-period, fixed sequence, drug interaction study to evaluate the effect of once-weekly RPT and isoniazid (INH) on the pharmacokinetics (PKs) of DOR in healthy volunteers. DOR 100 mg was administered alone twice-daily for 4 days in period 1. In period 2, once-weekly RPT + INH were co-administered with multiple doses of DOR 100 mg twice-daily for study days 7, 14, and 21. Plasma was obtained for DOR PKs when given alone and co-administered with RPT + INH. Eleven healthy volunteers enrolled and completed the study. The geometric mean ratios and 90% confidence intervals for DOR area under the concentration-time curve from zero to 12 hours (AUC ) and C in the presence of RPT + INH compared with DOR alone were 0.71 (0.60-0.85) and 0.69 (0.54-0.89), respectively. Although exposures were moderately reduced in the presence of RPT + INH, trough DOR values were within the concentration range associated with virological suppression. These results demonstrate that a modest decrease in DOR exposure would unlikely be clinically relevant in a virally suppressed patient co-administered once-weekly RPT + INH. |
| 2020 | The implementation of rifapentine and isoniazid (3HP) in two remote Arctic communities with a predominantly Inuit population, the Taima TB 3HP study. | Int J Circumpolar Health | : The incidence of TB among Inuit is the highest in Canada. A significantly shorter latent TB infection (LTBI) treatment with Rifapentine and isoniazid once weekly for 12 weeks (3HP) is now available in limited settings in Canada.: A prospective open-label 2-year observational postmarketing study was conducted introducing 3HP for the first time in Canada in Iqaluit followed by a program rollout in Qikiqtarjuaq, Nunavut.: A total of 247 people were offered 3HP, 102 in the Iqaluit postmarketing study and 145 in the Qikiqtarjuaq program roll out. Although statistical significance was not reached, more people who started treatment completed treatment in the 3HP group (Iqaluit, 60/73 (82.2%) and Qikiqtarjuaq, 89/115 (77.4%)) than in the historical control 9INHgroup (306/420 = 72.9%) (p = 0.2). Most of the adverse events in 3HP treated patients were associated with mild discomfort but no disruption of normal daily activity. Not drinking alcohol was associated with increased 3HP completion (OR 13.33, 95% CI, 2.27-78.20) as was not taking concomitant medications (OR 7.19, 95% CI, 1.47-35.30).: The present study supports the feasibility and safety profile of 3HP for the treatment of LTBI in Nunavut. |
| 2020 | How are high burden countries implementing policies and tools for latent tuberculosis infection? A survey of current practices and barriers. | Health Sci Rep | Despite the World Health Organization (WHO)'s updated guidelines on tuberculosis (TB) preventive treatment, the scale-up of TB preventive therapy remains low in many high-burden countries (HBCs). We conducted a survey to better understand the current status of policy implementation and barriers for scale-up.Survey questions pertained to HBCs' current latent TB infection (LTBI) screening and treatment strategies, and the availability of LTBI tests and newer treatments (eg, isoniazid/Rifapentine [3HP]). The 19-question survey was piloted and sent out via email in June 2019 as a protected Microsoft Word document to contacts [National TB Program (NTP) staff, researchers, and health officials] in the 30 TB HBCs. Responses were accepted until February 2020.Thirty-seven completed surveys from 24 HBCs were received. Respondents from five countries (Brazil, Lesotho, Mozambique, Russia, Zambia) reported having LTBI guidelines that are fully implemented. Among respondents who indicated their country currently has no LTBI guideline implementation (Angola, China, DRC, India, Indonesia, Kenya, Myanmar), the most often cited barrier to implementation was the prioritization of active TB over LTBI management (n = 5, Angola, China, DRC, India, Kenya). Of the 16 countries in which respondents reported using purified protein derivative (PPD), 9 reported having experienced a PPD shortage within the past year (from time of survey). Respondents from six countries reported currently using Interferon-gamma Release Assays (IGRAs) in their NTP, and 13 cited high cost as a barrier to IGRA use. Lastly, Rifapentine was stated not be available in 8 HBCs.This survey indicates limited implementation of WHO LTBI guidelines in HBCs and provides some insight into barriers to implementation, including shortage of products (eg, PPD), high costs (eg, IGRAs), and lack of regulatory approval of newer treatments (eg, Rifapentine). Thus, we should work towards price reductions for LTBI tests and treatments, and the development of tests that can be more easily implemented at peripheral healthcare levels. |
| 2020 | Risk-benefit analysis of tuberculosis infection testing for household contact management in high-burden countries: a mathematical modelling study. | Lancet Glob Health | Preventive therapy for tuberculosis reduces the risk of disease in people who have been infected but who are not sick. Countries with a high burden of tuberculosis that are expanding preventive therapy use must decide how tuberculosis infection testing should be used for risk stratification among household contacts of patients with tuberculosis.We modelled the risks of tuberculosis disease and severe adverse events, comparing the following two preventive therapy strategies: preventive therapy for all household contacts, or preventive therapy for only household contacts with a positive tuberculin skin test (TST) result. We used data from clinical trials and literature on tuberculosis natural history to model outcomes, assuming different preventive therapy regimens, ages, and TST positivity prevalence.Assuming 25% prevalence of TST positivity among 1000 household contacts aged 0-17 years, a treat-all approach with isoniazid and Rifapentine compared with a treat-TST-only approach led to 13 fewer incident tuberculosis cases (IQR -5 to -18) and four additional severe adverse events (2 to 6). With rifampicin, the difference was 11 fewer incident tuberculosis cases (-3 to -17) and two additional severe adverse events (1 to 3). For adults, a treat-all approach led to fewer incident tuberculosis cases, and additional adverse events increased with age. Assuming 25% prevalence of TST positivity among adult contacts, a treat-all approach would lead to around two fewer tuberculosis cases per 1000 contacts for all regimens; the number of additional severe adverse events ranged from seven (IQR 5 to 8) for 18 to 34-year-olds treated with rifampicin to 63 (50 to 74) for people older than 64 years treated with isoniazid and Rifapentine. A rifampicin-only regimen was associated with the fewest additional severe adverse events (seven [IQR 5 to 8] per 1000 adults aged 18-34 years and 35-64 years, and 17 [9 to 23] per 1000 adults older than 64 years).Based on the available data, giving preventive therapy to all household contacts would probably reduce the incidence of tuberculosis cases in high-burden settings. Adverse events could be minimised by using non-isoniazid regimens and, in adults older than 18 years, focusing treatment on individuals with a positive infection test.Bill & Melinda Gates Foundation, UK Medical Research Council, and UK Department for International Development. |
| 2020 | A 21-Year-Old Immune-Competent Man With Recurrent Cough. | Chest | A 21-year-old Chinese man presented with a nonproductive cough for the past 5 months. He denied fevers, chills, night sweats, chest pain, dyspnea, hemoptysis, or weight loss. He was an undergraduate with an unremarkable medical history. He denied any sick contacts and he never smoked. Laboratory tests showed a leukocyte count of 11,200/μL (normal range, 3,500-9,500/μL) with a high neutrophil count and a raised erythrocyte sedimentation rate of 81 mm/h. The purified protein derivative skin test result was positive, and a TB test (T.SPOT.TB; Oxford Immunotec) produced a positive result. The HIV test result was negative. The lung window of the patient's thoracic CT scan showed mottled, patchy opacification in the right lower lobe, and enlarged mediastinal and right hilar lymph nodes (Fig 1A). Bronchoscopy showed mucosal swelling and congestion (Fig 1B). A lymph node (station 11R) biopsy, obtained by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) (Fig 1C), showed nonspecific necrosis. An acid-fast bacillus smear of bronchial secretion produced negative results. He was administered empiric anti-TB therapy (ethambutol, isoniazid, pyrazinamide, and Rifapentine). But his cough had not improved by 4 months later. Thus he came to our hospital for a second opinion. |
| 2020 | Once-weekly rifapentine and isoniazid for tuberculosis prevention in patients with HIV taking dolutegravir-based antiretroviral therapy: a phase 1/2 trial. | Lancet HIV | Short-course preventive therapy with 12 doses of once-weekly Rifapentine (900 mg) plus isoniazid (900 mg) could greatly improve tuberculosis control, especially in areas with high co-endemicity with HIV. However, a small previous trial of such therapy with dolutegravir in healthy, HIV-negative adults was halted early after two of the four patients developed serious adverse events. Because of the potential use of this therapy, and variable safety outcomes of tuberculosis drugs seen in patients with and without HIV, we aimed to characterise safety, pharmacokinetics, and virological suppression in adults who are HIV positive.DOLPHIN was a phase 1/2, single-arm trial done at The Aurum Institute (Tembisa Clinical Research Site, Tembisa, South Africa), with pharmacokinetic visits done at VxPharma (Pretoria, South Africa). Adults (≥18 years) with HIV infection and undetectable viral load (<40 copies per mL) after at least 8 weeks of efavirenz-based or dolutegravir-based regimens were recruited in three consecutive groups, subject to approval by the independent safety monitoring committee. Participants received 50 mg of daily dolutegravir in place of efavirenz for 8 weeks, then began once-weekly Rifapentine (900 mg)-isoniazid (900 mg) for 12 weeks. Groups 1A (n=12) and 1B (n=18) had intensive dolutegravir pharmacokinetic sampling at week 8 (before Rifapentine-isoniazid), at week 11 (after the third dose of Rifapentine)-isoniazid and at week 16 after the eighth dose. Group 2 (n=30) were treated with the same schedule and had sparse dolutegravir pharmacokinetic sampling at weeks 8, 11, and 16. Participants were followed 4 weeks after completion of prophylactic tuberculosis treatment. HIV viral loads were measured at baseline and at weeks 11 and 24. Primary endpoints were adverse events (grade 3 or higher) and dolutegravir population pharmacokinetics, assessed in participants who began Rifapentine-isoniazid. This trial was registered at ClinicalTrials.gov, NCT03435146.Between Jan 24, 2018, and Nov 25, 2018, 61 participants were enrolled into three groups; one participant withdrew (from group 1A). 43 (70%) of 60 participants were women and all participants were black African. Median age was 40 years (IQR 35-48), CD4 cell count was 683 cells per μL (447-935), and body-mass index was 28·9 kg/m (24·0-32·9). Three grade 3 adverse events occurred; two elevated creatinine and one hypertension. Rifapentine-isoniazid increased dolutegravir clearance by 36% (relative standard error 13%) resulting in a 26% decrease in dolutegravir area under the curve. Overall geometric mean ratio of trough concentrations with versus without Rifapentine-isoniazid was 0·53 (90% CI 0·49-0·56) though this ratio varied by day after Rifapentine-isoniazid dose. All but one trough value was above the 90% maximal inhibitory concentration for dolutegravir and HIV viral loads were less than 40 copies per mL in all patients.Our results suggest 12 doses of once-weekly Rifapentine-isoniazid can be given for tuberculosis prophylaxis to patients with HIV taking dolutegravir-based antiretroviral therapy, without dose adjustments. Further exploration of the pharmacokinetics, safety, and efficacy in children and pharmacodynamics in individuals naive to antiretroviral therapy is needed.UNITAID. |
| 2020 | Development and in vitro characterization of rifapentine microsphere-loaded bone implants: a sustained drug delivery system. | Ann Palliat Med | This study aimed to develop and evaluate a sustained drug delivery system for the treatment of osteoarticular tuberculosis (TB) to address the issues surrounding low drug concentration in lesions and bone defects or nonunion after debridement.The effects of Rifapentine on the proliferation and cell cycle of bone marrow mesenchymal stem cells (BMSCs) were evaluated by Cell Counting Kit-8 (CCK-8) and flow cytometry. Rifapentine polylactic acid (PLA) sustained-release microspheres (RPSMs) were prepared through the double emulsion solvent evaporation method and investigated the antibacterial activity in vitro. In this study, two sustained drug delivery systems were prepared by integrating RPSMs and BMSCs into hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) or allogeneic bone. We evaluated these drug delivery systems for dynamics of drug release and osteogenic ability by in vitro release test, alkaline phosphatase (ALP) and alizarin red staining, and real-time PCR.The results showed that Rifapentine concentrations up to 45.0 μg/mL had no effect on cell proliferation and cell cycle. The encapsulation and drug loading efficiency of the fabricated RPSMs were 78.11%±1.16% and 35.57%±0.85%, respectively. The RPSMs had uniform particle size distribution and a long-term anti-bacterium effect. The HA/β-TCP-implanted drug delivery system was found to be more effective in reducing the burst release and having a longer duration of sustained release and retention compared to allogeneic bone. The ALP and alizarin red staining and real-time PCR results showed that it had excellent osteoconductive and osteoinductive properties.In conclusion, the sustained drug delivery system with HA/β-TCP as scaffold material represents a potential new strategy for TB infections and bone defects. |
| 2020 | Cost-effectiveness of IGRA/QFT-Plus for TB screening of migrants in Oman. | Int J Infect Dis | To estimate the cost of a screening program for identifying latent tuberculosis (TB) infections in migrants to Oman.A Markov model was used to estimate the cost of screening using an interferon-gamma release assay (IGRA) applied to all migrants from high TB endemic countries, followed by preventive TB treatment.The model compared seven different scenarios, with a comparison of the direct cost and the quality-adjusted life-years (QALYs) saved.IGRA testing followed by 3 months of preventive treatment with Rifapentine/isoniazid (3HP) was the most cost-effective intervention. |
| 2020 | Antibiofilm and intraosteoblastic activities of rifamycins against Staphylococcus aureus: promising in vitro profile of rifabutin. | J Antimicrob Chemother | Targeting biofilm-embedded and intraosteoblastic Staphylococcus aureus, rifampicin gained a pivotal role in bone and joint infection (BJI) treatment. Two other rifamycins, rifabutin and Rifapentine, may represent better-tolerated alternatives, but their activity against bacterial reservoirs associated with BJI chronicity has never been evaluated.To evaluate the activities of rifampicin, rifabutin and Rifapentine in osteoblast infection models.Using three S. aureus isolates, rifamycins were compared regarding: (i) their intracellular activity in 'acute' (24 h) and 'chronic' (7 days) osteoblast infection models at 0.1× MIC, 1× MIC, 10× MIC and 100× MIC, while impacting infection-induced cytotoxicity (MTT assay), intracellular phenol-soluble modulin (PSM) secretion (RT-PCR), resistance selection and small colony variant (SCV) emergence; and (ii) their minimal biofilm eradication concentration (MBEC) and their MIC to prevent biofilm formation (bMIC).At 0.1× MIC, only rifabutin significantly reduced intracellular inoculum and PSM secretion. All rifamycins allowed a 50% reduction of intraosteoblastic inoculum at higher concentrations, with no difference between acute and chronic infection models, while reducing infection-induced cytotoxicity and PSM secretion. Dose-dependent emergence of intracellular SCVs was observed for all molecules. No intracellular emergence of resistance was detected. bMICs were equivalent for all molecules, but MBEC90s of Rifapentine and rifabutin were 10- to 100-fold lower than those of rifampicin, respectively.All rifamycins are efficient in reducing the S. aureus intraosteoblastic reservoir while limiting infection-induced cytotoxicity, with a higher activity of rifabutin at low concentrations. All molecules prevent biofilm formation, but only Rifapentine and rifabutin consistently reduce formed biofilm-embedded bacteria for all isolates. The activity of rifabutin at lower doses highlights its therapeutic potential. |
| 2020 | Management of latent tuberculosis infection in China: Exploring solutions suitable for high-burden countries. | Int J Infect Dis | China is one of the countries with a high burden of tuberculosis (TB) and latent tuberculosis infection (LTBI). It was recently estimated that China had the highest LTBI burden in the world, with approximately 350 million persons living with the infection. The prevalence of LTBI in China is overestimated by tuberculin skin test (TST) as compared to interferon-gamma release assay (IGRA). A population-based study found that IGRA positivity rates ranged between 13.5% and 19.8%. The annual TB infection rate in the rural population was 1.5% based on persistent positive IGRA results in converters. The development of active TB from LTBI in the general rural population was 0.87 per 100 person-years in the first 2 years among individuals who newly converted to IGRA-positive. TB control in students has been paid more attention by the government, which also improved LTBI management among students in close contact with active TB patients. A 3-month regimen of twice-weekly Rifapentine plus isoniazid (3HP, both with a maximum dose of 600 mg) has been practiced for LTBI treatment in China for years. With respect to LTBI management in populations using immune inhibitors, an expert consensus on TB prevention and management in tumor necrosis factor antagonist application was published in 2013 in China. In order to achieve the global goals of the End TB Strategy, China needs innovative ideas and technologies to reduce the TB incidence by management of LTBI, such as the identification of populations for LTBI testing and treatment, selecting and developing reliable LTBI tests, exploring safe and effective preventive treatment tools, and establishing a set of optimized LTBI management systems. |
| 2020 | Frequency, Risk Factors, and Outcome of Active Tuberculosis following Allogeneic Hematopoietic Stem Cell Transplantation. | Biol Blood Marrow Transplant | We aimed to investigate the frequency, risk factors, and outcome of active tuberculosis (TB) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This retrospective, nested, case-control study reviewed data from 6236 patients who received allo-HSCT from January 2008 to December 2018 at a single center; thirty-three patients (0.5%) with active TB and 99 controls without active TB after allo-HSCT were identified. We performed propensity score matching by randomly selecting 3 controls for each identified active TB patient according to the time of transplantation and follow-up period. History of pretransplant active TB previously treated and inactive at time of transplantation (P< .001) was an independent risk factor. No significant differences in overall survival (P= .342), nonrelapse mortality (P= .497), or incidence of relapse (P= .807) were found. Thirty (90.9%) patients were treated with 4-drug (isoniazid, rifampicin/three Rifapentine, pyrazinamide, and ethambutol) or 3-drug combination first-line therapy, with a response rate of 76.7%. Twenty-six (78.8%) patients were treated with first-line and second-line combined therapy, and the response rate was 76.9%. Five (15.2%) patients developed hepatotoxicity. In conclusion, history of pretransplant active TB previously treated and inactive at time of transplantation was an independent risk factor of active TB after allo-HSCT. No significant differences in prognosis between the TB and control groups were found. More studies are needed to help develop standardized therapeutic strategies for patients with post-transplant TB. |
| 2020 | Dynamic changes of interferon gamma release assay results with latent tuberculosis infection treatment. | Clin Microbiol Infect | Using QuantiFERON-TB Gold In-Tube (QFT-GIT) for monitoring tuberculosis (TB) and latent TB infection treatment effect is controversial. The present study aimed to evaluate the dynamic changes of interferon gamma (IFN-γ) levels along with latent TB infection treatment via a randomized controlled study.A total of 910 participants treated with 8 weeks of once-weekly Rifapentine plus isoniazid (group A), 890 treated with 6 weeks of twice-weekly Rifapentine plus isoniazid (group B) and 818 untreated controls (group C) were followed for 2 years to track active TB development. QFT-GIT tests were repeated three times for all groups: before treatment (T0), at completion of treatment (T1) and 3 months after completion of treatment (T2).Similar rates of persistent QFT-GIT reversion were observed in groups A (19.0%, 173/910), B (18.5%, 165/890) and C (20.7%, 169/818) (p 0.512). The dynamic changes of IFN-γ levels were not statistically significant among the three groups. In treated participants, individuals with higher baseline IFN-γ levels showed increased TB occurrence (1.0%, 9/896) compared to those with lower baseline levels (0.2%, 2/904) (p 0.037). A similar but statistically insignificant trend was also observed in untreated controls (1.8% (7/400) vs. 0.5% (2/418), p 0.100). When TB cases were matched with non-TB cases on baseline IFN-γ levels, no significant differences were found with respect to the dynamic changes in IFN-γ levels with time, regardless of whether they received treatment.QFT-GIT reversion or decreased IFN-γ levels should not be used for monitoring host response to latent TB infection treatment. |
| 2020 | Guidelines for the Treatment of Latent Tuberculosis Infection: Recommendations from the National Tuberculosis Controllers Association and CDC, 2020. | MMWR Recomm Rep | Comprehensive guidelines for treatment of latent tuberculosis infection (LTBI) among persons living in the United States were last published in 2000 (American Thoracic Society. CDC targeted tuberculin testing and treatment of latent tuberculosis infection. Am J Respir Crit Care Med 2000;161:S221-47). Since then, several new regimens have been evaluated in clinical trials. To update previous guidelines, the National Tuberculosis Controllers Association (NTCA) and CDC convened a committee to conduct a systematic literature review and make new recommendations for the most effective and least toxic regimens for treatment of LTBI among persons who live in the United States.The systematic literature review included clinical trials of regimens to treat LTBI. Quality of evidence (high, moderate, low, or very low) from clinical trial comparisons was appraised using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. In addition, a network meta-analysis evaluated regimens that had not been compared directly in clinical trials. The effectiveness outcome was tuberculosis disease; the toxicity outcome was hepatotoxicity. Strong GRADE recommendations required at least moderate evidence of effectiveness and that the desirable consequences outweighed the undesirable consequences in the majority of patients. Conditional GRADE recommendations were made when determination of whether desirable consequences outweighed undesirable consequences was uncertain (e.g., with low-quality evidence).These updated 2020 LTBI treatment guidelines include the NTCA- and CDC-recommended treatment regimens that comprise three preferred rifamycin-based regimens and two alternative monotherapy regimens with daily isoniazid. All recommended treatment regimens are intended for persons infected with Mycobacterium tuberculosis that is presumed to be susceptible to isoniazid or rifampin. These updated guidelines do not apply when evidence is available that the infecting M. tuberculosis strain is resistant to both isoniazid and rifampin; recommendations for treating contacts exposed to multidrug-resistant tuberculosis were published in 2019 (Nahid P, Mase SR Migliori GB, et al. Treatment of drug-resistant tuberculosis. An official ATS/CDC/ERS/IDSA clinical practice guideline. Am J Respir Crit Care Med 2019;200:e93-e142). The three rifamycin-based preferred regimens are 3 months of once-weekly isoniazid plus Rifapentine, 4 months of daily rifampin, or 3 months of daily isoniazid plus rifampin. Prescribing providers or pharmacists who are unfamiliar with rifampin and Rifapentine might confuse the two drugs. They are not interchangeable, and caution should be taken to ensure that patients receive the correct medication for the intended regimen. Preference for these rifamycin-based regimens was made on the basis of effectiveness, safety, and high treatment completion rates. The two alternative treatment regimens are daily isoniazid for 6 or 9 months; isoniazid monotherapy is efficacious but has higher toxicity risk and lower treatment completion rates than shorter rifamycin-based regimens.In summary, short-course (3- to 4-month) rifamycin-based treatment regimens are preferred over longer-course (6-9 month) isoniazid monotherapy for treatment of LTBI. These updated guidelines can be used by clinicians, public health officials, policymakers, health care organizations, and other state and local stakeholders who might need to adapt them to fit individual clinical circumstances. |
| 2020 | Addressing Latent Tuberculosis Infection Treatment Through a Collaborative Care Model With Community Pharmacies and a Health Department. | Prev Chronic Dis | The objective of this study was to evaluate a novel collaborative care model using community pharmacies as additional access points for latent tuberculosis infection (LTBI) treatment for patients using combination weekly therapy with isoniazid and Rifapentine (3HP) plus directly observed therapy for 12 weeks.This prospective pilot study included adult patients diagnosed with LTBI. Patients were eligible for study participation if they spoke English or Spanish and were followed by the New Mexico Department of Health (NM DOH). Patients were excluded if they were pregnant, receiving concomitant HIV antiretroviral therapy, or had contraindications to 3HP due to allergy or drug interactions. Community pharmacy sites included chain, independent, and hospital outpatient pharmacies in Albuquerque and Santa Fe, New Mexico.A total of 40 patients initiated treatment with 3HP and were included. Most were female (55%) and had a mean age of 46 years (standard deviation, 12.6 y). A total of 75.0% of patients completed LTBI treatment with 3HP in a community pharmacy site. Individuals of Hispanic ethnicity were more likely to complete treatment (76.7% vs 40.0%, P = .04). Most patients (60%; n = 24) reported experiencing an adverse drug event (ADE) with 3HP therapy. Patients who completed treatment were less likely to experience an ADE than patients who discontinued treatment (50.0% vs 90.0%, P = .03). Pharmacists performed 398 LTBI treatment visits (40 initial visits, 358 follow-up visits), saving the NM DOH approximately 143 hours in patient contact time.High completion rates and safe administration of LTBI treatment can be achieved in the community pharmacy setting. |
| 2020 | Advances in the diagnosis and treatment of latent tuberculosis infection. | Curr Opin Infect Dis | This review describes the major developments in the rationale for treating latent tuberculosis infection; new approaches to identifying persons with latent infection who are most likely to progress to active disease; and the development of novel short-course regimens for treatment of latent tuberculosis.As many as one-third of the world's population has latent infection with Mycobacterium tuberculosis. Models demonstrate that tuberculosis will not be eliminated without large-scale treatment of persons with latent TB. Current tools for identifying persons at risk for active tuberculosis disease include TST and IGRA, which have poor positive predictive values. Newer approaches using gene expression profiling show promise and are being studied in the ongoing trials. Development of short-course regimens are a major advance in treatment of latent TB. Three months of Rifapentine with isoniazid, 4 months of rifampin, and 1 month of Rifapentine with isoniazid have been found to be noninferior to the standard 9 months of isoniazid.Progress towards TB elimination can be accelerated by instituting public health measures that take into account new developments in identifying and treating persons with latent tuberculosis infection who are most likely to progress to active disease. |
| 2020 | High-dose rifapentine with or without moxifloxacin for shortening treatment of pulmonary tuberculosis: Study protocol for TBTC study 31/ACTG A5349 phase 3 clinical trial. | Contemp Clin Trials | Phase 2 clinical trials of tuberculosis treatment have shown that once-daily regimens in which rifampin is replaced by high dose Rifapentine have potent antimicrobial activity that may be sufficient to shorten overall treatment duration. Herein we describe the design of an ongoing phase 3 clinical trial testing the hypothesis that once-daily regimens containing high dose Rifapentine in combination with other anti-tuberculosis drugs administered for four months can achieve cure rates not worse than the conventional six-month treatment regimen.S31/A5349 is a multicenter randomized controlled phase 3 non-inferiority trial that compares two four-month regimens with the standard six-month regimen for treating drug-susceptible pulmonary tuberculosis in HIV-negative and HIV-positive patients. Both of the four-month regimens contain high-dose Rifapentine instead of rifampin, with ethambutol replaced by moxifloxacin in one regimen. All drugs are administered seven days per week, and under direct observation at least five days per week. The primary outcome is tuberculosis disease-free survival at twelve months after study treatment assignment. A total of 2500 participants will be randomized; this gives 90% power to show non-inferiority with a 6.6% margin of non-inferiority.This phase 3 trial formally tests the hypothesis that augmentation of rifamycin exposures can shorten tuberculosis treatment to four months. Trial design and standardized implementation optimize the likelihood of obtaining valid results. Results of this trial may have important implications for clinical management of tuberculosis at both individual and programmatic levels.NCT02410772. Registered 8 April 2015,https://www.clinicaltrials.gov/ct2/show/NCT02410772?term=02410772&rank=1. |
| 2020 | Optimization of Rifapentine-Loaded Lipid Nanoparticles Using a Quality-by-Design Strategy. | Pharmaceutics | This work aims to optimize and assess the potential use of lipid nanoparticles, namely nanostructured lipid carriers (NLCs), as drug delivery systems of Rifapentine (RPT) for the treatment of tuberculosis (TB). A Box-Behnken design was used to increase drug encapsulation efficiency (EE) and loading capacity (LC) of RPT-loaded NLCs. The optimized nanoparticles were fully characterized, and their effect on cell viability was assessed. The quality-by-design approach allowed the optimization of RPT-loaded NLCs with improved EE and LC using the minimum of experiments. Analyses of variance were indicative of the validity of this model to optimize this nanodelivery system. The optimized NLCs had a mean diameter of 242 ± 9 nm, polydispersity index <0.2, and a highly negative zeta potential. EE values were higher than 80%, and differential scanning calorimetry analysis enabled the confirmation of the efficient encapsulation of RPT. Transmission electron microscopy analysis showed spherical nanoparticles, uniform in shape and diameter, with no visible aggregation. Stability studies indicated that NLCs were stable over time. No toxicity was observed in primary human macrophage viability for nanoparticles up to 1000 μg mL. Overall, the optimized NLCs are efficient carriers of RPT and should be considered for further testing as promising drug delivery systems to be used in TB treatment. |
| 2020 | Treatment of latent tuberculosis infection with short-course regimens in potential living kidney donors. | Transpl Infect Dis | Treatment data for latent tuberculosis infection (LTBI) among potential living kidney donors are scarce.This retrospective study was performed to evaluate the prevalence of positive QuantiFERON-TB Gold In-Tube (QFT-GIT) among potential living kidney donors that were screened from 2009 to 2017. We investigated if there was any difference in the time to donation between QFT-GIT-positive and QFT-GIT-negative donors. We assessed the regimens used to treat LTBI and whether the recipients of QFT-GIT-positive donors developed active tuberculosis (TB).Forty out of 427 (9%) potential living kidney donors had a positive QFT-GIT. QFT-GIT-positive donors were as likely as negative donors to undergo donation (30 [75%] vs 315 [81%], P = .33). The time from QFT-GIT testing to donation was longer among QFT-GIT-positive donors (median 221 days [range: 4-1139] vs 86 days [range: 3-1887], P = .001). Twelve-week Rifapentine (RPT)/Isoniazid (INH) was the most common treatment used and was not associated with significant adverse reactions. There was a trend toward longer time to donation among QFT-GIT-positive donors who were treated for LTBI compared with QFT-GIT-positive donors who were not (252 days [range: 88-1139] vs 95 days [range: 4-802], P = .05). Twenty-nine recipients of QFT-GIT-positive living kidney donors were evaluated. Eleven of these recipients received kidneys from donors that were not treated for LTBI. Two of these recipients were treated with INH post-transplantation.The time from QFT-GIT testing to donation was longer among QFT-GIT-positive donors. The short-course regimens appear to be excellent options for LTBI treatment among living kidney donors and avoid delaying organ donation further. |
| 2019 | Association of Drug Metabolic Enzyme Genetic Polymorphisms and Adverse Drug Reactions in Patients Receiving Rifapentine and Isoniazid Therapy for Latent Tuberculosis. | Int J Environ Res Public Health | Weekly Rifapentine and isoniazid therapy (3HP) is the most frequent treatment for latent tuberculosis infection (LTBI). However, the association between major adverse drug reactions (ADRs) and drug metabolic enzyme single-nucleotide polymorphisms (SNPs) remains unclear. In this study, 377 participants who received the 3HP regimen were recruited and examined for genotyping of CYP5A6, CYP2B6, CYP2C19, CYP2E1, and NAT2 SNPs. In our study, 184 participants (48.4%) developed ADRs. Moreover, CYP2C19 rs4986893 (TT vs. CC+CT, odds ratio [OR] [95% CI]: 2.231 [1.015-4.906]), CYP2E1 rs2070676 (CC vs. CG+GG, OR [95% CI]: 1.563 [1.022-2.389]), and CYP2E1 rs2515641 (CC vs. CT+TT, OR [95% CI]: 1.903 [1.250-2.898]) were associated with ADR development. In conclusion, CYP2C19 and CYP2E1 SNPs may provide useful information regarding ADRs in LTBI patients receiving the 3HP regimen. |
| 2020 | Infection risk in patients undergoing treatment for inflammatory arthritis: non-biologics versus biologics. | Expert Rev Clin Immunol | : Despite the therapeutic effectiveness of biologics targeting immune cells or cytokines in patients with inflammatory arthritis, which reflects their pathogenic roles, an increased infection risk is observed in those undergoing biological treatment. However, there are limited data regarding the comparison of infection risks in inflammatory arthritis patients treated with non-biologics (csDMARDs), biologics (bDMARDs), including tumor necrosis factor (TNF) inhibitors and non-TNF inhibitors, or targeted synthetic (ts)DMARDs.: Through a review of English-language literature as of 30 June 2019, we focus on the existing evidence on the risk of infections caused by bacteria, , and hepatitis virus in inflammatory arthritis patients undergoing treatment with csDMARDs, bDMARDs, or tsDMARDs.: While the risks of bacterial and mycobacterial infection are increased in arthritis patients treated with csDMARDs, the risks are further higher in those receiving bDMARDs therapy, particularly TNF inhibitors. Regarding HBV infection, antiviral therapy may effectively prevent HBV reactivation in patients receiving bDMARDs, especially rituximab. However, more data are needed to establish effective preventive strategies for HBsAg-negative/HBcAb-positive patients. It seems safe to use cyclosporine and TNF inhibitors in patients with HCV infection, while those undergoing rituximab therapies should be frequently monitored for HCV activity.: ABT: abatacept; ADA: adalimumab; AS: ankylosing spondylitis; bDMARDs: biologic disease-modifying anti-rheumatic drugs; CKD: chronic kidney disease; COPD: chronic obstructive pulmonary disease; CS: corticosteroids; CsA: cyclosporine A; csDMARDs: conventional synthetic disease-modifying anti-rheumatic drugs; CZP: certolizumab; DAAs: direct-acting antiviral agents; DM: diabetes mellitus; DOT: directly observed therapy; EIN: Emerging Infections Network; ETN: etanercept; GOL: golimumab; GPRD: General Practice Research Database; HBV: hepatitis B virus; HBVr: HBV reactivation; HBsAg+: HBsAg-positive; HBsAg-/anti-HBc+: HBsAg-negative anti-HBc antibodies-positive; HCV: hepatitis C virus; HCQ: hydroxychloroquine: IFX: infliximab; IL-6: interleukin-6; JAK: Janus kinase; LEF: leflunomide; LTBI: latent tuberculosis infection; mAb: monoclonal antibody; MTX: methotrexate; OR: odds ratio; PsA: psoriatic arthritis; PMS: post-marketing surveillance; RA: rheumatoid arthritis; TNF: tumor necrosis factor; TNFi: tumor necrosis factor inhibitor; SCK: secukinumab; SSZ: sulfasalazine; TOZ: tocilizumab; RCT: randomized controlled trial; RR: relative risk; RTX: rituximab; 3HP: 3-month once-weekly isoniazid plus Rifapentine; TB: tuberculosis; tsDMARDs: targeted synthetic disease-modifying anti-rheumatic drugs; UTK: ustekinumab; WHO: World Health Organization. |
| 2019 | Shortened treatment regimens versus the standard regimen for drug-sensitive pulmonary tuberculosis. | Cochrane Database Syst Rev | Tuberculosis causes more deaths than any other infectious disease worldwide, with pulmonary tuberculosis being the most common form. Standard first-line treatment for drug-sensitive pulmonary tuberculosis for six months comprises isoniazid, rifampicin, pyrazinamide, and ethambutol (HRZE) for two months, followed by HRE (in areas of high TB drug resistance) or HR, given over a four-month continuation phase. Many people do not complete this full course. Shortened treatment regimens that are equally effective and safe could improve treatment success.To evaluate the efficacy and safety of shortened treatment regimens versus the standard six-month treatment regimen for individuals with drug-sensitive pulmonary tuberculosis.We searched the following databases up to 10 July 2019: the Cochrane Infectious Diseases Group Specialized Register; the Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; MEDLINE (PubMed); Embase; the Latin American Caribbean Health Sciences Literature (LILACS); Science Citation Index-Expanded; Indian Medlars Center; and the South Asian Database of Controlled Clinical Trials. We also searched the World Health Organization (WHO) International Clinical Trials Registry Platform, ClinicalTrials.gov, the Clinical Trials Unit of the International Union Against Tuberculosis and Lung Disease, the UK Medical Research Council Clinical Trials Unit, and the Clinical Trials Registry India for ongoing trials. We checked the reference lists of identified articles to find additional relevant studies.We searched for randomized controlled trials (RCTs) or quasi-RCTs that compared shorter-duration regimens (less than six months) versus the standard six-month regimen for people of all ages, irrespective of HIV status, who were newly diagnosed with pulmonary tuberculosis by positive sputum culture or GeneXpert, and with presumed or proven drug-sensitive tuberculosis. The primary outcome of interest was relapse within two years of completion of anti-tuberculosis treatment (ATT).Two review authors independently selected trials, extracted data, and assessed risk of bias for the included trials. For dichotomous outcomes, we used risk ratios (RRs) with 95% confidence intervals (CIs). When appropriate, we pooled data from the included trials in meta-analyses. We assessed the certainty of evidence using the GRADE approach.We included five randomized trials that compared fluoroquinolone-containing four-month ATT regimens versus standard six-month ATT regimens and recruited 5825 adults with newly diagnosed drug-sensitive pulmonary tuberculosis from 14 countries with high tuberculosis transmission in Asia, Africa, and Latin Ameria. Three were multi-country trials that included a total of 572 HIV-positive people. These trials excluded children, pregnant or lactating women, people with serious comorbid conditions, and those with diabetes mellitus. Four trials had multiple treatment arms. Moxifloxacin replaced ethambutol in standard four-month, daily or thrice-weekly ATT regimens in two trials; moxifloxacin replaced isoniazid in four-month ATT regimens in two trials, was given daily in one trial, and was given with Rifapentine instead of rifampicin daily for two months and twice weekly for two months in one trial. Moxifloxacin was added to standard ATT drugs for three to four months in one ongoing trial that reported interim results. Gatifloxacin replaced ethambutol in standard ATT regimens given daily or thrice weekly for four months in two trials. Follow-up ranged from 12 months to 24 months after treatment completion for the majority of participants. Moxifloxacin-containing four-month ATT regimens Moxifloxacin-containing four-month ATT regimens that replaced ethambutol or isoniazid probably increased the proportions who experienced relapse after successful treatment compared to standard ATT regimens (RR 3.56, 95% CI 2.37 to 5.37; 2265 participants, 3 trials; moderate-certainty evidence). For death from any cause, there was probably little or no difference between the two regimens (2760 participants, 3 trials; moderate-certainty evidence). Treatment failure was rare, and there was probably little or no difference in proportions with treatment failure between ATT regimens (2282 participants, 3 trials; moderate-certainty evidence). None of the participants given moxifloxacin-containing regimens developed resistance to rifampicin, and these regimens may not increase the risk of acquired resistance (2282 participants, 3 trials; low-certainty evidence). Severe adverse events were probably little or no different with moxifloxacin-containing four-month regimens that replaced ethambutol or isoniazid, and with three- to four-month regimens that augmented standard ATT with moxifloxacin, when compared to standard six-month ATT regimens (3548 participants, 4 trials; moderate-certainty evidence). Gatifloxacin-containing four-month ATT regimens Gatifloxacin-containing four-month ATT regimens that replaced ethambutol probably increased relapse compared to standard six-month ATT regimens in adults with drug-sensitive pulmonary tuberculosis (RR 2.11, 95% CI 1.56 to 2.84; 1633 participants, 2 trials; moderate-certainty evidence). The four-month regimen probably made little or no difference in death compared to the six-month regimen (1886 participants, 2 trials; moderate-certainty evidence). Treatment failure was uncommon and was probably little or no different between the four-month and six-month regimens (1657 participants, 2 trials; moderate-certainty evidence). Acquired resistance to isoniazid or rifampicin was not detected in those given the gatifloxacin-containing shortened ATT regimen, but we are uncertain whether acquired drug resistance is any different in the four- and six-month regimens (429 participants, 1 trial; very low-certainty evidence). Serious adverse events were probably no different with either regimen (1993 participants, 2 trials; moderate-certainty evidence).Evidence to date does not support the use of shortened ATT regimens in adults with newly diagnosed drug-sensitive pulmonary tuberculosis. Four-month ATT regimens that replace ethambutol with moxifloxacin or gatifloxacin, or isoniazid with moxifloxacin, increase relapse substantially compared to standard six-month ATT regimens, although treatment success and serious adverse events are little or no different. The results of six large ongoing trials will help inform decisions on whether shortened ATT regimens can replace standard six-month ATT regimens. 9 December 2019 Up to date All studies incorporated from most recent search All eligible published studies found in the last search (10 Jul, 2019) were included. |
| 2020 | Simple and sensitive method for the analysis of 14 antituberculosis drugs using liquid chromatography/tandem mass spectrometry in human plasma. | Rapid Commun Mass Spectrom | Monitoring plasma concentration and adjusting doses of antituberculosis (TB) drugs are beneficial for improving responses to drug treatment and avoiding adverse drug reactions. A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed to measure the plasma concentrations of 14 anti-TB drugs: ethambutol, isoniazid, pyrazinamide, levofloxacin, gatifloxacin, moxifloxacin, prothionamide, linezolid, rifampin, Rifapentine, rifabutin, cycloserine, p-aminosalicylic acid, and clofazimine.Human plasma was precipitated by acetonitrile and was subsequently separated by an AQ-C18 column with a gradient elution. Drug concentrations were determined using multiple reaction monitoring in positive ion electrospray ionization mode. According to pharmacokinetic data of patients, the peak concentration ranges and the timing of blood collection were determined.Intra- and interday precision was < 14.8%. Linearity, accuracy, extraction recovery, and matrix effect were acceptable for each drug. The stability of the method satisfied different storage conditions.The method allowed the sensitive and reproducible determination of 14 frequently used anti-TB drugs which has already been of benefit for some TB patients. |
| 2020 | Preventive tuberculosis treatment effect on QuantiFERON TB-Gold in-tube testing in a high tuberculosis-endemic country: A clinical trial. | Int J Infect Dis | Whether T-cell interferon-γ responses to Mycobacterium tuberculosis-specific antigens can be influenced by tuberculosis preventive treatment in a high-endemic country is uncertain.In this prospective, open-label, controlled study, 513 individuals with silicosis were randomly selected for TB preventive treatment with Rifapentine and isoniazid or for observation. QuantiFERON-TB Gold in-tube (QFT-GIT) assay was used to measure IFN-γ response to M. tuberculosis antigens at baseline (T0) and at 6 (T1) and 33 (T2) months after completion of therapy.A total of 220 subjects were included in the final analysis: 105 and 115 in the prevention and observation arms, respectively. The proportions of QFT-GIT reversion from baseline to T1 were similar in the prevention and observation arms (18.4% vs 12.8%, P=0.566). However, reversion from baseline to T2 was more frequent in the prevention arm than in the observation arm, but the difference was not significant (24.2% vs 6.3%, P=0.881). No significant difference was observed in the quantitative responses of QFT-GIT between the two arms during follow-up at T1 (P=0.648) and T2 (P=0.918).Preventive tuberculosis treatment has no effect on interferon-γ responses measured by serial QFT-GIT assays in a high tuberculosis-endemic country.http://www.clinicaltrials.gov NCT02430259. |
| 2019 | Treatment of Latent Tuberculosis Infection-An Update. | Clin Chest Med | Treatment of latent tuberculosis infection (LTBI) is an important component of TB control and elimination. LTBI treatment regimens include once-weekly isoniazid plus Rifapentine for 3 months, daily rifampin for 4 months, daily isoniazid plus rifampin for 3-4 months, and daily isoniazid for 6-9 months. Isoniazid monotherapy is efficacious in preventing TB disease, but the rifampin- and Rifapentine-containing regimens are shorter and have similar efficacy, adequate safety, and higher treatment completion rates. Novel vaccine strategies, host immunity-directed therapies and ultrashort antimicrobial regimens for TB prevention, such as daily isoniazid plus Rifapentine for 1 month, are under evaluation. |
| 2020 | Evaluation of 3 Months of Once-Weekly Rifapentine and Isoniazid for Latent Tuberculosis Infection. | Ann Pharmacother | Centers for Disease Control and Prevention recommends 3 months of once-weekly Rifapentine/isoniazid (3HP) for latent tuberculosis infection (LTBI) treatment given by directly observed therapy (DOT) or self-administered therapy (SAT) in patients ≥2 years old. 3HP has been associated with increased incidence of hepatic, gastrointestinal, flu-like, and cutaneous adverse drug reactions (ADRs) compared with isoniazid monotherapy. This study evaluated 3HP completion rates and tolerability for LTBI treatment in a real-world setting. A single-center retrospective cohort with a nested case-control study, comparing patients experiencing ADRs with those who did not, evaluated patients ≥18 years old receiving 3HP by DOT or SAT for LTBI at Cleveland Clinic from October 2011 through July 2018. Information on baseline characteristics, 3HP administrations, and ADRs were collected. Of 199 patients screened, 144 were included (111 DOT, 33 SAT). 3HP completion rates were high at 82.6% and similar between DOT and SAT groups. During treatment, 92/144 (63.9%) patients experienced any ADR. The most common ADR included flu-like symptoms (38.2%) and gastrointestinal (31.9%) and hepatic (2.1%) reactions. Despite high rate of overall ADRs, rates of significant ADRs (grade 2 or higher) were 4.2%. Overall, 9% of patients discontinued 3HP because of ADRs. After adjusting for other factors associated with ADRs at baseline, SAT was not associated with increased incidence of ADRs, but female sex was a significant predictor (odds ratio = 2.61 [95% CI, 1.23 to 5.56]). This study observed high 3HP treatment completion rates, low incidence of significant ADRs, and low discontinuation rates resulting from ADRs. |
| 2020 | Nonparticipation reasons in a randomized international trial of a new latent tuberculosis infection regimen. | Clin Trials | Efficient recruitment of eligible participants, optimizing time and sample size, is a crucial component in conducting a successful clinical trial. Inefficient participant recruitment can impede study progress, consume staff time and resources, and limit quality and generalizability or the power to assess outcomes. Recruitment for disease prevention trials poses additional challenges because patients are asymptomatic. We evaluated candidates for a disease prevention trial to determine reasons for nonparticipation and to identify factors that can be addressed to improve recruitment efficiency.During 2001-2009, the Tuberculosis Trials Consortium conducted Study 26 (PREVENT TB), a randomized clinical trial at 26 sites in four countries, among persons with latent tuberculosis infection at high risk for tuberculosis disease progression, comparing 3 months of directly observed once-weekly Rifapentine plus isoniazid with 9 months of self-administered daily isoniazid. During March 2005-February 2008, non-identifying demographic information, risk factors for experiencing active tuberculosis disease, and reasons for not enrolling were collected from screened patients to facilitate interpretation of trial data, to meet Consolidated Standards of Reporting Trials standards, and to evaluate reasons for nonparticipation.Of the 7452 candidates screened in Brazil, Canada, Spain, and the United States, 3584 (48%) were not enrolled, because of ineligibility (41%), site decision (10%), or patient choice (49%). Among those who did not enroll by own choice, and for whom responses were recorded on whether they would accept treatment outside of the study (n = 1430), 68% reported that they planned to accept non-study latent tuberculosis infection treatment. Among 1305 patients with one or more reported reasons for nonparticipation, study staff recorded a total of 1886 individual reasons (reason count: median = 1/patient; range = 1-9) for why patients chose not to enroll, including grouped concerns about research (24% of 1886), work or school conflicts (20%), medication or health beliefs (16%), latent tuberculosis infection beliefs (11%), and patient lifestyle and family concerns (10%).Educational efforts addressing clinical research concerns and beliefs about medication and health, as well as study protocols that accommodate patient-related concerns (e.g. work, school, and lifestyle) might increase willingness to enter clinical trials. Findings from this evaluation can support development of communication and education materials for clinical trial sites at the beginning of a trial to allow study staff to address potential participant concerns during study screening. |
| 2019 | Ulcerative intestinal tuberculosis case as a complication of treatment by infliximab for intestinal Behçet's disease: A case report. | Medicine (Baltimore) | Intestinal Behçet's disease (BD) is characterized by intestinal ulcerations and gastrointestinal symptoms. Ulcerative intestinal tuberculosis (TB) is usually with dyspepsia, abdominal pain, vomiting, and weight loss. The 2 diseases exhibit similar clinical manifestations, but the most critical aspects of their clinical courses and required treatments are not at all similar.We present a case in which a patient with intestinal Behçet's disease developed a de novo ulcerative intestinal TB infection after the start of anti-tumor necrosis factor-α treatment. This was despite histopathologic examination without caseous necrosis granuloma and negative for acid-fast staining and latent TB screen.Intestinal Behçet's disease and intestinal TB.The patient was treated with quadruple antituberculous chemotherapy, comprising Rifapentine, isoniazid, ethambutol, and pyrazinamide.At follow-up about 3 months, the therapy of oral antituberculous drugs and thalidomide was continued and the patient's condition had stabilized.This case illustrates the importance of closely monitoring patients who are on infliximab for possible onset of TB, even without abdominal symptoms, and with negative screening results for latent TB. |
| 2020 | Isoniazid and Rifapentine Treatment Eradicates Persistent in Macaques. | Am J Respir Crit Care Med | The authors have informed the Journal that they have become aware that some of the data in this article may be unreliable. Therefore, we have added this expression of concern while the situation is being reviewed. Direct evidence for persistence of () during asymptomatic latent tuberculosis infection (LTBI) in humans is currently lacking. Moreover, although a 12-week regimen of once-weekly isoniazid and Rifapentine (3HP) is currently recommended by the CDC as treatment for LTBI, experimental evidence for 3HP-mediated clearance of persistent infection in human lungs has not been established. Using a nonhuman primate (NHP) model of TB, we sought to assess 3HP treatment-mediated clearance of infection in latently infected macaques. Sixteen NHPs were infected via inhalation with ∼10 cfu of CDC1551, after which asymptomatic animals were either treated with 3HP or left untreated. Pharmacokinetics of the 3HP regimen were measured. Following treatment, animals were coinfected with simian immunodeficiency virus to assess reactivation of LTBI and development of active TB disease. Fourteen NHPs remained free of clinical signs or microbiological evidence of active TB following infection with and were subsequently either treated with 3HP ( = 7) or left untreated ( = 7). Untreated NHPs were asymptomatic for 7 months but harbored persistent infection, as shown by reactivation of latent infection following simian immunodeficiency virus coinfection. However, none of the treated animals developed TB reactivation disease, and they remained without clinical or microbiological evidence of persistent bacilli, suggesting treatment-mediated clearance of bacteria. can persist in asymptomatic macaques for at least 7 months. Furthermore, 3HP treatment effectively cleared bacteria and prevented reactivation of TB in latently infected macaques. |
| Adverse event and treatment completion rates of a 12-dose weekly isoniazid and rifapentine course for South Korean healthcare workers. | Respir Med | We investigated the adverse events (AEs) and treatment completion rates of a 3 month course of once-weekly isoniazid and Rifapentine (3HP) in South Korean health care workers (HCWs) with latent tuberculosis infection (LTBI).HCWs who were candidates for LTBI treatment were enrolled from two tertiary referral centers between December 2016 and October 2017. From December 2016 through March 2017, HCWs who agreed were treated with the 3HP regimen (3HP group). Their compliance and AEs were prospectively collected. From April 2017 onward, HCWs who required LTBI treatment received 3 months of isoniazid plus rifampin (3HR group), and their medical records were retrospectively reviewed.During the study period, 406 HCWs were treated, 226 (55.7%) in the 3HP group, and 180 (44.3%) in the 3HR group. The number of subjects with AEs was significantly greater in the 3HP group (75.2% vs 56.7%, P < 0.001), in particular a flu-like syndrome (19.0% vs. 0%, P < 0.001). However, hepatotoxicity occurred less frequently in those receiving 3HP (7.5% vs. 20.0%, P < 0.001). Per protocol definition, anaphylaxis developed in 1.8% of the 3HP group. The overall treatment completion rate was greater in the 3HP group (92.9% vs 86.7%, P = 0.036).The 3HP regimen had a higher treatment completion rate and lower hepatotoxicity compared with the 3HR regimen. However, it resulted in a higher rate of flu-like syndromes. Additionally, a few subjects had anaphylaxis, although there were no fatalities. |
| 2019 | Specific Interactions between Rifamycin Antibiotics and Water Influencing Ability To Overcome Natural Cell Barriers and the Range of Antibacterial Potency. | ACS Infect Dis | Rifamycins are a group of macrocyclic antibiotics mainly used for the treatment of various bacterial infections including tuberculosis. Spectroscopic studies of rifamycins evidence the formation of temperature- and solvent-dependent equilibria between A-, B-, and C-type conformers in solutions. The B- and C-type conformers of rifamycin antibiotics are exclusively formed in the presence of water molecules. A- and B-type conformers exhibit a hydrophilic and "open" -bridge nature whereas the C-type conformer is more lipophilic due to the presence of a "closed" -bridge structure. The involvement of the lactam moiety of the -bridge in intramolecular H-bonds within Rifapentine and rifampicin implicates the formation of a more hydrophilic A-type conformer. In contrast to rifampicin and Rifapentine, for rifabutin and rifaximin, the "free" lactam group enhances conformational flexibility of the -bridge, thereby enabling interconversion between A- and C-type conformers. In turn, an equilibrium between A- and C-type conformers for rifamycins improves their adaptation to the changing nature of bacteria cell membranes, especially those of Gram-negative strains and/or to efflux pump systems. |
| 2019 | Activity of Rifampin, Rifabutin, Rifapentine, and Rifaximin against Planktonic and Biofilm States of Staphylococci Isolated from Periprosthetic Joint Infection. | Antimicrob Agents Chemother | The activities of rifampin, rifabutin, Rifapentine, and rifaximin were tested against 200 periprosthetic joint infection (PJI)-associated staphylococci. Seven rifampin-resistant isolates had MICs of ≥4 μg/ml. Three isolates had rifampin MICs of 0.25 to 1 μg/ml and harbored an Asp471Gly RpoB variant, suggesting that the CLSI rifampin-susceptible staphylococcal breakpoint of ≤1 μg/ml may be too high. The remaining isolates had rifampin MICs of ≤0.016 μg/ml, and the rifampin, rifabutin, Rifapentine, and rifaximin minimum biofilm bactericidal concentrations (MBBC) for ≥50% of isolates were 8, 1, 2, and 4 μg/ml (for ) and 2, 0.06, 0.25, and 0.5 μg/ml (for ), respectively, for rifampin-susceptible isolates. Nonrifampin rifamycins have promising staphylococcal activity, including antibiofilm activity. |
| 2019 | Prevention of Opportunistic Infections in Women With HIV Infection. | Clin Obstet Gynecol | Opportunistic infections are those that are either more frequent or more severe as a result of the patient's immunosuppressed condition. Opportunistic infections are, of course, the distinguishing feature of HIV infection, and they can be the cause of serious morbidity and even mortality. Some opportunistic infections can be prevented by vaccination, for example, pneumococcal infection, meningococcal infection, influenza, hepatitis A and B, and varicella. Other major opportunistic infections require prophylactic antibiotics or antiviral medications. In obstetric patients, pneumocystis infections and toxoplasmosis are most effectively prevented by the administration of trimethoprim-sulfamethoxazole. The most effective agents for prevention of reactivation of tuberculosis are isoniazid, rifampin, and Rifapentine. Fluconazole is of value in preventing cryptococcal infection and candidiasis. Acyclovir, valacyclovir, and famiclovir are effective in preventing recurrent outbreaks of herpes simplex virus. Ultimately; however, the best way to prevent opportunistic infections is to treat the patient with highly active antiretroviral agents and restore her immune competence. |
| 2019 | Latent tuberculosis treatment completion rates from prescription drug administrative data. | Can J Public Health | In the province of Manitoba, Canada, given that latent tuberculosis infection (LTBI) treatment is provided at no cost to the patient, treatment completion rates should be optimal. The objective of this study was to estimate LTBI treatment completion using prescription drug administrative data and identify patient characteristics associated with completion.Prescription drug data (1999-2014) were used to identify individuals dispensed isoniazid (INH) or rifampin (RIF) monotherapy. Treatment completion was defined as being dispensed INH for ≥ 180 days (INH180) or ≥ 270 days (INH270) or RIF for ≥ 120 days (RIF120). Logistic regression models tested socio-demographic and comorbidity characteristics associated with treatment completion.The study cohort comprised 4985 (90.4%) persons dispensed INH and 529 (9.6%) RIF. Overall treatment completion was 60.2% and improved from 43.1% in 1999-2003 to 67.3% in 2009-2014. INH180 showed the highest completion (63.8%) versus INH270 (40.4%) and RIF120 (27.0%). INH180 completion was higher among those aged 0-18 years (68.5%) compared with those aged 19+ (61.0%). Sex, geography, First Nations status, income quintile, and comorbidities were not associated with completion.Benchmark 80% treatment completion rates were not achieved in Manitoba. Factors associated with non-completion were older age, INH270, and RIF120. Access to shorter LTBI treatments, such as Rifapentine/INH, may improve treatment completion. |
| 2019 | Isoniazid Concentration and Genotype Predict Risk of Systemic Drug Reactions during 3HP for LTBI. | J Clin Med | Weekly Rifapentine and isoniazid therapy (known as 3HP) for latent tuberculosis infection (LTBI) is increasingly used, but systemic drug reactions (SDR) remain a major concern. Methods: We prospectively recruited two LTBI cohorts who received the 3HP regimen. In the single-nucleotide polymorphism (SNP) cohort, we collected clinical information of SDRs and examined the , , and SNPs. In the pharmacokinetic (PK) cohort, we measured plasma drug and metabolite levels at 6 and 24 h after 3HP administration. The generalised estimating equation model was used to identify the factors associated with SDRs. Candidate SNPs predicting SDRs were validated in the PK cohort. A total of 177 participants were recruited into the SNP cohort and 129 into the PK cohort, with 14 (8%) and 13 (10%) in these two cohorts developing SDRs, respectively. In the SNP cohort, rs1041983 (TT vs. CC+CT, odds ratio [OR] [95% CI]: 7.00 [2.03-24.1]) and rs2070673 (AA vs. TT+TA, OR [95% CI]: 3.50 [1.02-12.0]) were associated with SDR development. In the PK cohort, isoniazid level 24 h after 3HP administration (OR [95% CI]: 1.61 [1.15-2.25]) was associated with SDRs. Additionally, the association between the SNP and SDRs was validated in the PK cohort (rs1041983 TT vs. CC+CT, OR [95% CI]: 4.43 [1.30-15.1]). Conclusions: Isoniazid played a role in the development of 3HP-related SDRs. This could provide insight for further design of a more optimal regimen for latent TB infection. |
| Completion Rates, Adverse Effects, and Costs of a 3-Month and 9-Month Treatment Regimen for Latent Tuberculosis Infection in California Inmates, 2011-2014. | Public Health Rep | In California, about 80% of tuberculosis disease is caused by untreated latent tuberculosis infection (LTBI), and the rate of LTBI is higher among incarcerated persons (16%) than among nonincarcerated persons (6%). We compared 2 regimens to treat LTBI in an adult prison population in California: 9 months of twice-weekly isoniazid (9H; previous standard of care) and 12 once-weekly doses of isoniazid and Rifapentine (3HP; introduced in 2011).We evaluated the rates of completion and discontinuation caused by hepatotoxicity among randomly selected patients with LTBI prescribed the 9H regimen in 2011 and among patients with LTBI prescribed the 3HP regimen who entered California prisons during September 2013-March 2014. We compared the cost per fully treated patient for the 2 regimens.Of 92 patients treated with the 9H regimen, the treatment completion rate was 42% and discontinuation due to hepatotoxicity was 14%. Of 122 patients who accepted the 3HP regimen, the completion rate was 90% and discontinuation due to hepatotoxicity was 2%. The cost per fully treated patient for the 9H regimen was $981 and for 3HP was $652.In an incarcerated population, the 3HP regimen had a higher completion rate, lower hepatotoxicity, and lower cost per fully treated patient than the 9H regimen. If coupled with a high treatment initiation rate, the high rate of LTBI treatment completion with 3HP may contribute to reducing tuberculosis morbidity in California. |
| 2019 | Shortening Buruli Ulcer Treatment with Combination Therapy Targeting the Respiratory Chain and Exploiting Mycobacterium ulcerans Gene Decay. | Antimicrob Agents Chemother | Buruli ulcer is treatable with antibiotics. An 8-week course of rifampin (RIF) and either streptomycin (STR) or clarithromycin (CLR) cures over 90% of patients. However, STR requires injections and may be toxic, and CLR shares an adverse drug-drug interaction with RIF and may be poorly tolerated. Studies in a mouse footpad infection model showed that increasing the dose of RIF or using the long-acting rifamycin Rifapentine (RPT), in combination with clofazimine (CFZ), a relatively well-tolerated antibiotic, can shorten treatment to 4 weeks. CFZ is reduced by a component of the electron transport chain (ETC) to produce reactive oxygen species toxic to bacteria. Synergistic activity of CFZ with other ETC-targeting drugs, the ATP synthase inhibitor bedaquiline (BDQ) and the : oxidase inhibitor Q203 (now named telacebec), was recently described against Recognizing that mutants lacking the alternative oxidase are hypersusceptible to Q203 and that is a natural oxidase-deficient mutant, we tested the susceptibility of to Q203 and evaluated the treatment-shortening potential of novel 3- and 4-drug regimens combining RPT, CFZ, Q203, and/or BDQ in a mouse footpad model. The MIC of Q203 was extremely low (0.000075 to 0.00015 μg/ml). Footpad swelling decreased more rapidly in mice treated with Q203-containing regimens than in mice treated with RIF and STR (RIF+STR) and RPT and CFZ (RPT+CFZ). Nearly all footpads were culture negative after only 2 weeks of treatment with regimens containing RPT, CFZ, and Q203. No relapse was detected after only 2 weeks of treatment in mice treated with any of the Q203-containing regimens. In contrast, 15% of mice receiving RIF+STR for 4 weeks relapsed. We conclude that it may be possible to cure patients with Buruli ulcer in 14 days or less using Q203-containing regimens rather than currently recommended 56-day regimens. |
| 2018 | Addressing tuberculosis among Inuit in Canada. | Can Commun Dis Rep | The average annual rate of tuberculosis (TB) among Inuit in Canada is now more than 290 times higher than Canadian born non-Indigenous people. How did this happen? Using the Territory of Nunavut as a case example, the roots of this situation can largely be traced back to social determinants of health and challenges in access to health care. Half (52%) of all Nunavut residents live in social housing, often under overcrowded conditions. Many experience food insecurity, with food prices in Nunavut that are twice those in southern Canada. Sixty percent of Nunavut residents smoke. Challenges in health care delivery include the small isolated communities, with few roads and difficult weather conditions during the long winters, which impede the ability to reach or provide healthcare, staff that arrive with little TB experience or cultural knowledge, multiple competing health care demands, limited resources and high staff turnover. The housing shortage is not only a social determinant of health, it also impacts the ability to hire new staff or mount an effective response in the event of an outbreak. Yet despite these challenges, progress has been made. Tuberculosis care in Nunavut includes active case finding, contact tracing for all cases of infectious TB, and screening of school age children. Rapid testing with the GeneXpert platform has resulted in a quicker diagnosis of active TB, earlier treatment (preventing progression of disease) and less transmission. Progressively, there has been a switch from plain film to digital x-rays reducing x-ray turnaround time from as long as two to three weeks to one or two days. Standard treatment protocols include quadruple therapy until sensitivities are known, the use of home isolation for active cases and directly observed treatment (DOT) for both latent and active TB. Special access to Rifapentine (Priftin), and its use in combination therapy (3HP), requires only once weekly treatments that can be completed in 12 visits instead of 78 visits for isoniazid (INH) or 120 visits for rifampin, which increases adherence and greatly reduces the health care resources needed to treat TB. In October 2017, the Honourable Jane Philpott, then Minister of Health and now Minister of Indigenous Services, and Natan Obed, president of Inuit Tapiriit Kanatami (ITK) announced the establishment of a Task Force to develop an Inuit TB Elimination Action Framework, accompanied by regional action plans. It is hoped that the task force, and current efforts in Nunavut, will lead to the long term changes needed to ultimately eliminate TB among Inuit in Canada. |
| 2019 | Outlook for tuberculosis elimination in California: An individual-based stochastic model. | PLoS One | As part of the End TB Strategy, the World Health Organization calls for low-tuberculosis (TB) incidence settings to achieve pre-elimination (<10 cases per million) and elimination (<1 case per million) by 2035 and 2050, respectively. These targets require testing and treatment for latent tuberculosis infection (LTBI).To estimate the ability and costs of testing and treatment for LTBI to reach pre-elimination and elimination targets in California.We created an individual-based epidemic model of TB, calibrated to historical cases. We evaluated the effects of increased testing (QuantiFERON-TB Gold) and treatment (three months of isoniazid and Rifapentine). We analyzed four test and treat targeting strategies: (1) individuals with medical risk factors (MRF), (2) non-USB, (3) both non-USB and MRF, and (4) all Californians. For each strategy, we estimated the effects of increasing test and treat by a factor of 2, 4, or 10 from the base case. We estimated the number of TB cases occurring and prevented, and net and incremental costs from 2017 to 2065 in 2015 U.S. dollars. Efficacy, costs, adverse events, and treatment dropout were estimated from published data. We estimated the cost per case averted and per quality-adjusted life year (QALY) gained.In the base case, 106,000 TB cases are predicted to 2065. Pre-elimination was achieved by 2065 in three scenarios: a 10-fold increase in the non-USB and persons with MRF (by 2052), and 4- or 10-fold increase in all Californians (by 2058 and 2035, respectively). TB elimination was not achieved by any intervention scenario. The most aggressive strategy, 10-fold in all Californians, achieved a case rate of 8 (95% UI 4-16) per million by 2050. Of scenarios that reached pre-elimination, the incremental net cost was $20 billion (non-USB and MRF) to $48 billion. These had an incremental cost per QALY of $657,000 to $3.1 million. A more efficient but somewhat less effective single-lifetime test strategy reached as low as $80,000 per QALY.Substantial gains can be made in TB control in coming years by scaling-up current testing and treatment in non-USB and those with medical risks. |
| 2019 | Treatment-Shortening Effect of a Novel Regimen Combining Clofazimine and High-Dose Rifapentine in Pathologically Distinct Mouse Models of Tuberculosis. | Antimicrob Agents Chemother | Clofazimine and high-dose Rifapentine have each separately been associated with treatment-shortening activity when incorporated into tuberculosis (TB) treatment regimens. We hypothesized that both modifications, i.e., the addition of clofazimine and the replacement of rifampin with high-dose Rifapentine, in the first-line regimen for drug-susceptible TB would significantly shorten the duration of treatment necessary for cure. We tested this hypothesis in a well-established BALB/c mouse model of TB chemotherapy and also in a C3HeB/FeJ mouse model in which mice can develop caseous necrotic lesions, an environment where Rifapentine and clofazimine may individually be less effective. In both mouse models, replacing rifampin with high-dose Rifapentine and adding clofazimine in the first-line regimen resulted in greater bactericidal and sterilizing activity than either modification alone, suggesting that a Rifapentine- and clofazimine-containing regimen may have the potential to significantly shorten the treatment duration for drug-susceptible TB. These data provide preclinical evidence supporting the evaluation of regimens combining high-dose Rifapentine and clofazimine in clinical trials. |
| 2019 | Tuberculosis. | Lancet | Tuberculosis remains the leading cause of death from an infectious disease among adults worldwide, with more than 10 million people becoming newly sick from tuberculosis each year. Advances in diagnosis, including the use of rapid molecular testing and whole-genome sequencing in both sputum and non-sputum samples, could change this situation. Although little has changed in the treatment of drug-susceptible tuberculosis, data on increased efficacy with new and repurposed drugs have led WHO to recommend all-oral therapy for drug-resistant tuberculosis for the first time ever in 2018. Studies have shown that shorter latent tuberculosis prevention regimens containing rifampicin or Rifapentine are as effective as longer, isoniazid-based regimens, and there is a promising vaccine candidate to prevent the progression of infection to the disease. But new tools alone are not sufficient. Advances must be made in providing high-quality, people-centred care for tuberculosis. Renewed political will, coupled with improved access to quality care, could relegate the morbidity, mortality, and stigma long associated with tuberculosis, to the past. |
| 2019 | Facile in situ generation of bismuth tungstate nanosheet-multiwalled carbon nanotube composite as unconventional affinity material for quartz crystal microbalance detection of antibiotics. | J Hazard Mater | Overuse and thus a constant presence of antibiotics leads to various environmental hazards and health risks. Thus, accurate sensors are required to determine their presence. In this work, we present a mass-sensitive sensor for the detection of rifampicin. We chose this molecule as it is an important antibiotic for tuberculosis, one of the leading causes of deaths worldwide. Herein, we have prepared a carbon nanotube reinforced with bismuth tungstate nanocomposite material in a well-defined nanosheet morphology using a facile in situ synthesis mechanism. Morphological characterization revealed the presence of bismuth tungstate in the form of square nanosheets embedded in the intricate network of carbon nanotubes, resulting in higher surface roughness of the nanocomposite. The synergy of the composite, so formed, manifested a high affinity for rifampicin as compared to the individual components of the composite. The developed sensor possessed a high sensitivity toward rifampicin with a detection limit of 0.16 μM and excellent specificity, as compared to rifabutin and Rifapentine. Furthermore, the sensor yielded statistically good recoveries for the monitoring of rifampicin in human urine samples. This work opens up a new horizon for the exploration of unconventional nanomaterials bearing different morphologies for the detection of pharmaceuticals. |
| 2019 | One Month of Rifapentine plus Isoniazid to Prevent HIV-Related Tuberculosis. | N Engl J Med | Tuberculosis is the leading killer of patients with human immunodeficiency virus (HIV) infection. Preventive therapy is effective, but current regimens are limited by poor implementation and low completion rates.We conducted a randomized, open-label, phase 3 noninferiority trial comparing the efficacy and safety of a 1-month regimen of daily Rifapentine plus isoniazid (1-month group) with 9 months of isoniazid alone (9-month group) in HIV-infected patients who were living in areas of high tuberculosis prevalence or who had evidence of latent tuberculosis infection. The primary end point was the first diagnosis of tuberculosis or death from tuberculosis or an unknown cause. Noninferiority would be shown if the upper limit of the 95% confidence interval for the between-group difference in the number of events per 100 person-years was less than 1.25.A total of 3000 patients were enrolled and followed for a median of 3.3 years. Of these patients, 54% were women; the median CD4+ count was 470 cells per cubic millimeter, and half the patients were receiving antiretroviral therapy. The primary end point was reported in 32 of 1488 patients (2%) in the 1-month group and in 33 of 1498 (2%) in the 9-month group, for an incidence rate of 0.65 per 100 person-years and 0.67 per 100 person-years, respectively (rate difference in the 1-month group, -0.02 per 100 person-years; upper limit of the 95% confidence interval, 0.30). Serious adverse events occurred in 6% of the patients in the 1-month group and in 7% of those in the 9-month group (P = 0.07). The percentage of treatment completion was significantly higher in the 1-month group than in the 9-month group (97% vs. 90%, P<0.001).A 1-month regimen of Rifapentine plus isoniazid was noninferior to 9 months of isoniazid alone for preventing tuberculosis in HIV-infected patients. The percentage of patients who completed treatment was significantly higher in the 1-month group. (Funded by the National Institute of Allergy and Infectious Diseases; BRIEF TB/A5279 ClinicalTrials.gov number, NCT01404312.). |
| 2019 | Treatment of latent Mycobacterium tuberculosis infection with 12 once weekly directly-observed doses of isoniazid and rifapentine among persons experiencing homelessness. | PLoS One | To investigate treatment outcomes and associated characteristics of persons experiencing homelessness who received 12-weekly doses of directly observed isoniazid and Rifapentine (3HP/DOT) treatment for latent TB infection (LTBI).Among homeless persons treated with 3HP/DOT during July 2011 -June 2015 in 11 U.S. TB programs, we conducted descriptive analyses of observational data, and identified associations between sociodemographic factors and treatment outcomes. Qualitative interviews were conducted to understand programmatic experiences.Of 393 persons experiencing homelessness (median age: 50 years; range: 13-74 years), 301 (76.6%) completed treatment, 55 (14.0%) were lost to follow-up, 18 (4.6%) stopped because of an adverse event (AE), and 19 (4.8%) stopped after relocations or refusing treatment. Eighty-one (20.6%) had at least one AE. Persons aged ≥65 were more likely to discontinue treatment than persons aged 31-44 years. Programs reported difficulty in following up with persons experiencing homelessness because of relocations, mistrust, and alcohol or drug use.This study demonstrates the feasibility of administering the 3HP/DOT LTBI regimen to persons experiencing homelessness, a high-risk population. |
| 2019 | Recent Innovations in Diagnosis and Treatment of Pediatric Tuberculosis. | Curr Infect Dis Rep | Tuberculosis is leading cause of global morbidity and mortality and a significant proportion of the burden of disease occurs in children. In the past 5 years, a number of innovations have improved the diagnosis and treatment for children with both latent tuberculosis infection and active disease.This review discusses three key areas of innovation. First, we assess utilization and performance of interferon-gamma release assays (IGRAs) in different clinical and epidemiologic scenarios. Recent literature has demonstrated good performance of IGRAs for diagnosis of latent tuberculosis infection, particularly in low-incidence settings such as TB control programs in North America. For high-incidence populations, or when testing is done for possible active TB disease, IGRA performance has some important limitations, but IGRA sensitivity when measured against culture proven disease may be better than earlier studies suggested. The second area of innovation is in increased uptake of nucleic acid amplification (NAA) tests and broader application in non-sputum samples for both pediatric pulmonary and extrapulmonary tuberculosis. Finally, recent studies have provided solid evidence in support of shorter treatment courses for pediatric latent tuberculosis infection, such as 12 weeks of weekly isoniazid and Rifapentine or 4 months daily rifampin, that improve compliance and may reduce resources required for TB control. Many recent innovations in pediatric tuberculosis relate to an improved understanding of how to optimally use existing tests and treatments. Until diagnostic tests and interventions such as vaccination are developed that can dramatically alter the paradigm of pediatric TB management and control, it is important for stakeholders to have a nuanced understanding of tools currently available. |
| 2019 | Activity of a Long-Acting Injectable Bedaquiline Formulation in a Paucibacillary Mouse Model of Latent Tuberculosis Infection. | Antimicrob Agents Chemother | The potent antituberculosis activity and long half-life of bedaquiline make it an attractive candidate for use in long-acting/extended-release formulations for the treatment of latent tuberculosis infection (LTBI). Our objective was to evaluate a long-acting injectable (LAI) bedaquiline formulation in a validated paucibacillary mouse model of LTBI. Following immunization with rBCG30, BALB/c mice were challenged by aerosol infection with H37Rv. Treatment began 13 weeks after challenge infection with one of the following regimens: an untreated negative-control regimen; positive-control regimens of daily rifampin (10 mg/kg of body weight), once-weekly Rifapentine (15 mg/kg) and isoniazid (50 mg/kg), or daily bedaquiline (25 mg/kg); test regimens of one, two, or three monthly doses of LAI bedaquiline at 160 mg/dose (B); and test regimens of daily bedaquiline at 2.67 mg/kg (B), 5.33 mg/kg (B), or 8 mg/kg (B) to deliver the same total amount of bedaquiline as one, two, or three doses of B, respectively. All drugs were administered orally, except for B (intramuscular injection). The primary outcome was the decline in lung CFU counts during 12 weeks of treatment. The negative- and positive-control regimens performed as expected. One, two, and three doses of B resulted in decreases of 2.9, 3.2, and 3.5 log CFU/lung, respectively, by week 12. Daily oral dosing with B, B, and B decreased lung CFU counts by 1.6, 2.8, and 4.1 log, respectively. One dose of B exhibited activity for at least 12 weeks. The sustained activity of B indicates that it shows promise as a short-course LTBI treatment requiring few patient encounters to ensure treatment completion. |
| 2019 | Development of dual delivery antituberculotic system containing rifapentine microspheres and adipose stem cells seeded in hydroxyapatite/tricalcium phosphate. | Drug Des Devel Ther | Low drug concentration in the tuberculosis (TB) lesion and bone defects or nonunion after debridement are two major problems that occur in the course of treating osteo-articular TB. Thus, the combination of drug-delivery system and bone tissue repair appears to be the most promising option for osteoarticular TB treatment.Herein, we report a novel anti-TB dual delivery system based on Rifapentine polylactic acid microspheres (RPMs) to treat infections, with the addition of adipose-derived mesenchymal stem cells (ASCs) seeded in hydroxyapatite/tricalcium phosphate (HA/TCP) to promote bone formation. Cell proliferation, osteogenesis, and apoptosis were performed to investigate the effects of Rifapentine on ASCs. The RPMs were synthesized by emulsion-solvent evaporation method, and then the monolayer composite (ASC + RPM) and three-dimensional (3D) composite scaffold (ASC + RPM + HA/TCP) were constructed, respectively. The alkaline phosphatase (ALP) activity and real-time PCR were used for determining the osteogenic differentiation. The concentrations of Rifapentine resulting from the composites were detected.The results showed that Rifapentine has no influence on ASCs proliferation and osteogenesis when the drug concentration was below 20 µg/mL, which was significantly higher than minimal inhibitory concentration. The drug loading and encapsulation efficiency of RPMs were 40.56%±2.63% and 70.24%±2.18%, respectively. The proliferation of the cells in monolayer was higher than that in 3D composite, and the addition of RPMs slightly increased the proliferation. The ALP activity and gene expression of osteocalcin and osteopontin were higher in the 3D composite than those in the monolayer. Good biocompatibility was observed by microscopic image and H&E stain. The release tests revealed that the 3D composite exhibited sustained release profiles of Rifapentine for 76 days. The dual delivery systems in 3D composite could moderate the burst release and extend the length of release time when compared to single delivery in monolayers.In conclusion, such dual delivery antituberculotic scaffold represents a potential new strategy for TB infections and bone defects. |
| 2019 | A Population Pharmacokinetic Analysis Shows that Arylacetamide Deacetylase (AADAC) Gene Polymorphism and HIV Infection Affect the Exposure of Rifapentine. | Antimicrob Agents Chemother | Rifapentine is a rifamycin used to treat tuberculosis. As is the case for rifampin, plasma exposures of Rifapentine are associated with the treatment response. While concomitant food intake and HIV infection explain part of the pharmacokinetic variability associated with Rifapentine, few studies have evaluated the contribution of genetic polymorphisms. We evaluated the effects of functionally significant polymorphisms of the genes encoding OATP1B1, the pregnane X receptor (PXR), constitutive androstane (CAR), and arylacetamide deacetylase (AADAC) on Rifapentine exposure. Two studies evaluating novel regimens among southern African patients with drug-susceptible pulmonary tuberculosis were included in this analysis. In the RIFAQUIN study, Rifapentine was administered in the continuation phase of antituberculosis treatment in 1,200-mg-once-weekly or 900-mg-twice-weekly doses. In the Daily RPE study, 450 or 600 mg was given daily during the intensive phase of treatment. Nonlinear mixed-effects modeling was used to describe the pharmacokinetics of Rifapentine and to identify significant covariates. A total of 1,144 drug concentration measurements from 326 patients were included in the analysis. Pharmacogenetic information was available for 162 patients. A one-compartment model with first-order elimination and transit compartment absorption described the data well. In a typical patient (body weight, 56 kg; fat-free mass, 45 kg), the values of clearance and volume of distribution were 1.33 liters/h and 25 liters, respectively. Patients carrying the AA variant (65.4%) of rs1803155 were found to have a 10.4% lower clearance. HIV-infected patients had a 21.9% lower bioavailability. Once-weekly doses of 1,200 mg were associated with a reduced clearance (13.2%) compared to that achieved with more frequently administered doses. Bioavailability was 23.3% lower among patients participating in the Daily RPE study than in those participating in the RIFAQUIN study. This is the first study to report the effect of rs1803155AA on Rifapentine clearance. The observed increase in exposure is modest and unlikely to be of clinical relevance. The difference in bioavailability between the two studies is probably related to the differences in food intake concomitant with the dose. HIV-coinfected patients had lower Rifapentine exposures. |
| 2018 | Three-month weekly rifapentine plus isoniazid for tuberculosis preventive treatment: a systematic review. | Int J Tuberc Lung Dis | Uptake of preventive treatment for tuberculosis (TB) remains poor. A 3-month regimen of Rifapentine (RPT) plus isoniazid (INH) (3HP) could facilitate its scale-up. We conducted a systematic review to assess the effects of 3HP compared with daily 6- or 9-month INH monotherapy.We searched the following databases to identify randomised controlled trials: PubMed, Embase, the Web of Science, Cochrane Central Register of Controlled Trials, three ongoing trial registers and conference abstracts up to 24 January 2017. Where possible, we pooled data using a random-effects model.Four studies were included. Of those, we included two studies that compared 3HP with daily 6- or 9-month INH (6/9H) among adults with human immunodeficiency virus (HIV) co-infection, one among HIV-negative adults and one among predominantly HIV-negative children and adolescents. Risk of active TB was not significantly different between 3HP and 6/9H (risk ratio [RR] 0.73, 95%CI 0.23-2.29, in adults with HIV; RR 0.44, 95%CI 0.18-1.07, in adults without HIV; RR 0.13, 95%CI 0.01-2.54, in children and adolescents). Risk of hepatotoxicity was significantly lower in the 3HP group among adults with HIV (RR 0.26, 95%CI 0.12-0.55) and those without HIV (RR 0.16, 95%CI 0.10-0.27). 3HP was also associated with a higher completion rate in all subgroups.HP was shown to have a preventive effect similar to that of INH monotherapy, with fewer adverse events and higher completion rates. 3HP can contribute significantly to the scale-up of preventive treatment. |
| 2018 | Using Video Technology to Increase Treatment Completion for Patients With Latent Tuberculosis Infection on 3-Month Isoniazid and Rifapentine: An Implementation Study. | J Med Internet Res | Since January 2013, the New York City (NYC) Health Department Tuberculosis (TB) Program has offered persons diagnosed with latent TB infection (LTBI) the 3-month, once-weekly isoniazid and Rifapentine (3HP) treatment regimen. Patients on this treatment are monitored in-person under directly observed therapy (DOT). To address patient and provider barriers to in-person DOT, we piloted the use of a videoconferencing software app to remotely conduct synchronous DOT (video directly observed therapy; VDOT) for patients on 3HP.The objective of our study was to evaluate the implementation of VDOT for patients on 3HP and to assess whether treatment completion for these patients increased when they were monitored using VDOT compared with that using the standard in-person DOT.Between February and October 2015, patients diagnosed with LTBI at any of the four NYC Health Department TB clinics who met eligibility criteria for treatment with 3HP under VDOT (V3HP) were followed until 16 weeks after treatment initiation, with treatment completion defined as ingestion of 11 doses within 16 weeks. Treatment completion of patients on V3HP was compared with that of patients on 3HP under clinic-based, in-person DOT who were part of a prior study in 2013. Furthermore, outcomes of video sessions with V3HP patients were collected and analyzed.During the study period, 70% (50/71) of eligible patients were placed on V3HP. Treatment completion among V3HP patients was 88% (44/50) compared with 64.9% (196/302) among 3HP patients on clinic DOT (P<.001). A total of 360 video sessions were conducted for V3HP patients with a median of 8 (range: 1-11) sessions per patient and a median time of 4 (range: 1-59) minutes per session. Adherence issues (eg, >15 minutes late) during video sessions occurred 104 times. No major side effects were reported by V3HP patients.The NYC TB program observed higher treatment completion with VDOT than that previously seen with clinic DOT among patients on 3HP. Expanding the use of VDOT may improve treatment completion and corresponding outcomes for patients with LTBI. |
| 2019 | High-Dose Rifamycins Enable Shorter Oral Treatment in a Murine Model of Mycobacterium ulcerans Disease. | Antimicrob Agents Chemother | Buruli ulcer (BU), caused by , is a neglected tropical skin and soft tissue infection that is associated with disability and social stigma. The mainstay of BU treatment is an 8-week course of rifampin (RIF) at 10 mg/kg of body weight and 150 mg/kg streptomycin (STR). Recently, the injectable STR has been shown to be replaceable with oral clarithromycin (CLR) for smaller lesions for the last 4 weeks of treatment. A shorter, all-oral, highly efficient regimen for BU is needed, as the long treatment duration and indirect costs currently burden patients and health systems. Increasing the dose of RIF or replacing it with the more potent rifamycin drug Rifapentine (RPT) could provide such a regimen. Here, we performed a dose-ranging experiment of RIF and RPT in combination with CLR over 4 weeks of treatment in a mouse model of disease. A clear dose-dependent effect of RIF on both clinical and microbiological outcomes was found, with no ceiling effect observed with tested doses up to 40 mg/kg. RPT-containing regimens were more effective on All RPT-containing regimens achieved culture negativity after only 4 weeks, while only the regimen with the highest RIF dose (40 mg/kg) did so. We conclude that there is dose-dependent efficacy of both RIF and RPT and that a ceiling effect is not reached with the current standard regimen used in the clinic. A regimen based on higher rifamycin doses than are currently being evaluated against tuberculosis in clinical trials could shorten and improve therapy of Buruli ulcer. |
| 2018 | Treatment completion for latent tuberculosis infection in Norway: a prospective cohort study. | BMC Infect Dis | Successful treatment of latent tuberculosis infection (LTBI) is essential to reduce tuberculosis (TB) incidence rates in low-burden countries. This study measures treatment completion and determinants of non-completion of LTBI treatment in Norway in 2016.This prospective cohort study included all individuals notified with LTBI treatment to the Norwegian Surveillance System for Infectious Diseases (MSIS) in 2016. We obtained data from MSIS and from a standardized form that was sent to health care providers at the time of patient notification to MSIS. We determined completion rates. Pearson's chi squared test was used to study associations between pairs of categorical variables and separate crude and multivariable logistic regression models were used to identify factors associated with treatment completion and adverse drug effects.We obtained information on treatment completion from 719 of the 726 individuals notified for LTBI treatment in 2016. Overall, 91% completed treatment. Treatment completion was highest in the foreign-born group [foreign-born, n = 562 (92%) vs Norwegian-born, n = 115 (85%), p = 0.007]. Treatment completion did not differ significantly between prescribed regimens (p = 0.124). Adverse events were the most common reason for incomplete treatment. We found no significant differences in adverse events when comparing weekly Rifapentine (3RPH) with three months daily isoniazid and rifampicin (3RH). However, there were significantly fewer adverse events with 3RPH compared to other regimens (p = 0.037). Age over 35 years was significantly associated with adverse events irrespective of regimen (p = 0.024), whereas immunosuppression was not significantly associated with adverse events after adjusting for other variables (p = 0.306). Treatment under direct observation had a significant effect on treatment completion for foreign-born (multivariate Wald p-value = 0.017), but not for Norwegian-born (multivariate Wald p-value = 0.408) individuals.We report a very high treatment completion rate, especially among individuals from countries with high TB incidence. The follow-up from tuberculosis-coordinators and the frequent use of directly observed treatment probably contributes to this. Few severe adverse events were reported, even with increased age and in individuals that are more susceptible. While these results are promising, issues of cost-effectiveness and targeting treatment to individuals at highest risk of TB are important components of public health impact. |
| 2019 | Evolution of Rifampin Resistance in Escherichia coli and Mycobacterium smegmatis Due to Substandard Drugs. | Antimicrob Agents Chemother | Poor-quality medicines undermine the treatment of infectious diseases, such as tuberculosis, which require months of treatment with rifampin and other drugs. Rifampin resistance is a critical concern for tuberculosis treatment. While subtherapeutic doses of medicine are known to select for antibiotic resistance, the effect of drug degradation products on the evolution of resistance is unknown. Here, we demonstrate that substandard drugs that contain degraded active pharmaceutical ingredients select for gene alterations that confer resistance to standard drugs. We generated drug-resistant and strains by serially culturing bacteria in the presence of the rifampin degradation product rifampin quinone. We conducted Sanger sequencing to identify mutations in rifampin-resistant populations. Strains resistant to rifampin quinone developed cross-resistance to the standard drug rifampin, with some populations showing no growth inhibition at maximum concentrations of rifampin. Sequencing of the rifampin quinone-treated strains indicated that they acquired mutations in the DNA-dependent RNA polymerase B subunit. These mutations were localized in the rifampin resistance-determining region (RRDR), consistent with other reports of rifampin-resistant and mycobacteria. Rifampin quinone-treated mycobacteria also had cross-resistance to other rifamycin class drugs, including rifabutin and Rifapentine. Our results strongly suggest that substandard drugs not only hinder individual patient outcomes but also restrict future treatment options by actively contributing to the development of resistance to standard medicines. |
| 2018 | A High-Throughput Screening Approach To Repurpose FDA-Approved Drugs for Bactericidal Applications against Staphylococcus aureus Small-Colony Variants. | mSphere | Drug repurposing offers an expedited and economical route to develop new clinical therapeutics in comparison to traditional drug development. Growth-based high-throughput screening is concomitant with drug repurposing and enables rapid identification of new therapeutic uses for investigated drugs; however, this traditional method is not compatible with microorganisms with abnormal growth patterns such as small-colony variants (SCV). SCV subpopulations are auxotrophic for key compounds in biosynthetic pathways, which result in low growth rate. SCV formation is also associated with reduced antibiotic susceptibility, and the SCV's ability to revert to the normal cell growth state is thought to contribute to recurrence of infections. Thus, there is a critical need to identify antimicrobial agents that are potent against SCV in order to effectively treat chronic infections. Accordingly, here we describe adapting an adenylate kinase (AK)-based cell death reporter assay to identify members of a Food and Drug Administration (FDA)-approved drug library that display bactericidal activity against SCV. Four library members, daunorubicin, ketoconazole, Rifapentine, and sitafloxacin, exhibited potent SCV bactericidal activity against a stable SCV. Further investigation showed that sitafloxacin was potent against methicillin-susceptible and -resistant , as well as within an established biofilm. Taken together, these results demonstrate the ability to use the AK assay to screen small-molecule libraries for SCV bactericidal agents and highlight the therapeutic potential of sitafloxacin to be repurposed to treat chronic infections associated with SCV and/or biofilm growth states. Conventional antibiotics fail to successfully treat chronic osteomyelitis, endocarditis, and device-related and airway infections. These recurring infections are associated with the emergence of SCV, which are recalcitrant to conventional antibiotics. Studies have investigated antibiotic therapies to treat SCV-related infections but have had little success, emphasizing the need to identify novel antimicrobial drugs. However, drug discovery is a costly and time-consuming process. An alternative strategy is drug repurposing, which could identify FDA-approved and well-characterized drugs that could have off-label utility in treating SCV. In this study, we adapted a high-throughput AK-based assay to identify 4 FDA-approved drugs, daunorubicin, ketoconazole, Rifapentine, and sitafloxacin, which display antimicrobial activity against SCV, suggesting an avenue for drug repurposing in order to effectively treat SCV-related infections. Additionally, this screening paradigm can easily be adapted for other drug/chemical libraries to identify compounds bactericidal against SCV. |
| 2018 | Short-course regimens of rifapentine plus isoniazid to treat latent tuberculosis infection in older Chinese patients: a randomised controlled study. | Eur Respir J | Latent tuberculosis infection (LTBI) management is now a critical component of the World Health Organization's End TB Strategy.In this randomised controlled trial (Chinese Clinical Trial Registry identifier ChiCTR-IOR-15007202), two short-course regimens with Rifapentine plus isoniazid (a 3-month once-weekly regimen and a 2-month twice-weekly regimen) were initially designed to be evaluated for rural residents aged 50-69 years with LTBI in China.Due to the increasingly rapid growth and unexpected high frequency of adverse effects, the treatments were terminated early (after 8 weeks for the once-weekly regimen and after 6 weeks for the twice-weekly regimen). In the modified intention-to-treat analysis on the completed doses, the cumulative rate of active disease during 2 years of follow-up was 1.21% (14 out of 1155) in the untreated controls, 0.78% (10 out of 1284) in the group that received the 8-week once-weekly regimen and 0.46% (six out of 1299) in the group that received the 6-week twice-weekly regimen. The risk of active disease was decreased, with an adjusted hazard ratio of 0.63 (95% CI 0.27-1.43) and 0.41 (95% CI 0.15-1.09) for the treatments, respectively. No significant difference was found in the occurrence of hepatotoxicity (1.02% (13 out of 1279) 1.17% (15 out of 1279); p=0.704).The short regimens tested must be used with caution among the elderly because of the high rates of adverse effects. Further work is necessary to test the ultrashort regimens in younger people with LTBI. |
| 2018 | Improved treatment completion with shorter treatment regimens for latent tuberculous infection. | Int J Tuberc Lung Dis | Four New York City (NYC) Health Department tuberculosis (TB) clinics.To assess the effectiveness of preferentially offering two shorter treatment regimens-4 months of daily rifampin (4R) and 3 months of once-weekly isoniazid and Rifapentine (3HP)-as an alternative to 9 months of daily isoniazid (9H) for the treatment of latent tuberculous infection (LTBI).Retrospective analysis of patients treated for LTBI from January to June 2015. Poisson regression with robust standard error was used to examine the factors associated with treatment completion.Of the patients on 9H, 49% (27/55) completed treatment compared with 70% (187/269) of patients on 4R ( 0.003) and 79% (99/125) of patients on 3HP ( < 0.001). When adjusting for age, sex, and TB risk factors, patients on 4R (adjusted risk ratio [aRR] 1.39, 95%CI 1.07-1.81) and 3HP (aRR 1.67, 95%CI 1.27-2.19) were more likely to complete treatment than patients on 9H. Treatment was discontinued due to side effects in 1% (3/269) of patients on 4R, 2% (2/125) of patients on 3HP, and 4% (2/55) of patients on 9H.Most patients were placed on shorter regimens for LTBI treatment, and higher treatment completion was observed. Encouraging community providers to use shorter regimens for LTBI treatment would reduce the TB disease burden in NYC. |
| 2019 | Cost-effectiveness of 3 months of weekly rifapentine and isoniazid compared with other standard treatment regimens for latent tuberculosis infection: a decision analysis study. | J Antimicrob Chemother | Latent tuberculosis infection (LTBI) is a critical driver of the global burden of active TB, and therefore LTBI treatment is key for TB elimination. Treatment regimens for LTBI include self-administered daily isoniazid for 6 (6H) or 9 (9H) months, self-administered daily rifampicin plus isoniazid for 3 months (3RH), self-administered daily rifampicin for 4 months (4R) and weekly Rifapentine plus isoniazid for 3 months self-administered (3HP-SAT) or administered by a healthcare worker as directly observed therapy (3HP-DOT). Data on the relative cost-effectiveness of these regimens are needed to assist policymakers and clinicians in selecting an LTBI regimen.To evaluate the cost-effectiveness of all regimens for treating LTBI.We developed a Markov model to investigate the cost-effectiveness of 3HP-DOT, 3HP-SAT, 4R, 3RH, 9H and 6H for LTBI treatment in a cohort of 10000 adults with LTBI. Cost-effectiveness was evaluated from a health system perspective over a 20 year time horizon.Compared with no preventive treatment, 3HP-DOT, 3HP-SAT, 4R, 3RH, 9H and 6H prevented 496, 470, 442, 418, 370 and 276 additional cases of active TB per 10000 patients, respectively. All regimens reduced costs and increased QALYs compared with no preventive treatment. 3HP was more cost-effective under DOT than under SAT at a cost of US$27948 per QALY gained.Three months of weekly Rifapentine plus isoniazid is more cost-effective than other regimens. Greater recognition of the benefits of short-course regimens can contribute to the scale-up of prevention and achieving the 'End TB' targets. |
| 2018 | Updates in the Treatment of Active and Latent Tuberculosis. | Semin Respir Crit Care Med | First-line therapy for active tuberculosis (TB) has remained unchanged for nearly 40 years. Isoniazid, rifampin, pyrazinamide, and ethambutol for the initial two-month phase followed by isoniazid and rifampin for 4 to 7 months is standard treatment for people at low risk for drug-resistant disease. Directly-observed therapy (DOT) remains the standard of care for pulmonary TB. Virtual treatment monitoring using digital technologies is becoming more common as a way to provide a more patient-centered approach to care. Attempts to shorten treatment duration have been unsuccessful based on recent clinical trials evaluating the role of fluoroquinolones. Treatment-shortening trials using higher doses of rifamycins are currently underway. Recently approved medications for TB treatment are recommended only for drug-resistant disease, but novel agents in varying stages of development are being evaluated. Rifamycin-based regimens for latent TB infection (LTBI) have been successful in preventing progression to TB disease. Once-weekly isoniazid and Rifapentine for 12 weeks by DOT was shown to be safe and effective compared with 9 months of isoniazid. The same regimen was shown to have acceptable treatment completion when given self-administered. Newer studies are investigating even shorter LTBI treatment with durations of less than 2 months. Treatment of LTBI in people likely infected with multidrug resistant TB is very limited, but one observational study found that fluoroquinolones appear to be effective. The first randomized trials for treating LTBI in contacts to MDR-TB are currently enrolling. |
| 2018 | Nanoplasmonics for Real-Time and Label-Free Monitoring of Microbial Biofilm Formation. | ACS Sens | Microbial biofilms possess intrinsic resistance against conventional antibiotics and cleaning procedures; thus, a better understanding of their complex biological structures is crucial in both medical and industrial applications. Existing laboratory methodologies have focused on macroscopic and mostly indirect characterization of mechanical and microbiological properties of biofilms adhered on a given substrate. However, the kinetics underlying the biofilm formation is not well understood, while such information is critical to understanding how drugs and chemicals influence the biofilm formation. Herein, we report the use of localized surface plasmon resonance (LSPR) for real-time, label-free monitoring of E. coli biofilm assembly on a nanoplasmonic substrate consisting of gold mushroom-like structures. Our LSPR sensor is able to capture the signatures of biofilm formation in real-time by measuring the wavelength shift in the LSPR resonance peak with high temporal resolution. We employ this sensor feature to elucidate how biofilm formation is affected by different drugs, including conventional antibiotics (kanamycin and ampicillin) as well as Rifapentine, a molecule preventing cell adhesion yet barely affecting bacterial viability and vitality. Due to its flexibility and simplicity, our LSPR based platform can be used on a wide variety of clinically relevant bacteria, thus representing a valuable tool in biofilm characterization and drug screening. |
| 2018 | Twelve-dose weekly rifapentine plus isoniazid for latent tuberculosis infection: A multicentre randomised controlled trial in Taiwan. | Tuberculosis (Edinb) | Treatment of latent tuberculosis (TB) infection (LTBI) effectively prevents its progression to active TB. However, long treatment duration and drug-related hepatotoxicity limit the effectiveness of the 9-month daily isoniazid (9H). Data on the 3-month weekly Rifapentine plus isoniazid (3 HP) in Asian populations are currently unavailable. We prospectively randomised the LTBI contacts aged ≥12 years with positive tuberculin skin test into 9H and 3 HP groups in four hospitals between January 2014 and May 2016 in Taiwan. The primary and secondary outcomes were treatment completion rate and adverse drug reactions (ADRs), respectively. Overall, 263 participants with LTBI were randomised into the 3 HP (n = 132) and 9H groups (n = 131); 14 (10.6%) and 29 (22.1%) participants in the 3 HP and 9H groups, respectively, discontinued therapy (p = 0.011). Discontinuation rates owing to ADRs were 9.1% (3 HP) and 5.3% (9H) (p = 0.241). Clinically relevant hepatotoxicity was more common in the 9H than in the 3 HP group (5.3% vs. 1.5%; p = 0.103), whereas systemic drug reaction was more common in the 3 HP than in the 9H group (3.8% vs. 0%; p = 0.060). Women had a significantly higher rate of Grade II fever than men (13.7% vs. 1.2%; p = 0.003). Compared with the 9H regimen, the 3 HP regimen had a higher completion rate with lower hepatotoxicity and well-tolerated ADR.number NCT02208427. |
| High Completion Rate for 12 Weekly Doses of Isoniazid and Rifapentine as Treatment for Latent Mycobacterium tuberculosis Infection in the Federal Bureau of Prisons. | J Public Health Manag Pract | Correctional facilities provide unique opportunities to diagnose and treat persons with latent tuberculosis infection (LTBI). Studies have shown that 12 weekly doses of isoniazid and Rifapentine (INH-RPT) to treat LTBI resulted in high completion rates with good tolerability.To evaluate completion rates and clinical signs or reported symptoms associated with discontinuation of 12 weekly doses of INH-RPT for LTBI treatment.During July 2012 to February 2015, 7 Federal Bureau of Prisons facilities participated in an assessment of 12 weekly doses of INH-RPT for LTBI treatment among 463 inmates.Fisher exact test was used to assess the associations between patient sociodemographic characteristics and clinical signs or symptoms with discontinuation of treatment.Of 463 inmates treated with INH-RPT, 424 (92%) completed treatment. Reasons for discontinuation of treatment for 39 (8%) inmates included the following: 17 (44%) signs/symptoms, 9 (23%) transfer or release, 8 (21%) treatment refusal, and 5 (13%) provider error. A total of 229 (49.5%) inmates reported experiencing at least 1 sign or symptom during treatment; most frequently reported were fatigue (16%), nausea (13%), and abdominal pain (7%). Among these 229 inmates, signs/symptoms significantly associated with discontinuation of treatment included abdominal pain (P < .001), appetite loss (P = .02), fever/chills (P = .01), nausea (P = .03), sore muscles (P = .002), and elevation of liver transaminases 5× upper limits of normal or greater (P = .03).The LTBI completion rates were high for the INH-RPT regimen, with few inmates discontinuing because of signs or symptoms related to treatment. This regimen also has practical advantages to aid in treatment completion in the correctional setting and can be considered a viable alternative to standard LTBI regimens. |
| 2018 | Modelling the long-acting administration of anti-tuberculosis agents using PBPK: a proof of concept study. | Int J Tuberc Lung Dis | Anti-tuberculosis formulations necessitate uninterrupted treatment to cure tuberculosis (TB), but are characterised by suboptimal adherence, which jeopardises therapeutic efficacy. Long-acting injectable (LAI) formulations or implants could address these associated issues.niazid, Rifapentine, bedaquiline and delamanid-in adults for treatment for latent tuberculous infection (LTBI).PBPK models were developed and qualified against available clinical data by integrating drug physicochemical properties and in vitro and population pharmacokinetic data into a mechanistic description of drug distribution. Combinations of optimal dose and release rates were simulated such that plasma concentrations were maintained over the epidemiological cut-off or minimum inhibitory concentration for the dosing interval.The PBPK model identified 1500 mg of delamanid and 250 mg of Rifapentine as sufficient doses for monthly intramuscular administration, if a formulation or device can deliver the required release kinetics of 0.001-0.0025 h-1 and 0.0015-0.0025 h-1, respectively. Bedaquiline and isoniazid would require weekly to biweekly intramuscular dosing.We identified the theoretical doses and release rates of LAI anti-tuberculosis formulations. Such a strategy could ease the problem of suboptimal adherence provided the associated technological complexities for LTBI treatment are addressed. |
| 2018 | Update of Recommendations for Use of Once-Weekly Isoniazid-Rifapentine Regimen to Treat Latent Mycobacterium tuberculosis Infection. | MMWR Morb Mortal Wkly Rep | Treatment of latent tuberculosis infection (LTBI) is critical to the control and elimination of tuberculosis disease (TB) in the United States. In 2011, CDC recommended a short-course combination regimen of once-weekly isoniazid and Rifapentine for 12 weeks (3HP) by directly observed therapy (DOT) for treatment of LTBI, with limitations for use in children aged <12 years and persons with human immunodeficiency virus (HIV) infection (1). CDC identified the use of 3HP in those populations, as well as self-administration of the 3HP regimen, as areas to address in updated recommendations. In 2017, a CDC Work Group conducted a systematic review and meta-analyses of the 3HP regimen using methods adapted from the Guide to Community Preventive Services. In total, 19 articles representing 15 unique studies were included in the meta-analysis, which determined that 3HP is as safe and effective as other recommended LTBI regimens and achieves substantially higher treatment completion rates. In July 2017, the Work Group presented the meta-analysis findings to a group of TB experts, and in December 2017, CDC solicited input from the Advisory Council for the Elimination of Tuberculosis (ACET) and members of the public for incorporation into the final recommendations. CDC continues to recommend 3HP for treatment of LTBI in adults and now recommends use of 3HP 1) in persons with LTBI aged 2-17 years; 2) in persons with LTBI who have HIV infection, including acquired immunodeficiency syndrome (AIDS), and are taking antiretroviral medications with acceptable drug-drug interactions with Rifapentine; and 3) by DOT or self-administered therapy (SAT) in persons aged ≥2 years. |
| 2019 | Three months of rifapentine and isoniazid for latent tuberculosis infection in hemodialysis patients: High rates of adverse events. | J Microbiol Immunol Infect | The consequences of once-weekly Rifapentine plus isoniazid for 3 months (3HP) against latent tuberculosis infections in hemodialysis patients have not been studied before. This is the first study to evaluate the safety and tolerability of 3HP in this population and revealed a completion rate of 65.4%. The therapy was not associated with hepatotoxicity, but with high rates of adverse events (69.2%). |
| 2018 | Deciphering the late steps of rifamycin biosynthesis. | Nat Commun | Rifamycin-derived drugs, including rifampin, rifabutin, Rifapentine, and rifaximin, have long been used as first-line therapies for the treatment of tuberculosis and other deadly infections. However, the late steps leading to the biosynthesis of the industrially important rifamycin SV and B remain largely unknown. Here, we characterize a network of reactions underlying the biosynthesis of rifamycin SV, S, L, O, and B. The two-subunit transketolase Rif15 and the cytochrome P450 enzyme Rif16 are found to mediate, respectively, a unique C-O bond formation in rifamycin L and an atypical P450 ester-to-ether transformation from rifamycin L to B. Both reactions showcase interesting chemistries for these two widespread and well-studied enzyme families. |
| 2018 | Ethambutol and isoniazid induced severe neurotoxicity in a patient undergoing continuous ambulatory peritoneal dialysis. | BMJ Case Rep | Ethambutol (EMB) and isoniazid (INH) are the first-line antituberculosis (anti-TB) drugs. However, their neurotoxicity could cause adverse effect and the patients with end-stage renal disease are especially vulnerable due to the reduction in renal drug clearance. Here, we report a 36-year-old man receiving peritoneal dialysis developed progressive paralysis in lower extremities, vision loss and hoarseness 4 months after anti-TB treatment with INH, EMB and Rifapentine because of concomitant pulmonary tuberculosis. A diagnosis of EMB/INH-induced peripheral neuropathy, retrobulbar neuritis and laryngoparalysis was made. The patient's neuropathy gradually improved 2 years after discontinuation of EMB/INH. Since EMB and INH may cause simultaneously severe and complex multineuropathy in dialysis patients, their adverse effects should be closely supervised in dialysis patients. |
| 2018 | Effect of the alkyl group in the piperazine N-substitution on the therapeutic action of rifamycins: A drug-membrane interaction study. | Chem Biol Interact | In this work, we studied the effects of the N-alkyl group (methyl, cyclopentyl) in the piperazine ring of, respectively, rifampicin (RIF) and Rifapentine (RPT) to correlate this substitution with their differential pharmacokinetic properties and overall clinical performance. Since this group is their only structural change, and given that they share the same pharmacological target, differences in their therapeutic behavior may respond to this asset, particularly in their interaction with lipid membranes across the organism. In this study, surface pressure-area isotherms, as well as spectroscopic and microscopic techniques of characterization of phospholipid monolayers at the air/water interface were used to gain insight into drug-membrane interactions. Differences in the affinity for lipid membranes for both drugs, given by the vibration frequency of characteristic chemical groups in the lipid, as well as by reflectivity and mean molecular area of the monolayer, seem to be due to the N-alkyl substituent and can contribute to provide a molecular explanation as why they pose different choices in the chemotherapy against the deadliest infectious disease, tuberculosis. |
| 2018 | Pharmacokinetics of rifapentine and rifampin in a rabbit model of tuberculosis and correlation with clinical trial data. | Sci Transl Med | In clinical trials of two rifamycin antibiotics (rifampin and Rifapentine) for treating tuberculosis (TB), patients with cavitary lung lesions did not appear to derive benefit from Rifapentine. Rifapentine was found not to outperform rifampin, despite a lower minimum inhibitory concentration against in mouse models of TB. To understand these findings, we have developed a rabbit model of TB that reliably develops lung cavities with features similar to those of patients with pulmonary cavitary TB. After single or multiple doses of rifampin or Rifapentine that produced human-equivalent plasma exposures, rabbits were sacrificed at different time points after dosing. We measured site-of-disease drug pharmacokinetics and tissue drug distribution. We used pharmacokinetic-pharmacodynamic (PK/PD) modeling to estimate drug penetration into different types of tubercular lesions. Both drugs penetrated rabbit lung cellular lesions, as well as the fibrotic cavity wall of cavitary lesions (penetration coefficients ≥1 compared to plasma). For the necrotic liquefied material inside cavitary lesions known as caseum (which contains high numbers of bacteria), the penetration coefficient was 1.0 for rifampin but only 0.25 for Rifapentine. When estimates of site-of-disease drug PK were substituted into clinical PK/PD models, the relationship between site-of-action exposure and sputum culture conversion was significant ( < 10). We propose that poor penetration of Rifapentine into lung cavitary lesions explains, in part, why Rifapentine doses required to improve treatment outcomes in two phase 2 clinical trials were four times higher in TB patients with large cavities compared to TB patients without cavitary lung disease. |
| 2018 | Cost-effectiveness of Preventive Therapy for Tuberculosis With Isoniazid and Rifapentine Versus Isoniazid Alone in High-Burden Settings. | Clin Infect Dis | A short-course regimen of 3 months of weekly Rifapentine and isoniazid (3HP) has recently been recommended by the World Health Organization as an alternative to at least 6 months of daily isoniazid (isoniazid preventive therapy [IPT]) for prevention of tuberculosis (TB). The contexts in which 3HP may be cost-effective compared to IPT among people living with human immunodeficiency virus are unknown.We used a Markov state transition model to estimate the incremental cost-effectiveness of 3HP relative to IPT in high-burden settings, using a cohort of 1000 patients in a Ugandan HIV clinic as an emblematic scenario. Cost-effectiveness was expressed as 2017 US dollars per disability-adjusted life year (DALY) averted from a healthcare perspective over a 20-year time horizon. We explored the conditions under which 3HP would be considered cost-effective relative to IPT.Per 1000 individuals on antiretroviral therapy in the reference scenario, treatment with 3HP rather than IPT was estimated to avert 9 cases of TB and 1 death, costing $9402 per DALY averted relative to IPT. Cost-effectiveness depended strongly on the price of Rifapentine, completion of 3HP, and prevalence of latent TB. At a willingness to pay of $1000 per DALY averted, 3HP is likely to be cost-effective relative to IPT only if the price of Rifapentine can be greatly reduced (to approximately $20 per course) and high treatment completion (85%) can be achieved.3HP may be a cost-effective alternative to IPT in high-burden settings, but cost-effectiveness depends on the price of Rifapentine, achievable completion rates, and local willingness to pay. |
| 2018 | A systematic review of adverse events of rifapentine and isoniazid compared to other treatments for latent tuberculosis infection. | Pharmacoepidemiol Drug Saf | Tuberculosis (TB) remains a common cause of death globally. A regimen of 12 doses of isoniazid (INH) and Rifapentine given once weekly (INH/RPT-3) has recently been recommended by the World Health Organization for the treatment of latent TB infection (LTBI). We aimed to determine whether the INH/RPT-3 regimen had similar or lesser rates of adverse events compared to other LTBI regimens, namely INH for 9 months, INH for 6 months, rifampin for 3 to 4 months, and rifampin plus INH for 3 to 4 months.We searched MEDLINE, Embase, CENTRAL, PubMed, ICTRP, clinicaltrials.gov, and Canadian Agency for Drugs and Technologies in Health's Gray Matters Light for randomized, postmarketing, and comparative nonrandomized studies of patients with confirmed LTBI that reported the frequency of at least 1 adverse event of relevance for a regimen of interest. The search included studies published until March 2017. The frequencies of adverse events were extracted and are presented descriptively.Data from 23 randomized and 55 nonrandomized studies were included. Although inconsistent event reporting and high heterogeneity limited comparisons, the adverse event profile of INH/RPT-3 appeared generally favorable. Flu-like reactions were reported with an increased frequency and hepatotoxicity with a lower frequency than standard treatment.While INH/RPT-3 had an overall low frequency of adverse events compared to INH monotherapy, reporting of adverse events for many regimens was limited meaning results should be interpreted cautiously. Future studies of LTBI treatment would benefit from more complete collection and reporting of adverse events and more consistent definitions of hepatotoxicity. |
| 2018 | Barriers to treatment adherence for individuals with latent tuberculosis infection: A systematic search and narrative synthesis of the literature. | Int J Health Plann Manage | We investigated the rates of initiation and completion of treatment for latent TB infection (LTBI), factors explaining nonadherence and interventions to improve treatment adherence in countries with low TB incidence.A systematic search was performed in PubMed and Embase. All included articles were assessed for risk of bias. A narrative synthesis of the results was conducted.There were 54 studies included in this review. The proportion of people initiating treatment varied from 24% to 98% and the proportion of people completing treatment varied from 19% to 90%. The main barriers to adherence included the fear or experience of adverse effects, long duration of treatment, financial barriers, lack of transport to clinics (for patients), and insufficient resources for LTBI control. While interventions like peer counseling, incentives, and culturally specific case management have been used to improve adherence, the proportion of people who initiate and complete LTBI treatment still remains low.To further improve treatment and LTBI control and to fulfill the World Health Organization goal of eliminating TB in low-incidence countries, greater priority should be given to the use of treatment regimens involving shorter durations and fewer adverse effects, like the 3-month regimen of weekly Rifapentine plus isoniazid, supported by innovative patient education and incentive strategies. |
| 2018 | Cytokine-Mediated Systemic Adverse Drug Reactions in a Drug-Drug Interaction Study of Dolutegravir With Once-Weekly Isoniazid and Rifapentine. | Clin Infect Dis | Once-weekly isoniazid and Rifapentine for 3 months is a treatment option in persons with human immunodeficiency virus and latent tuberculosis infection. This study aimed to examine pharmacokinetic drug-drug interactions between this regimen and dolutegravir, a first-line antiretroviral medication.This was a single-center, open-label, fixed-sequence, drug-drug interaction study in healthy volunteers. Subjects received oral dolutegravir 50 mg once daily alone (days 1-4) and concomitantly with once-weekly isoniazid 900 mg, Rifapentine 900 mg, and pyridoxine 50 mg (days 5-19). Dolutegravir concentrations were measured on days 4, 14, and 19, and Rifapentine, 25-desacetyl-Rifapentine, and isoniazid concentrations were measured on day 19. Cytokines and antidrug antibodies to isoniazid and Rifapentine were examined at select time points.The study was terminated following the development of flu-like syndrome and elevated aminotransferase levels in 2 of 4 subjects after the third isoniazid-Rifapentine dose. Markedly elevated levels of interferon-γ, CXCL10, C-reactive protein, and other cytokines were temporally associated with symptoms. Antidrug antibodies were infrequently detected. Dolutegravir area under the curve (AUC) was decreased by 46% (90% confidence interval, 27-110%; P = .13) on day 14. Rifapentine and 25-desacetyl Rifapentine levels on day 19 were comparable to reference data, whereas isoniazid AUCs were approximately 67%-92% higher in the subjects who developed toxicities.The combined use of dolutegravir with once-weekly isoniazid-Rifapentine resulted in unexpected and serious toxicities that were mediated by endogenous cytokine release. Additional investigations are necessary to examine the safety and efficacy of coadministering these medications.NCT02771249. |
| 2018 | Exposure to Latent Tuberculosis Treatment during Pregnancy. The PREVENT TB and the iAdhere Trials. | Ann Am Thorac Soc | Data are limited regarding the safety of 12-dose once-weekly isoniazid (H, 900 mg) plus Rifapentine (P, 900 mg) (3HP) for latent infection treatment during pregnancy.To assess safety and pregnancy outcomes among pregnant women who were inadvertently exposed to study medications in two latent tuberculosis infection trials (PREVENT TB or iAdhere) evaluating 3HP and 9 months of daily isoniazid (H, 300 mg) (9H).Data from reproductive-age (15-51 yr) women who received one or more study dose of 3HP or 9H in either trial were analyzed. Drug exposure during pregnancy occurred if the estimated date of conception was on or before the last dose date.Of 126 pregnancies (125 participants) that occurred during treatment or follow-up, 87 were exposed to study drugs. Among these, fetal loss was reported for 4/31 (13%) and 8/56 (14%), 3HP and 9H, respectively (difference, 13% - 14% = -1%; 95% confidence interval = -17% to +18%) and congenital anomalies in 0/20 and 2/41 (5%) live births, 3HP and 9H, respectively (difference, 0% - 5% = -5%; 95% confidence interval = -18% to +16%). All fetal losses occurred in pregnancies of less than 20 weeks. Of the total 126 pregnancies, fetal loss was reported in 8/54 (15%) and 9/72 (13%), 3HP and 9H, respectively; and congenital anomalies in 1/37 (3%) and 2/56 (4%) live births, 3HP and 9H, respectively. The overall proportion of fetal loss (17/126 [13%]) and anomalies (3/93 [3%]) were similar to those estimated for the United States, 17% and 3%, respectively.Among reported pregnancies in these two latent tuberculosis infection trials, there was no unexpected fetal loss or congenital anomalies. These data offer some preliminary reassurance to clinicians and patients in circumstances when these drugs and regimens are the best option in pregnancy or in women of child-bearing potential. This work used the identifying trial registration numbers NCT00023452 and NCT01582711, corresponding to the primary clinical trials PREVENT TB and iAdhere (Tuberculosis Trials Consortium Study 26 and 33). |
| 2018 | Completion Rate and Safety of Tuberculosis Infection Treatment With Shorter Regimens. | Pediatrics | The traditional treatment of tuberculosis (TB) infection (9 months of daily isoniazid [9H]) is safe but completion rates of <50% are reported. Shorter regimens (3 months of once-weekly isoniazid and Rifapentine [3HP] or 4 months of daily rifampin [4R]) are associated with improved adherence in adults.This was a retrospective cohort study (2014-2017) of children (0-18 years old) seen at a children's TB clinic in a low-incidence nation. We compared the frequency of completion and adverse events (AEs) in children receiving 3HP, 4R, and 9H; the latter 2 regimens could be administered by families (termed self-administered therapy [SAT]) or as directly observed preventive therapy (DOPT); 3HP was always administered under DOPT.TB infection treatment was started in 667 children: 283 (42.4%) 3HP, 252 (37.8%) 9H, and 132 (19.8%) 4R. Only 52% of children receiving 9H via SAT completed therapy. Children receiving 3HP were more likely to complete therapy than the 9H (SAT) group (odds ratio [OR] 27.4, 95% confidence interval [CI]: 11.8-63.7). Multivariate analyses found receipt of medication under DOPT (OR: 5.72, 95% CI: 3.47-9.43), increasing age (OR: 1.09, 95% CI: 1.02-1.17), and the absence of any AE (OR: 1.70, 95% CI: 0.26-0.60) to be associated with completing therapy. AEs were more common in the 9H group (OR: 2.51, 95% CI: 1.48-4.32). Two (0.9%) children receiving 9H developed hepatotoxicity; no child receiving 3HP or 4R developed hepatotoxicity.Shorter regimens are associated with increased completion rates and fewer AEs than 9H. |
| 2018 | A human xenobiotic nuclear receptor contributes to nonresponsiveness of to the antituberculosis drug rifampicin. | J Biol Chem | is the causative agent of tuberculosis (TB). It acquires phenotypic drug resistance inside macrophages, and this resistance mainly arises from host-induced stress. However, whether cellular drug-efflux mechanisms in macrophages contribute to nonresponsiveness of to anti-TB drugs is unclear. Here, we report that xenobiotic nuclear receptors mediate TB drug nonresponsiveness by modulating drug-efflux transporters in macrophages. This was evident from expression analysis of drug-efflux transporters in macrophages isolated from TB patients. Among patients harboring rifampicin-susceptible we observed increased intracellular survival of upon rifampicin treatment of macrophages isolated from patients not responding to anti-TB drugs compared with macrophages from patients who did respond. Of note, infection and rifampicin exposure synergistically modulated macrophage drug-efflux transporters We also found that the xenobiotic nuclear receptor pregnane X receptor (PXR) modulates macrophage drug-efflux transporter expression and activity, which compromised the anti-TB efficacy of rifampicin. We further validated this finding in a TB mouse model in which use of the PXR antagonist ketoconazole rescued rifampicin anti-TB activity. We conclude that PXR activation in macrophages compromises the efficacy of the anti-TB drug rifampicin. Alternative therapeutic strategies, such as use of the rifampicin derivatives Rifapentine and rifabutin, which do not activate PXR, or of a PXR antagonist, may be effective for tackling drug nonresponsiveness of that arises from drug-efflux systems of the host. |
| 2018 | Treatment of Latent Tuberculosis Infection and Its Clinical Efficacy. | Tuberc Respir Dis (Seoul) | The role of the treatment for latent tuberculosis infection (LTBI) has been underscored in the intermediate tuberculosis (TB) burden countries like South Korea. LTBI treatment is recommended only for patients at risk for progression to active TB-those with frequent exposure to active TB cases, and those with clinical risk factors (e.g., immunocompromised patients). Recently revised National Institute for Health and Care Excellence (NICE) guideline recommended that close contacts of individuals with active pulmonary or laryngeal TB, aged between 18 and 65 years, should undergo LTBI treatment. Various regimens for LTBI treatment were recommended in NICE, World Health Organization (WHO), and Centers for Disease Control and Prevention guidelines, and superiority of one recommended regimen over another was not yet established. Traditional 6 to 9 months of isoniazid (6H or 9H) regimen has an advantage of the most abundant evidence for clinical efficacy-60%-90% of estimated protective effect. However, 6H or 9H regimen is related with hepatotoxicity and low compliance. Four months of rifampin regimen is characterized by less hepatotoxicity and better compliance than 9H, but has few evidence of clinical efficacy. Three months of isoniazid plus rifampin was proved equivalence with 6H or 9H regimen in terms of efficacy and safety, which was recommended in NICE and WHO guidelines. The clinical efficacy of isoniazid plus Rifapentine once-weekly regimen for 3 months was demonstrated recently, which is not yet introduced into South Korea. |
| 2018 | Combinations of registered drugs reduce treatment times required to deplete Wolbachia in the Litomosoides sigmodontis mouse model. | PLoS Negl Trop Dis | Filarial parasites can be targeted by antibiotic treatment due to their unique endosymbiotic relationship with Wolbachia bacteria. This finding has led to successful treatment strategies in both, human onchocerciasis and lymphatic filariasis. A 4-6 week treatment course using doxycycline results in long-term sterility and safe macrofilaricidal activity in humans. However, current treatment times and doxycycline contraindications in children and pregnant women preclude widespread administration of doxycycline in public health control programs; therefore, the search for shorter anti-wolbachial regimens is a focus of ongoing research. We have established an in vivo model for compound screening, using mice infected with Litomosoides sigmodontis. We could show that gold standard doxycycline treatment did not only deplete Wolbachia, it also resulted in a larval arrest. In this model, combinations of registered antibiotics were tested for their anti-wolbachial activity. Administration of rifamycins in combination with doxycycline for 7 days successfully depleted Wolbachia by > 2 log (>99% reduction) and thus resulted in a significant reduction of the treatment duration. Using a triple combination of a tetracycline (doxycycline or minocycline), a rifamycin and a fluoroquinolone (moxifloxacin) led to an even greater shortening of the treatment time. Testing all double combinations that could be derived from the triple combinations revealed that the combination of Rifapentine (15mg/kg) and moxifloxacin (2 x 200mg/kg) showed the strongest reduction of treatment time in intraperitoneal and also oral administration routes. The Rifapentine plus moxifloxacin combination was equivalent to the triple combination with additional doxycycline (>99% Wolbachia reduction). These investigations suggest that it is possible to shorten anti-wolbachial treatment times with combination treatments in order to achieve the target product profile (TPP) requirements for macrofilaricidal drugs of no more than 7-10 days of treatment. |
| 2018 | Cellulose-based amorphous solid dispersions enhance rifapentine delivery characteristics in vitro. | Carbohydr Polym | The efficacy of Rifapentine, an oral antibiotic used to treat tuberculosis, may be reduced due to degradation at gastric pH and low solubility at intestinal pH. We hypothesized that delivery properties would be improved in vitro by incorporating Rifapentine into pH-responsive amorphous solid dispersions (ASDs) with cellulose derivatives including: hydroxypropylmethylcellulose acetate succinate (HPMCAS), cellulose acetate suberate (CASub), and 5-carboxypentyl hydroxypropyl cellulose (CHC). ASDs generally reduced Rifapentine release at gastric pH, with CASub affording >31-fold decrease in area under the curve (AUC) compared to Rifapentine alone. Critically, reduced gastric dissolution was accompanied by reduced degradation to 3-formylrifamycin. Certain ASDs also enhanced apparent solubility and stabilization of supersaturated solutions at intestinal pH, with HPMCAS providing nearly 4-fold increase in total AUC vs. Rifapentine alone. These results suggest that Rifapentine delivery via ASD with these cellulosic polymers may improve bioavailability in vivo. |
| 2017 | SIRCLE: a randomised controlled cost comparison of self-administered short-course isoniazid and rifapentine for cost-effective latent tuberculosis eradication. | Intern Med J | Currently, treatment of latent tuberculosis infection (LTBI) in Australia consists most commonly of a 9-month course of isoniazid (9H). A 3-month course of weekly isoniazid and Rifapentine (3HP) has been shown to be as effective as 9 months of daily isoniazid, and associated with less hepatotoxicity; however, Rifapentine is not currently available in Australia. Introduction of this regimen would have apparent advantages for people with LTBI in Victoria by safely shortening duration of LTBI therapy. However, the cost benefit of this new therapeutic approach is uncertain.Cost-analysis of standard and short-course therapy for LTBI in an Australian context.Single-centre randomised controlled trial conducted between December 2013-March 2016. Participants underwent 1:1 randomisation to either a 9-month course of daily isoniazid or a 12-week course of weekly isoniazid and Rifapentine. The primary outcome measure was total healthcare system costs (in Australian dollars; AUD) per completed course of LTBI therapy. Secondary cost analyses were performed to consider varying assumptions regarding commercial cost of Rifapentine.Overall, 34 of 40 (85%) participants in the 9H group and 36/40 (90%) in the 3HR group completed therapy. One patient in the 3HP group was hospitalised for a febrile illness; no hospitalisations were recorded in the 9H group. The cost per completed course of 9H was 601 AUD, while that of 3HP was significantly lower at 511 AUD (P < 0.01).This study provides cost analysis evidence to support the use of 3HP for the treatment of LTBI in Australia. |
| 2017 | Self-administered Versus Directly Observed Once-Weekly Isoniazid and Rifapentine Treatment of Latent Tuberculosis Infection: A Randomized Trial. | Ann Intern Med | Expanding latent tuberculosis treatment is important to decrease active disease globally. Once-weekly isoniazid and Rifapentine for 12 doses is effective but limited by requiring direct observation.To compare treatment completion and safety of once-weekly isoniazid and Rifapentine by self-administration versus direct observation.An open-label, phase 4 randomized clinical trial designed as a noninferiority study with a 15% margin. Seventy-five percent or more of study patients were enrolled from the United States for a prespecified subgroup analysis. (ClinicalTrials.gov: NCT01582711).Outpatient tuberculosis clinics in the United States, Spain, Hong Kong, and South Africa.1002 adults (aged ≥18 years) recommended for treatment of latent tuberculosis infection.Participants received once-weekly isoniazid and Rifapentine by direct observation, self-administration with monthly monitoring, or self-administration with weekly text message reminders and monthly monitoring.The primary outcome was treatment completion, defined as 11 or more doses within 16 weeks and measured using clinical documentation and pill counts for direct observation, and self-reports, pill counts, and medication event-monitoring devices for self-administration. The main secondary outcome was adverse events.Median age was 36 years, 48% of participants were women, and 77% were enrolled at the U.S. sites. Treatment completion was 87.2% (95% CI, 83.1% to 90.5%) in the direct-observation group, 74.0% (CI, 68.9% to 78.6%) in the self-administration group, and 76.4% (CI, 71.3% to 80.8%) in the self-administration-with-reminders group. In the United States, treatment completion was 85.4% (CI, 80.4% to 89.4%), 77.9% (CI, 72.7% to 82.6%), and 76.7% (CI, 70.9% to 81.7%), respectively. Self-administered therapy without reminders was noninferior to direct observation in the United States; no other comparisons met noninferiority criteria. A few drug-related adverse events occurred and were similar across groups.Persons with latent tuberculosis infection enrolled in South Africa would not routinely be treated programmatically.These results support using self-administered, once-weekly isoniazid and Rifapentine to treat latent tuberculosis infection in the United States, and such treatment could be considered in similar settings when direct observation is not feasible.Centers for Disease Control and Prevention. |
| 2017 | Assessment of vocation of rifabutin and rifapentine in replace of rifampcin in drug resistance leprosy patients: a molecular simulation study. | Mol Biol Res Commun | The emergence of drug resistance in leprosy is a major hurdle in leprosy elimination programme. Although the problem of drug resistance is presently not acute, it is important that we collect data more systematically and monitor the trend carefully so that effective measures to combat this problem can be developed. The present study aimed at the explication of cross resistance of rifabutin and Rifapentine to rifampicin which would be helpful to programme managers for implementing rifabutin or Rifapentine in replace of rifampicin. In this study we built 3D model of the rpoB using Swiss Model and the modelled structure was docked with rifampicin, rifabutin and Rifapentine. We established that these 3 antibiotics interact with the same binding region in the modelled rpoB of Thus we conclude that vocation of rifabutin and Rifapentine could not be suitable in replace of rifampicin to combat with drug resistance leprosy. |
| 2017 | Clinical and pharmacological hallmarks of rifapentine's use in diabetes patients with active and latent tuberculosis: do we know enough? | Drug Des Devel Ther | Rifapentine is a rifamycin derivate approved by the US Food and Drug Administration in 1998 for the treatment of active, drug-susceptible tuberculosis (TB). In 2014, Rifapentine was approved for the treatment of latent TB infection in patients at high risk of progression to active disease and is currently under evaluation by the European Medicines Agency. Expanding indications of Rifapentine largely affect diabetes patients, since about one-third of them harbor latent TB. Clinical consequences of Rifapentine use in this population and potentially harmful interactions with hypoglycemic agents are widely underexplored and generally considered similar to the ones of rifampicin. Indeed, Rifapentine too may decrease blood levels of many oral antidiabetics and compete with them for protein-binding sites and/or transporters. However, the two drugs differ in protein-binding degree, the magnitude of cytochrome P450 induction and auto-induction, the degree of renal elimination, and so on. Rifapentine seems to be more suitable for use in diabetes patients with renal impairment, owing to the fact that it does not cause renal toxicity, and it is eliminated via kidneys in smaller proportions than rifampicin. On the other hand, there are no data related to Rifapentine use in patients >65 years, and hypoalbuminemia associated with diabetic kidney disease may affect a free fraction of Rifapentine to a greater extent than that of rifampicin. Until more pharmacokinetic information and information on the safety of Rifapentine use in diabetic patients and drug-drug interactions are available, diabetes in TB patients treated with Rifapentine should be managed with insulin analogs, and glucose and Rifapentine plasma levels should be closely monitored. |
| 2017 | Cost-effectiveness of Testing and Treatment for Latent Tuberculosis Infection in Residents Born Outside the United States With and Without Medical Comorbidities in a Simulation Model. | JAMA Intern Med | Testing for and treating latent tuberculosis infection (LTBI) is among the main strategies to achieve TB elimination in the United States. The best approach to testing among non-US born residents, particularly those with comorbid conditions, is uncertain.To estimate health outcomes, costs, and cost-effectiveness of LTBI testing and treatment among non-US born residents with and without medical comorbidities.Decision analytic tree and Markov cohort simulation model among non-US born residents with no comorbidities, with diabetes, with HIV infection, or with end-stage renal disease (ESRD) using a health care sector perspective with 3% annual discounting. Strategies compared included no testing, tuberculin skin test (TST), interferon gamma release assay (IGRA), confirm positive (initial TST, IGRA only for TST-positive results; both tests positive indicates LTBI), and confirm negative (initial IGRA, then TST for IGRA-negative; any test positive indicates LTBI). All strategies were coupled to treatment with 3 months of self-administered Rifapentine and isoniazid.Number needed to test and treat to prevent 1 case of TB reactivation, discounted quality-adjusted life-years (QALYs), discounted lifetime medical costs, and incremental cost-effectiveness ratios (ICERs).Improving health outcomes increased costs, with choice of test dependent on willingness to pay. Strategies ranked by ascending costs and benefits: no testing, confirm positive, TST, IGRA, and confirm negative. The ICERs varied by non-US born patient risk group: patients with no comorbidities, IGRA was likely cost-effective at $83 000/QALY; patients with diabetes, both confirm positive ($53 000/QALY) and IGRA ($120 000/QALY) were likely cost-effective; patients with HIV, confirm negative was clearly preferred ($63 000/QALY); and patients with ESRD, no testing was cost-effective. Increased LTBI prevalence and reduced return for TST reading improved IGRA's relative performance. In 10 000 probabilistic simulations among non-US born patients with no comorbidities, with diabetes, and with HIV, some form of testing was virtually always cost-effective. These simulations highlight the uncertainty of test choice for non-US born patients with no comorbidities and non-US born patients with diabetes, but strategies including IGRA were preferred in over 60% of simulations for all non-US born populations except those with ESRD.Testing for and treating LTBI among non-US born residents with and without selected comorbidities is likely cost-effective except among those with ESRD in whom competing risks of death limit benefits. Strategies including IGRA fell below a $100 000/QALY willingness-to-pay threshold for non-US born patients with no comorbidities, patients with diabetes, and patients with HIV. |
| 2017 | Management of Latent Tuberculosis Infection Among Healthcare Workers: 10-Year Experience at a Single Center. | Clin Infect Dis | The risk of infection with Mycobacterium tuberculosis among healthcare workers (HCWs) is estimated to be higher than the general population. However, HCW acceptance and compliance with available latent tuberculosis infection (LTBI) treatment regimens has been problematic. Recently, regimens have become available that might improve HCW acceptance and compliance with LTBI treatment.A retrospective single-center review of Employee Health and Wellness Services records of all HCWs diagnosed with LTBI was conducted. HCWs diagnosed with LTBI were offered 9-month isoniazid (INH), 4-month rifampin (RIF), weekly Rifapentine/isoniazid (RPT/INH) for 12 weeks, or no treatment. Acceptance, completion rates, and side effects were reported for each regimen. Comparisons of regimens were assessed using Fisher exact test.Between 2005 and 2014, 363 of 927 (39%) HCWs diagnosed with LTBI accepted treatment. Of 363, 202 chose INH, 106 RIF, and 55 RPT/INH. Completion rates for each regimen were 58%, 80%, and 87%, respectively. HCWs were significantly more likely to have completed treatment with RIF (P < .0001) or RPT/INH (P < .0001) than INH. Rates of discontinuation owing to side effects were 35% for INH, 21% for RIF, and 10% for RPT/INH. Discontinuation of therapy due to side effects was significantly more frequent in the INH than the RPT/INH group (P = .0042).Completion of RIF and RPT/INH for LTBI in an HCW population is more likely than INH. Rates of discontinuation due to side effects were lower among those taking RPT/INH. Shorter LTBI treatment regimens should be more widely considered for HCWs in the United States. |
| 2017 | Use of Rifapentine and Isoniazid Directly Observed Therapy for the Treatment of Latent Tuberculosis Infection in a Military Clinic. | Mil Med | There are 8.6 million cases of active tuberculosis (TB) worldwide, and an estimated one-third of the world population has latent tuberculosis infection (LTBI). In the United States, up to 80% of active cases may be caused by untreated reactivated latent infection. A case of TB can spread rapidly impacting the readiness of a unit. To prevent the development of TB, it is critical that active duty service members with LTBI complete treatment. The use of isoniazid (INH) and Rifapentine (RPT) as a directly observed therapy (DOT) treatment option was recommended by the Centers for Disease Control and Prevention in late 2011. Since then, there have been limited studies on the use of this treatment regimen in a civilian clinic setting and to our knowledge no studies within a military setting.This study compares the completion rate of LTBI treatment in 2 military public health clinics, using a retrospective chart review of 179 subjects who attempted treatment with INH/RPT DOT and 186 with the non-INH/RPT non-DOT regimen.When compared to other LTBI regimens completed or attempted in this period, completion rates were higher in INH/RPT DOT regimens. The INH/RPT DOT treatment regimen allowed enough flexibility with completion between 11 and 16 weeks for active duty service members to increase completion to 94.6%, compared to 73% in the non-INH/RPT regimen.This project demonstrated the feasibility of INH/RPT DOT treatment within the military population resulting in a higher completion rate than the non-INH/RPT non-DOT regimen. The use of the INH/RPT DOT regimen should be considered for use in all military or similar populations. |
| 2017 | Immunodeficiency and Intermittent Dosing Promote Acquired Rifamycin Monoresistance in Murine Tuberculosis. | Antimicrob Agents Chemother | More-permissive preclinical models may be useful in evaluating antituberculosis regimens for their propensity to select drug-resistant mutants. To evaluate whether acquired rifamycin monoresistance could be recapitulated in mice and, if so, to evaluate the effects of immunodeficiency, intermittent dosing, and drug exposures, athymic nude and BALB/c mice were infected. Controls received daily Rifapentine alone or 2 months of rifampin, isoniazid, pyrazinamide, and ethambutol, followed by 4 months of rifampin/isoniazid, either daily or twice weekly with one of two isoniazid doses. Test groups received the same intensive regimen followed by once-weekly Rifapentine or isoniazid/Rifapentine with Rifapentine doses of 10, 15, or 20 mg/kg of body weight plus one of two isoniazid doses. All combination regimens rendered BALB/c mouse cultures negative but selected mutants resistant to isoniazid (8.5%, 12/140) or rifampin (3.5%, 5/140) in nude mice ( < 0.001). Intermittently dosed intensive-phase therapy selected isoniazid and rifampin resistance in 10% (8/80, < 0.001) and 20% (16/80, = 0.009) of nude mice, respectively, compared to 0% treated with a daily regimen. Once-weekly Rifapentine-containing continuation-phase regimens selected rifampin-resistant mutants at a rate of 18.0% (18/100, = 0.035 compared to rifampin/isoniazid regimens). Higher isoniazid doses in the intermittent-treatment control regimen and higher Rifapentine doses in once-weekly regimens were associated with less selection of isoniazid resistance. Acquired resistance, including rifamycin monoresistance, was more likely to occur in nude mice despite administration of combination therapy. These results recapitulate clinical outcomes and indicate that nude mice may be useful for evaluating the ability of novel regimens to prevent the selection of resistance. |
| 2017 | NOS2-deficient mice with hypoxic necrotizing lung lesions predict outcomes of tuberculosis chemotherapy in humans. | Sci Rep | During active TB in humans a spectrum of pulmonary granulomas with central necrosis and hypoxia exists. BALB/c mice, predominantly used in TB drug development, do not reproduce this complex pathology thereby inaccurately predicting clinical outcome. We found that Nos2 mice incapable of NO-production in immune cells as microbial defence uniformly develop hypoxic necrotizing lung lesions, widely observed in human TB. To study the impact of hypoxic necrosis on the efficacy of antimycobacterials and drug candidates, we subjected Nos2 mice with TB to monotherapy before or after establishment of human-like pathology. Isoniazid induced a drug-tolerant persister population only when necrotic lesions were present. Rifapentine was more potent than rifampin prior to development of human-like pathology and equally potent thereafter, in agreement with recent clinical trials. Pretomanid, delamanid and the pre-clinical candidate BTZ043 were bactericidal independent of pulmonary pathology. Linezolid was bacteriostatic in TB-infected Nos2 mice but significantly improved lung pathology. Hypoxic necrotizing lesions rendered moxifloxacin less active. In conclusion, Nos2 mice are a predictive TB drug development tool owing to their consistent development of human-like pathology. |
| 2017 | Rifampin vs. rifapentine: what is the preferred rifamycin for tuberculosis? | Expert Rev Clin Pharmacol | One-third of the world's population is infected with Mycobacterium tuberculosis (M.tb.). Latent tuberculosis infection (LTBI) can progress to tuberculosis disease, the leading cause of death by infection. Rifamycin antibiotics, like rifampin and Rifapentine, have unique sterilizing activity against M.tb. What are the advantages of each for LTBI or tuberculosis treatment? Areas covered: We review studies assessing the pharmacokinetics (PK), pharmacodynamics (PD), drug interaction risk, safety, and efficacy of rifampin and Rifapentine and provide basis for comparing them. Expert commentary: Rifampin has shorter half-life, higher MIC against M.tb, lower protein binding, and better distribution into cavitary contents than Rifapentine. Drug interactions for the two drugs maybe similar in magnitude. For LTBI, Rifapentine is effective as convenient, once-weekly, 12-week course of treatment. Rifampin is also effective for LTBI, but must be given daily for four months, therefore, drug interactions are more problematic. For drug-sensitive tuberculosis disease, rifampin remains the standard of care. Safety profile of rifampin is better-described; adverse events differ somewhat for the two drugs. The registered once-weekly Rifapentine regimen is inadequate, but higher doses of either drugs may shorten the treatment duration required for effective management of TB. Results of clinical trials evaluating high-dose rifamycin regimens are eagerly awaited. |
| Fighting tuberculosis by drugs targeting nonreplicating bacilli. | Int J Mycobacteriol | Current tuberculosis (TB) treatment requires 6 months of combination therapy with isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), and ethambutol for active TB and 9 months of INH or 3 months of Rifapentine (RFP) + INH for latent TB. The lungs of patients with active and latent TB contain heterogeneous mixtures of cellular and caseous granulomas harboring Mycobacterium tuberculosis bacilli ranging from actively replicating (AR) to nonreplicating (NR), phenotypically drug-resistant stages. Several in vitro models to obtain NR cells were reported, including exposure to hypoxia, nutrient starvation, acid + nitric oxide, and stationary phase. Overall, these models showed that RIF, RFP, PA-824 (PA), metronidazole (MZ), bedaquiline (BQ), and fluoroquinolones were the most active drugs against NR M. tuberculosis. In hypoxia at pH 5.8, some combinations killed AR plus NR cells, as shown by lack of regrowth in liquid media, whereas in hypoxia at pH 7.3 (the pH of the caseum), only RIF and RFP efficiently killed NR bacilli while several other drugs showed little effect. In conventional mouse models, combinations containing RFP, BQ, PA, PZA, moxifloxacin, sutezolid, linezolid, and clofazimine sterilized animals in ≤2 months, as shown by lack of viable bacilli in lung homogenates after 3 months without therapy. Drugs were less effective in C3HeB/FeJ mice forming caseous granulomas. Overall, in vitro observations and in vivo studies suggest that the search for new TB drugs could be addressed to low lipophilic molecules (e.g., new rpoB inhibitors with clogP < 3) killing NR M. tuberculosis in hypoxia at neutral pH and reaching high rates of unbound drug in the caseum. |
| 2017 | A Review of Moxifloxacin for the Treatment of Drug-Susceptible Tuberculosis. | J Clin Pharmacol | Moxifloxacin, an 8-methoxy quinolone, is an important drug in the treatment of multidrug-resistant tuberculosis and is being investigated in novel drug regimens with pretomanid, bedaquiline, and pyrazinamide, or Rifapentine, for the treatment of drug-susceptible tuberculosis. Early results of these studies are promising. Although current evidence does not support the use of moxifloxacin in treatment-shortening regimens for drug-susceptible tuberculosis, it may be recommended in patients unable to tolerate standard first-line drug regimens or for isoniazid monoresistance. Evidence suggests that the standard 400-mg dose of moxifloxacin used in the treatment of tuberculosis may be suboptimal in some patients, leading to worse tuberculosis treatment outcomes and emergence of drug resistance. Furthermore, a drug interaction with the rifamycins results in up to 31% reduced plasma concentrations of moxifloxacin when these are combined for treatment of drug-susceptible tuberculosis, although the clinical relevance of this interaction is unclear. Moxifloxacin exhibits extensive interindividual pharmacokinetic variability. Higher doses of moxifloxacin may be needed to achieve drug exposures required for improved clinical outcomes. Further study is, however, needed to determine the safety of proposed higher doses and clinically validated targets for drug exposure to moxifloxacin associated with improved tuberculosis treatment outcomes. We discuss in this review the evidence for the use of moxifloxacin in drug-susceptible tuberculosis and explore the role of moxifloxacin pharmacokinetics, pharmacodynamics, and drug interactions with rifamycins, on tuberculosis treatment outcomes when used in first-line tuberculosis drug regimens. |
| 2017 | High Rate of Treatment Completion in Program Settings With 12-Dose Weekly Isoniazid and Rifapentine for Latent Mycobacterium tuberculosis Infection. | Clin Infect Dis | Randomized controlled trials have demonstrated that the newest latent tuberculosis (LTBI) regimen, 12 weekly doses of directly observed isoniazid and Rifapentine (3HP), is as efficacious as 9 months of isoniazid, with a greater completion rate (82% vs 69%); however, 3HP has not been assessed in routine healthcare settings.Observational cohort of LTBI patients receiving 3HP through 16 US programs was used to assess treatment completion, adverse drug reactions, and factors associated with treatment discontinuation.Of 3288 patients eligible to complete 3HP, 2867 (87.2%) completed treatment. Children aged 2-17 years had the highest completion rate (94.5% [155/164]). Patients reporting homelessness had a completion rate of 81.2% (147/181). In univariable analyses, discontinuation was lowest among children (relative risk [RR], 0.44 [95% confidence interval {CI}, .23-.85]; P = .014), and highest in persons aged ≥65 years (RR, 1.72 [95% CI, 1.25-2.35]; P < .001). In multivariable analyses, discontinuation was lowest among contacts of patients with tuberculosis (TB) disease (adjusted RR [ARR], 0.68 [95% CI, .52-.89]; P = .005) and students (ARR, 0.45 [95% CI, .21-.98]; P = .044), and highest with incarceration (ARR, 1.43 [95% CI, 1.08-1.89]; P = .013) and homelessness (ARR, 1.72 [95% CI, 1.25-2.39]; P = .001). Adverse drug reactions were reported by 1174 (35.7%) patients, of whom 891 (76.0%) completed treatment.Completion of 3HP in routine healthcare settings was greater overall than rates reported from clinical trials, and greater than historically observed using other regimens among reportedly nonadherent populations. Widespread use of 3HP for LTBI treatment could accelerate elimination of TB disease in the United States. |
| 2017 | New Paradigm for Translational Modeling to Predict Long-term Tuberculosis Treatment Response. | Clin Transl Sci | Disappointing results of recent tuberculosis chemotherapy trials suggest that knowledge gained from preclinical investigations was not utilized to maximal effect. A mouse-to-human translational pharmacokinetics (PKs) - pharmacodynamics (PDs) model built on a rich mouse database may improve clinical trial outcome predictions. The model included Mycobacterium tuberculosis growth function in mice, adaptive immune response effect on bacterial growth, relationships among moxifloxacin, Rifapentine, and rifampin concentrations accelerating bacterial death, clinical PK data, species-specific protein binding, drug-drug interactions, and patient-specific pathology. Simulations of recent trials testing 4-month regimens predicted 65% (95% confidence interval [CI], 55-74) relapse-free patients vs. 80% observed in the REMox-TB trial, and 79% (95% CI, 72-87) vs. 82% observed in the Rifaquin trial. Simulation of 6-month regimens predicted 97% (95% CI, 93-99) vs. 92% and 95% observed in 2RHZE/4RH control arms, and 100% predicted and observed in the 35 mg/kg rifampin arm of PanACEA MAMS. These results suggest that the model can inform regimen optimization and predict outcomes of ongoing trials. |
| 2017 | Drug Susceptibility of 33 Reference Strains of Slowly Growing Mycobacteria to 19 Antimicrobial Agents. | Biomed Res Int | . Slowly growing mycobacteria (SGM) are prevalent worldwide and cause an extensive spectrum of diseases. . In this study, the antimicrobial susceptibility of 33 reference strains of SGM to 19 antimicrobial agents was tested using a modified microdilution method. . Cefmetazole (32/33) and azithromycin (32/33) exhibited the highest antimicrobial activity, and dapsone (9/33) exhibited the lowest activity against the tested strains. Cefoxitin (30/33), cefoperazone (28/33), and cefepime (28/33) were effective against a high proportion of strains, and macrolides were also highly effective as well as offering the benefit of convenient oral administration to patients. Linezolid (27/33), meropenem (26/33), sulfamethoxazole (26/33), and tigecycline (25/33) showed the highest activity; clofazimine (20/33) and doxycycline (18/33) showed intermediate activity; and Rifapentine (13/33), rifabutin (13/33), and minocycline (11/33) showed low antimicrobial activity, closely followed by thioacetazone (10/33) and pasiniazid (10/33), against the tested organisms. According to their susceptibility profiles, the slowly growing species and were the least susceptible to the tested drugs, whereas , , , , , and were the most susceptible. . In summary, cephalosporins and macrolides, particularly cefmetazole, azithromycin, clarithromycin, and roxithromycin, showed good antimicrobial activity against the reference strains of SGM. |
| 2017 | Use of Video Directly Observed Therapy for Treatment of Latent Tuberculosis Infection - Johnson County, Kansas, 2015. | MMWR Morb Mortal Wkly Rep | Tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis and is spread from person to person through the air. TB can be spread in congregate settings, such as school environments, to varying degrees, based on factors including duration of contact and air ventilation (1); therefore, evaluating potential contacts and exposures can be challenging. In February 2015, a student at a Kansas high school received a diagnosis of active pulmonary TB disease. Screening of 385 (91%) school contacts, four (100%) household contacts, and 19 (90%) social contacts resulted in the identification of 50 persons with latent TB infection. Johnson County Department of Health and Environment (JCDHE) Public Health Emergency Preparedness personnel used their experience with points of distribution logistics to optimize testing clinic layouts and implement the incident command structure. Open communication with students, school staff members, the public, and the media about the investigation from the outset was imperative to reduce rumors and unease that can accompany a large communicable disease investigation. The large number of persons needing treatment for latent TB overwhelmed JCDHE's two TB nurses. As a result, JCDHE developed a policy and procedure to allow persons who met eligibility requirements to complete 12 weekly doses of isoniazid and Rifapentine treatment using video directly observed therapy (VDOT) rather than traditional in-person directly observed therapy (DOT). This procedure facilitated treatment compliance and completion; among the eligible 15 persons who chose the 12-week VDOT option, 14 (93%) completed treatment. State and local health departments might consider use of VDOT to monitor treatment of persons with latent TB infection. |
| 2017 | Efficacy and completion rates of rifapentine and isoniazid (3HP) compared to other treatment regimens for latent tuberculosis infection: a systematic review with network meta-analyses. | BMC Infect Dis | We conducted a systematic review and network meta-analysis (NMA) to examine the efficacy and completion rates of treatments for latent tuberculosis infection (LTBI). While a previous review found newer, short-duration regimens to be effective, several included studies did not confirm LTBI, and analyses did not account for variable follow-up or assess completion.We searched MEDLINE, Embase, CENTRAL, PubMed, and additional sources to identify RCTs in patients with confirmed LTBI that involved a regimen of interest and reported on efficacy or completion. Regimens of interest included isoniazid (INH) with Rifapentine once weekly for 12 weeks (INH/RPT-3), 6 and 9 months of daily INH (INH-6; INH-9), 3-4 months daily INH plus rifampicin (INH/RFMP 3-4), and 4 months daily rifampicin alone (RFMP-4). NMAs were performed to compare regimens for both endpoints.Sixteen RCTs (n = 44,149) and 14 RCTs (n = 44,128) were included in analyses of efficacy and completion. Studies were published between 1968 and 2015, and there was diversity in patient age and comorbidities. All regimens of interest except INH-9 showed significant benefits in preventing active TB compared to placebo. Comparisons between active regimens did not reveal significant differences. While definitions of regimen completion varied across studies, regimens of 3-4 months were associated with a greater likelihood of adequate completion.Most of the active regimens showed an ability to reduce the risk of active TB relative to no treatment, however important differences between active regimens were not found. Shorter rifamycin-based regimens may offer comparable benefits to longer INH regimens. Regimens of 3-4 months duration are more likely to be completed than longer regimens. |
| 2017 | Treatment of a subdural empyema complicated by intracerebral abscess due to Brucella infection. | Braz J Med Biol Res | A 55-year-old male presented with fever, stupor, aphasia, and left hemiparesis. A history of head trauma 3 months before was also reported. Cranial magnetic resonance imaging revealed slight contrast enhancement of lesions under the right frontal skull plate and right frontal lobe. Because of deterioration in nutritional status and intracranial hypertension, the patient was prepared for burr hole surgery. A subdural empyema (SDE) recurred after simple drainage. After detection of Brucella species in SDE, craniotomy combined with antibiotic treatment was undertaken. The patient received antibiotic therapy for 6 months (two doses of 2 g ceftriaxone, two doses of 100 mg doxycycline, and 700 mg Rifapentine for 6 months) that resulted in complete cure of the infection. Thus, it was speculated that the preexisting subdural hematoma was formed after head trauma, which was followed by a hematogenous infection caused by Brucella species. |
| 2017 | Use of whole-genome sequencing to distinguish relapse from reinfection in a completed tuberculosis clinical trial. | BMC Med | RIFAQUIN was a tuberculosis chemotherapy trial in southern Africa including regimens with high-dose Rifapentine with moxifloxacin. Here, the application of whole-genome sequencing (WGS) is evaluated within RIFAQUIN for identifying new infections in treated patients as either relapses or reinfections. WGS is further compared with mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR) typing. This is the first report of WGS being used to evaluate new infections in a completed clinical trial for which all treatment and epidemiological data are available for analysis.DNA from 36 paired samples of Mycobacterium tuberculosis cultured from patients before and after treatment was typed using 24-loci MIRU-VNTR, in silico spoligotyping and WGS. Following WGS, the sequences were mapped against the reference strain H37Rv, the single-nucleotide polymorphism (SNP) differences between pairs were identified, and a phylogenetic reconstruction was performed.WGS indicated that 32 of the paired samples had a very low number of SNP differences (0-5; likely relapses). One pair had an intermediate number of SNP differences, and was likely the result of a mixed infection with a pre-treatment minor genotype that was highly related to the post-treatment genotype; this was reclassified as a relapse, in contrast to the MIRU-VNTR result. The remaining three pairs had very high SNP differences (>750; likely reinfections).WGS and MIRU-VNTR both similarly differentiated relapses and reinfections, but WGS provided significant extra information. The low proportion of reinfections seen suggests that in standard chemotherapy trials with up to 24 months of follow-up, typing the strains brings little benefit to an analysis of the trial outcome in terms of differentiating relapse and reinfection. However, there is a benefit to using WGS as compared to MIRU-VNTR in terms of the additional genotype information obtained, in particular for defining the presence of mixed infections and the potential to identify known and novel drug-resistance markers. |
| 2017 | Three months of weekly rifapentine plus isoniazid for latent tuberculosis treatment in solid organ transplant candidates. | Infection | Isoniazid daily for 9 months is the recommended regimen for latent tuberculosis infection (LTBI) in solid organ transplant (SOT) candidates, but its use is controversial, due to reports of hepatotoxicity and low treatment completion rates. A 12-week course of once weekly directly observed therapy (DOT) with isoniazid plus Rifapentine (3HP) is a new LTBI treatment regimen. Tolerability and safety data of 3HP LTBI treatment in SOT candidates are limited.Twelve consecutive SOT candidates who underwent DOT with 3HP for LTBI at Westchester Medical Center, Valhalla, New York, USA, between January 2013 and August 2016 were prospectively evaluated for tolerability and safety of 3HP. The diagnosis of LTBI was made in a person with a positive interferon-gamma release test, without a history of previously treated active or latent tuberculosis infection, and without signs, symptoms, or radiographic evidence of active tuberculosis. Patients were followed up 1 month after treatment completion and at routine follow-up visits with their transplant providers.Eleven patients were men, and the median age was 60 years (range 44-72). Eight patients were liver, and four kidney transplant candidates. The median Model for End-Stage Liver Disease (MELD score) was 17 (range 10-31). All patients completed treatment. Only a single patient developed transaminitis greater than twice the baseline value. Three patients underwent liver transplantation. None of them developed tuberculosis at 9, 22, or 40 months following transplantation.Directly observed 3HP LTBI treatment was not associated with hepatotoxicity, even in patients with higher MELD scores. Further studies are needed to confirm the safety and efficacy of this LTBI treatment regimen in the SOT population. |
| 2017 | A shorter treatment regimen for latent tuberculosis infection holds promise for at-risk Canadians. | Can Commun Dis Rep | Despite recent success in reducing its incidence, tuberculosis remains a considerable challenge in Canada, particularly among foreign-born and Indigenous populations. A key component of the strategy for controlling the disease is the treatment of latent tuberculosis infection. The standard treatment consists of isoniazid (INH) daily for nine months. In recent years, shorter regimens have been developed in the hope of increasing rates of treatment acceptance and completion. Of these, the shortest and most recently developed is a combination of INH and Rifapentine taken once weekly for 12 doses (3HP), typically using directly observed therapy (DOT). This regimen has been approved by the Food and Drug Administration in the United States but is not yet authorized in Canada. Based on a rapidly expanding number of observational studies and randomized controlled trials, 12 weeks of 3HP appears to have similar efficacy to nine months of INH, a favourable adverse event profile and potentially improved rates of treatment completion. Although rates of treatment acceptance, the role of self-administered therapy and the regimen's cost-effectiveness within the Canadian context remain uncertain, 3HP is a promising alternative to existing treatments for LTBI. |
| 2017 | The tuberculosis taboo. | Int J Tuberc Lung Dis | The treatment of latent tuberculous infection (TBI) is a productive and meaningful approach to tuberculosis (TB) control, and an important component of the World Health Organization's (WHO's) new End TB Strategy, especially in high-risk contacts. Unfortunately, although recognized and recommended by the WHO, it continues to be underutilized, and has even been ignored for decades in some high-risk groups, as though it were a taboo. Historical approaches to treating TBI in contacts of drug-susceptible and drug-resistant TB are presented and discussed as compelling experiences. In the United States, the Centers for Disease Control and Prevention have recently shown that a directly observed or even self-administered 12-month regimen to treat TBI with once-weekly isoniazid (INH) and Rifapentine is as effective as 9 months of daily INH. Treating TBI in drug-susceptible cases and their contacts should not still be considered taboo-such a short, effective regimen is more akin to the Holy Grail. While not yet confirmed in a clinical trial, treating contacts of drug-resistant TB with the same drugs that are effective in the source case would be expected intuitively and practically to prevent TB in contacts and should be introduced now instead of waiting until clinical trials are completed. |
| 2016 | Drug Release Characteristics and Tissue Distribution of Rifapentine Polylactic Acid Sustained-Release Microspheres in Rabbits after Paravertebral Implantation. | Iran Red Crescent Med J | Rates of drug-resistant tuberculosis (TB) and TB associated with human immunodeficiency virus (HIV) infection have increased dramatically, intensifying challenges in TB control. New formulations of TB treatment drugs that control drug release and increase local drug concentrations will have a significant impact on mitigating the toxic side effects and increasing the clinical efficacy of anti-TB drugs.The aim was to observe the sustained release characteristics of Rifapentine polylactic acid sustained-release microspheres in vivo and the accumulation of Rifapentine in other tissues following paravertebral implantation.This study is a basic animal experimental study that began on July 17, 2014 in the Fifth Affiliated hospital of Xinjiang Medical University. One hundred and eight New Zealand white rabbits (weighing 2.8 - 3.0 kg, male and female, China) were randomly divided into three groups of 36 rabbits each. Blood and tissue samples from the liver, lungs, kidneys, vertebrae, and paravertebral muscle were collected at different time points post-surgery. High performance liquid chromatography (HPLC) analysis with a biological internal standard was used to determine the drug concentrations in samples.In group A, no significant differences in Rifapentine concentrations in the liver were detected between any two time points (P > 0.05). However, the differences in Rifapentine concentrations between day 10 and day 21 were statistically significant (P < 0.05); for days 21, 35, 46, and 60, the differences in Rifapentine concentrations between two sequential time points were not statistically significant (P > 0.05). In group B, the differences in Rifapentine concentration between days 3 and 10 in vertebral bone and in paravertebral muscles were statistically significant (P < 0.05). Rifapentine was detected in the vertebral bone tissue in the group C animals. The Rifapentine concentrations between two sequential time points were statistically significant (P < 0.05). Rifapentine could not be detected in the paravertebral muscles 46 days after the operation. The differences in Rifapentine concentrations between two sequential time points among days 3, 10, 21, and 35 were statistically significant (P < 0.05).After paravertebral implantation of Rifapentine polylactic acid sustained-release microspheres, the concentration of Rifapentine in local vertebral bone tissues was maintained above the TB minimum inhibitory concentration for up to 60 days with no apparent accumulation of the drug in other tissues. |
| 2017 | Treatment completion for latent tuberculosis infection: a retrospective cohort study comparing 9 months of isoniazid, 4 months of rifampin and 3 months of isoniazid and rifapentine. | BMC Infect Dis | The U.S. Centers for Disease Control and Prevention (CDC) recommended a new regimen for treatment of latent tuberculosis (three months of weekly isoniazid and Rifapentine) in late 2011. While completion rates of this regimen were reported to be higher than nine months of isoniazid, little is known about the completion rates of three months of isoniazid and Rifapentine compared to nine months of isoniazid or four months of rifampin in actual use scenarios.We conducted a retrospective cohort study comparing treatment completion for latent tuberculosis (TB) infection in patients treated with nine months of isoniazid, three months of isoniazid and Rifapentine or four months of rifampin in outpatient clinics and a public health TB clinic in Seattle, Washington. The primary outcome of treatment completion was defined as 270 doses of isoniazid within 12 months, 120 doses of rifampin within six months and 12 doses of isoniazid and Rifapentine within four months.Three hundred ninety-three patients were included in the study. Patients were equally likely to complete three months of weekly isoniazid and Rifapentine or four months of rifampin (85% completion rate of both regimens), as compared to 52% in the nine months of isoniazid group (p < 0.001). These associations remained statistically significant even after adjusting for clinic location and type of monitoring. Monitoring type (weekly versus monthly versus less often than monthly) had less impact on treatment completion than the type of treatment offered.Patients were equally as likely to complete the three months of isoniazid and Rifapentine as four months of rifampin. Four months of rifampin is similar in efficacy compared to placebo as isoniazid and Rifapentine but does not require directly observed therapy (DOT), and is less expensive compared to combination therapy with isoniazid and Rifapentine, and thus can be the optimal treatment regimen to achieve the maximal efficacy in a community setting. |
| 2017 | Antimicrobial susceptibility and MIC distribution of 41 drugs against clinical isolates from China and reference strains of nontuberculous mycobacteria. | Int J Antimicrob Agents | To treat nontuberculous mycobacteria (NTM) infections more optimally, further research pertaining to mycobacterial susceptibility to antimicrobial agents is required. A total of 82 species of NTM reference strains and 23 species of NTM clinical isolates were included. Minimum inhibitory concentrations (MICs) for 41 drugs were determined using the microdilution method in cation-adjusted Mueller-Hinton broth. The results showed that most of the NTM were susceptible to aminoglycosides, quinolones, three macrolides (clarithromycin, azithromycin and roxithromycin), cefmetazole, linezolid and capreomycin. Rapidly growing mycobacterium strains were additionally susceptible to cefoxitin, clofazimine, Rifapentine, doxycycline, minocycline, tigecycline, meropenem and sulfamethoxazole, whereas slowly growing mycobacterium strains were additionally susceptible to rifabutin. This study on the susceptibility of NTM includes the largest sample size of Chinese clinical isolates and reference strains. NTM species-specific drug susceptibility patterns suggested that it is urgent to identify the species of NTM, to normalise the treatment of NTM infectious disease and to clarify the resistance mechanisms of NTM. |
| 2017 | Defining the optimal dose of rifapentine for pulmonary tuberculosis: Exposure-response relations from two phase II clinical trials. | Clin Pharmacol Ther | Rifapentine is a highly active antituberculosis antibiotic with treatment-shortening potential; however, exposure-response relations and the dose needed for maximal bactericidal activity have not been established. We used pharmacokinetic/pharmacodynamic data from 657 adults with pulmonary tuberculosis participating in treatment trials to compare Rifapentine (n = 405) with rifampin (n = 252) as part of intensive-phase therapy. Population pharmacokinetic/pharmacodynamic analyses were performed with nonlinear mixed-effects modeling. Time to stable culture conversion of sputum to negative was determined in cultures obtained over 4 months of therapy. Rifapentine exposures were lower in participants who were coinfected with human immunodeficiency virus, black, male, or fasting when taking drug. Rifapentine exposure, large lung cavity size, and geographic region were independently associated with time to culture conversion in liquid media. Maximal treatment efficacy is likely achieved with Rifapentine at 1,200 mg daily. Patients with large lung cavities appear less responsive to treatment, even at high Rifapentine doses. |
| 2016 | Activity of drugs against dormant Mycobacterium tuberculosis. | Int J Mycobacteriol | Heterogeneous mixtures of cellular and caseous granulomas coexist in the lungs of tuberculosis (TB) patients, with Mycobacterium tuberculosis (Mtb) existing from actively replicating (AR) to dormant, nonreplicating (NR) stages. Within cellular granulomas, the pH is estimated to be less than 6, whereas in the necrotic centres of hypoxic, cholesterol/triacylglycerol-rich, caseous granulomas, the pH varies between 7.2 and 7.4. To combat TB, we should kill both AR and NR stages of Mtb. Dormant Mtb remodels lipids of its cell wall, and so lipophilic drugs may be active against NR Mtb living in caseous, lipid-rich, granulomas. Lipophilicity is expressed as logP, that is, the logarithm of the partition coefficient (P) ratio P/P. In this study, the activity of lipophilic drugs (logP>0) and hydrophilic drugs (logP⩽0) against AR and NR Mtb was measured in hypoxic conditions under acidic and slightly alkaline pHs.The activity of drugs was determined against AR Mtb (5-day-old aerobic cells: A5) and NR Mtb (12- and 19-day-old hypoxic cells: H12 and H19) in a Wayne dormancy model of Mtb H37Rv at pH 5.8, to mimic the environment of cellular granulomas. Furthermore, AR and NR bacilli were grown for 40days in Wayne models at pH 6.6, 7.0, 7.4, and 7.6, to set up conditions mimicking the caseous granulomas (hypoxia+slightly alkaline pH), to measure drug activity against NR cells. Mtb viability was determined by colony-forming unit (CFU) counts.At pH 5.8, lipophilic drugs (rifampin, Rifapentine, bedaquiline, PA-824, clofazimine, nitazoxanide: logP⩾2.14) reduced CFU of all cells (H12, H19, and A5) by ⩾2log. Among hydrophilic drugs (isoniazid, pyrazinamide, ethambutol, amikacin, moxifloxacin, metronidazole: logP⩽0.01), none reduced H12 and H19 CFUs by ⩾2log, with the exception of metronidazole. When Mtb was grown at different pHs the following Mtb growth was noted: at pH 6.6, AR cells grew fluently while NR cells grew less, with a CFU increase up to Day 15, followed by a drop to Day 40. AR and NR Mtb grown at pH 7.0, 7.4, and 7.6 showed up to 1 log CFU lower than their growth at pH 6.6. The pHs of all AR cultures tended to reach pH 7.2-7.4 on Day 40. The pHs of all NR cultures remained stable at their initial values (6.6, 7.0, 7.4, and 7.6) up to Day 40. The activity of drugs against H12 and H19 cells was tested in hypoxic conditions at a slightly alkaline pH. Under these conditions, some lipophilic drugs were more active (>5 log CFU decrease after 21days of exposure) against H12 and H19 cells than clofazimine, nitazoxanide, isoniazid, pyrazinamide, amikacin (<1 log CFU decrease after 21days of exposure). Testing of other drugs is in progress.Lipophilic drugs were more active than hydrophilic agents against dormant Mtb in hypoxic conditions at pH 5.8. The Wayne model under slightly alkaline conditions was set up, and in hypoxic conditions at a slightly alkaline pH some lipophilic drugs were more active than other drugs against NR Mtb. Overall, these models can be useful for testing drug activity against dormant Mtb under conditions mimicking the environments of cellular and caseous granulomas. |
| 2017 | Mycobacterium tuberculosis Is Selectively Killed by Rifampin and Rifapentine in Hypoxia at Neutral pH. | Antimicrob Agents Chemother | The activities of rifampin, Rifapentine, bedaquiline, PA-824, clofazimine, nitazoxanide, isoniazid, amikacin, moxifloxacin, niclosamide, thioridazine, and pyrazinamide were tested against nonreplicating (dormant) H37Rv under conditions of hypoxia at pHs 5.8 and 7.3, mimicking environments of cellular granulomas and caseous granulomas, respectively. At pH 5.8, several drugs killed dormant bacilli, with the best being rifampin and Rifapentine. At pH 7.3, only rifampin and Rifapentine efficiently killed dormant bacilli, while all other drugs showed little activity. |
| 2017 | Inhalation of Respirable Crystalline Rifapentine Particles Induces Pulmonary Inflammation. | Mol Pharm | Rifapentine is an anti-tuberculosis (anti-TB) drug with a prolonged half-life, but oral delivery results in low concentrations in the lungs because of its high binding (98%) to plasma proteins. We have shown that inhalation of crystalline Rifapentine overcomes the limitations of oral delivery by significantly enhancing and prolonging the drug concentration in the lungs. The delivery of crystalline particles to the lungs may promote inflammation. This in vivo study characterizes the inflammatory response caused by pulmonary deposition of the Rifapentine particles. The Rifapentine powder was delivered to BALB/c mice by intratracheal insufflation at a dose of 20 mg/kg. The inflammatory response in the lungs and bronchoalveolar lavage (BAL) was examined at 12 h, 24 h, and 7 days post-treatment by flow cytometry and histopathology. At 12 and 24 h post-treatment, there was a significant influx of neutrophils into the lungs, and this returned to normal by day 7. A significant recruitment of macrophages occurred in the BAL at 24 h. Consistent with these findings, histopathological analysis demonstrated pulmonary vascular congestion and significant macrophage recruitment at 12 and 24 h post-treatment. In conclusion, the pulmonary delivery of crystalline Rifapentine caused a transient neutrophil-associated inflammatory response in the lungs that resolved over 7 days. This observation may limit pulmonary delivery of Rifapentine to once a week at a dose of 20 mg/kg or less. The effectiveness of weekly dosing with inhalable Rifapentine will be assessed in murine Mycobacterium tuberculosis infection. |
| 2016 | Xpert MTB/RIF Assay Shows Faster Clearance of Mycobacterium tuberculosis DNA with Higher Levels of Rifapentine Exposure. | J Clin Microbiol | The Xpert MTB/RIF assay is both sensitive and specific as a diagnostic test. Xpert also reports quantitative output in cycle threshold (C) values, which may provide a dynamic measure of sputum bacillary burden when used longitudinally. We evaluated the relationship between Xpert C trajectory and drug exposure during tuberculosis (TB) treatment to assess the potential utility of Xpert C for treatment monitoring. We obtained serial sputum samples from patients with smear-positive pulmonary TB who were consecutively enrolled at 10 international clinical trial sites participating in study 29X, a CDC-sponsored Tuberculosis Trials Consortium study evaluating the tolerability, safety, and antimicrobial activity of Rifapentine at daily doses of up to 20 mg/kg of body weight. Xpert was performed at weeks 0, 2, 4, 6, 8, and 12. Longitudinal C data were modeled using a nonlinear mixed effects model in relation to Rifapentine exposure (area under the concentration-time curve [AUC]). The rate of change of C was higher in subjects receiving Rifapentine than in subjects receiving standard-dose rifampin. Moreover, Rifapentine exposure, but not assigned dose, was significantly associated with rate of change in C (P = 0.02). The estimated increase in C slope for every additional 100 μg · h/ml of Rifapentine drug exposure (as measured by AUC) was 0.11 C/week (95% confidence interval [CI], 0.05 to 0.17). Increasing Rifapentine exposure is associated with a higher rate of change of Xpert C, indicating faster clearance of Mycobacterium tuberculosis DNA. These data suggest that the quantitative outputs of the Xpert MTB/RIF assay may be useful as a dynamic measure of TB treatment response. |
| Cost effectiveness of interferon-gamma release assay for tuberculosis screening using three months of rifapentine and isoniazid among long-term expatriates from low to high incidence countries. | Travel Med Infect Dis | Long-term expatriates from low to high tuberculosis (TB) incidence countries get high rates of active TB and latent TB infection (LTBI). TB screening for expatriates is important for occupational health. Interferon-gamma release assays are more accurate than tuberculin skin test (TST). Rifapentine plus isoniazid for 3 months (3HP) is as effective as 9 months of isoniazid (9H) with a higher treatment-completion rate.Decision trees and Markov models were constructed using a societal perspective on a lifetime horizon. The target population was a hypothetical cohort of 30 year-old expatriates. Seven strategies; TST with 3HP or 9H, QuantiFERON-TB Gold In-Tube (QFT) with 3HP or 9H, T-SPOT.TB (TSPOT) with 3HP or 9H and chest X-ray examination (CXR) were modeled. The main outcome measure of effectiveness was quality-adjusted life-years (QALYs) gained.QFT with 3HP yielded the greatest benefits with the lowest cost ($US 674.8; 25.95660 QALYs [year 2012 values]). CXR was the least cost-effective ($US 13,666.8; 24.62917 QALYs). Cost-effectiveness was sensitive to adherence rate of 3HP and QFT specificity, but not to BCG vaccination rate.Entry LTBI screening using QFT treated with 3HP is recommended on the basis of cost effectiveness among long-term expatriates from low to high incidence countries. |
| 2016 | Predictors of Latent Tuberculosis Infection Treatment After Introduction of a New Regimen: A Retrospective Cohort Study at an Inner City Clinic. | Open Forum Infect Dis | Despite the low and decreasing prevalence of tuberculosis (TB) in the United States, there remain certain high-risk groups with high incidence rates. The targeted screening and treatment of latent TB infection (LTBI) among these high-risk groups are needed to achieve TB elimination; however, by most accounts, LTBI treatment completion rates remain low. We retrospectively studied all patients accepting treatment for LTBI at the Fulton County Health Department TB clinic over 2 years. Medical chart abstraction was performed to collect information on sociodemographics, medical, and LTBI treatment history. Treatment completion was defined as finishing ≥88% of the prescribed regimen. Logistic regression analysis was performed to identify predictors of treatment completion. Among 547 adults offered LTBI treatment, 424 (78%) accepted treatment and 298 of 424 (70%) completed treatment. The median age was 42 years, most patients were black (77%), and close to one third did not have stable housing. No significant difference in completion rates was found between the 3 regimens of 9 months isoniazid (65%), 4 months rifampin (71%), and 3 months of weekly Rifapentine and isoniazid (79%). In multivariate analysis, having stable housing increased the odds of finishing treatment, whereas tobacco use and an adverse event decreased the odds. Utilizing comprehensive case management, we demonstrated high rates of LTBI treatment completion, including among those receiving a 3-month regimen. Completion rates were higher among persons with stable housing, and this finding highlights the need to develop strategies that will improve adherence among homeless persons. |
| 2016 | Sterilizing Activity of Fully Oral Intermittent Regimens against Mycobacterium Ulcerans Infection in Mice. | PLoS Negl Trop Dis | The treatment of Buruli ulcer (BU) that is caused by Mycobacterium ulcerans, is currently based on a daily administration of rifampin and streptomycin (RIF-STR). A fully oral intermittent regimen would greatly simplify its treatment on the field.The objective of this study was to assess the bactericidal and sterilizing activities of intermittent oral regimens in a murine model of established M. ulcerans infection. Regimens combining Rifapentine (RFP 20 mg/kg) with either moxifloxacin (MXF 200 mg/kg), clarithromycin (CLR 100 mg/kg) or bedaquiline (BDQ 25 mg/kg) were administrated twice (2/7) or three (only for RFP-CLR 3/7) times weekly during 8 weeks. The bactericidal but also the sterilizing activities of these four intermittent oral regimens were at least as good as those obtained with control weekdays regimens, i.e. RFP-CLR 5/7 or RIF-STR 5/7. A single mouse from the RFP-MFX 2/7 group had culture-positive relapse at the end of the 28 weeks following treatment completion among the 157 mice treated with one of the four intermittent regimens (40 RFP-CLR 2/7, 39 RFP-CLR 3/7, 39 RFP-MXF 2/7, 39 RFP-BDQ 2/7).These results open the door for a fully intermittent oral drug regimen for BU treatment avoiding intramuscular injections and facilitating supervision by health care workers. |
| The Possible Innovative Use of Bifidobacterium longum W11 in Association With Rifaximin: A New Horizon for Combined Approach? | J Clin Gastroenterol | The aim of the study was to unequivocally demonstrate the nontransmissibility of the genes mediating the resistance of the strain Bifidobacterium longum W11 (LMG P-21586) to rifaximin.Most antibiotic treatments can induce unfavorable side effects such as antibiotic-associated diarrhea, which is largely attributable to the disruption of the intestinal microbiota. The parallel intake of probiotic bacteria might reduce these events, even if with generally very poor results. In this regard, the use of antibiotic-resistant beneficial bacteria could represent a worthy strategy.Rifaximin was tested in parallel with rifampicin, Rifapentine, and rifabutin, all rifamycin derivates, using 5 different concentrations. Susceptibility tests were performed by the disc diffusion method of Kirby-Bauer, and inhibition zones were measured after incubation at 37°C. B. longum BL03 was used as comparison. The B. longum W11 genome was sequenced on Illumina MiSeq with a 250 PE reads module. After mapping the reads with the reference bacterial genome, the alignment data were processed using FreeBayes software.B. longum BL03 was inhibited by all antibiotics even at the lowest concentration. In contrast, the W11 strain was inhibited by rifampicin, rifabutin, and rifaximin only at the highest concentration (512 μg/mL). The genomic analysis showed a mutation into the chromosomal DNA. No transposable elements were found, and the genetic locus was not flanked by close mobile genetic elements.B. longum W11 could be used in combined therapy with rifaximin, thus opening new focused frontiers in the probiotic era while preserving the necessary safety of use for consumers. |
| 2017 | The Delivery of High-Dose Dry Powder Antibiotics by a Low-Cost Generic Inhaler. | AAPS J | The routine of loading multiple capsules for delivery of high-dose antibiotics is time consuming, which may reduce patient adherence to inhaled treatment. To overcome this limitation, an investigation was carried out using four modified versions of the Aerolizer® that accommodate a size 0 capsule for delivery of high payload formulations. In some prototypes, four piercing pins of 0.6 mm each were replaced with a single centrally located 1.2-mm pin and one-third reduced air inlet of the original design. The performance of these inhalers was evaluated using spray-dried antibiotic powders with distinct morphologies: spherical particles with a highly corrugated surface (colistin and tobramycin) and needle-like particles (Rifapentine). The inhalers were tested at capsule loadings of 50 mg (colistin), 30 mg (Rifapentine) and 100 mg (tobramycin) using a multistage liquid impinger (MSLI) operating at 60 L/min. The device with a single pin and reduced air inlet showed a superior performance than the other prototypes in dispersing colistin and Rifapentine powders, with a fine particle fraction (FPF wt% <5 μm in the aerosol) between 62 and 68%. Subsequently, an Aerolizer® with the same configuration (single pin and one-third air inlet) that accommodates a size 00 capsule was designed to increase the payload of colistin and Rifapentine. The performance of the device at various inspiratory flow rates and air volumes achievable by most cystic fibrosis (CF) patients was examined at the maximum capsule loading of 100 mg. The device showed optimal performance at 45 L/min with an air volume of 1.5-2.0 L for colistin and 60 L/min with an air volume of 2.0 L for Rifapentine. In conclusion, the modified size 00 Aerolizer® inhaler as a low-cost generic device demonstrated promising results for delivery of various high-dose formulations for treatment of lung infections. |
| 2016 | Repurposing clinically approved cephalosporins for tuberculosis therapy. | Sci Rep | While modern cephalosporins developed for broad spectrum antibacterial activities have never been pursued for tuberculosis (TB) therapy, we identified first generation cephalosporins having clinically relevant inhibitory concentrations, both alone and in synergistic drug combinations. Common chemical patterns required for activity against Mycobacterium tuberculosis were identified using structure-activity relationships (SAR) studies. Numerous cephalosporins were synergistic with rifampicin, the cornerstone drug for TB therapy, and ethambutol, a first-line anti-TB drug. Synergy was observed even under intracellular growth conditions where beta-lactams typically have limited activities. Cephalosporins and rifampicin were 4- to 64-fold more active in combination than either drug alone; however, limited synergy was observed with Rifapentine or rifabutin. Clavulanate was a key synergistic partner in triple combinations. Cephalosporins (and other beta-lactams) together with clavulanate rescued the activity of rifampicin against a rifampicin resistant strain. Synergy was not due exclusively to increased rifampicin accumulation within the mycobacterial cells. Cephalosporins were also synergistic with new anti-TB drugs such as bedaquiline and delamanid. Studies will be needed to validate their in vivo activities. However, the fact that cephalosporins are orally bioavailable with good safety profiles, together with their anti-mycobacterial activities reported here, suggest that they could be repurposed within new combinatorial TB therapies. |
| 2017 | Absolute Quantification of Rifampicin by MALDI Imaging Mass Spectrometry Using Multiple TOF/TOF Events in a Single Laser Shot. | J Am Soc Mass Spectrom | Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) allows for the visualization of molecular distributions within tissue sections. While providing excellent molecular specificity and spatial information, absolute quantification by MALDI IMS remains challenging. Especially in the low molecular weight region of the spectrum, analysis is complicated by matrix interferences and ionization suppression. Though tandem mass spectrometry (MS/MS) can be used to ensure chemical specificity and improve sensitivity by eliminating chemical noise, typical MALDI MS/MS modalities only scan for a single MS/MS event per laser shot. Herein, we describe TOF/TOF instrumentation that enables multiple fragmentation events to be performed in a single laser shot, allowing the intensity of the analyte to be referenced to the intensity of the internal standard in each laser shot while maintaining the benefits of MS/MS. This approach is illustrated by the quantitative analyses of rifampicin (RIF), an antibiotic used to treat tuberculosis, in pooled human plasma using Rifapentine (RPT) as an internal standard. The results show greater than 4-fold improvements in relative standard deviation as well as improved coefficients of determination (R) and accuracy (>93% quality controls, <9% relative errors). This technology is used as an imaging modality to measure absolute RIF concentrations in liver tissue from an animal dosed in vivo. Each microspot in the quantitative image measures the local RIF concentration in the tissue section, providing absolute pixel-to-pixel quantification from different tissue microenvironments. The average concentration determined by IMS is in agreement with the concentration determined by HPLC-MS/MS, showing a percent difference of 10.6%. Graphical Abstract ᅟ. |
| 2015 | Cell-Based High-Throughput Screening Identifies Rifapentine as an Inhibitor of Amyloid and Biofilm Formation in Escherichia coli. | ACS Infect Dis | Escherichia coli assemble functional amyloid fibers termed curli that contribute to bacterial adhesion, biofilm formation, and host pathogenesis. We developed a cell-based high-throughput screen to identify inhibitors of curli-mediated adhesion in the laboratory strain MC4100 and curli-associated biofilm formation in the uropathogenic E. coli clinical isolate UTI89. Inhibitors of biofilm formation can operate through many mechanisms, and such inhibitors could hold therapeutic value in preventing and treating urinary tract infections. The curli-specific screen allows the identification of compounds that inhibit either curli expression, curli biogenesis, or adhesion by normally produced curli. In screening the NIH Clinical Collection of 446 compounds, we identified Rifapentine as a potent inhibitor in both of these screens. Rifapentine is an antibiotic used to treat tuberculosis that targets RNA polymerase, but prevents curli-dependent adhesion and biofilm formation in E. coli at concentrations below those that affect viability. Rifapentine inhibits curli production and prevents biofilm formation on plastic, on agar, and at the air-liquid interface by inhibiting curli gene transcription. Comparisons with a cephalosporin antibiotic further revealed that curli production is not affected by standard antibiotic treatment and cell killing pressure. Thus, we reveal a new role independent of killing activity for Rifapentine as an inhibitor of curli and curli-mediated biofilm formation. |
| 2016 | Primary Care Screening and Treatment for Latent Tuberculosis Infection in Adults: Evidence Report and Systematic Review for the US Preventive Services Task Force. | JAMA | Five to ten percent of individuals with latent tuberculosis infection (LTBI) progress to active tuberculosis (TB) disease. Identifying and treating LTBI is a key component of the strategy for reducing the burden of TB disease.To review the evidence about targeted screening and treatment for LTBI among adults in primary care settings to support the US Preventive Services Task Force in updating its 1996 recommendation.MEDLINE, Cochrane Library, and trial registries, searched through August 3, 2015; references from pertinent articles; and experts. Literature surveillance was conducted through May 31, 2016.English-language studies of LTBI screening, LTBI treatment with recommended pharmacotherapy, or accuracy of the tuberculin skin test (TST) or interferon-gamma release assays (IGRAs). Studies of individuals for whom LTBI screening and treatment is part of public health surveillance or disease management were excluded.Two investigators independently reviewed abstracts and full-text articles. When at least 3 similar studies were available, random-effects meta-analysis was used to generate pooled estimates of outcomes.Sensitivity, specificity, reliability, active TB disease, mortality, hepatotoxicity, and other harms.The review included 72 studies (n = 51 711). No studies evaluated benefits and harms of screening compared with no screening. Pooled estimates for sensitivity of the TST at both 5-mm and 10-mm induration thresholds were 0.79 (5-mm: 95% CI, 0.69-0.89 [8 studies, n = 803]; 10 mm: 95% CI, 0.71-0.87 [11 studies; n = 988]), and those for IGRAs ranged from 0.77 to 0.90 (57 studies; n = 4378). Pooled estimates for specificity of the TST at the 10-mm and 15-mm thresholds and for IGRAs ranged from 0.95 to 0.99 (34 studies; n = 23 853). A randomized clinical trial (RCT) of 24 weeks of isoniazid in individuals with pulmonary fibrotic lesions and LTBI (n = 27 830) found a reduction in absolute risk of active TB at 5 years from 1.4% to 0.5% (relative risk [RR], 0.35 [95% CI, 0.24-0.52]) and an increase in absolute risk for hepatoxicity from 0.1% to 0.5% (RR, 4.59 [95% CI, 2.03-10.39]) for 24 weeks of daily isoniazid compared with placebo. An RCT (n = 6886) found that 3 months of once-weekly Rifapentine plus isoniazid was noninferior to 9 months of isoniazid alone for preventing active TB. The risk difference for hepatoxicity comparing isoniazid with rifampin ranged from 3% to 7%, with a pooled RR of 3.29 (95% CI, 1.72-6.28 [3 RCTs; n = 1327]).No studies evaluated the benefits and harms of screening compared with no screening. Both the TST and IGRAs are moderately sensitive and highly specific within countries with low TB burden. Treatment reduced the risk of active TB among the populations included in this review. Isoniazid is associated with higher rates of hepatotoxicity than placebo or rifampin. |
| 2016 | Impacts of 12-dose regimen for latent tuberculosis infection: Treatment completion rate and cost-effectiveness in Taiwan. | Medicine (Baltimore) | Treatment of latent tuberculosis infection (LTBI) is essential for eradicating tuberculosis (TB). Moreover, the patient adherence is crucial in determining the effectiveness of TB control. Isoniazid given by DOTS daily for 9 months (9H) is the standard treatment for LTBI in Taiwan. However, the completion rate is low due to the long treatment period and its side effects. The combined regimen using a high dose of Rifapentine/isoniazid once weekly for 12 weeks (3HP) has been used as an alternative treatment option for LTBI in the United States. This may result in a higher completion rate. In this pilot study, patient adherence and cost of these 2 treatment regimens were investigated. Thus, we aimed to assess the treatment completion rate and costs of 3HP and compare to those with 9H.Data from 691 cases of LTBI treatments including 590 cases using the conventional regimen and 101 cases with Rifapentine/Isoniazid were collected. The cost was the sum of the cost of treatment with Isoniazid for 9 months or with rifapentin/Isoniazid for 3 months of all contacts. The effectiveness was the cost of cases of tuberculosis avoided.In this study, the treatment completion rate for patients prescribed with the 3 months Rifapentine/isoniazid regimen (97.03%) was higher than those given the conventional 9-month isoniazid regimen (87.29%) (P <0.001). The cost of 3HP and 9H was US$261.24 and US$717.3, respectively. The cost-effectiveness ratio with isoniazid for 9 months was US$ 15392/avoided 1 case of tuberculosis and US$ 5225/avoided 1 case of tuberculosis with 3HP. In addition, when compared with the conventional regimen, there were fewer patients discontinued with Rifapentine/isoniazid regimen due to undesirable side effects.This was the first study to compare the 2 treatment regimens in Taiwan, and it showed that a short-term high-dosage Rifapentine/isoniazid treatment regimen reduced costs and resulted in higher treatment completion than the standard LTBI isoniazid treatment. |
| 2017 | Twelve-Week Rifapentine Plus Isoniazid Versus 9-Month Isoniazid for the Treatment of Latent Tuberculosis in Renal Transplant Candidates. | Transplantation | Renal transplant candidates (RTC) with latent tuberculosis infection (LTBI) are at significant risk for tuberculosis reactivation. Twelve-week Rifapentine (RPT)/isoniazid (INH) is effective for LTBI but clinical experience in RTC is scarce.We conducted a retrospective study of RTC with LTBI treated with either 12-week RPT/INH or 9-month INH from March 1, 2012, through February 28, 2014. We evaluated both groups for differences in rates of treatment completion, monthly follow-up visit compliance, transaminase elevations, and adverse reactions leading to discontinuation of LTBI treatment. The utility of weekly reminders was also evaluated in the 12-week regimen. Direct observed therapy was not performed in our study.Of 153 patients, 43 (28%) and 110 (72%) were started on 12-week RPT/INH and 9-month INH, respectively. The treatment completion and monthly follow-up visit compliance rates were higher in the 12-week RPT/INH group (40 [93%] vs 52 [47%], P < 0.001) and (11/40 [28%] vs 13/104 [13%], P = 0.03), respectively. Transaminase elevations were not observed in the RPT/INH group, but occurred in 6 (5%) of the INH group. There were no differences in adverse reactions leading to discontinuation of LTBI treatment.Twelve-week RPT/INH appears to be an excellent choice for LTBI in RTC. It has a higher treatment completion rate and causes less transaminase elevations, and weekly reminders may be an alternative when direct observed therapy is not feasible. |
| 2016 | Rifapentine for the treatment of latent tuberculosis. | Expert Rev Clin Pharmacol | The goal of this article is to review the use of Rifapentine in the treatment of latent tuberculosis infection (LTBI). Controlling LTBI is an important part of the global strategy to end the spread of tuberculosis. Rifapentine's potent sterilizing effect against Mycobacterium tuberculosis combined with its long half-life make it an attractive LTBI treatment option. Areas covered: A systematic literature search of Pubmed using the terms 'Rifapentine' and 'tuberculosis' was performed. Articles identified were cross-referenced for other relevant publications. The mechanisms of action and resistance, pharmacokinetic and pharmacodynamics, potential drug interactions and side effects are discussed. Expert commentary: Rifapentine in combination with isoniazid for twelve weeks is the best available option for treating latent TB in the majority of patients in the United States due to its favorable safety profile and the increased likelihood of completing therapy. Currently, Rifapentine is not registered or available in other countries. |
| 2016 | In vitro evaluation of novel inhalable dry powders consisting of thioridazine and rifapentine for rapid tuberculosis treatment. | Eur J Pharm Biopharm | Thioridazine is an orally administered antipsychotic drug with potential for treatment of drug-resistant tuberculosis (TB). However, drug-induced adverse cardiac effects have been reported when thioridazine was used at an efficacious oral dose of 200mg/day to treat TB. Pulmonary delivery of thioridazine could be a rational approach to reduce dose-related side effects while enabling high drug concentrations at the primary site of infection. The present study compares in vitro aerosol performance, storage stability, and in vitro antimicrobial activity and cytotoxicity of two inhalable powders composed of thioridazine and a first-line anti-TB drug, Rifapentine. Formulation 1 is a combination of amorphous thioridazine and crystalline Rifapentine, while Formulation 2 consisted of both drugs as amorphous forms. Both thioridazine-Rifapentine formulations were found suitable for inhalation with a total fine particle fraction (<5μm) of 68-76%. The two powders had similar MIC90 to Rifapentine alone, being 0.000625μg/mL and 0.005μg/ml against Mycobacterium tuberculosis H37Ra and M. tuberculosis H37Rv, respectively. In contrast, thioridazine alone had a MIC90 of 12.5μg/mL and 500μg/mL, against M. tuberculosis H37Ra and M. tuberculosis H37Rv, respectively, demonstrating no synergistic anti-TB activity. However, thioridazine and Rifapentine in a ratio of 1:3 enhanced the killing of M. tuberculosis H37Ra within the human monocyte-derived macrophages (THP-1) compared to the single drug treatments. Both powders showed an acceptable half maximal inhibitory concentration (IC50) of 31.25μg/mL on both THP-1 and human lung epithelial (A549) cells. However, Formulation 1 showed greater chemical stability than Formulation 2 after three months of storage under low humidity (vacuum) at 20±3°C. In conclusion, we have demonstrated a novel inhalable powder consisted of amorphous thioridazine and crystalline Rifapentine (Formulation 1) with a good aerosol performance, potent anti-TB activity and storage stability, which deserves further in vivo investigations. |
| Evaluation of New Antibacterial Drugs and their Combinations in a Murine Model to Identify Short Duration Alternative Chemotherapy for Leprosy. | Indian J Lepr | The objective of the research is to test the efficacy of new drugs and drug combinations in mice infected with Mycobacterium leprae (M. leprae) as alternative to current WHO MDT. Individual drugs tested were Rifampicin (RMP), Rifapentine (RPT) and Moxifloxacin (MOXI). Drug combinations were RMP, Clarithromycin (CLARI), Minocycline (MINO) and RMP, MINO and Ofloxacin (OFLO). RPT drug combinations were RPT, CLARI,MINO and RPT, OFLO, MINO. Both the drugs and drug combinations were used as daily regimen and intermittent regimen. WHO MB MDT served as a positive control. Mice pre-inoculated with M. leprae were allotted to daily and intermittent groups and administered selected drugs and drug combinations. At the end of 12 months post sub-inoculation, mice were sacrificed and the proportion % of viable bacilli were counted using Spearman and Karber method. It was noted that RMP, RPT and Moxifloxacin indicated a range of 89.99% to 99.99% bactericidal effect when used in daily or intermittent doses in both normal and TR mice. Drug combinations showed bactericidal effect comparable to that of WHO MDT. From the study it was concluded that if the present duration of MDT has to be shortened then daily dose regimen with RMP/MINO/OFLO or RPT/CLARI/MINO are recommended for a clinical trial. |
| Evaluation of anti-bacterial activity of Rifapentine, Clarithromycin, Minocycline, Moxifloxacin, Ofloxacin and their combinations in Murine Model of Rifampicin Resistant Leprosy. | Indian J Lepr | Leprosy, a debilitating disease of the skin and peripheral nerves is caused by Mycobacterium leprae (M. leprae) and is treated by multidrug therapy (MDT) comprising of Dapsone, Rifampicin and Clofazimine. Resistance to any of these drugs poses a threat to the current disease control strategies. With the emergence of Rifampicin resistance in leprosy, it is important that alternative drugs need to be tested to develop a treatment strategy to combat drug resistant leprosy. In the current study, we have investigated WHO MDT, Rifapentine, Clarithromycin, Minocycline, Moxifloxacin, Ofloxacin and their combinations in intermittent and daily dose regimens in rifampicin resistant strains of M. leprae through mouse foot pad experiments in order to determine the loss in viability of M. leprae in response to these drugs and their combinations. Our findings suggest that WHO MDT is still the best combination in Rifampicin resistance cases. Combination of Moxifloxacin with Minocycline and Clarithromycin may also be taken up for clinical trials in cases with Rifampicin resistant leprosy. Rifapentine and Moxifloxacin can be effective alternative drugs to replace Rifampicin where required either in daily dose shorter duration regimens or intermittent dose longer regimen to treat resistant strains. |
| 2017 | Tackling Drug-Resistant Tuberculosis: Current Trends and Approaches. | Mini Rev Med Chem | Tuberculosis is very much rampant in our society and accounts for a large number of deaths annually. In spite of consistent efforts being made, the disease has not been curtailed yet. The emergence of MDR and XDR strains in the society along with an increase in the number of HIV cases and that of latent TB, have further aggravated the problem making the disease very much persistent. The current situation clearly manifests the need to discover and develop new potent molecules/approaches that could help to tackle drug resistance. Various molecules, such as derivatives of fluoroquinolones (e.g. gatifloxacin, moxifloxacin and DC-159a), rifamycins (Rifapentine), oxazolidinones (linezolid, sutezolid/PNU-100480), diarylquinolines (TMC207/bedaquiline), antifungal azoles, pyrrole (LL3858), nitroimidazopyran (PA824), nitroimidazole (OPC67683, TBA-354), diamine (SQ109) and benzothiazinone (BTZ043) are being developed in an attempt to combat the disease. This review presents a general introduction to the current status of the disease, the biology of the pathogen as well as the state of drug development against tuberculosis (TB) with emphasis on the major problems and bottlenecks associated with the same. Starting from the first drug against TB, the review discusses the entire history and the course of development of the drugs which are available today in the market as well as those which are under various phases of clinical and pre-clinical trials along with their mechanism of action. It also talks about the possible role of nanosciences in combating TB. |
| 2016 | Rifamycins, Alone and in Combination. | Cold Spring Harb Perspect Med | Rifamycins inhibit RNA polymerase of most bacterial genera. Rifampicin remains part of combination therapy for treating tuberculosis (TB), and for treating Gram-positive prosthetic joint and valve infections, in which biofilms are prominent. Rifabutin has use for AIDS patients in treating mycobacterial infections TB and Mycobacterium avium complex (MAC), having fewer drug-drug interactions that interfere with AIDS medications. Rifabutin is occasionally used in combination to eradicate Helicobacter pylori (peptic ulcer disease). Rifapentine has yet to fulfill its potential in reducing time of treatment for TB. Rifaximin is a monotherapeutic agent to treat gastrointestinal (GI) disorders, such as hepatic encephalopathy, irritable bowel syndrome, and travelers' diarrhea. Rifaximin is confined to the GI tract because it is not systemically absorbed on oral dosing, achieving high local concentrations, and showing anti-inflammatory properties in addition to its antibacterial activity. Resistance issues are unavoidable with all the rifamycins when the bioburden is high, because of mutations that modify RNA polymerase. |
| 2016 | Physiologically Based Pharmacokinetic Model of Rifapentine and 25-Desacetyl Rifapentine Disposition in Humans. | Antimicrob Agents Chemother | Rifapentine (RPT) is a rifamycin antimycobacterial and, as part of a combination therapy, is indicated for the treatment of pulmonary tuberculosis (TB) caused by Mycobacterium tuberculosis Although the results from a number of studies indicate that Rifapentine has the potential to shorten treatment duration and enhance completion rates compared to other rifamycin agents utilized in antituberculosis drug regimens (i.e., regimens 1 to 4), its optimal dose and exposure in humans are unknown. To help inform such an optimization, a physiologically based pharmacokinetic (PBPK) model was developed to predict time course, tissue-specific concentrations of RPT and its active metabolite, 25-desacetyl Rifapentine (dRPT), in humans after specified administration schedules for RPT. Starting with the development and verification of a PBPK model for rats, the model was extrapolated and then tested using human pharmacokinetic data. Testing and verification of the models included comparisons of predictions to experimental data in several rat tissues and time course RPT and dRPT plasma concentrations in humans from several single- and repeated-dosing studies. Finally, the model was used to predict RPT concentrations in the lung during the intensive and continuation phases of a current recommended TB treatment regimen. Based on these results, it is anticipated that the PBPK model developed in this study will be useful in evaluating dosing regimens for RPT and for characterizing tissue-level doses that could be predictors of problems related to efficacy or safety. |
| 2016 | Three months of weekly rifapentine and isoniazid for treatment of Mycobacterium tuberculosis infection in HIV-coinfected persons. | AIDS | Compare the effectiveness, tolerability, and safety of 3 months of weekly Rifapentine and isoniazid under direct observation (3HP) versus 9 months of daily isoniazid (9H) in HIV-infected persons.Prospective, randomized, and open-label noninferiority trial.The United States , Brazil, Spain, Peru, Canada, and Hong Kong.HIV-infected persons who were tuberculin skin test positive or close contacts of tuberculosis cases.3HP versus 9H.The effectiveness endpoint was tuberculosis; the noninferiority margin was 0.75%. The tolerability endpoint was treatment completion; the safety endpoint was drug discontinuation because of adverse drug reaction.Median baseline CD4 cell counts were 495 (IQR 389-675) and 538 (IQR 418-729) cells/μl in the 3HP and 9H arms, respectively (P = 0.09). In the modified intention-to-treat analysis, there were two tuberculosis cases among 206 persons [517 person-years (p-y) of follow-up] in the 3HP arm (0.39 per 100 p-y) and six tuberculosis cases among 193 persons (481 p-y of follow-up) in the 9H arm (1.25 per 100 p-y). Cumulative tuberculosis rates were 1.01 versus 3.50% in the 3HP and 9H arms, respectively (rate difference: -2.49%; upper bound of the 95% confidence interval of the difference: 0.60%). Treatment completion was higher with 3HP (89%) than 9H (64%) (P < 0.001), and drug discontinuation because of an adverse drug reaction was similar (3 vs. 4%; P = 0.79) in 3HP and 9H, respectively.Among HIV-infected persons with median CD4 cell count of approximately 500 cells/μl, 3HP was as effective and safe for treatment of latent Mycobacterium tuberculosis infection as 9H, and better tolerated. |
| 2016 | A Phase 2 Randomized Trial of a Rifapentine plus Moxifloxacin-Based Regimen for Treatment of Pulmonary Tuberculosis. | PLoS One | The combination of Rifapentine and moxifloxacin administered daily with other anti-tuberculosis drugs is highly active in mouse models of tuberculosis chemotherapy. The objective of this phase 2 clinical trial was to determine the bactericidal activity, safety, and tolerability of a regimen comprised of Rifapentine, moxifloxacin, isoniazid, and pyrazinamide administered daily during the first 8 weeks of pulmonary tuberculosis treatment.Adults with sputum smear-positive pulmonary tuberculosis were randomized to receive either Rifapentine (approximately 7.5 mg/kg) plus moxifloxacin (investigational arm), or rifampin (approximately 10 mg/kg) plus ethambutol (control) daily for 8 weeks, along with isoniazid and pyrazinamide. The primary endpoint was sputum culture status at completion of 8 weeks of treatment.121 participants (56% of accrual target) were enrolled. At completion of 8 weeks of treatment, negative cultures using Löwenstein-Jensen (LJ) medium occurred in 47/60 (78%) participants in the investigational arm vs. 43/51 (84%, p = 0.47) in the control arm; negative cultures using liquid medium occurred in 37/47 (79%) in the investigational arm vs. 27/41 (66%, p = 0.23) in the control arm. Time to stable culture conversion was shorter for the investigational arm vs. the control arm using liquid culture medium (p = 0.03), but there was no difference using LJ medium. Median Rifapentine area under the concentration-time curve (AUC0-24) was 313 mcg*h/mL, similar to recent studies of Rifapentine dosed at 450-600 mg daily. Median moxifloxacin AUC0-24 was 28.0 mcg*h/mL, much lower than in trials where Rifapentine was given only intermittently with moxifloxacin. The proportion of participants discontinuing assigned treatment for reasons other than microbiological ineligibility was higher in the investigational arm vs. the control arm (11/62 [18%] vs. 3/59 [5%], p = 0.04) although the proportions of grade 3 or higher adverse events were similar (5/62 [8%] in the investigational arm vs. 6/59 [10%, p = 0.76] in the control arm).For intensive phase daily tuberculosis treatment in combination with isoniazid and pyrazinamide, a regimen containing moxifloxacin plus low dose Rifapentine was at least as bactericidal as the control regimen containing ethambutol plus standard dose rifampin.www.ClinicalTrials.gov NCT00728507. |
| 2016 | Tackling the unknowns of short-course rifapentine-based treatment for active tuberculosis: a decision analysis. | Int J Tuberc Lung Dis | Shorter treatment regimens for tuberculosis (TB) are deemed vital for advancing TB control. Murine studies have suggested potential new regimens; however, Phase II human studies of these drug combinations have not shown clear improvement in 2-month culture conversion over current therapy. Nevertheless, drugs such as Rifapentine (RPT) may have additional sterilizing effects after 2 months that are difficult to measure in current Phase II studies.To model potential bactericidal effects of RPT in a Phase III trial of a 4-month anti-tuberculosis regimen.We developed a Markov model of anti-tuberculosis treatment to compare two regimens for treating TB: a 6-month standard (rifampin-based) treatment and a 4-month regimen using high-dose RPT. The primary outcome was the number of relapses.In the base-case scenario, standard therapy resulted in fewer relapses; improvement in 2-month culture conversion rates in the RPT arm did not change this result. However, while RPT has better sterilizing ability during months 3 and 4 (as observed in the mouse model), the 4-month regimen results in fewer relapses.Higher 2-month culture conversion rates are neither sufficient nor necessary for making a theoretical 4-month anti-tuberculosis treatment regimen advantageous. |
| 2016 | Safety and Adherence for 12 Weekly Doses of Isoniazid and Rifapentine for Pediatric Tuberculosis Infection. | Pediatr Infect Dis J | Traditional treatment of tuberculosis infection (TBI) is efficacious, but adherence is low. Eighty children with TBI received a 12-dose once-weekly isoniazid/Rifapentine regimen; 79 (99%) completed therapy, 94% reported no adverse events, 1 child had mildly elevated transaminases but 1 adolescent later developed pulmonary TB. Isoniazid/Rifapentine is safe, is well tolerated and has much higher completion rates than traditional TBI regimens. |
| 2016 | School-based Study to Identify and Treat Adolescent Students at Risk for Tuberculosis Infection. | Pediatr Infect Dis J | Screening for and treating tuberculosis (TB) infection in children and adolescents is an effective way of decreasing future TB cases. However, current approaches leave many children at risk for TB unidentified.We recruited adolescent students from 2 public high schools (a magnet and a low-income) in the Houston Independent School District. Compared with the magnet school, the student population at the low-income school was larger, primarily Hispanic and economically disadvantaged. Students were educated about TB, and parents completed a risk factor questionnaire. Students with TB risk factors were tested using 2 interferon gamma release assays (IGRAs). Those with a positive IGRA received a 12-dose regimen of weekly isoniazid/Rifapentine (3HP) administered via direct observation at school.Nine hundred twenty-five students received TB education; 73% of their parents submitted the TB questionnaire. Eighty-six percent of students (n = 415) with a TB risk factor identified on the study questionnaire agreed to IGRA testing. Sixteen students had at least one positive IGRA (1% [magnet], 4.1% [low-income]; P = 0.005). Recent student travel to a high-risk country (7) or contact with TB disease (2) were associated with IGRA positivity (P < 0.05). All students with a positive IGRA accepted, tolerated and completed 3HP treatment at school.School-based TB education, screening, testing using IGRAs and administration of 3HP treatment is feasible to improve the identification and treatment of adolescent students at risk for TB. |
| 2016 | Rifapentine-loaded PLGA microparticles for tuberculosis inhaled therapy: Preparation and in vitro aerosol characterization. | Eur J Pharm Sci | Inhaled delivery of drugs incorporated into poly (lactic-co-glycolic acid) (PLGA) microparticles allows a sustained lung concentration and encourages phagocytosis by alveolar macrophages that harboring Mycobacterium tuberculosis. However, limited data are available on the effects of physicochemical properties of PLGA, including the monomer ratio (lactide:glycide) and molecular weight (MW) on the aerosol performance, macrophage uptake, and toxicity profile. The present study aims to address this knowledge gap, using PLGAs with monomer ratios of 50:50, 75:25 and 85:15, MW ranged 24 - 240kDa and an anti-tuberculosis (TB) drug, Rifapentine. The PLGA-Rifapentine powders were produced through a solution spray drying technique. The particles were spherical with a smooth surface and a volume median diameter around 2μm (span ~2). When the powders were dispersed using an Osmohaler(®) at 100L/min for 2.4s, the fine particle fraction (FPFtotal, wt.% particles in aerosol <5μm relative to the total recovered drug mass) was ranged between 52 and 57%, with no significant difference between the formulations. This result suggests that the monomer ratio and MW are not crucial parameters for the aerosol performance of PLGA. The phagocytosis analysis was performed using Thp-1 monocyte-derived macrophages. The highest rate of uptake was observed in PLGA 85:15 followed by 75:25 and 50:50 with about 90%, 80% and 70%, respectively phagocytosis over 4h of exposure. Furthermore, the cytotoxicity analysis on Thp-1 and human lung adenocarcinoma epithelial cells demonstrated that PLGA concentration up to 1.5mg/mL, regardless of the monomer composition and MW, were non-toxic. In conclusion, the monomer ratio and MW are not crucial in determining the aerosol performance and cytotoxicity profile of PLGA however, the particles with high lactide composition have a superior tendency for macrophage uptake. |
| 2016 | Characterization of 22 Antituberculosis Drugs for Inhibitory Interaction Potential on Organic Anionic Transporter Polypeptide (OATP)-Mediated Uptake. | Antimicrob Agents Chemother | We investigated the inhibitory interaction potential of 22 currently marketed antituberculosis (TB) drugs on organic anion-transporting polypeptide 1B1 (OATP1B1)-, OATP2B1-, and OATP1B3-mediated uptake using in vitro Xenopus oocytes and HEK cells. Rifabutin, ethambutol, amoxicillin, linezolid, p-amino salicylic acid, and Rifapentine exhibited mild to moderate inhibitory effects on OATP-mediated uptake of estrone-3 sulfate, estradiol 17β-d-glucuronide, and rosuvastatin. The 50% inhibitory concentration (IC50) values of rifabutin, amoxicillin, ethambutol, p-amino salicylic acid, and linezolid were 35.4, 36.2, 57.6, 72.6, and 65.9 μM, respectively, for uptake mediated by organic anionic transporter polypeptide 1B1 (OATP1B1) and 28.8, 28.9, 53.9, 31.5, and 61.0 μM, respectively, for uptake mediated by organic anionic transporter polypeptide 1B3 (OATP1B3). Streptomycin and linezolid showed greater inhibition of organic anionic transporter polypeptide 2B1 (OATP2B1)-mediated uptake, with IC50 values of 33.2 and 35.6 μM, respectively, along with mild inhibition of other drugs. Furthermore, rifabutin, amoxicillin, and Rifapentine significantly inhibited OATP1B1-mediated rosuvastatin uptake, with IC50 values of 12.3, 13.0, and 11.0 μM, respectively, which showed a similar profile to estrone-3 sulfate uptake. The calculated R values ([I]u inlet,max/Ki, where [I]u inlet,max represents the maximum estimated inhibitor concentration inlet to the liver and Ki is the inhibition constant) as the drug-drug interaction (DDI) indexes of PAS, ethambutol, and amoxicillin were 26.1, 6.5, and 4.3 for OATP1B1 and 52.0, 8.0, and 4.6 for OATP1B3, and those for streptomycin, amikacin, and linezolid were 5.0, 4.2, and 4.4 for OATP2B1, respectively, suggesting a higher possibility of in vivo DDIs. This study is the first comprehensive report to show the novel inhibitory potential of 22 marketed anti-TB drugs on OATP-mediated uptake, providing evidence for future in vivo clinical DDI studies. |
| 2016 | Factors Associated With Noncompletion of Latent Tuberculosis Infection Treatment: Experience From the PREVENT TB Trial in the United States and Canada. | Clin Infect Dis | Overall rates of noncompletion of treatment (NCT) for latent tuberculosis infection (LTBI) in the PREVENT TB trial were 18% for 3 months of directly observed once-weekly Rifapentine (maximum dose, 900 mg) plus isoniazid (maximum dose, 900 mg) (3HP-DOT) and 31% for 9 months of daily self-administered isoniazid (maximum dose, 300 mg; 9H-SAT). NCT for LTBI reduces its effectiveness. The study objective was to assess factors associated with NCT for LTBI among adult participants enrolled at US and Canadian sites of the PREVENT TB trial.This was a post hoc exploratory analysis of the randomized, open-label PREVENT TB trial. Factors were analyzed by univariate and multivariate logistic regression (with enrollment site as a random effect).From 6232 participants analyzed, 1406 (22.6%) did not complete LTBI treatment (317 NCT attributed to an adverse event [NCT-AE] and 1089 NCT attributed to reasons other than an adverse event [NCT-O]). The proportion of NCT-AE was similar with both regimens (3HP-DOT = 6.4% vs 9H-SAT = 5.9%; P = .23); NCT-O was higher among participants enrolled in 9H-SAT (9H-SAT = 24.5% vs 3HP-DOT = 12.7%; P = .02). Among those in the NCT-AE group, being non-Hispanic and receiving 3HP-DOT, having cirrhosis and receiving 9H-SAT, alcohol consumption among men, and use of concomitant medication were associated with NCT-AE. Among those in the NCT-O group, receiving 9H-SAT, missing ≥1 early visit, men receiving 9H-SAT, men with a history of incarceration, alcohol abuse, use ever of intravenous drugs, younger age receiving 9H-SAT, and smoking were associated with NCT-O.Factors associated with NCT, such as missing a clinic visit early during treatment, might help identify persons for whom tailored interventions could improve completion of LTBI treatment.NCT00023452. |
| 2016 | Validation of a simple HPLC-UV method for rifampicin determination in plasma: Application to the study of rifampicin arteriovenous concentration gradient. | J Pharm Biomed Anal | In clinical practice, rifampicin exposure is estimated from its concentration in venous blood samples. In this study, we hypothesized that differences in rifampicin concentration may exist between arterial and venous plasma. An HPLC-UV method for determining rifampicin concentration in plasma using Rifapentine as an internal standard was validated. The method, which requires a simple protein precipitation procedure as sample preparation, was performed to compare venous and arterial plasma kinetics after a single therapeutic dose of rifampicin (8.6 mg/kg i.v, infused over 30 min) in baboons (n=3). The method was linear from 0.1 to 40 μg mL(-1) and all validation parameters fulfilled the international requirements. In baboons, rifampicin concentration in arterial plasma was higher than in venous plasma. Arterial Cmax was 2.1±0.2 fold higher than venous Cmax. The area under the curve (AUC) from 0 to 120 min was ∼80% higher in arterial plasma, indicating a significant arteriovenous concentration gradient in early rifampicin pharmacokinetics. Arterial and venous plasma concentrations obtained 6h after rifampicin injection were not different. An important arteriovenous equilibration delay for rifampicin pharmacokinetics is reported. Determination in venous plasma concentrations may considerably underestimate rifampicin exposure to organs during the distribution phase. |
| 2016 | Completion Rate and Side-Effect Profile of Three-Month Isoniazid and Rifapentine Treatment for Latent Tuberculosis Infection in an Urban County Jail. | Open Forum Infect Dis | In an urban jail population, 3 months of isoniazid and Rifapentine (3HP) was associated with an 85% latent tuberculosis infection treatment completion rate compared with 18% in a standard 9-month isoniazid treatment group. Among the 91 patients who started 3HP therapy, there were 2 treatment discontinuations from adverse drug reactions. |
| 2016 | In Vitro Evaluation of Inhalable Verapamil-Rifapentine Particles for Tuberculosis Therapy. | Mol Pharm | Recent studies have demonstrated that efflux pumps of Mycobacterium tuberculosis (M. tb) provide a crucial mechanism in the development of drug resistant to antimycobacterial drugs. Drugs that inhibit these efflux pumps, such as verapamil, have shown the potential in enhancing the treatment success. We therefore hypothesized that the combined inhaled administration of verapamil and a first-line rifamycin antibiotic will further improve the treatment efficacy. An inhalable dry powder consisting of amorphous verapamil and crystalline Rifapentine with l-leucine as an excipient was produced by spray drying. The in vitro aerosol characteristic of the powder, its microbiological activity and stability were assessed. When the powder was dispersed by an Osmohaler, the total fine particle fraction (FPFtotal, wt % of particles in aerosol <5 μm) of verapamil and Rifapentine was 77.4 ± 1.1% and 71.5 ± 2.0%, respectively. The combination drug formulation showed a minimum inhibitory concentration (MIC90) similar to that of Rifapentine alone when tested against both M. tb H37Ra and M. tb H37Rv strains. Importantly, the combination resulted in increased killing of M. tb H37Ra within the infected macrophage cells compared to either verapamil or Rifapentine alone. In assessing cellular toxicity, the combination exhibited an acceptable half maximal inhibitory concentration (IC50) values (62.5 μg/mL) on both human monocytic (THP-1) and lung alveolar basal epithelial (A549) cell lines. Finally, the powder was stable after 3 months storage in 0% relative humidity at 20 ± 3 °C. |
| [Toxicological Evaluation of Intravenous Formulation of Rifapentine.] | Antibiot Khimioter | Rifapentine belongs to the most potent antituberculosis drugs. Nevertheless, there are some limitations for its clinical use because of the low aqueous solubility and side effects. A technological approach to development of Rifapentine intravenous formulation based on human serum albumin was described earlier and its efficacy against experimental tuberculosis was estimated. Toxicological evaluation of that water-compatible form of Rifapentine revealed its low acute toxicity (LD₅₀ 340 mg/kg). Chronic toxicity tests of both the oral substance and the injectable formulation of Rifapentine demonstrated similar adverse effects. However, in contrast to the conventional oral formulations, the intravenous formulation of Rifapentine had no gastrointestinal toxic effects or cardiotoxicity, thus suggesting its usefulness for clinical application. |
| 2016 | Interspecies scaling of excretory amounts using allometry - retrospective analysis with rifapentine, aztreonam, carumonam, pefloxacin, miloxacin, trovafloxacin, doripenem, imipenem, cefozopran, ceftazidime, linezolid for urinary excretion and rifapentine, cabotegravir, and dolutegravir for fecal excretion. | Xenobiotica | 1. Interspecies allometry scaling for prediction of human excretory amounts in urine or feces was performed for numerous antibacterials. Antibacterials used for urinary scaling were: Rifapentine, pefloxacin, trovafloxacin (Gr1/low; <10%); miloxacin, linezolid, PNU-142300 (Gr2/medium; 10-40%); aztreonam, carumonam, cefozopran, doripenem, imipenem, and ceftazidime (Gr3/high; >50%). Rifapentine, cabotegravir, and dolutegravir was used for fecal scaling (high; >50%). 2. The employment of allometry equation: Y = aW(b) enabled scaling of urine/fecal amounts from animal species. Corresponding predicted amounts were converted into % recovery by considering the respective human dose. Comparison of predicted/observed values enabled fold difference and error calculations (mean absolute error [MAE] and root mean square error [RMSE]). Comparisons were made for urinary/fecal data; and qualitative assessment was made amongst Gr1/Gr2/Gr3 for urine. 3. Average correlation coefficient for the allometry scaling was >0.995. Excretory amount predictions were largely within 0.75- to 1.5-fold differences. Average MAE and RMSE were within ±22% and 23%, respectively. Although robust predictions were achieved for higher urinary/fecal excretion (>50%), interspecies scaling was applicable for low/medium excretory drugs. 4. Based on the data, interspecies scaling of urine or fecal excretory amounts may be potentially used as a tool to understand the significance of either urinary or fecal routes of elimination in humans in early development. |
| 2015 | Improving Treatment Completion Rates for Latent Tuberculosis Infection: A Review of Two Treatment Regimens at a Community Health Center. | J Health Care Poor Underserved | Prophylactic treatment of latent tuberculosis infection (LTBI) is necessary for controlling TB in low-incidence settings. However, treatment is often limited by poor completion rates.At a community health center serving low-income Hispanics, treatment completion among patients accepting 12 weekly doses of isoniazid (INH) plus Rifapentine (RPT) administered as directly observed therapy (DOT) was compared with that among patients accepting nine months of daily self-administered INH during 2012 and 2013 (n=139).Among patients who agreed to treatment, INH-RPT combination therapy was associated with higher completion rates (OR 3.06; 95% CI, 1.23-7.62; p=.016) when compared to INH only. Overall completion rates were 77.8% (35/45) for INH-RPT combination therapy and 52.1% (49/94) for INH monotherapy.High completion rates for LTBI treatment can be achieved at a community health center using INH-RPT administered via DOT. Greater success treating with INH-RPT may be attributed to DOT strategy and a shorter treatment regimen. |
| 2015 | [Role of Human Orphan Esterases in Drug-induced Toxicity]. | Yakugaku Zasshi | Esterases hydrolyze compounds containing ester, amide, and thioester bonds, causing prodrug activation or detoxification. Among esterases, carboxylesterases have been studied in depth due to their ability to hydrolyze a variety of drugs. However, there are several drugs for which the involved esterase(s) is unknown. We found that flutamide, phenacetin, rifamycins (rifampicin, rifabutin, and Rifapentine), and indiplon are hydrolyzed by arylacetamide deacetylase (AADAC), which is highly expressed in human liver and gastrointestinal tissues. Flutamide hydrolysis is considered associated with hepatotoxicity. Phenacetin, a prodrug of acetaminophen, was withdrawn due to side effects such as methemoglobinemia and renal failure. It was demonstrated in vitro and in vivo using mice that AADAC is responsible for phenacetin hydrolysis, which leads to methemoglobinemia. In addition, it was shown that AADAC-mediated hydrolysis attenuates the cytotoxicity of rifamycins. Thus AADAC plays critical roles in drug-induced toxicity. Another orphan esterase, α/β hydrolase domain containing 10 (ABHD10), was found responsible for deglucuronidation of acyl-glucuronides including mycophenolic acid acyl-glucuronide and probenecid acyl-glucuronide. Because acyl-glucuronides appear associated with toxicity, ABHD10 would function as a detoxification enzyme. The roles of orphan esterases are becoming increasingly understood. Further studies will facilitate our knowledge of the pharmacologic and toxicological significance of orphan esterases in drug therapy. |
| Rifapentine for latent tuberculosis infection treatment in the general population and human immunodeficiency virus-positive patients: summary of evidence. | Rev Soc Bras Med Trop | Latent tuberculosis infection (LTBI) and human immunodeficiency virus (HIV)-coinfection are challenges in the control of tuberculosis transmission. We aimed to assess and summarize evidence available in the literature regarding the treatment of LTBI in both the general and HIV-positive population, in order to support decision making by the Brazilian Tuberculosis Control Program for LTBI chemoprophylaxis. We searched MEDLINE, Cochrane Library, Centre for Reviews and Dissemination, Embase, LILACS, SciELO, Trip database, National Guideline Clearinghouse, and the Brazilian Theses Repository to identify systematic reviews, randomized clinical trials, clinical guidelines, evidence-based synopses, reports of health technology assessment agencies, and theses that investigated Rifapentine and isoniazid combination compared to isoniazid monotherapy. We assessed the quality of evidence from randomized clinical trials using the Jadad Scale and recommendations from other evidence sources using the Grading of Recommendations, Assessment, Development, and Evaluations approach. The available evidence suggests that there are no differences between Rifapentine + isoniazid short-course treatment and the standard 6-month isoniazid therapy in reducing active tuberculosis incidence or death. Adherence was better with directly observed Rifapentine therapy compared to self-administered isoniazid. The quality of evidence obtained was moderate, and on the basis of this evidence, Rifapentine is recommended by one guideline. Available evidence assessment considering the perspective of higher adherence rates, lower costs, and local peculiarity context might support Rifapentine use for LTBI in the general or HIV-positive populations. Since novel trials are ongoing, further studies should include patients on antiretroviral therapy. |
| 2015 | Management of latent Mycobacterium tuberculosis infection: WHO guidelines for low tuberculosis burden countries. | Eur Respir J | Latent tuberculosis infection (LTBI) is characterised by the presence of immune responses to previously acquired Mycobacterium tuberculosis infection without clinical evidence of active tuberculosis (TB). Here we report evidence-based guidelines from the World Health Organization for a public health approach to the management of LTBI in high risk individuals in countries with high or middle upper income and TB incidence of <100 per 100 000 per year. The guidelines strongly recommend systematic testing and treatment of LTBI in people living with HIV, adult and child contacts of pulmonary TB cases, patients initiating anti-tumour necrosis factor treatment, patients receiving dialysis, patients preparing for organ or haematological transplantation, and patients with silicosis. In prisoners, healthcare workers, immigrants from high TB burden countries, homeless persons and illicit drug users, systematic testing and treatment of LTBI is conditionally recommended, according to TB epidemiology and resource availability. Either commercial interferon-gamma release assays or Mantoux tuberculin skin testing could be used to test for LTBI. Chest radiography should be performed before LTBI treatment to rule out active TB disease. Recommended treatment regimens for LTBI include: 6 or 9 month isoniazid; 12 week Rifapentine plus isoniazid; 3-4 month isoniazid plus rifampicin; or 3-4 month rifampicin alone. |
| 2014 | Activism on rifapentine pricing: removing cost barriers to improve the uptake of tuberculosis research innovations. | Public Health Action | As recent advances have been made in developing tools to fight tuberculosis (TB), there is also a trend towards increasing advocacy by the civil society for TB research and access. One recent successful effort to increase access to treatment options for TB involved a collaborative effort to identify the need for and barriers to the use of Rifapentine (RPT) use in the United States. Survey responses confirmed the under-utilization of RPT: 82% of survey respondents selected cost as a significant or potential barrier to use. Survey results provided data to support a year-long advocacy campaign urging the drug company Sanofi to lower the price of RPT. This campaign was based on a common evidence base built in part by the stakeholders themselves. After multiple engagements with communities and providers, Sanofi US announced on 12 December 2013 that they would drop the price of RPT to US$32 per blister pack of 32 tablets for US public health programs. While further work remains to secure access to RPT in the United States and worldwide, the lowering of the price of RPT reflects the positive impact that collaborative advocacy can accomplish, and sets an example for other drug companies to follow. |
| 2015 | Uniform and amorphous rifampicin microspheres obtained by freezing induced LLPS during lyophilization. | Int J Pharm | By lyophilization of rifampicin (RIF) solution in TBA/water with various solvent compositions, uniform and amorphous rifampicin (RIF) microspheres were produced. Using 55% TBA solution, the obtained RIF microspheres have a mono-dispersive size distribution with diameters range from 1 to 3 μm. The RIF microspheres are found to be amorphous by X-ray diffraction, and are expected to dissolve much faster than the crystalline RIF upon inhalation. Mechanistic investigation revealed that the amorphous RIF microspheres were formed due to liquid-liquid phase separation (LLPS) occurred during the freezing of the TBA/water solution. We also observed that the RIF microspheres can be readily phagocytized by activated THP-1 cells within 15 min. The suitable size distribution, high solubility, and readiness for phagocytosis by macrophages, all suggest that the lyophilized amorphous RIF microspheres could be potentially used as an anti-tuberculosis inhalation therapy. In addition, similar process was used to lyophilize TBA/water solutions of several other drugs, including rifaximin, Rifapentine, paclitaxel, and isoniazid. We found that for drugs with appropriate physiochemical properties, such as paclitaxel and rifaximin, mono-dispersive microspheres could be obtained as well, which demonstrated that freezing induced LLPS could be utilized as a novel particle engineering methodology to produce drug microspheres by lyophilization. |
| 2015 | Drug Susceptibility Testing of 31 Antimicrobial Agents on Rapidly Growing Mycobacteria Isolates from China. | Biomed Res Int | Several species of rapidly growing mycobacteria (RGM) are now recognized as human pathogens. However, limited data on effective drug treatments against these organisms exists. Here, we describe the species distribution and drug susceptibility profiles of RGM clinical isolates collected from four southern Chinese provinces from January 2005 to December 2012.Clinical isolates (73) were subjected to in vitro testing with 31 antimicrobial agents using the cation-adjusted Mueller-Hinton broth microdilution method. The isolates included 55 M. abscessus, 11 M. fortuitum, 3 M. chelonae, 2 M. neoaurum, and 2 M. septicum isolates.M. abscessus (75.34%) and M. fortuitum (15.07%), the most common species, exhibited greater antibiotic resistance than the other three species. The isolates had low resistance to amikacin, linezolid, and tigecycline, and high resistance to first-line antituberculous agents, amoxicillin-clavulanic acid, Rifapentine, dapsone, thioacetazone, and pasiniazid. M. abscessus and M. fortuitum were highly resistant to ofloxacin and rifabutin, respectively. The isolates showed moderate resistance to the other antimicrobial agents.Our results suggest that tigecycline, linezolid, clofazimine, and cefmetazole are appropriate choices for M. abscessus infections. Capreomycin, sulfamethoxazole, tigecycline, clofazimine, and cefmetazole are potentially good choices for M. fortuitum infections. Our drug susceptibility data should be useful to clinicians. |
| 2016 | Treatment for Tuberculosis Infection With 3 Months of Isoniazid and Rifapentine in New York City Health Department Clinics. | Clin Infect Dis | Completion of treatment for tuberculosis infection (TBI) with 9 months of self-administered daily isoniazid (9H) has historically been low (<50%) among New York City (NYC) Health Department tuberculosis clinic patients. Treatment of TBI with 3 months of once-weekly isoniazid and Rifapentine (3HP) administered under directly observed therapy (DOT) might increase treatment acceptance and completion.The study population included patients diagnosed with TBI at 2 NYC Health Department tuberculosis clinics from January 2013 through November 2013. Treatment acceptance and completion with 3HP were compared with historical estimates. Treatment outcomes, side effects, and reasons for refusing 3HP were described.Among 631 patients eligible for TBI treatment, 503 (80%) were offered 3HP; 302 (60%) accepted, 92 (18%) chose other treatment, and 109 (22%) refused treatment. The most common reason for refusing 3HP was the clinic-based DOT requirement. Forty (13%) patients treated with 3HP experienced side effects--9 were restarted on 3HP, 18 switched treatment regimens, and 13 discontinued. Although treatment acceptance did not differ from historical estimates (78% vs 79%, P = .75), treatment completion increased significantly (65% vs 34%, P < .01).Implementation of 3HP in 2 NYC Health Department tuberculosis clinics increased TBI treatment completion by 31 percentage points compared with historical estimates. More flexible DOT options may improve acceptance of 3HP. Wider use of 3HP may substantially improve TBI treatment completion in NYC and advance progress toward tuberculosis elimination. |
| 2015 | Three months of weekly rifapentine plus isoniazid is less hepatotoxic than nine months of daily isoniazid for LTBI. | Int J Tuberc Lung Dis | Nine months of daily isoniazid (9H) and 3 months of once-weekly Rifapentine plus isoniazid (3HP) are recommended treatments for latent tuberculous infection (LTBI). The risk profile for 3HP and the contribution of hepatitis C virus (HCV) infection to hepatotoxicity are unclear.To evaluate the hepatotoxicity risk associated with 3HP compared to 9H, and factors associated with hepatotoxicity.Hepatotoxicity was defined as aspartate aminotransferase (AST) >3 times the upper limit of normal (ULN) with symptoms (nausea, vomiting, jaundice, or fatigue), or AST >5 x ULN. We analyzed risk factors among adults who took at least 1 dose of their assigned treatment. A nested case-control study assessed the role of HCV.Of 6862 participants, 77 (1.1%) developed hepatotoxicity; 52 (0.8%) were symptomatic; 1.8% (61/3317) were on 9H and 0.4% (15/3545) were on 3HP (P < 0.0001). Risk factors for hepatotoxicity were age, female sex, white race, non-Hispanic ethnicity, decreased body mass index, elevated baseline AST, and 9H. In the case-control study, HCV infection was associated with hepatotoxicity when controlling for other factors.The risk of hepatotoxicity during LTBI treatment with 3HP was lower than the risk with 9H. HCV and elevated baseline AST were risk factors for hepatotoxicity. For persons with these risk factors, 3HP may be preferred. |
| 2015 | Treatment of Staphylococcus aureus-induced chronic osteomyelitis with bone-like hydroxyapatite/poly amino acid loaded with rifapentine microspheres. | Drug Des Devel Ther | The purpose of this study was to investigate the curative effect of bone-like hydroxyapatite/poly amino acid (BHA/PAA) as a carrier for poly(lactic-co-glycolic acid)-coated Rifapentine microsphere (RPM) in the treatment of rabbit chronic osteomyelitis induced by Staphylococcus aureus.RPM was prepared through an oil-in-water emulsion solvent evaporation method, and RPM was combined with BHA/PAA to obtain drug-loaded, slow-releasing materials. Twenty-six New Zealand white rabbits were induced to establish the animal model of chronic osteomyelitis. After debridement, the animals were randomly divided into three groups (n=8): the experimental group (with RPM-loaded BHA/PAA), the control group (with BHA/PAA), and the blank group. The RPM-loaded BHA/PAA was evaluated for antibacterial activity, dynamics of drug release, and osteogenic ability through in vitro and in vivo experiments.In vitro, RPM-loaded BHA/PAA released the antibiotics slowly, inhibiting the bacterial growth of S. aureus for up to 5 weeks. In vivo, at week 4, the bacterial colony count was significantly lower in the experimental group than in the control and blank groups (P<0.01). At week 12, the chronic osteomyelitis was cured and the bone defect was repaired in the experimental group, whereas the infection and bone defect persisted in the control and blank groups.In vitro and in vivo experiments demonstrated that RPM-loaded BHA/PAA effectively cured S. aureus-induced chronic osteomyelitis. Therefore, BHA/PAA has potential value as a slow-releasing material in clinical setting. Further investigation is needed to determine the optimal dosage for loading Rifapentine. |
| 2015 | Inhibitory Potential of Twenty Five Anti-tuberculosis Drugs on CYP Activities in Human Liver Microsomes. | Biol Pharm Bull | The direct inhibitory potential of twenty five anti-tuberculosis drugs on eight CYP-specific reactions in human liver microsomes was investigated to predict in vivo drug-drug interactions (DDIs) from in vitro data. Rifampicin, rifabutin, and thioacetazone inhibited one CYP reaction. Isoniazid and clofazimine had inhibitory effects on four CYP reactions, and Rifapentine, ethionamide, and prothionamide widely inhibited CYP reactions. Based on the inhibition constant (Ki) and the therapeutic total inhibitor concentrations [I]max of eight drugs in human plasma, [I]max/Ki values were calculated to evaluate clinical DDIs. The [I]max/Ki values were 0.20 or less for rifampicin, rifabutin, and thioacetazone; 0.15-2.0 for isoniazid; 0.14-1.5 for Rifapentine; 0.29-1.4 for ethionamide; 0.41-2.2 for prothionamide; and 0.12-6.3 for clofazimine. The highest [I]max/Ki values were 2.0 for isoniazid on CYP3A4 [testosterone (T)]; 1.5 for Rifapentine on CYP3A4 [midazolam (M)]; 1.4 for ethionamide on CYP2C8; 2.2, 1.8, and 1.3 for prothionamide on CYP2B6, CYP2C19, and CYP2C8, respectively; and 6.3 and 5.7 for clofazimine on CYP3A4 (M) and CYP3A4 (T), respectively. These drugs with high [I]max/Ki values lead to clinical DDIs. Considering the drug regimens for tuberculosis (TB) and co-infection with TB and human immunodeficiency virus, the inhibitory potential for CYP3A4 and CYP2B6 is particularly important. These results suggest that clofazimine and prothionamide are likely to cause clinically relevant DDIs when co-administered with products metabolized by CYP3A4 and CYP2B6, respectively. Isoniazid and Rifapentine may cause DDIs with drugs metabolized by CYP3A4. |
| 2015 | Efavirenz Pharmacokinetics and Pharmacodynamics in HIV-Infected Persons Receiving Rifapentine and Isoniazid for Tuberculosis Prevention. | Clin Infect Dis | Concomitant use of rifamycins to treat or prevent tuberculosis can result in subtherapeutic concentrations of antiretroviral drugs. We studied the interaction of efavirenz with daily Rifapentine and isoniazid in human immunodeficiency virus (HIV)-infected individuals receiving a 4-week regimen to prevent tuberculosis.Participants receiving daily Rifapentine and isoniazid with efavirenz had pharmacokinetic evaluations at baseline and weeks 2 and 4 of concomitant therapy. Efavirenz apparent oral clearance was estimated and the geometric mean ratio (GMR) of values before and during Rifapentine and isoniazid was calculated. HIV type 1 (HIV-1) RNA was measured at baseline and week 8.Eighty-seven participants were evaluable: 54% were female, and the median age was 35 years (interquartile range [IQR], 29-44 years). Numbers of participants with efavirenz concentrations ≥1 mg/L were 85 (98%) at week 0; 81 (93%) at week 2; 78 (90%) at week 4; and 75 (86%) at weeks 2 and 4. Median efavirenz apparent oral clearance was 9.3 L/hour (IQR, 6.42-13.22 L/hour) at baseline and 9.8 L/hour (IQR, 7.04-15.59 L/hour) during Rifapentine/isoniazid treatment (GMR, 1.04 [90% confidence interval, .97-1.13]). Seventy-nine of 85 (93%) participants had undetectable HIV-1 RNA (<40 copies/mL) at entry; 71 of 75 (95%) participants had undetectable HIV-1 RNA at week 8. Two participants with undetectable HIV-1 RNA at study entry were detectable (43 and 47 copies/mL) at week 8.The proportion of participants with midinterval efavirenz concentrations ≥1 mg/L did not cross below the prespecified threshold of >80%, and virologic suppression was maintained. Four weeks of daily Rifapentine plus isoniazid can be coadministered with efavirenz without clinically meaningful reductions in efavirenz mid-dosing concentrations or virologic suppression.NCT 01404312. |
| 2015 | Two-stage activity-safety study of daily rifapentine during intensive phase treatment of pulmonary tuberculosis. | Int J Tuberc Lung Dis | Rifapentine (RPT) has potent activity against Mycobacterium tuberculosis; however, the optimal dose for anti-tuberculosis treatment is unknown.To determine the antimicrobial activity, safety and tolerability of RPT 450 mg or 600 mg administered daily during the first 8 weeks of treatment for pulmonary tuberculosis (TB).In a two-stage, randomised open-label study, adults with sputum smear-positive TB were randomised to receive RPT 450 mg, RPT 600 mg or rifampicin (RMP) 600 mg daily for 8 weeks with isoniazid, pyrazinamide and ethambutol. The primary endpoint was sputum culture status on Löwenstein-Jensen (LJ) medium at completion of 8 weeks of treatment.A total of 153 participants were enrolled. Both RPT regimens met pre-specified criteria to advance to stage 2. At completion of 8 weeks of treatment, LJ culture conversion occurred in 85% (35/41), 96% (43/45) and 94% (34/36) of participants in the RPT 450 mg, RPT 600 mg and RMP groups, respectively. The proportions of participants discontinuing treatment were similar (respectively 1/54 [2.0%], 1/51 [2.0%] and 4/48 [8.3%] in the RPT 450 mg, RPT 600 mg and RMP groups), as were ⩾grade 3 adverse events (0/54 [0%], 1/51 [2.0%] and 4/48 [8.3%]).There was a trend towards greater efficacy with RPT 600 mg than with RPT 450 mg. Daily RPT was safe and well-tolerated. |
| 2015 | Heterogeneous disease progression and treatment response in a C3HeB/FeJ mouse model of tuberculosis. | Dis Model Mech | Mice are the most commonly used species for non-clinical evaluations of drug efficacy against tuberculosis (TB). Unlike commonly used strains, C3HeB/FeJ mice develop caseous necrosis in the lung, which might alter the representation of drug efficacy in a way that is more like human TB. Because the development of such pathology requires time, we investigated the effect of infection incubation period on the activity of six drugs in C3HeB/FeJ and BALB/c mice. Mice were aerosol infected and held for 6, 10 or 14 weeks before receiving therapy with rifampin (RIF), Rifapentine (RPT), pyrazinamide (PZA), linezolid (LZD), sutezolid (PNU) or metronidazole (MTZ) for 4-8 weeks. Outcomes included pathological assessments, pH measurements of liquefied caseum and assessment of colony-forming unit (CFU) counts from lung cultures. Remarkable heterogeneity in the timing and extent of disease progression was observed in C3HeB/FeJ mice, largely independent of incubation period. Likewise, drug efficacy in C3HeB/FeJ mice was not affected by incubation period. However, for PZA, LZD and PNU, dichotomous treatment effects correlating with the presence or absence of large caseous lesions were observed. In the case of PZA, its poor activity in the subset of C3HeB/FeJ mice with large caseous lesions might be explained by the pH of 7.36±0.09 measured in liquefied caseum. This study highlights the potential value of C3HeB/FeJ mice for non-clinical efficacy testing, especially for investigating the interaction of lesion pathology and drug effect. Careful use of this model could enhance the bridging of non-clinical results with clinical outcomes. |
| Rifapentine-proliposomes for inhalation: in vitro and in vivo toxicity. | Toxicol Int | Oral therapy for pulmonary tuberculosis (TB) treatment suffers from the limitation of hepatic metabolism leading insufficient concentration of antitubercular (anti-TB) drugs in alveolar macrophage which harbors Mycobacterium tuberculosis (MTB). Targeted aerosol delivery of antituberculous drug to lung is efficient for treating local lung TB infection.The present study was aimed to evaluate Rifapentine (RPT) loaded proliposomal dry powder for inhalation (RLDPI) for anti-TBactivity and cytotoxicity in vitro. In vivo toxicity study was also undertaken in Wistar rats to determine safe concentration of RLDPI for administration.Anti-TB activity of developed RLDPI was assessed using drug susceptibility testing (DST) on Mycobacteria growth indicator tube (MGIT) method. In vitro cytotoxicity was performed in A549 cell lines and IC50 values were used to compare the cytotoxicity of formulation with pure RPT. In vivo repeated dose toxicity study was undertaken using Wistar rats at three different doses for 28-days by intratracheal insufflations method.The results of DST study revealed sensitivity of tubercle bacteria to RLDPI at concentration equivalent to 10 μg/mL of RPT. This study confirmed anti-TB potential of RPT in spray-dried RLDPI, though the spray drying method is reported to reduce activity of drugs. Cytotoxicity study in A549 cells demonstrated that RPT when encapsulated in liposomes as RLDPI was safe to cells as compared to pure RPT. In vivo toxicity study revealed that RPT in the form of RLDPI was safe at 1 and 5 mg/kg dose. However, mortality was seen at higher dose (10 mg/kg), possibly because of liver and kidney damage.Thus, these studies demonstrated safety of RLDPI for the treatment of pulmonary TB. |
| 2015 | Flu-like and Other Systemic Drug Reactions Among Persons Receiving Weekly Rifapentine Plus Isoniazid or Daily Isoniazid for Treatment of Latent Tuberculosis Infection in the PREVENT Tuberculosis Study. | Clin Infect Dis | Weekly Rifapentine plus isoniazid for 3 months (3HP) is as effective as daily isoniazid for 9 months (9H) for latent tuberculosis infection in high-risk persons, but there have been reports of possible flu-like syndrome.We identified clinically significant systemic drug reactions (SDR) and evaluated risk factors in patients who did not complete treatment in the PREVENT Tuberculosis study.Among 7552 persons who received ≥ 1 dose of study drug, 153 had a SDR: 138/3893 (3.5%) with 3HP vs 15/3659 (0.4%) with 9H (P < .001). In the 3HP arm, 87 (63%) had flu-like syndrome and 23 (17%) had cutaneous reactions; 13/3893 (0.3%) had severe reactions (6 were hypotensive) and 6 reported syncope. Symptoms occurred after a median of 3 doses, and 4 hours after the dose; median time to resolution was 24 hours. There were no deaths. In multivariate logistic regression analysis, factors independently associated with SDR included receipt of 3HP (adjusted odds ratio [aOR] 9.4; 95% confidence interval [CI], 5.5, 16.2), white non-Hispanic race/ethnicity (aOR 3.3; 95% CI, 2.3, 4.7), female sex (aOR 2.0; 95% CI, 1.4, 2.9), age ≥ 35 years (aOR 2.0; 95% CI, 1.4, 2.9), and lower body mass index (body mass index [BMI]; P = .009). In a separate multivariate analysis among persons who received 3HP, severe SDR were associated with white non-Hispanic race/ethnicity (aOR 5.4; 95% CI, 1.8, 16.3), and receipt of concomitant non-study medications (aOR 5.9; 95% CI, 1.3, 27.1).SDR were more common with 3HP, and mostly flu-like. Persons of white race, female sex, older age, and lower BMI were at increased risk. Severe reactions were rare and associated with 3HP, concomitant medication, and white race. The underlying mechanism is unclear.NCT00023452. |
| 2015 | Novel dosing strategies increase exposures of the potent antituberculosis drug rifapentine but are poorly tolerated in healthy volunteers. | Antimicrob Agents Chemother | Rifapentine is a potent antituberculosis drug currently in phase III trials. Bioavailability decreases with increasing dose, yet high daily exposures are likely needed to improve efficacy and shorten the tuberculosis treatment duration. Further, the limits of tolerability are poorly defined. The phase I multicenter trial in healthy adults described here investigated two strategies to increase Rifapentine exposures: dividing the dose or giving the drug with a high-fat meal. In arm 1, Rifapentine was administered at 10 mg/kg of body weight twice daily and 20 mg/kg once daily, each for 14 days, separated by a 28-day washout; the dosing sequence was randomized. In arm 2, 15 mg/kg Rifapentine once daily was given with a high-fat versus a low-fat breakfast. Sampling for pharmacokinetic analysis was performed on days 1 and 14. Population pharmacokinetic analyses were performed. This trial was stopped early for poor tolerability and because of safety concerns. Of 44 subjects, 20 discontinued prematurely; 11 of these discontinued for protocol-defined toxicity (a grade 3 or higher adverse event or grade 2 or higher rifamycin hypersensitivity). Taking Rifapentine with a high-fat meal increased the median steady-state area under the concentration-time curve from time zero to 24 h (AUC0-24ss) by 31% (relative standard error, 6%) compared to that obtained when the drug was taken with a low-fat breakfast. Dividing the dose increased exposures substantially (e.g., 38% with 1,500 mg/day). AUC0-24ss was uniformly higher in our study than in recent tuberculosis treatment trials, in which toxicity was rare. In conclusion, two strategies to increase Rifapentine exposures, dividing the dose or giving it with a high-fat breakfast, successfully increased exposures, but toxicity was common in healthy adults. The limits of tolerability in patients with tuberculosis remain to be defined. (AIDS Clinical Trials Group study A5311 has been registered at ClinicalTrials.gov under registration no. NCT01574638.). |
| 2015 | Bacteriological and virulence study of a Mycobacterium chimaera isolate from a patient in China. | Antonie Van Leeuwenhoek | A clinical isolate from a patient was identified as Mycobacterium chimaera, a recently identified species of nontuberculous Mycobacteria. The biochemical and molecular identity, drug sensitivity and virulence of this isolated strain were investigated. 16S rRNA, the 16S-23S ITS, hsp65 and rpoB were amplified, and their sequence similarities with other mycobacteria were analyzed. The minimum inhibitory concentrations of 22 anti-microbial agents against this isolate were established, and the virulence of the isolate was evaluated by intravenous injection into C57BL/6 mice using Mycobacterium tuberculosis H37Rv as a control strain. Growth and morphological characteristics and mycolic acid profile analysis revealed that this isolated strain was a member of the Mycobacterium avium complex. BLAST analysis of the amplified sequences showed that the isolated strain was closely related to M. chimaera. Susceptibility testing showed that the isolate was sensitive to rifabutin, Rifapentine, clarithromycin, azithromycin, imipenem and cefoxitin. Bacterial load determination and tissue histopathology of the infected mice indicated that the isolate was highly virulent. The first case of M. chimaera infection in China was evaluated. The information derived from this case may offer valuable guidance for clinical diagnosis and treatment. |
| 2015 | Treatment for preventing tuberculosis in children and adolescents: a randomized clinical trial of a 3-month, 12-dose regimen of a combination of rifapentine and isoniazid. | JAMA Pediatr | Three months of a once-weekly combination of Rifapentine and isoniazid for treatment of latent tuberculosis infection is safe and effective for persons 12 years or older. Published data for children are limited.To compare treatment safety and assess noninferiority treatment effectiveness of combination therapy with Rifapentine and isoniazid vs 9 months of isoniazid treatment for latent tuberculosis infection in children.A pediatric cohort nested within a randomized, open-label clinical trial conducted from June 11, 2001, through December 17, 2010, with follow-up through September 5, 2013, in 29 study sites in the United States, Canada, Brazil, Hong Kong (China), and Spain. Participants were children (aged 2-17 years) who were eligible for treatment of latent tuberculosis infection.Twelve once-weekly doses of the combination drugs, given with supervision by a health care professional, for 3 months vs 270 daily doses of isoniazid, without supervision by a health care professional, for 9 months.We compared rates of treatment discontinuation because of adverse events (AEs), toxicity grades 1 to 4, and deaths from any cause. The equivalence margin for the comparison of AE-related discontinuation rates was 5%. Tuberculosis disease diagnosed within 33 months of enrollment was the main end point for testing effectiveness. The noninferiority margin was 0.75%.Of 1058 children enrolled, 905 were eligible for evaluation of effectiveness. Of 471 in the combination-therapy group, 415 (88.1%) completed treatment vs 351 of 434 (80.9%) in the isoniazid-only group (P = .003). The 95% CI for the difference in rates of discontinuation attributed to an AE was -2.6 to 0.1, which was within the equivalence range. In the safety population, 3 of 539 participants (0.6%) who took the combination drugs had a grade 3 AE vs 1 of 493 (0.2%) who received isoniazid only. Neither arm had any hepatotoxicity, grade 4 AEs, or treatment-attributed death. None of the 471 in the combination-therapy group developed tuberculosis vs 3 of 434 (cumulative rate, 0.74%) in the isoniazid-only group, for a difference of -0.74% and an upper bound of the 95% CI of the difference of +0.32%, which met the noninferiority criterion.Treatment with the combination of Rifapentine and isoniazid was as effective as isoniazid-only treatment for the prevention of tuberculosis in children aged 2 to 17 years. The combination-therapy group had a higher treatment completion rate than did the isoniazid-only group and was safe.clinicaltrials.gov Identifier: NCT00023452. |
| 2015 | Murine pharmacokinetics of rifapentine delivered as an inhalable dry powder. | Int J Antimicrob Agents | A novel inhalable Rifapentine dry powder formulation could improve pulmonary Rifapentine concentrations resulting in a significantly shorter time to treat tuberculosis infection. The pharmacokinetics of Rifapentine (20mg/kg) in healthy mice was compared following intratracheal (IT) and intraperitoneal (IP) administration. Plasma, bronchoalveolar lavage (BAL) and tissue samples were collected and drug levels were quantified at time points up to 24h. Concentration-time data were analysed using a mixed-effects modelling approach to provide model-based estimates of area under the concentration-time curve from time 0 to infinity (AUC0-∞). IT delivery had considerably higher peak Rifapentine lung and BAL concentrations and associated AUC0-∞ compared with IP delivery. The plasma AUC0-∞ following IT dry powder delivery was ca. four-fold smaller than the value for IP delivery. Inhaled delivery of Rifapentine has the potential to selectively enhance therapeutic efficacy at the pulmonary site of infection whilst minimising systemic exposure and related toxicity. |
| 2015 | Rifampicin and rifapentine significantly reduce concentrations of bedaquiline, a new anti-TB drug. | J Antimicrob Chemother | Bedaquiline is the first drug of a new class approved for the treatment of TB in decades. Bedaquiline is metabolized by cytochrome P450 (CYP) 3A4 to a less-active M2 metabolite. Its terminal half-life is extremely long (5-6 months), complicating evaluations of drug-drug interactions. Rifampicin and Rifapentine, two anti-TB drugs now being optimized to shorten TB treatment duration, are potent inducers of CYP3A4. This analysis aimed to predict the effect of repeated doses of rifampicin or Rifapentine on the steady-state pharmacokinetics of bedaquiline and its M2 metabolite from single-dose data using a model-based approach.Pharmacokinetic data for bedaquiline and M2 were obtained from a Phase I study involving 32 individuals each receiving two doses of bedaquiline, alone or together with multiple-dose rifampicin or Rifapentine. Sampling was performed over 14 days following each bedaquiline dose. Pharmacokinetic analyses were performed using non-linear mixed-effects modelling. Models were used to simulate potential dose adjustments.Rifamycin co-administration increased bedaquiline clearance substantially: 4.78-fold [relative standard error (RSE) 9.10%] with rifampicin and 3.96-fold (RSE 5.00%) with Rifapentine. Induction of M2 clearance was equally strong. Average steady-state concentrations of bedaquiline and M2 are predicted to decrease by 79% and 75% when given with rifampicin or Rifapentine, respectively. Simulations indicated that increasing the bedaquiline dosage to mitigate the interaction would yield elevated M2 concentrations during the first treatment weeks.Rifamycin antibiotics reduce bedaquiline concentrations substantially. In line with current treatment guidelines for drug-susceptible TB, concomitant use is not recommended, even with dose adjustment. |
| 2014 | Revisiting Anti-tuberculosis Activity of Pyrazinamide in Mice. | Mycobact Dis | The mechanism of action of pyrazinamide, a key sterilizing drug in the treatment of tuberculosis, remains elusive; pyrazinamide is a pro-drug that requires activation by a bacterial-encoded enzyme, and its activity is most apparent on non-replicating . Recently, it has been suggested that pyrazinamide might exert also some host-directed effect in addition to its antimicrobial activity. To address this possibility, three sequential experiments were conducted in immune-competent BALB/c and in immune-deficient, athymic nude mice. In the first experiment, BALB/c mice infected with , which is naturally resistant to pyrazinamide because it is unable to activate the drug, were treated with standard drug regimens with and without pyrazinamide to specifically detect a host-directed effect. As no effect was observed, pyrazinamide activity was compared in -infected BALB/c and nude mice to determine whether the effect of pyrazinamide would be reduced in the immune deficient mice. As pyrazinamide did not appear to have any affect in the nude mice, a third experiment was performed in which rifampin was replaced with Rifapentine (a similar drug with a longer half-life) to permanently suppress mycobacterial growth. In these experimental conditions, the antimicrobial effect of pyrazinamide was clear. Therefore, the results of our studies rule out a significant host-directed effect of pyrazinamide in the TB infected host. |
| 2015 | Evaluation of the pharmacokinetic interaction between repeated doses of rifapentine or rifampin and a single dose of bedaquiline in healthy adult subjects. | Antimicrob Agents Chemother | This study assessed the effects of Rifapentine or rifampin on the pharmacokinetics of a single dose of bedaquiline and its M2 metabolite in healthy subjects using a two-period single-sequence design. In period 1, subjects received a single dose of bedaquiline (400 mg), followed by a 28-day washout. In period 2, subjects received either Rifapentine (600 mg) or rifampin (600 mg) from day 20 to day 41, as well as a single bedaquiline dose (400 mg) on day 29. The pharmacokinetic profiles of bedaquiline and M2 were compared over 336 h after the administration of bedaquiline alone and in combination with steady-state Rifapentine or rifampin. Coadministration of bedaquiline with Rifapentine or rifampin resulted in lower bedaquiline exposures. The geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for the maximum observed concentration (Cmax), area under the concentration-time curve to the last available concentration time point (AUC0-t), and AUC extrapolated to infinity (AUC0-inf) of bedaquiline were 62.19% (53.37 to 72.47), 42.79% (37.77 to 48.49), and 44.52% (40.12 to 49.39), respectively, when coadministered with Rifapentine. Similarly, the GMRs and 90% CIs for the Cmax, AUC0-t, and AUC0-inf of bedaquiline were 60.24% (51.96 to 69.84), 41.36% (37.70 to 45.36), and 47.32% (41.49 to 53.97), respectively, when coadministered with rifampin. The Cmax, AUC0-t, and AUC0-inf of M2 were also altered when bedaquiline was coadministered with Rifapentine or rifampin. Single doses of bedaquiline, administered alone or with multiple doses of Rifapentine or rifampin, were well tolerated, with no safety concerns related to coadministration. Daily administration of Rifapentine to patients with tuberculosis presents the same drug interaction challenges as rifampin and other rifamycins. Strong inducers of the cytochrome P450 isoenzyme CYP3A4 should be avoided when considering the use of bedaquiline. (This study is registered at clinicaltrials.gov under identifier NCT02216331.). |
| 2015 | Daily rifapentine for treatment of pulmonary tuberculosis. A randomized, dose-ranging trial. | Am J Respir Crit Care Med | Rifapentine has potent activity in mouse models of tuberculosis chemotherapy but its optimal dose and exposure in humans are unknown.We conducted a randomized, partially blinded dose-ranging study to determine tolerability, safety, and antimicrobial activity of daily Rifapentine for pulmonary tuberculosis treatment.Adults with sputum smear-positive pulmonary tuberculosis were assigned Rifapentine 10, 15, or 20 mg/kg or rifampin 10 mg/kg daily for 8 weeks (intensive phase), with isoniazid, pyrazinamide, and ethambutol. The primary tolerability end point was treatment discontinuation. The primary efficacy end point was negative sputum cultures at completion of intensive phase.A total of 334 participants were enrolled. At completion of intensive phase, cultures on solid media were negative in 81.3% of participants in the rifampin group versus 92.5% (P = 0.097), 89.4% (P = 0.29), and 94.7% (P = 0.049) in the Rifapentine 10, 15, and 20 mg/kg groups. Liquid cultures were negative in 56.3% (rifampin group) versus 74.6% (P = 0.042), 69.7% (P = 0.16), and 82.5% (P = 0.004), respectively. Compared with the rifampin group, the proportion negative at the end of intensive phase was higher among Rifapentine recipients who had high Rifapentine areas under the concentration-time curve. Percentages of participants discontinuing assigned treatment for reasons other than microbiologic ineligibility were similar across groups (rifampin, 8.2%; Rifapentine 10, 15, or 20 mg/kg, 3.4, 2.5, and 7.4%, respectively).Daily Rifapentine was well-tolerated and safe. High Rifapentine exposures were associated with high levels of sputum sterilization at completion of intensive phase. Further studies are warranted to determine if regimens that deliver high Rifapentine exposures can shorten treatment duration to less than 6 months. Clinical trial registered with www.clinicaltrials.gov (NCT 00694629). |
| 2015 | Determination of the rifamycin antibiotics rifabutin, rifampin, rifapentine and their major metabolites in human plasma via simultaneous extraction coupled with LC/MS/MS. | J Pharm Biomed Anal | A novel assay using high pressure liquid chromatography (HPLC) coupled to mass spectrometer (MS) detection was developed and validated for the rifamycin anti-tuberculosis antibiotics rifampicin (RIF), rifabutin (RBT), Rifapentine (RPT) and their active desacetyl metabolites (dRIF, dRBT and dRPT, respectively) in human plasma. The assay uses 50 μL of human plasma with a quick and simple protein-precipitation extraction to achieve a dynamic range of 75-30,000 ng/mL for RIF, RBT and RPT and 37.5-15,000 ng/mL for dRIF, dRBT and dRPT, respectively. The average %CV and %deviation were less than 20% at the lower limit of quantitation and less than 15% over the range of the curve. The method was fully validated according to FDA criteria for bioanalytical assays and has successfully been used to support three large international tuberculosis trials. |
| 2015 | Novel Inhaled Combination Powder Containing Amorphous Colistin and Crystalline Rifapentine with Enhanced Antimicrobial Activities against Planktonic Cells and Biofilm of Pseudomonas aeruginosa for Respiratory Infections. | Mol Pharm | Colistin has been increasingly used for the treatment of respiratory infections caused by Gram-negative bacteria. Unfortunately parenteral administration of colistin can cause severe adverse effects. This study aimed to develop an inhaled combination dry powder formulation of colistin and Rifapentine for the treatment of respiratory infections. The combination formulation was produced by spray-drying Rifapentine particles suspended in an aqueous colistin solution. The combination dry powder had enhanced antimicrobial activities against planktonic cells and biofilm cultures of Pseudomonas aeruginosa, with both minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) values (2 and 4 mg/L, respectively) being half that of pure colistin (MIC 4 mg/L and MBIC 8 mg/L) and 1/16th that of pure Rifapentine (MIC 32 mg/L and MBIC 64 mg/L). High aerosol performance, as measured via an Aerolizer device, was observed with emitted doses>89% and fine particle fraction (FPF) total>76%. The proportion of submicron particles of Rifapentine particles was minimized by the attachment of colistin, which increased the overall particle mass and aerodynamic size distribution. Using the spray-drying method described here, stable particles of amorphous colistin and crystalline Rifapentine were distributed homogeneously in each stage of the impinger. Unlike the colistin alone formulation, no deterioration in aerosol performance was found for the combination powder when exposed to a high relative humidity of 75%. In our previous study, surface coating by rifampicin contributed to the moisture protection of colistin. Here, a novel approach with a new mechanism was proposed whereby moisture protection was attributed to the carrier effect of elongated crystalline Rifapentine particles, which minimized contact between hygroscopic colistin particles. This inhaled combination antibiotic formulation with enhanced aerosol dispersion efficiency and in vitro efficacy could become a superior treatment for respiratory infections. |
| 2014 | Rifamycins (rifampicin, rifabutin and rifapentine) compared to isoniazid for preventing tuberculosis in HIV-negative people at risk of active TB. | Evid Based Child Health | Preventing active tuberculosis (TB) from developing in people with latent tuberculosis infection (LTBI) is important for global TB control. Isoniazid (INH) for six to nine months has 60% to 90% protective efficacy, but the treatment period is long, liver toxicity is a problem, and completion rates outside trials are only around 50%. Rifampicin or rifamycin-combination treatments are shorter and may result in higher completion rates.To compare the effects of rifampicin monotherapy or rifamycin-combination therapy versus INH monotherapy for preventing active TB in HIV-negative people at risk of developing active TB.We searched the Cochrane Infectious Disease Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; LILACS; clinical trials registries; regional databases; conference proceedings; and references, without language restrictions to December 2012; and contacted experts for relevant published, unpublished and ongoing trials.Randomized controlled trials (RCTs) of HIV-negative adults and children at risk of active TB treated with rifampicin, or rifamycin-combination therapy with or without INH (any dose or duration), compared with INH for six to nine months.At least two authors independently screened and selected trials, assessed risk of bias, and extracted data. We sought clarifications from trial authors. We pooled relative risks (RRs) with their 95% confidence intervals (CIs), using a random-effects model if heterogeneity was significant. We assessed overall evidence quality using the GRADE approach.Ten trials are included, enrolling 10,717 adults and children, mostly HIV-negative (2% HIV-positive), with a follow-up period ranging from two to five years. Rifampicin (three/four months) vs. INH (six months) Five trials published between 1992 to 2012 compared these regimens, and one small 1992 trial in adults with silicosis did not detect a difference in the occurrence of TB over five years of follow up (one trial, 312 participants; very low quality evidence). However, more people in these trials completed the shorter course (RR 1.19, 95% CI 1.01 to 1.30; five trials, 1768 participants; moderate quality evidence). Treatment-limiting adverse events were not significantly different (four trials, 1674 participants; very low quality evidence), but rifampicin caused less hepatotoxicity (RR 0.12, 95% CI 0.05 to 0.30; four trials, 1674 participants; moderate quality evidence). Rifampicin plus INH (three months) vs. INH (six months) The 1992 silicosis trial did not detect a difference between people receiving rifampicin plus INH compared to INH alone for occurrence of active TB (one trial, 328 participants; very low quality evidence). Adherence was similar in this and a 1998 trial in people without silicosis (two trials, 524 participants; high quality evidence). No difference was detected for treatment-limiting adverse events (two trials, 536 participants; low quality evidence), or hepatotoxicity (two trials, 536 participants; low quality evidence). Rifampicin plus pyrazinamide (two months) vs. INH (six months) Three small trials published in 1994, 2003, and 2005 compared these two regimens, and two reported a low occurrence of active TB, with no statistically significant differences between treatment regimens (two trials, 176 participants; very low quality evidence) though, apart from one child from the 1994 trial, these data on active TB were from the 2003 trial in adults with silicosis. Adherence with both regimens was low with no statistically significant differences (four trials, 700 participants; very low quality evidence). However, people receiving rifampicin plus pyrazinamide had more treatment-limiting adverse events (RR 3.61, 95% CI 1.82 to 7.19; two trials, 368 participants; high quality evidence), and hepatotoxicity (RR 4.59, 95% 2.14 to 9.85; three trials, 540 participants; moderate quality evidence). Weekly, directly-observed Rifapentine plus INH (three months) vs. daily, self-administered INH (nine months) A large trial conducted from 2001 to 2008 among close contacts of TB in the USA, Canada, Brazil and Spain found directly observed weekly treatment to be non-inferior to nine months self-administered INH for the incidence of active TB (0.2% vs 0.4%, RR 0.44, 95% CI 0.18 to 1.07, one trial, 7731 participants; moderate quality evidence). The directly-observed, shorter regimen had higher treatment completion (82% vs 69%, RR 1.19, 95% CI 1.16 to 1.22, moderate quality evidence), and less hepatotoxicity (0.4% versus 2.4%; RR 0.16, 95% CI 0.10 to 0.27; high quality evidence), though treatment-limiting adverse events were more frequent (4.9% versus 3.7%; RR 1.32, 95% CI 1.07 to 1.64 moderate quality evidence)Trials to date of shortened prophylactic regimens using rifampicin alone have not demonstrated higher rates of active TB when compared to longer regimens with INH. Treatment completion is probably higher and adverse events may be fewer with shorter rifampicin regimens. Shortened regimens of rifampicin with INH may offer no advantage over longer INH regimens. Rifampicin combined with pyrazinamide is associated with more adverse events. A weekly regimen of Rifapentine plus INH has higher completion rates, and less liver toxicity, though treatment discontinuation due to adverse events is probably more likely than with INH. |
| 2014 | A murine macrofilaricide pre-clinical screening model for onchocerciasis and lymphatic filariasis. | Parasit Vectors | New drugs effective against adult filariae (macrofilaricides) would accelerate the elimination of lymphatic filariasis and onchocerciasis. Anti-Onchocerca drug development is hampered by the lack of a facile model. We postulated that SCID mice could be developed as a fmacrofilaricide screening model.The filaricides: albendazole (ABZ), diethylcarbamazine (DEC), flubendazole (FBZ), ivermectin (IVM) and the anti-Wolbachia macrofilaricide, minocycline (MIN) were tested in Brugia malayi (Bm)-parasitized BALB/c SCID mice vs vehicle control (VC). Responses were compared to BALB/c wild type (WT). Onchocerca ochengi male worms or onchocercomata were surgically implanted into BALB/c SCID, CB.17 SCID, BALB/c WT mice or Meriones gerbils. Survival was evaluated at 7-15 days. BALB/c SCID were tested to evaluate the responsiveness of pre-clinical macrofilaricides FBZ and Rifapentine (RIFAP) against male Onchocerca.WT and SCID responded with >95% efficacy following ABZ or DEC treatments against Bm larvae (P < 0.0001). IVM was partially filaricidal against Bm larvae in WT and SCID (WT; 39.8%, P = 0.0356 and SCID; 56.7%, P = 0.026). SCID responded similarly to WT following IVM treatment of microfilaraemias (WT; 79%, P = 0.0194. SCID; 76%, P = 0.0473). FBZ induced a total macrofilaricidal response against adult Bm in WT and SCID (WT; P = 0.0067, SCID; P = 0.0071). MIN induced a >90% reduction in Bm Wolbachia burdens (P < 0.0001) and a blockade of microfilarial release (P = 0.0215) in SCID. Male Onchocerca survival was significantly higher in SCID vs WT mice, but not gerbils, after +15 days (60% vs 22% vs 39% P = 0.0475). Onchocercoma implants had engrafted into host tissues, with evidence of neovascularisation, after +7 days and yielded viable macro/microfilariae ex vivo. FBZ induced a macrofilaricidal effect in Onchocerca male implanted SCID at +5 weeks (FBZ; 1.67% vs VC; 43.81%, P = 0.0089). Wolbachia loads within male Onchocerca were reduced by 99% in implanted SCID receiving RIFAP for +2 weeks.We have developed a 'pan-filarial' small animal research model that is sufficiently robust, with adequate capacity and throughput, to screen existing and future pre-clinical candidate macrofilaricides. Pilot data suggests a murine onchocercoma xenograft model is achievable. |
| 2014 | High-dose rifapentine with moxifloxacin for pulmonary tuberculosis. | N Engl J Med | Tuberculosis regimens that are shorter and simpler than the current 6-month daily regimen are needed.We randomly assigned patients with newly diagnosed, smear-positive, drug-sensitive tuberculosis to one of three regimens: a control regimen that included 2 months of ethambutol, isoniazid, rifampicin, and pyrazinamide administered daily followed by 4 months of daily isoniazid and rifampicin; a 4-month regimen in which the isoniazid in the control regimen was replaced by moxifloxacin administered daily for 2 months followed by moxifloxacin and 900 mg of Rifapentine administered twice weekly for 2 months; or a 6-month regimen in which isoniazid was replaced by daily moxifloxacin for 2 months followed by one weekly dose of both moxifloxacin and 1200 mg of Rifapentine for 4 months. Sputum specimens were examined on microscopy and after culture at regular intervals. The primary end point was a composite treatment failure and relapse, with noninferiority based on a margin of 6 percentage points and 90% confidence intervals.We enrolled a total of 827 patients from South Africa, Zimbabwe, Botswana, and Zambia; 28% of patients were coinfected with the human immunodefiency virus. In the per-protocol analysis, the proportion of patients with an unfavorable response was 4.9% in the control group, 3.2% in the 6-month group (adjusted difference from control, -1.8 percentage points; 90% confidence interval [CI], -6.1 to 2.4), and 18.2% in the 4-month group (adjusted difference from control, 13.6 percentage points; 90% CI, 8.1 to 19.1). In the modified intention-to-treat analysis these proportions were 14.4% in the control group, 13.7% in the 6-month group (adjusted difference from control, 0.4 percentage points; 90% CI, -4.7 to 5.6), and 26.9% in the 4-month group (adjusted difference from control, 13.1 percentage points; 90% CI, 6.8 to 19.4).The 6-month regimen that included weekly administration of high-dose Rifapentine and moxifloxacin was as effective as the control regimen. The 4-month regimen was not noninferior to the control regimen. (Funded by the European and Developing Countries Clinical Trials Partnership and the Wellcome Trust; RIFAQUIN Current Controlled Trials number, ISRCTN44153044.). |
| 2014 | Novel on-line column extraction apparatus coupled with binary peak focusing for high-performance liquid chromatography determination of rifampicin in human plasma: a strategy for therapeutic drug monitoring. | J Sep Sci | In order to develop a method that is completely suitable for the routine therapeutic drug monitoring, a sensitive and fully automated on-line column extraction apparatus in combination with high-performance liquid chromatography allowing binary peak focusing was developed and validated for the determination of rifampicin in human plasma. Rifapentine was used as an internal standard. The analytical cycle started with the injection of 100 μL of the sample pretreated by protein precipitation in a Venusil SCX extraction column. After the elution, the analytes were transferred and concentrated in an Xtimate C18 trap column. Finally, the trapped analytes were separated by an Xtimate C18 analytical column and were analyzed by an ultraviolet detector at 336 nm. With this new strategy, continuous on-line analysis of the compounds was successfully performed. The method showed excellent performance for the analysis of rifampicin in plasma samples, including calibration curve linearity (All r were larger than 0.9996), sensitivity (lowest limit of quantification was 0.12 μg/mL), method accuracy (within 6.6% in terms of relative error), and precision (relative standard deviations of intra- and interday precision were less than 7.8%). These results demonstrated that the simple, reliable, and automatic method based on on-line column extraction and binary peak focusing is a promising approach for therapeutic drug monitoring in complex biomatrix samples. |
| 2013 | Diagnosis and treatment of latent tuberculosis infection: an update. | Curr Respir Care Rep | It is estimated that more than two billion people have latent infection, and this population serves as an important reservoir for future tuberculosis cases. Prevalence estimates are limited by difficulties in diagnosing the infection, including the lack of an ideal test, and an incomplete understanding of latency. Current tests include the tuberculin skin test and two interferon-γ release assays: QuantiFERON Gold In-Tube and T-SPOT.TB. This update focuses on recent publications regarding the ability of these tests to predict tuberculosis disease, their reproducibility over serial tests, and discordance between tests. We also discuss recent advances in the treatment of latent infection, including the three-month regimen of once-weekly Rifapentine plus isoniazid, and prolonged isoniazid therapy for HIV-infected persons living in high-tuberculosis-incidence settings. We provide an update on the tolerability of the three-month regimen. |
| 2015 | Tuberculosis: current treatment, diagnostics, and newer antitubercular agents in clinical trials. | Infect Disord Drug Targets | Tuberculosis (TB), a dreadful disease is one of the most important health problems worldwide, and is responsible for approximately 1.3 million death tolls in 2012. DOTS is the currently used drug therapy in TB and the long term drug regimens and patients' poor compliance lead to emergence of multidrug resistant (MDR) and extensively drug resistant (XDR) TB, which invigorates the research efforts to address the urgent need for the quick diagnosis and for newer antitubercular agents and vaccines to completely eradicate TB. Today we have at least 20 new diagnostic test platforms, 14 TB vaccine candidates in clinical trials and over 35 candidates in preclinical development, and among the antitubercular agents under clinical investigation, 4 anti-TB agents are in Phase III (efficacy) trials and 7 anti-TB agents are in Phase II, early bactericidal activity and sputum culture conversion trials (Rifapentine is in a Phase II and a Phase III trial), 5 anti-TB agents in preclinical development and 3 anti-TB agents in Good Laboratory Practice toxicity evaluation. Recently US FDA has approved TMC207 as a part of combination therapy to treat adults with MDR pulmonary TB in the absence of other alternatives. We provide here the concise review on the chemical entities currently in the clinical trials, the new vaccines in the developmental pipeline, and the new diagnostic test. |
| 2014 | Tuberculosis preventive therapy: an underutilised strategy to reduce individual risk of TB and contribute to TB control. | S Afr Med J | Tuberculosis (TB) remains a global health problem, and South Africa (SA) has one of the world's worst TB epidemics. The World Health Organization (WHO) estimated in 1999 that one-third of the world's population was latently infected with TB. In SA up to 88% of HIV-uninfected young adults (31 - 35 years) are latently infected with TB. In the most recent meta-analysis, 6 - 12 months of isoniazid preventive therapy (IPT) was associated with a lower incidence of active TB than placebo (relative risk (RR) 0.68; 95% confidence interval (CI) 0.54 - 0.85), with the greatest benefit among individuals with a positive tuberculin skin test (TST) (RR 0.38; 95% CI 0.25 - 0.57). A clinical trial of IPT given with antiretroviral therapy (ART) for 12 months reduced TB incidence by 37% compared with ART alone (hazard ratio (HR) 0.63; 95% CI 0.41 - 0.94). The effect of IPT is limited in high-burden countries. IPT for 36 months v. 6 months reduced TB incidence among HIV-positive, TST-positive participants by 74% (HR 0.26; 95% CI 0.09 - 0.80). A study of more than 24 000 goldminers confirmed that IPT is safe, with only 0.5% experiencing adverse events. A meta-analysis of studies of IPT since 1951 did not show an increased risk of developing resistance. Alternative TB preventive therapy regimens, including high-dose isoniazid and Rifapentine given weekly for 3 months, have been shown to have similar efficacy to IPT. Mathematical modelling suggests that scaling up continuous IPT targeted to HIV-positive persons, when used in combination with other treatment and prevention strategies, may substantially improve TB control. |
| 2014 | The Case for Using Higher Doses of First Line Anti-Tuberculosis Drugs to Optimize Efficacy. | Curr Pharm Des | Apart from new anti-tuberculosis drug development, another approach for tuberculosis (TB) treatment optimization is to derive maximum benefit from current agents. However, the dosage of current anti-TB drug regimens has never been optimized according to the exposure-effect relationships of each drug. The objective of this article is to review the latest pharmacokinetic, pharmacodynamic, experimental, and clinical data concerning the use of higher doses of first-line anti-TB drugs to improve the efficacy of pulmonary tuberculosis treatment. Exposure-effect relationships have been described for all first-line anti-TB agents. There is convincing evidence that patients would benefit from higher rifamycin exposure. This could be achieved by using higher daily doses of rifampin, or more frequent dosing of Rifapentine. The dose-dependent activity of pyrazinamide observed in hollow-fiber and animal models suggests that higher doses of pyrazimamide might be more efficacious, but the tolerability of such higher doses needs to be investigated in humans. It is likely that higher doses of ethambutol would be associated with higher antibacterial effect, but the dose-related ocular toxicity of the drug precludes such practice. For isoniazid, dose individualization is required to optimize patient care. The use of higher than standard doses of isoniazid in fast acetylators should result in greater early bactericidal activity. To conclude, the use of higher doses for some of the firstline anti-TB agents has definite potential for shortening or improving TB treatment. |
| 2014 | Quantification of rifapentine, a potent antituberculosis drug, from dried blood spot samples using liquid chromatographic-tandem mass spectrometric analysis. | Antimicrob Agents Chemother | The quantification of antituberculosis drug concentrations in multinational trials currently requires the collection of modest blood volumes, centrifugation, aliquoting of plasma, freezing, and keeping samples frozen during shipping. We prospectively enrolled healthy individuals into the Tuberculosis Trials Consortium Study 29B, a phase I dose escalation study of Rifapentine, a rifamycin under evaluation in tuberculosis treatment trials. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying Rifapentine in whole blood on dried blood spots (DBS) to facilitate pharmacokinetic/pharmacodynamic analyses in clinical trials. Paired plasma and whole-blood samples were collected by venipuncture, and whole blood was spotted on Whatman protein saver 903 cards. The methods were optimized for plasma and then validated for DBS. The analytical measuring range for quantification of Rifapentine and its metabolite was 50 to 80,000 ng/ml in whole-blood DBS. The analyte was stable on the cards for 11 weeks with a desiccant at room temperature and protected from light. The method concordance for paired plasma and whole-blood DBS samples was determined after correcting for participant hematocrit or population-based estimates of bias from Bland-Altman plots. The application of either correction factor resulted in acceptable correlation between plasma and whole-blood DBS (Passing-Bablok regression corrected for hematocrit; y = 0.98x + 356). Concentrations of Rifapentine may be determined from whole-blood DBS collected via venipuncture after normalization in order to account for the dilutional effects of red blood cells. Additional studies are focused on the application of this methodology to capillary blood collected by finger stick. The simplicity of processing, storage, shipping, and low blood volume makes whole-blood DBS attractive for Rifapentine pharmacokinetic evaluations, especially in international and pediatric trials. |
| 2014 | Resistance to rifampicin: a review. | J Antibiot (Tokyo) | Resistance to rifampicin (RIF) is a broad subject covering not just the mechanism of clinical resistance, nearly always due to a genetic change in the β subunit of bacterial RNA polymerase (RNAP), but also how studies of resistant polymerases have helped us understand the structure of the enzyme, the intricacies of the transcription process and its role in complex physiological pathways. This review can only scratch the surface of these phenomena. The identification, in strains of Escherichia coli, of the positions within β of the mutations determining resistance is discussed in some detail, as are mutations in organisms that are therapeutic targets of RIF, in particular Mycobacterium tuberculosis. Interestingly, changes in the same three codons of the consensus sequence occur repeatedly in unrelated RIF-resistant (RIF(r)) clinical isolates of several different bacterial species, and a single mutation predominates in mycobacteria. The utilization of our knowledge of these mutations to develop rapid screening tests for detecting resistance is briefly discussed. Cross-resistance among rifamycins has been a topic of controversy; current thinking is that there is no difference in the susceptibility of RNAP mutants to RIF, Rifapentine and rifabutin. Also summarized are intrinsic RIF resistance and other resistance mechanisms. |
| 2014 | Update on latent tuberculosis infection. | Am Fam Physician | Latent tuberculosis infection refers to an asymptomatic, nontransmissible infection with Mycobacterium tuberculosis, carrying a 5% to 10% lifetime risk of progressing to active disease. One-half of this risk occurs within the first two years after infection. High-risk groups include recent immigrants from high-incidence countries, health care professionals, persons living or working in institutional settings, and homeless persons. Risk factors for progression to active disease include immunodeficiency, recent exposure to tuberculosis, and chronic kidney disease requiring dialysis. Tuberculin skin testing has several limitations, including the need for multiple office visits and the potential for false-positive results in patients who have received the bacillus Calmette-Guérin vaccine or been exposed to environmental mycobacteria. Interferon-gamma release assays address these deficiencies but are limited by their cost and requirement for blood processing. Interferon-gamma release assays are preferred in immigrants exposed to bacillus Calmette-Guérin and in patients who are not likely to return for interpretation of skin test results. Tuberculin skin testing is preferred for children younger than five years. Active disease should be excluded before initiating treatment. The newest treatment option of 12 weekly doses of isoniazid and Rifapentine has similar or better effectiveness than standard nine-month therapy with daily isoniazid. A four-month regimen of daily rifampin is another alternative. |
| 2014 | Rifapentine Pharmacokinetics and Tolerability in Children and Adults Treated Once Weekly With Rifapentine and Isoniazid for Latent Tuberculosis Infection. | J Pediatric Infect Dis Soc | In a phase 3, randomized clinical trial (PREVENT TB) of 8053 people with latent tuberculosis infection, 12 once-weekly doses of Rifapentine and isoniazid had good efficacy and tolerability. Children received higher Rifapentine milligram per kilogram doses than adults. In the present pharmacokinetic study (a component of the PREVENT TB trial), Rifapentine exposure was compared between children and adults.Rifapentine doses in children ranged from 300 to 900 mg, and adults received 900 mg. Children who could not swallow tablets received crushed tablets. Sparse pharmacokinetic sampling was performed with 1 Rifapentine concentration at 24 hours after drug administration (C24). Rifapentine area under concentration-time curve (AUC) was estimated from a nonlinear, mixed effects regression model (NLME).There were 80 children (age: median, 4.5 years; range, 2-11 years) and 77 adults (age: median, 40 years; all ≥18 years) in the study. The geometric mean Rifapentine milligram per kilogram dose was greater in children than in adults (children, 23 mg/kg; adults, 11 mg/kg). Rifapentine geometric mean AUC and C24 were 1.3-fold greater in children (all children combined) than in adults. Children who swallowed whole tablets had 1.3-fold higher geometric mean AUC than children who received crushed tablets, and children who swallowed whole tablets had a 1.6-fold higher geometric mean AUC than adults. The higher Rifapentine doses in children were well tolerated. To obtain Rifapentine exposures comparable in children to adults, dosing algorithms modeled by NLME were developed.A 2-fold greater Rifapentine dose for all children resulted in a 1.3-fold higher AUC compared to adults administered a standard dose. Use of higher weight-adjusted Rifapentine doses for young children are warranted to achieve systemic exposures that are associated with successful treatment of latent tuberculosis infection in adults. |
| 2014 | Bedaquiline: a review of human pharmacokinetics and drug-drug interactions. | J Antimicrob Chemother | Bedaquiline has recently been approved for the treatment of pulmonary multidrug-resistant tuberculosis (TB) as part of combination therapy in adults. It is metabolized primarily by the cytochrome P450 isoenzyme 3A4 (CYP3A4) to a less-active N-monodesmethyl metabolite. Phase I and Phase II studies in healthy subjects and patients with drug-susceptible or multidrug-resistant TB have assessed the pharmacokinetics and drug-drug interaction profile of bedaquiline. Potential interactions have been assessed between bedaquiline and first- and second-line anti-TB drugs (rifampicin, Rifapentine, isoniazid, pyrazinamide, ethambutol, kanamycin, ofloxacin and cycloserine), commonly used antiretroviral agents (lopinavir/ritonavir, nevirapine and efavirenz) and a potent CYP3A inhibitor (ketoconazole). This review summarizes the pharmacokinetic profile of bedaquiline as well as the results of the drug-drug interaction studies. |
| 2014 | Bacteriological characterization of a Mycobacterium parascrofulaceum strain isolated from a Chinese pneumonia patient. | Int J Infect Dis | A Mycobacterium parascrofulaceum strain was isolated from a pneumonia patient-the first such reported case from China. The bacteriological characteristics of the strain were determined.Species identification was performed by homologue gene sequence comparison, then a series of biochemical tests was conducted to elucidate the bacteriological characteristics. Drug susceptibility and pathogenicity to mice of the strain were tested.The clinical M. parascrofulaceum strain presented a very similar phenotypic profile to that of Mycobacterium scrofulaceum. The M. parascrofulaceum strain was sensitive to rifabutin, Rifapentine, clarithromycin, azithromycin, cefoxitin, and moxifloxacin in vitro. At week 2 post-infection, the lung tissues of mice demonstrated a local inflammatory response denoted by peri-bronchiolar inflammatory infiltrates. At weeks 4 and 8, the lung tissues showed peri-bronchiolar inflammatory infiltrates with large aggregates of lymphocytes and part of the tissue showed granulomatous lesions; there was no appreciable necrosis. The colony-forming units (CFU) count of infected lung and spleen increased gradually during the 8 weeks of the experiment.The M. parascrofulaceum strain isolated in China was sensitive to rifabutin, Rifapentine, clarithromycin, azithromycin, cefoxitin, and moxifloxacin. The mycobacteria were capable of proliferating in mice and could lead to pathological changes in the lungs of the mice. |
| 2014 | Protein binding of rifapentine and its 25-desacetyl metabolite in patients with pulmonary tuberculosis. | Antimicrob Agents Chemother | Rifapentine is highly protein bound in blood, but the free, unbound drug is the microbiologically active fraction. In this exploratory study, we characterized the free plasma fraction of Rifapentine in 41 patients with tuberculosis. We found a lower total Rifapentine concentration but significantly higher free Rifapentine levels in African patients of black race compared to non-Africans. These data support larger pharmacokinetic/pharmacodynamic studies to confirm these findings and assess free Rifapentine in relation to microbiological and clinical outcomes. |
| 2015 | Using rifapentine - hen egg lipoprotein conjugate as macrophage-targeted drug delivery carrier against intracellular Staphylococcus aureus. | Drug Deliv | Hen egg low-density lipoprotein (heLDL), which is present in large quantities in egg yolk, share a high identity with human apolipoprotein B-100 precursor.This study investigated the use of heLDL as a macrophage-targeted drug delivery carrier against intracellular Staphylococcus aureus.Rifapentine (RPT) was incorporated into heLDL (RPT-heLDL). Staphylococcus aureus ATCC 29740 and human U937 macrophage were used as intracellular infection models.The loading efficiency of RPT into the heLDL was 66.10 ± 2.28 μg RPT/mg heLDL. Fluorescence microscopy and oil red O staining results indicated RPT-heLDL can be taken up by U937 macrophages. The cell viability (MTT assay) was increased when the concentration of heLDL was <150 μg/mL. Unloaded heLDL (100 μg/mL) can inhibit the growth of intracellular S. aureus compared with the untreated control group after 18 h incubation. RPT-heLDL (6.6 μg/mL RPT, 100 μg/mL heLDL) eliminated 94% of intracellular S. aureus, whereas the corresponding dose of free RPT (6.6 μg/mL) induced an 87% reduction. The in vitro results of the current study indicated that heLDL might be used as a suitable drug carrier for targeting human macrophages. |
| 2014 | Ability of preventive therapy to cure latent Mycobacterium tuberculosis infection in HIV-infected individuals in high-burden settings. | Proc Natl Acad Sci U S A | Trials of isoniazid preventive therapy (IPT) for people living with HIV in southern Africa have shown high rates of tuberculosis disease immediately after cessation of therapy. This could be due to the lack of cure following preventive therapy or reinfection with rapid progression to disease. Using a model fitted to trial data, we estimate the degree to which preventive therapies cure latent Mycobacterium tuberculosis infection in HIV-infected individuals in high-tuberculosis-burden settings. We identified randomized controlled trials that compared IPT to placebo or alternative regimen in HIV-positive, tuberculin skin test positive individuals. A mathematical model describing tuberculosis transmission in a closed cohort of HIV-positive, M. tuberculosis infected, antiretroviral therapy naive individuals following completion of preventive therapy (or placebo) was fitted to posttherapy tuberculosis rates to estimate the annual risk of M. tuberculosis reinfection and the proportion of individuals whose latent infection was cured after therapy. Three trials met our inclusion criteria. Estimated annual risks of reinfection ranged between 3.7 and 4.9%. Our results suggest 6 mo of isoniazid cured in a small proportion [estimated proportion cured = 0% (interquartile range 0-30.9%)]. The proportion cured for 3-mo regimens containing rifampicin or Rifapentine was 19-100%. IPT alone does not cure existing infections in the majority of HIV-infected individuals. In high-incidence settings, continuous IPT should be integrated with HIV care. Where the risk of reinfection is lower, preventive therapy with more curative drugs should be preferred for HIV-positive individuals to achieve durable patient benefit. |
| 2014 | Population pharmacokinetics of rifapentine and desacetyl rifapentine in healthy volunteers: nonlinearities in clearance and bioavailability. | Antimicrob Agents Chemother | Rifapentine is under active investigation as a potent drug that may help shorten the tuberculosis (TB) treatment duration. A previous Rifapentine dose escalation study with daily dosing indicated a possible decrease in bioavailability as the dose increased and an increase in clearance over time for Rifapentine and its active metabolite, desacetyl Rifapentine. This study aimed to assess the effects of increasing doses on Rifapentine absorption and bioavailability and to evaluate the clearance changes over 14 days. A population analysis was performed with nonlinear mixed-effects modeling. Absorption, time-varying clearance, bioavailability, and empirical and semimechanistic autoinduction models were investigated. A one-compartment model linked to a transit compartment absorption model best described the data. The bioavailability of Rifapentine decreased linearly by 2.5% for each 100-mg increase in dose. The autoinduction model suggested a dose-independent linear increase in clearance of the parent drug and metabolite over time from 1.2 and 3.1 liters · h(-1), respectively, after a single dose to 2.2 and 5.0 liters · h(-1), respectively, after 14 once-daily doses, with no plateau being reached by day 14. In clinical trial simulations using the final model, Rifapentine demonstrated less-than-dose-proportional pharmacokinetics, but there was no plateau in exposures over the dose range tested (450 to 1,800 mg), and divided dosing increased exposures significantly. Thus, the proposed compartmental model incorporating daily dosing of Rifapentine over a wide range of doses and time-related changes in bioavailability and clearance provides a useful tool for estimation of drug exposure that can be used to optimize Rifapentine dosing for TB treatment. (This study has been registered at ClinicalTrials.gov under registration no. NCT01162486.). |
| 2014 | A novel inhalable form of rifapentine. | J Pharm Sci | Recent murine studies found that Rifapentine, dosed daily, at least halved tuberculosis treatment times compared with standard rifampicin and isoniazid-containing regimens. However, in humans, an inhalable form of Rifapentine may be necessary to considerably shorten treatment duration because of the physiological barriers associated with oral therapy. The current study compares two inhalable Rifapentine dry powders-a novel pure crystalline form and an amorphous form-by a series of in vitro tests. The crystalline and amorphous powders had a mass median aerodynamic size of 1.68 ± 0.03 and 1.92 ± 0.01 μm, respectively, associated with a fine particle fraction of 83.2 ± 1.2% and 68.8 ± 2.1%, respectively. A quinone degradation product was identified in the amorphous powder stored for 1 month, whereas the crystalline form remained chemically stable after storage at both 0% and 60% relative humidity, 25°C, for at least 3 months. Solubilized Rifapentine was well tolerated by pulmonary tissue and macrophage cells up to approximately 50 μM. The accumulation of Rifapentine within alveolar macrophage cells was significantly higher than for rifampicin, indicating enhanced delivery to infected macrophages. The novel inhalable crystalline form of Rifapentine is suitable for targeted treatment of tuberculosis infection and may radically shorten treatment duration. |
| 2014 | An update on the use of rifapentine for tuberculosis therapy. | Expert Opin Drug Deliv | Tuberculosis (TB) remains rampant throughout the world, in large part due to the lengthy treatment times of current therapeutic options. Rifapentine, a rifamycin antibiotic, is currently approved for intermittent dosing in the treatment of TB. Recent animal studies have shown that more frequent administration of Rifapentine could shorten treatment times, for both latent and active TB infection. However, these results were not replicated in a subsequent human clinical trial.This review analyses the evidence for more frequent administration of Rifapentine and the reasons for the apparent lack of efficacy in shortening treatment times in human patients. Inhaled delivery is discussed as a potential option to achieve the therapeutic effect of Rifapentine by overcoming the barriers associated with oral administration of this drug. Avenues for developing an inhalable form of Rifapentine are also presented.Rifapentine is a promising active pharmaceutical ingredient with potential to accelerate treatment of TB if delivered by inhaled administration. Progression of current fundamental work on inhaled anti-tubercular therapies to human clinical trials is essential for determining their role in future treatment regimens. While the ultimate goal for global TB control is a vaccine, a short and effective treatment option is equally crucial. |
| 2014 | Pharmacokinetic interaction of rifapentine and raltegravir in healthy volunteers. | J Antimicrob Chemother | Latent tuberculosis infection and tuberculosis disease are prevalent worldwide. However, antimycobacterial rifamycins have drug interactions with many antiretroviral drugs. We evaluated the effect of Rifapentine on the pharmacokinetic properties of raltegravir.In this open-label, fixed-sequence, three-period study, 21 healthy volunteers were given: raltegravir alone (400 mg every 12 h for 4 days) on days 1-4 of Period 1; Rifapentine (900 mg once weekly for 3 weeks) on days 1, 8 and 15 of Period 2 and raltegravir (400 mg every 12 h for 4 days) on days 12-15 of Period 2; and Rifapentine (600 mg once daily for 10 scheduled doses) on days 1, 4-8 and 11-14 of Period 3 and raltegravir (400 mg every 12 h for 4 days) on days 11-14 of Period 3. Plasma raltegravir concentrations were measured. ClinicalTrials.gov database: NCT00809718.In 16 subjects who completed the study, coadministration of raltegravir with Rifapentine (900 mg once weekly; Period 2) compared with raltegravir alone resulted in the geometric mean of the raltegravir AUC from 0 to 12 h (AUC0-12) being increased by 71%; the peak concentration increased by 89% and the trough concentration decreased by 12%. Coadministration of raltegravir with Rifapentine in Period 3 did not change the geometric mean of the raltegravir AUC0-12 or the peak concentration, but it decreased the trough concentration by 41%. Raltegravir coadministered with Rifapentine was generally well tolerated.The increased raltegravir exposure observed with once-weekly Rifapentine was safe and tolerable. Once-weekly Rifapentine can be used with raltegravir to treat latent tuberculosis infection in patients who are infected with HIV. |
| 2014 | Old and new approaches to diagnosing and treating latent tuberculosis in children in low-incidence countries. | Curr Opin Pediatr | The primary purpose is to review guidance on the testing and treatment of latent tuberculosis infection (LTBI) in children. Most children and adults with LTBI have positive tuberculin skin test (TST) or interferon gamma release assay (IGRA) results, normal examinations, and normal chest radiographs. Diagnosis of and treatment completion for LTBI are critical to diminish future cases of tuberculosis (TB) disease.Children should be screened for TB risk factors, and only children with risk factors should be tested with either a TST or an IGRA. IGRAs measure interferon gamma production by lymphocytes after they are stimulated ex vivo by antigens that are primarily Mycobacterium tuberculosis-specific. The foundation of LTBI therapy in the United States has been 9 months of daily isoniazid, but shorter treatment regimens now exist, including a 12-dose regimen of weekly isoniazid and Rifapentine. These shorter regimens are associated with higher completion rates.There are two distinct modalities for LTBI diagnosis and several treatment regimens that can prevent TB disease in infected children. The selection of treatment regimen should take several factors into consideration, including adherence, drug susceptibility results of the presumed source case (if known), safety, cost, and patient preference. |
| 2013 | Cost-effectiveness of a 12-dose regimen for treating latent tuberculous infection in the United States. | Int J Tuberc Lung Dis | A large randomized controlled trial recently showed that for treating latent tuberculous infection (LTBI) in persons at high risk of progression to tuberculosis (TB) disease, a 12-dose regimen of weekly Rifapentine plus isoniazid (3HP) administered as directly observed treatment (DOT) can be as effective as 9 months of daily self-administered isoniazid (9H).To assess the cost-effectiveness of 3HP compared to 9H.A computational model was designed to simulate individuals with LTBI treated with 9H or 3HP. Costs and health outcomes were estimated to determine the incremental costs per active TB case prevented and per quality-adjusted life year (QALY) gained by 3HP compared to 9H.Over a 20-year period, treatment of LTBI with 3HP rather than 9H resulted in 5.2 fewer cases of TB and 25 fewer lost QALYs per 1000 individuals treated. From the health system and societal perspectives, 3HP would cost respectively US$21,525 and $4294 more per TB case prevented, and respectively $4565 and $911 more per QALY gained.3HP may be a cost-effective alternative to 9H, particularly if the cost of Rifapentine decreases, the effectiveness of 3HP can be maintained without DOT, and 3HP treatment is limited to those with a high risk of progression to TB disease. |
| 2013 | Molecular assays for determining Mycobacterium leprae viability in tissues of experimentally infected mice. | PLoS Negl Trop Dis | The inability of Mycobacterium leprae to grow on axenic media has necessitated specialized techniques in order to determine viability of this organism. The purpose of this study was to develop a simple and sensitive molecular assay for determining M. leprae viability directly from infected tissues.Two M. leprae-specific quantitative reverse transcription PCR (qRT-PCR) assays based on the expression levels of esxA, encoding the ESAT-6 protein, and hsp18, encoding the heat shock 18 kDa protein, were developed and tested using infected footpad (FP) tissues of both immunocompetent and immunocompromised (athymic nu/nu) mice. In addition, the ability of these assays to detect the effects of anti-leprosy drug treatment on M. leprae viability was determined using rifampin and Rifapentine, each at 10 mg/kg for 1, 5, or 20 daily doses, in the athymic nu/nu FP model. Molecular enumeration (RLEP PCR) and viability determinations (qRT-PCR) were performed via Taqman methodology on DNA and RNA, respectively, purified from ethanol-fixed FP tissue and compared with conventional enumeration (microscopic counting of acid fast bacilli) and viability assays (radiorespirometry, viability staining) which utilized bacilli freshly harvested from the contralateral FP. Both molecular and conventional assays demonstrated growth and high viability of M. leprae in nu/nu FPs over a 4 month infection period. In contrast, viability was markedly decreased by 8 weeks in immunocompetent mice. Rifapentine significantly reduced bacterial viability after 5 treatments, whereas rifampin required up to 20 treatments for the same efficacy. Neither drug was effective after a single treatment. In addition, host gene expression was monitored with the same RNA preparations.hsp18 and esxA qRT-PCR are sensitive molecular indicators, reliably detecting viability of M. leprae in tissues without the need for bacterial isolation or immediate processing, making these assays applicable for in vivo drug screening and promising for clinical and field applications. |
| 2014 | Short-course isoniazid plus rifapentine directly observed therapy for latent tuberculosis in solid-organ transplant candidates. | Transplantation | Short-course directly observed isoniazid plus Rifapentine (INH/RPT) combination could have potential advantages over a standard 9-month INH regimen for the treatment of latent tuberculosis infection in solid-organ transplant (SOT) candidates.We prospectively assessed the safety and tolerability of 12 weeks of INH/RPT given directly observed therapy in 17 consecutive SOT candidates with latent tuberculosis infection.The median age was 57 years and 82% were men. Of the 17 patients, 13 (76%) successfully completed therapy and 4 (24%) eventually underwent SOT. Treatment was prematurely discontinued in four patients. One of these patients underwent a kidney transplant. The overall dose compliance was 83% (169/204 scheduled doses), and 12 (71%) of 17 patients received 100% of scheduled doses. No patient developed transaminase elevations greater than twice baseline or greater than four times the upper limit of normal or clinical hepatotoxicity. No cases of TB developed during 20.4 months after transplant among INH/RPT-treated recipients.For carefully selected SOT candidates, combination INH/RPT weekly given as directly observed therapy seems to be reasonably well tolerated and is associated with a relatively high completion rate. Future larger prospective studies to confirm the safety and high completion rates reported here and to identify the most appropriate SOT candidates for this regimen are warranted. |
| 2013 | Pipeline of drugs for related diseases: tuberculosis. | Curr Opin HIV AIDS | For the first time in decades, there are multiple new drugs in the pipeline for the treatment of tuberculosis (TB). In addition, existing drugs are being repurposed or optimized for TB with the goal of shortened treatment duration for drug-sensitive TB and safer, shorter treatments for multidrug-resistant (MDR) TB. In this review, the results of recent trials evaluating novel combination regimens for TB disease and latent TB infection are described.High-dose rifamycins (rifampin and Rifapentine) and fluoroquinolones directly observed have treatment-shortening potential when used for drug-sensitive TB disease, and a 12-dose once-weekly regimen of Rifapentine along with isoniazid effectively treats latent TB. Bedaquiline, an anti-TB drug with a novel mechanism of action, and delamanid, a nitroimidazole, are entering phase 3 trials. Both improve rates of sputum culture conversion among patients with MDR-TB. Other nitroimidazoles and oxazolidinones are in Phase 2 testing, as are combinations involving multiple new chemical entities.With the resurgence of anti-TB drug discovery efforts, we now have a modestly robust pipeline of new anti-TB drugs. Several promising new regimens involving investigational and existing drugs that may be capable of shortening treatment for drug-sensitive TB and improving management of drug-resistant TB are in late-phase clinical evaluation. |
| 2013 | Transmission of Mycobacterium tuberculosis in a High School and School-Based Supervision of an Isoniazid-Rifapentine Regimen for Preventing Tuberculosis - Colorado, 2011-2012. | MMWR Morb Mortal Wkly Rep | Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB), is spread from person to person by the airborne route. It can be transmitted extensively in congregate settings, making investigating exposures and treating infected contacts challenging. In December 2011, a student at a Colorado high school with 1,381 students and school personnel received a diagnosis of pulmonary TB disease. One of five household contacts had TB disease, and the other four had latent M. tuberculosis infection (LTBI). Screening of 1,249 school contacts (90%) found one person with pulmonary TB disease, who was fully treated, and 162 with LTBI, of whom 159 started an LTBI treatment regimen for preventing progression to TB disease and 153 completed a regimen. Only the index patient required inpatient care for TB, and TB caused no deaths. Use of short-course treatment regimens, either 12-dose weekly isoniazid and Rifapentine directly observed at school or 4 months of self-supervised rifampin daily, facilitated treatment completion. State and county incident command structures led by county TB control authorities guided a response team from multiple jurisdictions. News media reports brought public scrutiny, but meetings with the community addressed the concerns and enhanced public participation. Two contacts of the index patient outside of the school had TB disease diagnosed after the school investigation. As of July 2013, no additional TB disease associated with in-school exposure had been found. An emergency plan for focusing widespread resources, an integral public communications strategy, and new, efficient interventions should be considered in other large TB contact investigations. |
| 2013 | Induction of influx and efflux transporters and cytochrome P450 3A4 in primary human hepatocytes by rifampin, rifabutin, and rifapentine. | Antimicrob Agents Chemother | Rifampin is a potent inducer of cytochrome P450 (CYP) enzymes and transporters. Drug-drug interactions during tuberculosis treatment are common. Induction by Rifapentine and rifabutin is understudied. Rifampin and rifabutin significantly induced CYP3A4 (80-fold and 20-fold, respectively) in primary human hepatocytes. The induction was concentration dependent. Rifapentine induced CYP3A4 in hepatocytes from 3 of 6 donors. Data were also generated for ABCB1, ABCC1, ABCC2, organic anion-transporting polypeptide 1B1 (OATP1B1), and OATP1B3. This work serves as a basis for further study of the extent to which rifamycins induce key metabolism and transporter genes. |
| 2013 | Treatment of latent tuberculosis infection. | Ther Adv Respir Dis | Treatment of latent tuberculosis (TB) infection is an important component of TB control programs in both high- and low-prevalence countries. Clinical trials of treatment of latent TB conducted over several decades have demonstrated that preventive treatment can reduce the risk of developing active TB up to 90%. Although 9 months of daily, self-administered isoniazid has been the most widely used and recommended regimen for the treatment of latent infection, other regimens such as 3 months of daily isoniazid and rifampin, or 4 months of daily rifampin alone have also been recommended and used. Most recently, a 12-dose regimen of once-weekly isoniazid and Rifapentine has been shown to be noninferior to 9 months of daily isoniazid in a large and well conducted clinical trial. Adoption of such a regimen on a large scale could have significant implications for TB elimination efforts. |
| 2013 | Treatment of Latent Tuberculosis Infection in Children. | J Pediatric Infect Dis Soc | Treatment of latent tuberculosis infection (LTBI) is an effective way of preventing future cases of tuberculosis disease. We review pediatric and adult studies of LTBI treatment (isoniazid and rifampin monotherapy, isoniazid plus rifampin, isoniazid plus Rifapentine, and rifampin plus pyrazinamide). Based upon this review and our pediatric experience, we can offer recommendations for routine (isoniazid) and alternative courses of therapy. |
| 2013 | Rifamycins (rifampicin, rifabutin and rifapentine) compared to isoniazid for preventing tuberculosis in HIV-negative people at risk of active TB. | Cochrane Database Syst Rev | Preventing active tuberculosis (TB) from developing in people with latent tuberculosis infection (LTBI) is important for global TB control. Isoniazid (INH) for six to nine months has 60% to 90% protective efficacy, but the treatment period is long, liver toxicity is a problem, and completion rates outside trials are only around 50%. Rifampicin or rifamycin-combination treatments are shorter and may result in higher completion rates.To compare the effects of rifampicin monotherapy or rifamycin-combination therapy versus INH monotherapy for preventing active TB in HIV-negative people at risk of developing active TB.We searched the Cochrane Infectious Disease Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; LILACS; clinical trials registries; regional databases; conference proceedings; and references, without language restrictions to December 2012; and contacted experts for relevant published, unpublished and ongoing trials.Randomized controlled trials (RCTs) of HIV-negative adults and children at risk of active TB treated with rifampicin, or rifamycin-combination therapy with or without INH (any dose or duration), compared with INH for six to nine months.At least two authors independently screened and selected trials, assessed risk of bias, and extracted data. We sought clarifications from trial authors. We pooled relative risks (RRs) with their 95% confidence intervals (CIs), using a random-effects model if heterogeneity was significant. We assessed overall evidence quality using the GRADE approach.Ten trials are included, enrolling 10,717 adults and children, mostly HIV-negative (2% HIV-positive), with a follow-up period ranging from two to five years. Rifampicin (three/four months) vs. INH (six months)Five trials published between 1992 to 2012 compared these regimens, and one small 1992 trial in adults with silicosis did not detect a difference in the occurrence of TB over five years of follow up (one trial, 312 participants; very low quality evidence). However, more people in these trials completed the shorter course (RR 1.19, 95% CI 1.01 to 1.30; five trials, 1768 participants; moderate quality evidence). Treatment-limiting adverse events were not significantly different (four trials, 1674 participants; very low quality evidence), but rifampicin caused less hepatotoxicity (RR 0.12, 95% CI 0.05 to 0.30; four trials, 1674 participants; moderate quality evidence). Rifampicin plus INH (three months) vs. INH (six months)The 1992 silicosis trial did not detect a difference between people receiving rifampicin plus INH compared to INH alone for occurrence of active TB (one trial, 328 participants; very low quality evidence). Adherence was similar in this and a 1998 trial in people without silicosis (two trials, 524 participants; high quality evidence). No difference was detected for treatment-limiting adverse events (two trials, 536 participants; low quality evidence), or hepatotoxicity (two trials, 536 participants; low quality evidence). Rifampicin plus pyrazinamide (two months) vs. INH (six months)Three small trials published in 1994, 2003, and 2005 compared these two regimens, and two reported a low occurrence of active TB, with no statistically significant differences between treatment regimens (two trials, 176 participants; very low quality evidence) though, apart from one child from the 1994 trial, these data on active TB were from the 2003 trial in adults with silicosis. Adherence with both regimens was low with no statistically significant differences (four trials, 700 participants; very low quality evidence). However, people receiving rifampicin plus pyrazinamide had more treatment-limiting adverse events (RR 3.61, 95% CI 1.82 to 7.19; two trials, 368 participants; high quality evidence), and hepatotoxicity (RR 4.59, 95% 2.14 to 9.85; three trials, 540 participants; moderate quality evidence). Weekly, directly-observed Rifapentine plus INH (three months) vs. daily, self-administered INH (nine months)A large trial conducted from 2001 to 2008 among close contacts of TB in the USA, Canada, Brazil and Spain found directly observed weekly treatment to be non-inferior to nine months self-administered INH for the incidence of active TB (0.2% vs 0.4%, RR 0.44, 95% CI 0.18 to 1.07, one trial, 7731 participants; moderate quality evidence). The directly-observed, shorter regimen had higher treatment completion (82% vs 69%, RR 1.19, 95% CI 1.16 to 1.22, moderate quality evidence), and less hepatotoxicity (0.4% versus 2.4%; RR 0.16, 95% CI 0.10 to 0.27; high quality evidence), though treatment-limiting adverse events were more frequent (4.9% versus 3.7%; RR 1.32, 95% CI 1.07 to 1.64 moderate quality evidence)Trials to date of shortened prophylactic regimens using rifampicin alone have not demonstrated higher rates of active TB when compared to longer regimens with INH. Treatment completion is probably higher and adverse events may be fewer with shorter rifampicin regimens. Shortened regimens of rifampicin with INH may offer no advantage over longer INH regimens. Rifampicin combined with pyrazinamide is associated with more adverse events. A weekly regimen of Rifapentine plus INH has higher completion rates, and less liver toxicity, though treatment discontinuation due to adverse events is probably more likely than with INH. |
| 2013 | Good response of malignant pleural effusion from carcinoma of unknown primary site to the anti-tuberculosis therapy: a case report. | Int J Clin Exp Pathol | Malignant pleural effusion in patients with cancers or malignant pleural mesothelioma may often appear at the late stage of disease and significantly affect the patients' life quality and survival. However, there is still no very effective treatment to control malignant pleural effusion. Here we report that malignant pleural effusion in one patient was completely relieved for 15 months by the anti-tuberculosis therapy.A 54-year-old female patient complained of cough, dyspnea, chest pain, night sweat and light fever in the afternoon. Computed tomography (CT) of the chest revealed bilateral pleural effusion. But no tumor was found in the lung, pleura and in other sites. Blood test revealed serum carcinoembryonic antigen (CEA) level at 300 ng/mL. One week after we tried anti-tuberculosis combined therapy with isoniazid, pyrazinamide, Rifapentine and ethambutol. The pleural effusion in patient was eliminated, along with decreasing CEA. But the CEA increased gradually again when the anti-tuberculosis treatment was forced to discontinuation. Sixteen months after anti-tuberculosis treatment, the symptoms of cough and breathing difficulty relapsed. Chest CT revealed left pleural effusion, pleural thickness and pericardium nodules. Thoracoscopy and biopsy were conducted. The pleural nodules specimen was pathologically diagnosed as squamous cell carcinoma.We reported a rare case of successfully treating malignant pleural effusion caused by squamous cell carcinoma of unknown primary site with the anti-tuberculosis combined. This report provides useful evidences for that the anti-tubercular agents may have potential anticancer activity in some carcinomas. |
| 2013 | Bactericidal activity does not predict sterilizing activity: the case of rifapentine in the murine model of Mycobacterium ulcerans disease. | PLoS Negl Trop Dis | Since 2004, treatment of Mycobacterium ulcerans disease, or Buruli ulcer, has shifted from surgery to daily treatment with streptomycin (STR) + rifampin (RIF) for 8 weeks. For shortening treatment duration, we tested the potential of daily Rifapentine (RPT), a long-acting rifamycin derivative, as a substitute for RIF.BALB/c mice were infected with M. ulcerans in the right hind footpad and treated either daily (7/7) with STR+RIF or five days/week (5/7) with STR+RIF or STR+RPT for 4 weeks, beginning 28 days after infection when CFU counts were 4.88±0.51. The relative efficacy of the drug treatments was compared by footpad CFU counts during treatment and median time to footpad swelling after treatment cessation as measure of sterilizing activity. All drug treatments were bactericidal. After 1 week of treatment, the decline in CFU counts was significantly greater in treated mice but not different between the three treated groups. After 2 weeks of treatment, the decline in CFU was greater in mice treated with STR+RPT 5/7 than in mice treated with STR+RIF 7/7 and STR+RIF 5/7. After 3 and 4 weeks of treatment, CFU counts were nil in mice treated with STR+RPT and reduced by more than 3 and 4 logs in mice treated with STR+RIF 5/7 and STR+RIF 7/7, respectively. In sharp contrast to the bactericidal activity, the sterilizing activity was not different between all drug regimens although it was in proportion to the treatment duration.The better bactericidal activity of daily STR+RIF and especially of STR+RPT did not translate into better prevention of relapse, possibly because relapse-freecure after treatment of Buruli ulcer is more related to the reversal of mycolactone-induced local immunodeficiency by drug treatment rather than to the bactericidal potency of drugs. |
| 2013 | Preliminary pharmacokinetic study of repeated doses of rifampin and rifapentine in guinea pigs. | Antimicrob Agents Chemother | Substitution of Rifapentine (RFP) for rifampin (RIF) in the standard antituberculous regimen reduces the time required to cure chronic tuberculosis (TB) infection in mice, but not in guinea pigs. In order to gain insight into these discrepant findings, we conducted a steady-state pharmacokinetic (PK) study in healthy guinea pigs to study the metabolism and autoinduction of RIF and RFP. Both RFP and RIF 25-desacetyl metabolites (desRFP and desRIF, respectively), were detected at low concentrations in the serum of guinea pigs. The metabolite concentrations in guinea pigs are much lower than those seen in humans at steady state. |
| 2013 | Update on rifampin, rifabutin, and rifapentine drug interactions. | Curr Med Res Opin | Rifampin is a potent inducer of both cytochrome P-450 oxidative enzymes and the P-glycoprotein transport system. Among numerous well documented, clinically significant interactions, examples include warfarin, oral contraceptives, itraconazole, digoxin, verapamil, simvastatin, and human immunodeficiency virus-related protease inhibitors. Rifabutin reduces serum concentrations of antiretroviral agents, but less so than rifampin. Rifapentine is also an inducer of drug metabolism.A literature search of English language journals from 2008 to March 2012 was completed using several databases, including PubMed, EMBASE, and SCOPUS. Search terms included rifampin, rifabutin, Rifapentine AND drug interactions.Examples of clinically relevant interactions with rifampin demonstrated by recent reports include posaconazole, voriconazole, oxycodone, risperidone, mirodenafil, and ebastine.To avoid a reduced therapeutic response, therapeutic failure, or toxic reactions when rifampin, rifabutin, or Rifapentine are added to or discontinued from medication regimens, clinicians need to be aware of these interactions. Recent studies have indicated that other transporter systems play a role in these drug interactions. As reports of rifampin drug interactions continue to grow, this review is a reminder to clinicians to be vigilant. |
| 2013 | Improving existing tools for Mycobacterium xenopi treatment: assessment of drug combinations and characterization of mouse models of infection and chemotherapy. | J Antimicrob Chemother | Mycobacterium xenopi is a common agent of non-tuberculous mycobacterial lung diseases in Europe. However, an optimal treatment regimen for M. xenopi infection has not yet been established. Appropriate in vitro and in vivo model systems are needed for characterization of the activity of potential drugs and drug combinations against M. xenopi.We utilized three experimental platforms to analyse the anti-M. xenopi activity of single and combination drug regimens. First, we determined the bacteriostatic and bactericidal activities of drugs alone and in combination in vitro. Second, we used serum from treated mice to evaluate drug activities ex vivo. Third, we analysed M. xenopi growth in four strains of mice (BALB/c, C57BL/6, beige and athymic nude) and developed a mouse model of chemotherapy for this infection.Two-drug combinations of ethambutol with rifampicin, Rifapentine or moxifloxacin, and of clarithromycin with moxifloxacin were bactericidal in vitro, and the combination of ethambutol and rifampicin with either clarithromycin or moxifloxacin showed significant bactericidal activity ex vivo. Nude mice were the most susceptible strain to M. xenopi infection, and in this model amikacin-containing regimens were the most effective against M. xenopi. No difference in activity was found between regimens containing clarithromycin and moxifloxacin in vivo.The ethambutol/rifampicin combination with clarithromycin or moxifloxacin had significant bactericidal activity against M. xenopi. The nude mouse, being highly susceptible to M. xenopi, can be utilized for in vivo chemotherapy studies for this infection. |
| 2013 | Rilpivirine: a new non-nucleoside reverse transcriptase inhibitor. | J Antimicrob Chemother | Rilpivirine is a new non-nucleoside reverse transcriptase inhibitor (NNRTI) that is approved for HIV-1 treatment-naive adult patients in combination with other antiretroviral agents. The recommended dose is a 25 mg tablet once daily taken orally with a meal. Due to cytochrome P450 3A4 enzyme induction or gastric pH increase, rilpivirine cannot be coadministered with a number of other drugs (anticonvulsants, rifabutin, rifampicin, Rifapentine, proton pump inhibitors, systemic dexamethasone and St John's wort). Rilpivirine should be used with caution when coadministered with a drug with a known risk for torsade de pointes. Rilpivirine has a better tolerability than a comparative NNRTI, efavirenz, in clinical trials, with fewer central nervous system adverse effects, rashes, lipid abnormalities and discontinuation rates. Virological failure occurs more commonly with higher baseline viral loads (>100,000 copies/mL) and lower baseline CD4 counts (<50 cells/mm(3)). Seventeen NNRTI mutations have been associated with decreased susceptibility to rilpivirine: K101E/P, E138A/G/K/Q/R, V179L, Y181C/I/V, H221Y, F227C, M230I/L, Y188L and the combination L100I + K103N. Resistance to rilpivirine largely excludes future use of the NNRTI class. |
| 2012 | Streptomycin-starved Mycobacterium tuberculosis 18b, a drug discovery tool for latent tuberculosis. | Antimicrob Agents Chemother | Mycobacterium tuberculosis 18b, a streptomycin (STR)-dependent mutant that enters a viable but nonreplicating state in the absence of STR, has been developed as a simple model for drug testing against dormant bacilli. Here, we further evaluated the STR-starved 18b (SS18b) model both in vitro and in vivo by comparing the behavior of 22 approved and experimental tuberculosis drugs. Using the resazurin reduction microplate assay (REMA), rifampin (RIF), Rifapentine (RPT), TMC207, clofazimine (CFM), and linezolid (LIN) were found to be active against SS18b in vitro, and their bactericidal activity was confirmed by determining the number of CFU. A latent 18b infection was established in mice, and some of the above-mentioned drugs were used for treatment, either alone or in combination with RIF. RIF, RPT, TMC207, CFM, and pyrazinamide (PZA) were all active in vivo, while cell wall inhibitors were not. A comparative kinetic study of rifamycin efficacy was then undertaken, and the results indicated that RPT clears latent 18b infection in mice faster than RIF. Intrigued by the opposing responses of live and dormant 18b cells to cell wall inhibitors, we conducted a systematic analysis of 14 such inhibitors using REMA. This uncovered an SS18b signature (CWPRED) that accurately predicted the activities of cell wall inhibitors and performed well in a blind study. CWPRED will be useful for establishing the mode of action of compounds with unknown targets, while the SS18b system should facilitate the discovery of drugs for treating latent tuberculosis. |
| 2012 | Substitution of rifapentine for rifampin during intensive phase treatment of pulmonary tuberculosis: study 29 of the tuberculosis trials consortium. | J Infect Dis | Rifapentine administered 5 days per week has potent activity in mouse models of antituberculosis chemotherapy, but efficacy and safety data are limited in humans. We compared the antimicrobial activity and safety of Rifapentine vs rifampin during the first 8 weeks of pulmonary tuberculosis treatment.In total, 531 adults with sputum smear-positive pulmonary tuberculosis were randomized to Rifapentine 10 mg/kg/dose or rifampin 10 mg/kg/dose, administered 5 days per week for 8 weeks (intensive phase), with isoniazid, pyrazinamide, and ethambutol. Coprimary outcomes were negative sputum culture on liquid and on solid media at completion of intensive phase.Negative cultures on solid media occurred in 145 of 174 participants (83.3%) in the rifampin group and 171 of 198 participants (86.4%) in the Rifapentine group (difference, 3.0%; 95% confidence interval [CI]: -4.3, 10.5); negative cultures in liquid media occurred in 110 of 169 (65.1%) in the rifampin group and 133 of 196 (67.9%) in the Rifapentine group (difference, 2.8%; 95% CI: -6.9, 12.4). Among 529 participants who received study therapy, 40 of 254 participants (15.7%) in the rifampin group and 40 of 275 participants (14.5%) in the Rifapentine group prematurely discontinued treatment (P=.79).The Rifapentine regimen was safe but not significantly more active than a standard rifampin regimen, by the surrogate endpoint of culture status at completion of intensive phase. Assessment of higher exposures to Rifapentine for tuberculosis treatment is warranted.NCT00694629. |
| 2012 | Pharmacokinetic/pharmacodynamic parameters and the choice of high-dosage rifamycins. | Int J Tuberc Lung Dis | Clinical trials and the behaviour of bacterial persisters.To explain why the efficacies of isoniazid (INH) and rifamycins during the treatment of tuberculosis (TB) are related not to the area under the curve (AUC)/minimum inhibitory concentration (MIC), but to peak drug concentrations.We examined the response in clinical trials with patients treated with INH alone and divided into slow and rapid acetylators of INH.The efficacy of INH is best related to peak concentrations, as repeated peaks can kill low-degree resistant mutants. A similar process might result in repeated peak concentrations of rifamycins killing low-tolerance persisters.If the efficacy of rifamycins is best related to peak concentrations, we can explain the discrepancy between mouse studies on daily Rifapentine (RPT) and the failure to accelerate elimination of TB from sputum in the TBTC Study 29A, as daily RPT greatly increases the AUC but not the peak concentrations. High dosage rifampicin may be better able than RPT to cause high peaks. |
| 2012 | New drugs for the treatment of tuberculosis: hope and reality. | Int J Tuberc Lung Dis | The objective of this review is to report evidence about the efficacy and potential of currently licensed drugs and new molecules beyond pre-clinical development for improving the chemotherapy of tuberculosis (TB). Rifapentine, a rifamycin with low minimum inhibitory concentration, long half-life and potent sterilizing activity in mice did not confirm its potential in a recent short-term clinical trial and is being extensively re-evaluated. Moxifloxacin, a fluoroquinolone, improved the activity of the standard drug regimen when substituted for ethambutol (EMB). It is being studied to shorten the duration of treatment for fully drug-susceptible TB (Remox study). Clofazimine, a fat-soluble dye with experimental activity against TB, but used only for leprosy in the last 50 years, requires further study because it has been included in a successful short 9-month combined drug regimen for the treatment of multidrug-resistant TB. The diarylquinoline TMC207 is the most promising among the new TB drugs because of its experimental and clinical rate of culture conversion. Also exciting, 200 mg daily doses in humans of the nitroimidazo-oxazine PA-824 and the nitro-dihydro-imidazooxazole OPC-67683 were safe and induced a bactericidal effect of respectively 0.098 ± 0.072 log(10) and 0.040 ± 0.056 log(10) per day. The new oxazolidinones PNU-100480 and AZD-5847 might be at least as active as linezolid and much less toxic. SQ109 is an EMB analogue that does not have cross-resistance with EMB and might have synergistic activity in combined regimens. Benzothiazinones and dinitrobenzamides show exciting in vitro anti-microbial activity and deserve careful attention. |
| 2012 | Dose-ranging comparison of rifampin and rifapentine in two pathologically distinct murine models of tuberculosis. | Antimicrob Agents Chemother | In previous experiments, replacing the 10-mg/kg of body weight daily dose of rifampin with 7.5 to 10 mg/kg of Rifapentine in combinations containing isoniazid and pyrazinamide reduced the duration of treatment needed to cure tuberculosis in BALB/c mice by approximately 50% due to Rifapentine's more potent activity and greater drug exposures obtained. In the present study, we performed dose-ranging comparisons of the bactericidal and sterilizing activities of rifampin and Rifapentine, alone and in combination with isoniazid and pyrazinamide with or without ethambutol, in BALB/c mice and in C3HeB/FeJ mice, which develop necrotic lung granulomas after infection with Mycobacterium tuberculosis. Each rifamycin demonstrated a significant increase in sterilizing activity with increasing dose. Rifapentine was roughly 4 times more potent in both mouse strains. These results reinforce the rationale for ongoing clinical trials to ascertain the highest well-tolerated doses of rifampin and Rifapentine. This study also provides an important benchmark for the efficacy of the first-line regimen in C3HeB/FeJ mice, a strain in which the lung lesions observed after M. tuberculosis infection may better represent the pathology of human tuberculosis. |
| 2012 | Moxifloxacin population pharmacokinetics in patients with pulmonary tuberculosis and the effect of intermittent high-dose rifapentine. | Antimicrob Agents Chemother | We described the population pharmacokinetics of moxifloxacin and the effect of high-dose intermittent Rifapentine in patients with pulmonary tuberculosis who were randomized to a continuation-phase regimen of 400 mg moxifloxacin and 900 mg Rifapentine twice weekly or 400 mg moxifloxacin and 1,200 mg Rifapentine once weekly. A two-compartment model with transit absorption best described moxifloxacin pharmacokinetics. Although Rifapentine increased the clearance of moxifloxacin by 8% during antituberculosis treatment compared to that after treatment completion without Rifapentine, it did not result in a clinically significant change in moxifloxacin exposure. |
| 2012 | Treatment of latent tuberculosis infection in HIV: shorter or longer? | Curr HIV/AIDS Rep | Nine months of daily isoniazid is efficacious in treating latent M. tuberculosis infection, but completion rates are low, limiting treatment effectiveness. In 2011, three important studies were published involving novel regimens for the treatment of latent M. tuberculosis infection. At least 36 months of isoniazid was more effective than 6 months of isoniazid in one study, but not in another-both of which were conducted among tuberculin skin test positive HIV-infected adults living in high tuberculosis incidence settings. Three months of once-weekly isoniazid plus Rifapentine or twice-weekly isoniazid plus rifampin (both given under direct observation) resulted in tuberculosis rates similar to those seen with 6 months of isoniazid among HIV-infected persons in high tuberculosis incidence settings. Three months of once-weekly, directly-observed isoniazid plus Rifapentine was at least as effective as 9 months of daily isoniazid among predominantly HIV-uninfected persons living in low and medium tuberculosis incidence countries. The 3-month once-weekly isoniazid plus Rifapentine regimen demonstrates promise for treatment of latent M. tuberculosis infection in HIV-infected persons. |
| 2012 | The cost-effectiveness of tuberculosis preventive therapy for HIV-infected individuals in southern India: a trial-based analysis. | PLoS One | Regimens for isoniazid-based preventive therapy (IPT) for tuberculosis (TB) in HIV-infected individuals have not been widely adopted given concerns regarding efficacy, adherence and drug resistance. Further, the cost-effectiveness of IPT has not been studied in India.We used an HIV/TB model to project TB incidence, life expectancy, cost and incremental cost-effectiveness of six months of isoniazid plus ethambutol (6EH), thirty-six months of isoniazid (36H) and no IPT for HIV-infected patients in India. Model input parameters included a median CD4 count of 324 cells/mm(3), and a rate ratio of developing TB of 0.35 for 6EH and 0.22 for 36H at three years as compared to no IPT. Results of 6EH and 36H were also compared to six months of isoniazid (6H), three months of isoniazid plus rifampin (3RH) and three months of isoniazid plus Rifapentine (3RPTH).Projected TB incidence decreased in the 6EH and 36H regimens by 51% and 62% respectively at three-year follow-up compared to no IPT. Without IPT, projected life expectancy was 136.1 months at a lifetime per person cost of $5,630. 6EH increased life expectancy by 0.8 months at an additional per person cost of $100 (incremental cost-effectiveness ratio (ICER) of $1,490/year of life saved (YLS)). 36H further increased life expectancy by 0.2 months with an additional per person cost of $55 (ICER of $3,120/YLS). The projected clinical impact of 6EH was comparable to 6H and 3RH; however when compared to these other options, 6EH was no longer cost-effective given the high cost of ethambutol. Results were sensitive to baseline CD4 count and adherence.Three, six and thirty-six-month regimens of isoniazid-based therapy are effective in preventing TB. Three months of isoniazid plus rifampin and six-months of isoniazid are similarly cost-effective in India, and should be considered part of HIV care. |
| 2012 | Rifapentine is not more active than rifampin against chronic tuberculosis in guinea pigs. | Antimicrob Agents Chemother | Rifamycins are key sterilizing drugs in the current treatment of active tuberculosis (TB). Daily dosing of Rifapentine (P), a potent rifamycin with high intracellular accumulation, in place of rifampin (R) in the standard antitubercular regimen significantly shortens the duration of treatment needed to prevent relapse in a murine model of active TB. We undertook the current study to compare directly the activities of human-equivalent doses of P and R in a guinea pig model of chronic TB, in which bacilli are predominantly extracellular within human-like necrotic granulomas. Hartley strain guinea pigs were aerosol infected with ~200 bacilli of Mycobacterium tuberculosis H37Rv, and treatment given 5 days/week was initiated 6 weeks later. R at 100 mg/kg of body weight and P at 100 mg/kg were given orally alone or in combination with isoniazid (H) at 60 mg/kg and pyrazinamide (Z) at 300 mg/kg. Culture-positive relapse was assessed in subgroups of guinea pigs after completion of 1 and 2 months of treatment. Human-equivalent doses of R and P showed equivalent bactericidal activity when used alone and in combination therapy. In guinea pigs treated with rifampin, isoniazid, and pyrazinamide (RHZ) or PHZ, microbiological relapse occurred in the lungs of 8/10 animals treated for 1 month and in 0/10 animals treated for 2 months. Substitution of P for R in the standard antitubercular regimen did not shorten the time to cure in this guinea pig model of chronic TB. Data from ongoing clinical trials comparing the activity of these two drugs are awaited to determine the relevance of the guinea pig TB model in preclinical drug screening. |
| 2012 | Safety and pharmacokinetics of escalating daily doses of the antituberculosis drug rifapentine in healthy volunteers. | Clin Pharmacol Ther | Rifapentine (RP T) is an antituberculosis drug that may shorten treatment duration when substituted for rifampin (RI F).The maximal tolerated daily dose of RP T and its potential for cytochrome 3A4 induction and autoinduction at clinically relevant doses are unknown. In this phase I, dose-escalation study among healthy volunteers, daily doses as high asa prespecified maximum of 20 mg/kg/day were well tolerated. Steady-state RP T concentrations increased with dose from 5 to 15 mg/kg, but area under the plasma concentration–time curve (AU C0–24) and maximum concentration (Cmax)were similar in the 15- and 20-mg/kg cohorts. Although RP T pharmacokinetics (PK) appeared to be time-dependent,accumulation occurred with daily dosing. The mean AU C0–12 of oral midazolam (MDZ), a cytochrome 3A (CYP 3A) probe drug, was reduced by 93% with the coadministration of RPT and by 74% with the coadministration of RIF (P < 0.01).Changes in the oral clearance of MDZ did not vary by RP T dose. In conclusion, RP T was tolerated at doses as high as20 mg/kg/day, its PK were less than dose-proportional, and its CYP 3A induction was robust. |
| 2012 | Sterilizing activities of novel combinations lacking first- and second-line drugs in a murine model of tuberculosis. | Antimicrob Agents Chemother | Novel oral regimens composed of new drugs with potent activity against Mycobacterium tuberculosis and no cross-resistance with existing agents are needed to shorten and simplify treatment for both drug-susceptible and drug-resistant tuberculosis. As part of a continuing effort to evaluate novel drug combinations for treatment-shortening potential in a murine model, we performed two long-term, relapse-based experiments. In the first experiment, several 3- and 4-drug combinations containing new agents currently in phase 2/3 trials (TMC207 [bedaquiline], PA-824 and PNU-100480 [sutezolid], and/or clofazimine) proved superior to the first-line regimen of rifampin, pyrazinamide, and isoniazid. TMC207 plus PNU-100480 was the most effective drug pair. In the second experiment, in which 3- and 4-drug combinations composed of TMC207 and pyrazinamide plus Rifapentine, clofazimine, PNU-100480, or both Rifapentine and clofazimine were evaluated, the rank order of drugs improving the sterilizing activity of TMC207 and pyrazinamide was as follows: Rifapentine plus clofazimine ≥ clofazimine ≥ Rifapentine > PNU-100480. The results revealed potential new building blocks for universally active short-course regimens for drug-resistant tuberculosis. The inclusion of pyrazinamide against susceptible isolates may shorten the duration of treatment further. |
| 2012 | Drugs for tuberculosis. | Treat Guidel Med Lett | The standard treatment for latent tuberculosis is nine months of isoniazid taken daily, or twice weekly under direct observation by a healthcare worker. Taking isoniazid and Rifapentine once weekly for 12 weeks under direct observation is an alternative for patients >12 years old. Initial therapy for patients with active or suspected tuberculosis should include isoniazid, rifampin,pyrazinamide and ethambutol until susceptibility is known. In patients with drug-susceptible pulmonary tuberculosis, the continuation phase of treatment should be a combination of isoniazid and either rifampin or Rifapentine, taken for 4 or 7 months depending on risk factors. Confirmed multidrug-resistant tuberculosis or extensively drug-resistant tuberculosis should be treated with directly observed therapy in collaboration with a clinician familiar with management of these conditions. Treatment must include at least 4 drugs to which the organism is susceptible; the duration of therapy should usually be 18-24 months. Directly observed therapy by a healthcare worker should be offered to all patients with active tuberculosis to minimize treatment failure, relapse and the emergence of drug resistance. |
| 2012 | Tuberculosis outbreak associated with a homeless shelter - Kane County, Illinois, 2007-2011. | MMWR Morb Mortal Wkly Rep | Despite the overall decline in tuberculosis (TB) incidence in the United States to a record low, outbreaks of TB among homeless persons continue to challenge TB control efforts. In January 2010, public health officials recognized an outbreak of TB after three overnight guests at a homeless shelter in Illinois received diagnoses of TB disease caused by Mycobacterium tuberculosis isolates with matching genotype patterns. As of September 2011, a total of 28 outbreak-associated cases involving shelter guests, dating back to 2007, had been recognized, indicating ongoing M. tuberculosis transmission. The subsequent investigation found that all patients were homeless and had been overnight shelter guests. Excess alcohol use was common (82%), and two bars emerged as additional sites of potential transmission. Patients with outbreak-associated TB were treated successfully for TB disease. To prevent future cases of TB, public health officials are implementing a program to offer 12 once-weekly doses of isoniazid and Rifapentine under direct observation for treatment of latent tuberculosis infection (LTBI) in this high-risk population. Although the United States has made progress toward TB elimination, this outbreak demonstrates the vulnerability of homeless persons to outbreaks of TB, highlighting the need for aggressive and sustained TB control efforts. |
| [Present and future in the use of anti-tubercular drugs]. | Pneumologia | After several decades without any notable progress, there are encouraging results in research and development of anti-TB drugs, the result of a large number of projects now in competition. Along with developing new drugs to treat tuberculosis (TMC207, SQ109, LL3858) are being reassessed others to optimize their effectiveness in order to shorten and simplify therapy (rifampin and Rifapentine) and three other drugs, currently used for other indications, were forwarded towards TB (gatifloxacin and moxifloxacin, linezolid). Time to approval as a antiTB drug is 10-15 years, consisting of phases of preclinical and clinical research. Substitution of moxifloxacin for isoniazid during intensive phase treatment of pulmonary tuberculosis resulted in a small but statistically nonsignificant increase in 8th- week culture negativity. TMC207, a diarylquinoline with a unique way to address Mycobacterial ATP synthetase, shows high activity in vitro against Mycobacterial strains sensitive or resistant to all drugs in the first and second line, including fluoroquinolones, demonstrating exceptional qualities in vivo against several species of mycobacteria, in various animal models. TMC207 was added to a basic standard regimen in a study of MDR-TB patients. After two months and satisfactory tolerability, sputum conversion rate in culture was 48% (versus 9% in the placebo group). Two nitroimidazole (PA-824 and OPC-67683) are currently in clinical development. PA-824 demonstrated good safety and tolerability in adult patients with pulmonary TB in South Africa, when given once daily for 7 days. Associating isoniazid, would prevent the selection of mutants resistant to Isoniazid. Linezolid 600 mg is currently being tested in a Phase II for treatment of XDR-TB in the Republic of Korea. PNU-100480, analogous to the previous one, has the potential to significantly shorten the treatment in cases where there is sensitivity and in those with resistance to drugs. 300 mg dose is under investigation in a phase II pilot study in MDR-TB in South Africa. With this interest and commitment, it appears that there is a chance of having a new drug available soon. |
| 2011 | New regimens for reducing the duration of the treatment of drug-susceptible pulmonary tuberculosis. | Drug Dev Res | Tuberculosis (TB) remains an important health problem worlwide. The structure necessary for delivering TB treatment and implementing the directly observed treatment accounts for more than two-thirds of its final cost. Furthemore, although with efficacy greater than 90%, the effectiveness of present treatment regimens ranges from 55-85%, depending on the setting, mainly due to poor adherence. Duration of treatment with the current first-line anti-TB drugs is a minimum of 6 months. Reducing the duration of the treatment from six to two months or less could result in significant increase of adherence to treatment and cost reduction. The aim of this review is to highlight potential new agents or new drug combinations that could reduce the time of treatment of drug-susceptible TB, currently under study or recently evaluated through clinical trials. We conducted a literature search in the English language for clinical studies as well as an electronic computer-assisted and manual search. The literature search was conducted on November 2010, using MEDLINE (2000-2010), EMBASE (2000-2010) and the National Institute of Health (NIH) Clinical Trials Register database (2000-2010). Most of the new agents identified as anti-TB drug candidates are still in the preclinical phases. Nitroimidazole-PA-824 and fluoroquinolones are evaluated while two first line drugs - rifampicin and Rifapentine -are re-evaluated to optimize their efficacy in new ultra-short anti-TB regimens through phases II/III clinical studies. A summary of the studies are presented, with their potential to change recommendations for TB treatment in the near future. |
| 2012 | In vitro reaction phenotyping studies on rifamycins to explain the auto-induction of rifabutin metabolism. | Int J Tuberc Lung Dis | A study was carried out to establish the relative contribution of human cytochrome P450 (CYP450) enzymes in the metabolism of rifampicin (RMP), Rifapentine (RPT) and rifabutin (RFB). It involved the incubation of the three drugs in five major CYP450 isoforms. Both RMP and RPT showed minimal metabolism by CYP450 enzymes, whereas RFB showed extensive metabolic degradation by CYP3A4. A known inducer of CYP3A4, RFB was shown in this study to be also a substrate for the same enzyme. The latter might be one of the reasons for the auto-induction of RFB metabolism and the consequent lower bioavailability of the drug on repeated administration. |
| 2011 | Recommendations for use of an isoniazid-rifapentine regimen with direct observation to treat latent Mycobacterium tuberculosis infection. | MMWR Morb Mortal Wkly Rep | Preventing tuberculosis (TB) by treating latent Mycobacterium tuberculosis infection (LTBI) is a cornerstone of the U.S. strategy for TB elimination. Three randomized controlled trials have shown that a new combination regimen of isoniazid (INH) and Rifapentine (RPT) administered weekly for 12 weeks as directly observed therapy (DOT) is as effective for preventing TB as other regimens and is more likely to be completed than the U.S. standard regimen of 9 months of INH daily without DOT. This report provides CDC recommendations for using the INH-RPT regimen. The new regimen is recommended as an equal alternative to the 9-month INH regimen for otherwise healthy patients aged≥12 years who have LTBI and factors that are predictive of TB developing (e.g., recent exposure to contagious TB). The new regimen also can be considered for other categories of patients when it offers practical advantages. Although the INH-RPT regimen was well tolerated in treatment trials, monitoring for adverse effects is recommended. Severe adverse effects should be reported to the Food and Drug Administration (FDA) and CDC. |
| 2011 | Three months of rifapentine and isoniazid for latent tuberculosis infection. | N Engl J Med | Treatment of latent Mycobacterium tuberculosis infection is an essential component of tuberculosis control and elimination. The current standard regimen of isoniazid for 9 months is efficacious but is limited by toxicity and low rates of treatment completion.We conducted an open-label, randomized noninferiority trial comparing 3 months of directly observed once-weekly therapy with Rifapentine (900 mg) plus isoniazid (900 mg) (combination-therapy group) with 9 months of self-administered daily isoniazid (300 mg) (isoniazid-only group) in subjects at high risk for tuberculosis. Subjects were enrolled from the United States, Canada, Brazil, and Spain and followed for 33 months. The primary end point was confirmed tuberculosis, and the noninferiority margin was 0.75%.In the modified intention-to-treat analysis, tuberculosis developed in 7 of 3986 subjects in the combination-therapy group (cumulative rate, 0.19%) and in 15 of 3745 subjects in the isoniazid-only group (cumulative rate, 0.43%), for a difference of 0.24 percentage points. Rates of treatment completion were 82.1% in the combination-therapy group and 69.0% in the isoniazid-only group (P<0.001). Rates of permanent drug discontinuation owing to an adverse event were 4.9% in the combination-therapy group and 3.7% in the isoniazid-only group (P=0.009). Rates of investigator-assessed drug-related hepatotoxicity were 0.4% and 2.7%, respectively (P<0.001).The use of Rifapentine plus isoniazid for 3 months was as effective as 9 months of isoniazid alone in preventing tuberculosis and had a higher treatment-completion rate. Long-term safety monitoring will be important. (Funded by the Centers for Disease Control and Prevention; PREVENT TB ClinicalTrials.gov number, NCT00023452.). |
| 2011 | The activity of several newer antimicrobials against logarithmically multiplying M. leprae in mice. | Lepr Rev | Moxifloxacin, rifampicin, Rifapentine, linezolid, and PA 824, alone and in combination, have been previously administered, as single doses and five times daily doses, to M. leprae infected mice during lag phase multiplication and were each found to have some bactericidal activity.The fluroquinolones, ofloxacin, moxifloxacin and gatifloxacin, (50 mg/kg, 150 mg/kg and 300 mg/kg) and the rifamycins (5 mg/kg, 10 mg/kg, and 20 mg/kg), rifampicin and Rifapentine, were evaluated alone and in combination for bactericidal activity against M. leprae using the mouse footpad model during logarithmic multiplication. Linezolid and PA 824 were similarly evaluated alone and linezolid in combination with rifampicin, minocycline and ofloxacin.The three fluroquinolones and rifamycins were found alone and in combination to be bactericidal at all dosage schedules. PA 824 had no activity against M. leprae, while linezolid at a dose of 25 mg/kg was bacteriostatic, and progressively more bactericidal at doses of 50 mg/kg and 100 mg/kg. No antagonisms were detected between any of these drugs when used in combinations.Moxifloxacin, gatifloxacin, Rifapentine and linezolid were found bactericidal against rapidly multiplying M. leprae. |
| 2011 | Penetration of anti-infective agents into pulmonary epithelial lining fluid: focus on antifungal, antitubercular and miscellaneous anti-infective agents. | Clin Pharmacokinet | Epithelial lining fluid (ELF) is often considered to be the site of extracellular pulmonary infections. During the past 25 years, a limited number of studies have evaluated the intrapulmonary penetration of antifungal, antitubercular, antiparasitic and antiviral agents. For antifungal agents, differences in drug concentrations in ELF or bronchoalveolar lavage (BAL) fluid were observed among various formulations or routes of administration, and between agents within the same class. Aerosolized doses of deoxycholate amphotericin B, liposomal amphotericin B and amphotericin B lipid complex resulted in higher concentrations in ELF or BAL fluid than after intravenous administration. The mean concentrations in ELF following intravenous administration of both anidulafungin and micafungin ranged between 0.04 and 1.38 μg/mL, and the ELF to plasma concentration ratios (based on the area under the concentration-time curve for total drug concentrations) were between 0.18 and 0.22 during the first 3 days of therapy. Among the azole agents, intravenous administration of voriconazole resulted in the highest mean ELF concentrations (range 10.1-48.3 μg/mL) and ratio of penetration (7.1). The range of mean ELF concentrations of itraconazole and posaconazole following oral administration was 0.2-1.9 μg/mL, and the ELF to plasma concentration ratios were <1. A series of studies have evaluated the intrapulmonary penetration of first- and second-line oral antitubercular agents in healthy adult subjects and patients with AIDS. The ELF to plasma concentration ratio was >1 for isoniazid, ethambutol, pyrazinamide and ethionamide. For rifampicin (rifampin) and Rifapentine, the ELF to plasma concentration ratio ranged between 0.2 and 0.32, but in alveolar macrophages the concentration of rifampicin was much higher (145-738 μg/mL compared with 3.3-7.5 μg/mL in ELF). No intrapulmonary studies have been conducted for rifabutin. Sex, AIDS status or smoking history had no significant effects on the magnitude of ELF concentrations of antitubercular agents. Subjects who were slow acetylators had higher plasma and ELF concentrations of isoniazid than those who were fast acetylators. Penetration of dapsone into ELF was very good, with the range of mean ELF to plasma concentration ratios being 0.65-2.91 at individual sampling times over 48 hours. Once-daily dosing of aerosolized pentamidine resulted in higher concentrations in BAL fluid than after intravenous administration. The mean BAL concentrations at 15-32 days after once- or twice-monthly administration of aerosolized pentamidine 300 and 600 mg ranged from 6.5 to 28.4 ng/mL. No differences in pentamidine BAL concentrations were observed in symptomatic patients who developed Pneumocystis jirovecii pneumonia compared with patients who did not. Zanamivir concentrations in ELF were similar in magnitude (range 141-326 ng/mL) following administration by continuous intravenous infusion (3 mg/hour), oral inhalation (10 mg every 12 hours) and intravenous bolus (200 mg every 12 hours). Data from case reports have suggested that concentrations of nelfinavir and saquinavir in ELF are undetectable, whereas tipranavir and lopinavir had measureable ELF concentrations (2.20 μmol/L and 14.4 μg/mL, respectively) when these protease inhibitors were co-administrated with ritonavir. While the clinical significance of ELF or BAL concentrations remains unknown for this group of anti-infective agents, the knowledge of drug penetration into the extracellular space of the lung should assist in re-evaluating and designing specific dosing regimens for use against potential pathogens. |
| 2011 | Sterilizing activity of novel TMC207- and PA-824-containing regimens in a murine model of tuberculosis. | Antimicrob Agents Chemother | To truly transform the landscape of tuberculosis treatment, novel regimens containing at least 2 new drugs are needed to simplify the treatment of both drug-susceptible and drug-resistant forms of tuberculosis. As part of an ongoing effort to evaluate novel drug combinations for treatment-shortening potential in a murine model, we performed two long-term, relapse-based experiments. In the first experiment, TMC207 plus pyrazinamide, alone or in combination with any third drug, proved superior to the first-line regimen including rifampin, pyrazinamide, and isoniazid. On the basis of CFU counts at 1 month, clofazimine proved to be the best third drug combined with TMC207 and pyrazinamide, whereas the addition of PA-824 was modestly antagonistic. Relapse results were inconclusive due to the low rate of relapse in all test groups. In the second experiment evaluating 3-drug combinations composed of TMC207, pyrazinamide, PA-824, moxifloxacin, and Rifapentine, TMC207 plus pyrazinamide plus either Rifapentine or moxifloxacin was the most effective, curing 100% and 67% of the mice treated, respectively, in 2 months of treatment. Four months of the first-line regimen did not cure any mice, whereas the combination of TMC207, PA-824, and moxifloxacin cured 50% of the mice treated. The results reveal new building blocks for novel regimens with the potential to shorten the duration of treatment for both drug-susceptible and drug-resistant tuberculosis, including the combination of TMC207, pyrazinamide, PA-824, and a potent fluoroquinolone. |
| 2011 | Human arylacetamide deacetylase is responsible for deacetylation of rifamycins: rifampicin, rifabutin, and rifapentine. | Biochem Pharmacol | Rifamycins such as rifampicin, rifabutin, and Rifapentine are used for the treatment of tuberculosis and induce various drug-metabolizing enzymes. Rifamycins have been reported to be mainly deacetylated by esterase(s) expressed in human liver microsomes (HLM) to 25-deacetylrifamycins, but the responsible enzyme remained to be determined. In this study, we found that recombinant human arylacetamide deacetylase (AADAC) could efficiently deacetylate rifamycins, whereas human carboxylesterases, which are enzymes responsible for the hydrolysis of many prodrugs, showed no activity. The involvement of AADAC in the deacetylation of rifamycins in HLM was verified by the similarities of the K(m) and K(i) values and the inhibitory characteristics between recombinant AADAC and HLM. Rifamycins exhibited potent cytotoxicity to HepG2 cells, but their 25-deacetylated metabolites did not. Luciferase assay using a reporter plasmid containing CYP3A4 direct repeat 3 and everted repeat 6 motifs revealed that 25-deacetylrifamycins have lesser potency to transactivate CYP3A4 compared with the parent drugs. Supporting these results, HepG2 cells infected with a recombinant adenovirus expressing human AADAC showed low cytotoxicity and induction potency of CYP3A4 by rifamycins. In addition, CYP3A4 induction in human hepatocytes by rifamycins was increased by transfecting siRNA for human AADAC. Thus, we found that human AADAC was the enzyme responsible for the deacetylation of rifamycins and would affect the induction rate of drug-metabolizing enzymes by rifamycins and their induced hepatotoxicity. |
| 2011 | New regimens to prevent tuberculosis in adults with HIV infection. | N Engl J Med | Treatment of latent tuberculosis in patients infected with the human immunodeficiency virus (HIV) is efficacious, but few patients around the world receive such treatment. We evaluated three new regimens for latent tuberculosis that may be more potent and durable than standard isoniazid treatment.We randomly assigned South African adults with HIV infection and a positive tuberculin skin test who were not taking antiretroviral therapy to receive Rifapentine (900 mg) plus isoniazid (900 mg) weekly for 12 weeks, rifampin (600 mg) plus isoniazid (900 mg) twice weekly for 12 weeks, isoniazid (300 mg) daily for up to 6 years (continuous isoniazid), or isoniazid (300 mg) daily for 6 months (control group). The primary end point was tuberculosis-free survival.The 1148 patients had a median age of 30 years and a median CD4 cell count of 484 per cubic millimeter. Incidence rates of active tuberculosis or death were 3.1 per 100 person-years in the Rifapentine-isoniazid group, 2.9 per 100 person-years in the rifampin-isoniazid group, and 2.7 per 100 person-years in the continuous-isoniazid group, as compared with 3.6 per 100 person-years in the control group (P>0.05 for all comparisons). Serious adverse reactions were more common in the continuous-isoniazid group (18.4 per 100 person-years) than in the other treatment groups (8.7 to 15.4 per 100 person-years). Two of 58 isolates of Mycobacterium tuberculosis (3.4%) were found to have multidrug resistance.On the basis of the expected rates of tuberculosis in this population of HIV-infected adults, all secondary prophylactic regimens were effective. Neither a 3-month course of intermittent Rifapentine or rifampin with isoniazid nor continuous isoniazid was superior to 6 months of isoniazid. (Funded by the National Institute of Allergy and Infectious Diseases and others; ClinicalTrials.gov number, NCT00057122.). |
| 2011 | Short-course chemotherapy with TMC207 and rifapentine in a murine model of latent tuberculosis infection. | Am J Respir Crit Care Med | Multidrug-resistant and extensively drug-resistant tuberculosis (MDR/XDR-TB) is an emerging global health threat. Proper management of close contacts of infectious patients is increasingly important. However, no evidence-based recommendations for treating latent TB infection (LTBI) after MDR/XDR-TB exposure (DR-LTBI) exist. An ultrashort regimen for LTBI caused by drug-susceptible strains (DS-LTBI) is also desirable. TMC207 has bactericidal and sterilizing activity in animal models of TB and improves the activity of current MDR-TB therapy in patients.The objective of this study was to determine whether TMC207 might enable short-course treatment of DR-LTBI and ultrashort treatment of DS-LTBI.Using an established experimental model of LTBI chemotherapy in which mice are aerosol-immunized with a recombinant bacillus Calmette-Guérin vaccine before low-dose aerosol infection with Mycobacterium tuberculosis, the efficacy of TMC207 alone and in combination with Rifapentine was compared with currently recommended control regimens as well as once-weekly Rifapentine + isoniazid and daily Rifapentine ± isoniazid.Outcomes included monthly lung colony-forming unit counts and relapse rates.Lung colony-forming unit counts were stable at about 3.75 log(10) for up to 7.5 months postinfection in untreated mice. Rifamycin-containing regimens were superior to isoniazid monotherapy. TMC207 exhibited sterilizing activity at least as strong as that of rifampin alone and similar to that of rifampin + isoniazid, but daily Rifapentine +/- isoniazid was superior to TMC207. Addition of TMC207 to Rifapentine did not improve the sterilizing activity of Rifapentine in this model.TMC207 has substantial sterilizing activity and may enable treatment of DR-LTBI in 3-4 months. |
| 2011 | New drugs for tuberculosis treatment. | Enferm Infecc Microbiol Clin | Available data on anti-tuberculosis drug research reveal different properties of the agents and provoke speculation about future directions. Higher doses of the rifamycins are promising and are currently being evaluated in regimens of shorter duration that the isoniazid plus rifampin-based, six-to-nine month-course therapy. Moxifloxacin and gatifloxacin might shorten tuberculosis treatment as well, possibly in combination with Rifapentine, while SQ109 could enhance the activity of rifampin-containing regimens. On the other hand, co-administration of moxifloxacin and PA-824 could be active against latent tuberculosis, whereas linezolid, PA-824 and TMC207 are candidates for a rifampin-free regimen in multidrug-resistant and extensively-resistant tuberculosis. Unfortunately, shorter than existent treatment regimens based on the new agents discussed here are likely to take at least another decade to be fully developed and implemented in clinical practice. |
| 2011 | Recent developments in treatment of latent tuberculosis infection. | Indian J Med Res | Latent tuberculosis infection (LTBI) can be detected with immune based tests such as the tuberculin skin test (TST) or interferon gamma release assays (IGRA). Therapy for those with positive tests can reduce the subsequent risk of re-activation and development of active TB. Current standard therapy is isoniazid (INH) which reduce the risk of active TB by as much as 90 per cent if taken daily for 9 months. However, this lengthy duration of therapy discourages patients, and the risk of serious adverse events such as hepatotoxicity, discourages both patients and providers. As a result completion of INH therapy is less than 50 per cent in many programmes. However, programmes that offer close follow up with supportive staff who emphasize patient education, have reported much better results. The problems with INH have stimulated development and evaluation of several shorter regimens. One alternative was two months daily rifampin and pyrazinamide; this regimen has been largely abandoned due to unacceptably high rates of hepatotoxicity and poor tolerability. The combination of INH and rifampin, taken for 3 or 4 months, has efficacy equivalent to 6 months INH albeit with somewhat increased hepatotoxicity. Four months rifampin has efficacy at least equivalent to 6 months INH but there are inadequate trial data on efficacy. The safety of this regimen has been demonstrated repeatedly. Most recently, a regimen of 3 months INH Rifapentine taken once weekly under direct observation has been evaluated in a large scale trial. Results have not yet been published, but if this regimen is as effective as INH, this may be a very good alternative. However, close monitoring and surveillance is strongly suggested for the first few years after its introduction. Evidence from several randomized trials has shown that the benefits of LTBI therapy is only in individuals who are tuberculin skin test (TST) positive even among those with HIV infection. Hence, LTBI therapy should be given only to those with positive tests for LTBI. We conclude that LTBI therapy is considerably underutilized in many settings, particularly in low and middle income countries. |
| 2011 | Treatment of tuberculosis with rifamycin-containing regimens in immune-deficient mice. | Am J Respir Crit Care Med | Daily Rifapentine plus isoniazid-pyrazinamide in mice infected with Mycobacterium tuberculosis produces cure in 3 months. Whether cure corresponds to latent infection contained by host immunity or true tissue sterilization is unknown.To determine the length of treatment with Rifapentine-isoniazid-pyrazinamide or rifampin-isoniazid-pyrazinamide needed to prevent relapse in immune-deficient mice.Aerosol-infected BALB/c and nude mice were treated 5 days per week with either 2 months of the Rifapentine-based regimen followed by Rifapentine-isoniazid up to 12 months or the same regimen with rifampin instead of Rifapentine. Cultures of lung homogenates were performed during the first 3 months and then every 3 months. Relapse rates were assessed after 3, 6, 9, and 12 months of treatment in BALB/c (± 1 mo of cortisone) and nude mice.All Rifapentine-treated mice were lung culture-negative at 3 months but 13% of BALB/c that received cortisone and 73% of nude mice relapsed. After 6, 9, and 12 months of treatment no mouse relapsed. Rifampin-treated BALB/c mice remained culture positive at 3 months. All were culture negative at 6, 9, and 12 months. None, including those receiving cortisone, relapsed. Rifampin-treated nude mice harbored more than 4 log(10) lung cfu at Month 2 and approximately 6 log(10) cfu with isoniazid resistance at Month 3. A supplementary experiment demonstrated that 7 days a week treatment did not prevent isoniazid resistance, whereas addition of ethambutol did.In nude mice, sterilization of tuberculosis is obtained with Rifapentine-containing treatment, whereas failure with development of isoniazid resistance is obtained with rifampin-containing treatment. |
| 2011 | Activities of rifampin, Rifapentine and clarithromycin alone and in combination against mycobacterium ulcerans disease in mice. | PLoS Negl Trop Dis | treatment of Mycobacterium ulcerans disease, or Buruli ulcer (BU), has shifted from surgery to treatment with streptomycin(STR)+rifampin(RIF) since 2004 based on studies in a mouse model and clinical trials. We tested two entirely oral regimens for BU treatment, rifampin(RIF)+clarithromycin(CLR) and Rifapentine(RPT)+clarithromycin(CLR) in the mouse model.BALB/c mice were infected in the right hind footpad with M. ulcerans strain 1059 and treated daily (5 days/week) for 4 weeks, beginning 11 days after infection. Treatment groups included an untreated control, STR+RIF as a positive control, and test regimens of RIF, RPT, STR and CLR given alone and the RIF+CLR and RPT+CLR combinations. The relative efficacy of the drug treatments was compared on the basis of footpad CFU counts and median time to footpad swelling. Except for CLR, which was bacteriostatic, treatment with all other drugs reduced CFU counts by approximately 2 or 3 log(10). Median time to footpad swelling after infection was 5.5, 16, 17, 23.5 and 36.5 weeks in mice receiving no treatment, CLR alone, RIF+CLR, RIF alone, and STR alone, respectively. At the end of follow-up, 39 weeks after infection, only 48%, 26.4% and 16.3% of mice treated with RPT+CLR, RPT alone and STR+RIF had developed swollen footpads. An in vitro checkerboard assay showed the interaction of CLR and RIF to be indifferent. However, in mice, co-administration with CLR resulted in a roughly 25% decrease in the maximal serum concentration (Cmax) and area under the serum concentration-time curve (AUC) of each rifamycin. Delaying the administration of CLR by one hour restored Cmax and AUC values of RIF to levels obtained with RIF alone.these results suggest that an entirely oral daily regimen of RPT+CLR may be at least as effective as the currently recommended combination of injected STR+oral RIF. |
| 2011 | Pharmacokinetic interactions between etravirine and non-antiretroviral drugs. | Clin Pharmacokinet | Etravirine (formerly TMC125) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) with activity against wild-type and NNRTI-resistant strains of HIV-1. Etravirine has been approved in several countries for use as part of highly active antiretroviral therapy in treatment-experienced patients. In vivo, etravirine is a substrate for, and weak inducer of, the hepatic cytochrome P450 (CYP) isoenzyme 3A4 and a substrate and weak inhibitor of CYP2C9 and CYP2C19. Etravirine is also a weak inhibitor of P-glycoprotein. An extensive drug-drug interaction programme in HIV-negative subjects has been carried out to assess the potential for pharmacokinetic interactions between etravirine and a variety of non-antiretroviral drugs. Effects of atorvastatin, clarithromycin, methadone, omeprazole, oral contraceptives, paroxetine, ranitidine and sildenafil on the pharmacokinetic disposition of etravirine were of no clinical relevance. Likewise, etravirine had no clinically significant effect on the pharmacokinetics of fluconazole, methadone, oral contraceptives, paroxetine or voriconazole. No clinically relevant interactions are expected between etravirine and azithromycin or ribavirin, therefore, etravirine can be combined with these agents without dose adjustment. Fluconazole and voriconazole increased etravirine exposure 1.9- and 1.4-fold, respectively, in healthy subjects, however, no increase in the incidence of adverse effects was observed in patients receiving etravirine and fluconazole during clinical trials, therefore, etravirine can be combined with these antifungals although caution is advised. Digoxin plasma exposure was slightly increased when co-administered with etravirine. No dose adjustments of digoxin are needed when used in combination with etravirine, however, it is recommended that digoxin levels should be monitored. Caution should be exercised in combining rifabutin with etravirine in the presence of certain boosted HIV protease inhibitors due to the risk of decreased exposure to etravirine. Although adjustments to the dose of clarithromycin are unnecessary for the treatment of most infections, the use of an alternative macrolide (e.g. azithromycin) is recommended for the treatment of Mycobacterium avium complex infection since the overall activity of clarithromycin against this pathogen may be altered when co-administered with etravirine. Dosage adjustments based on clinical response are recommended for clopidogrel, HMG-CoA reductase inhibitors (e.g. atorvastatin) and for phosphodiesterase type-5 inhibitors (e.g. sildenafil) because changes in the exposure of these medications in the presence of co-administered etravirine may occur. When co-administered with etravirine, a dose reduction or alternative to diazepam is recommended. When combining etravirine with warfarin, the international normalized ratio (INR) should be monitored. Systemic dexamethasone should be co-administered with caution, or an alternative to dexamethasone be found as dexamethasone induces CYP3A4. Caution is also warranted when co-administering etravirine with some antiarrhythmics, calcineurin inhibitors (e.g. ciclosporin) and antidepressants (e.g. citalopram). Co-administration of etravirine with some antiepileptics (e.g. carbamazepine and phenytoin), rifampicin (rifampin), Rifapentine or preparations containing St John's wort (Hypericum perforatum) is currently not recommended as these are potent inducers of CYP3A and/or CYP2C and may potentially decrease etravirine exposure. Antiepileptics that are less likely to interact based on their known pharmacological properties include gabapentin, lamotrigine, levetiracetam and pregabalin. Overall, pharmacokinetic and clinical data show etravirine to be well tolerated and generally safe when given in combination with non-antiretroviral agents, with minimal clinically significant drug interactions and no need for dosage adjustments of etravirine in any of the cases, or of the non-antiretroviral agent in the majority of cases studied. |
| 2010 | New approaches in the diagnosis and treatment of latent tuberculosis infection. | Respir Res | With nearly 9 million new active disease cases and 2 million deaths occurring worldwide every year, tuberculosis continues to remain a major public health problem. Exposure to Mycobacterium tuberculosis leads to active disease in only ~10% people. An effective immune response in remaining individuals stops M. tuberculosis multiplication. However, the pathogen is completely eradicated in ~10% people while others only succeed in containment of infection as some bacilli escape killing and remain in non-replicating (dormant) state (latent tuberculosis infection) in old lesions. The dormant bacilli can resuscitate and cause active disease if a disruption of immune response occurs. Nearly one-third of world population is latently infected with M. tuberculosis and 5%-10% of infected individuals will develop active disease during their life time. However, the risk of developing active disease is greatly increased (5%-15% every year and ~50% over lifetime) by human immunodeficiency virus-coinfection. While active transmission is a significant contributor of active disease cases in high tuberculosis burden countries, most active disease cases in low tuberculosis incidence countries arise from this pool of latently infected individuals. A positive tuberculin skin test or a more recent and specific interferon-gamma release assay in a person without overt signs of active disease indicates latent tuberculosis infection. Two commercial interferon-gamma release assays, QFT-G-IT and T-SPOT.TB have been developed. The standard treatment for latent tuberculosis infection is daily therapy with isoniazid for nine months. Other options include therapy with rifampicin for 4 months or isoniazid + rifampicin for 3 months or rifampicin + pyrazinamide for 2 months or isoniazid + Rifapentine for 3 months. Identification of latently infected individuals and their treatment has lowered tuberculosis incidence in rich, advanced countries. Similar approaches also hold great promise for other countries with low-intermediate rates of tuberculosis incidence. |
| 2010 | Drugs in development for tuberculosis. | Drugs | Tuberculosis (TB) drug research and development efforts have resurged in the past 10 years to meet urgent medical needs, but enormous challenges remain. These urgent needs are largely driven by the current long and arduous multidrug regimens, which have significant safety, tolerability and compliance issues; rising and disturbing rates of multidrug- and extensively drug-resistant TB; the existence of approximately 2 billion individuals already latently infected with Mycobacterium tuberculosis, the causative pathogen of TB; and a global TB-HIV co-epidemic. Stakeholders in TB drug development are moving to enable and streamline development and registration of novel, multidrug treatment regimens, comprised of multiple new chemical entities with novel mechanisms of action that do not demonstrate cross-resistance to current first- and second-line TB drugs. Ideally, these new regimens will ultimately provide a short, simple treatment suitable for essentially all TB patients, whether sensitive or resistant to the current anti-TB agents, whether HIV-positive or -negative, and irrespective of patient age. This article reviews the challenges faced by those trying to develop these novel regimens and the key agents currently in clinical testing for TB; the latter are organized for discussion into three categories: (i) novel drugs (TMC207, SQ109, sudoterb [LL3858]); (ii) present first-line TB drugs being re-evaluated to optimize their efficacy (rifampicin, Rifapentine); and (iii) currently licensed drugs for other indications and 'next-generation' compounds of the same chemical class being repurposed for TB (gatifloxacin and moxifloxacin; linezolid, PNU100480 and AZD5847; metronidazole, OPC-67683 and PA-824). |
| 2010 | [Therapeutic efficacy of drug susceptibility test-guided individualized anti-tuberculosis chemotherapy for spinal tuberculosis]. | Zhonghua Wai Ke Za Zhi | To investigate the efficacy of individualized anti-tuberculosis chemotherapy guided by drug susceptibility testing for spinal tuberculosis through analyses on the post-operative follow-up outcomes.The diagnoses of spinal tuberculosis were established by clinical, radiological and histological evaluation in 132 patients who were admitted from August 2005 to January 2010, 62 patients (37 male and 25 female) with follow-up more than 12 months in this study. The average age was 33.6 years (ranging from 4 - 67 years). The infected samples were collected during surgery. After processed in a routine laboratory procedure, the samples were inoculated into vials of the BACT/ALERT 3D system. The drug susceptibility testing was performed using absolute concentration method, which included 11 first-line and second-line drugs. Four or five anti-tuberculosis drug regimen was chosen according to the results of drug susceptibility testing. All the patients were followed up a month later, and then once 3 months in the following 11 months, and subsequently at intervals of half a year. The clinical status, erythrocyte sedimentation rate (ESR), roentgenogram, MRI and 3D-CT were concerned to estimate the progress of tuberculosis.The culture positive rate was 45.2% (28/62). The average detection time was 42 d (ranging from 28 - 58 d). The drug susceptibility testing showed a total drug resistance level of 24.2%:12.9% for isoniazid, 4.8% for rifampicin, 3.2% for ethambutol, 9.7% for streptomycin, 6.4% for pasiniazid, 14.5% for levofloxacin, 1.6% for Rifapentine. The mean follow-up period was 21 months (ranging from 12 - 44 months). According to Bridwell criteria, grade I bony fusion was obtained in all patients in 8 - 12 months.Guided by drug susceptibility testing, individualized anti-tuberculosis chemotherapy for 12 to 18 months is effective for spinal tuberculosis. |
| 2010 | Bactericidal potencies of new regimens are not predictive of their sterilizing potencies in a murine model of tuberculosis. | Antimicrob Agents Chemother | TMC207, Rifapentine, and moxifloxacin are in clinical testing for the treatment of tuberculosis. Five experimental regimens with various combinations of TMC207, Rifapentine, moxifloxacin, and pyrazinamide were tested for their bactericidal and sterilizing potencies in Swiss mice intravenously inoculated with Mycobacterium tuberculosis bacilli. TMC207 had the strongest bactericidal efficacy, while Rifapentine was the strongest contributor to sterilizing efficacy. The rank order of sterilizing potencies was different from the rank order of bactericidal potencies, underlining the importance of prioritizing new regimens designed to shorten the treatment duration by their sterilizing potencies rather than by their bactericidal potencies. Both 3 months of treatment with a regimen combining TMC207, pyrazinamide, and Rifapentine and 5 months of treatment with a regimen combining TMC207, pyrazinamide, and moxifloxacin resulted in relapse rates similar to the rate obtained by 6 months of treatment with rifampin-isoniazid-pyrazinamide. |
| 2010 | Effects of four different meal types on the population pharmacokinetics of single-dose rifapentine in healthy male volunteers. | Antimicrob Agents Chemother | Rifapentine and its primary metabolite, 25-desacetyl Rifapentine, are active against mycobacterium tuberculosis. The objectives of this study were to describe the population pharmacokinetics of Rifapentine and 25-desacetyl Rifapentine in fasting and fed states. Thirty-five male healthy volunteers were enrolled in an open-label, randomized, sequential, five-way crossover study. Participants received a single 900-mg dose of Rifapentine after meals with high fat (meal A), bulk and low fat (meal B), bulk and high fat (meal C), high fluid and low fat (meal D), or 200 ml of water (meal E). Venous blood samples were collected over 72 h after each Rifapentine dose, and plasma was analyzed for Rifapentine and 25-desacetyl Rifapentine using high-performance liquid chromatography. Pharmacokinetic data were analyzed by nonlinear mixed-effect modeling using NONMEM. Compared with the fasting state, meal A had the greatest effect on Rifapentine oral bioavailability, increasing it by 86%. Meals B, C, and D resulted in 33%, 46%, and 49% increases in Rifapentine oral bioavailability, respectively. Similar trends were observed for 25-desacetyl Rifapentine. As meal behavior has a substantial impact on Rifapentine exposure, it should be considered in the evaluation of optimal dosing approaches. |
| 2010 | Treatment of latent tuberculosis infection: An update. | Respirology | Isoniazid (INH) has been the mainstay of treatment of latent tuberculosis infection for almost 50 years. The currently recommended preferred regimen is 9 months daily self-administered INH (9H); this has efficacy of more than 90% if completed properly. Unfortunately, INH is associated with serious adverse events, including hepatotoxicity. Although risk factors for this complication are well established, allowing for better selection of candidates for therapy, this complication still occurs, and is occasionally fatal. Hence close follow up of patients is necessary, increasing the cost and complexity of treatment. This problem, plus the lengthy duration, results in poor acceptance by patients and providers, and poor adherence by patients. As a result, many preventable cases of tuberculosis continue to occur, and the public health impact of latent tuberculosis infection treatment is suboptimal. These problems have spurred interest in finding shorter, safer and cheaper alternative regimens, with similar efficacy. Of the many regimens that have been examined, 2 months of rifampin and pyrazinamide has excellent efficacy-in experimental studies in mice and randomized trials, largely in HIV-infected persons. However, while the safety of 2 months of rifampin and pyrazinamide appears acceptable in HIV-infected persons and children, in non-HIV-infected adults this regimen is associated with an unacceptably high rate of severe liver toxicity. Three to four months of INH and rifampin has had equivalent effectiveness as 6 months INH in several randomized trials. However, completion of therapy and toxicity has been the same as with INH-possibly because two drugs are taken rather than one. The fourth commonly studied regimen is 4 months rifampin. This has been found to have significantly better completion than 9H, with significantly less toxicity, especially hepatotoxicity. However, only one trial has evaluated efficacy and effectiveness of mono-rifampin therapy. In this trial, 3 months rifampin had somewhat better efficacy than either 3 months of isoniazid and rifampin (3HR) or 6 months isoniazid. Two large scale trials are ongoing; one is comparing efficacy and effectiveness of 9H with 4 months rifampin (both daily and self-administered), while the second, which is nearing completion, compares daily self-administered 9H with 3 months directly observed once weekly INH combined with Rifapentine. The results of these two trials will likely shape future recommendations substantially. |
| 2010 | Rip Van Winkle wakes up: development of tuberculosis treatment in the 21st century. | Clin Infect Dis | The increase in drug-resistant tuberculosis and the global pandemic of human immunodeficiency virus infection-related tuberculosis threaten global tuberculosis control. There are needs for improved therapy in all aspects of tuberculosis treatment: treatment of latent infection, active drug-susceptible disease, and particularly, drug-resistant disease. Fortunately, at this time of great need, the field of tuberculosis drug development has reemerged after >30 years of inactivity. I review the specific needs for new treatment regimens, the pathways of tuberculosis drug development, and the agents that are currently in clinical development. There is renewed interest in the rifamycin class; studies in the mouse model suggest that higher doses of rifampin or Rifapentine may markedly improve the treatment of drug-susceptible disease. Fluoroquinolones may allow shorter treatment durations for drug-susceptible disease, though initial phase 2B trials have shown inconsistent activity. Novel drugs, such as TMC207, OPC-67683, PA824, SQ109, and PNU-100480, may improve the treatment of drug-resistant and drug-susceptible tuberculosis. |
| 2010 | The near future: improving the activity of rifamycins and pyrazinamide. | Tuberculosis (Edinb) | While we wait for improved new anti-tuberculosis drugs, the main aim for improving current treatment should be to optimize the use of the two current drugs, rifampicin and the pro-drug pyrazinamide, which are responsible to a similar extent for the entire sterilizing activity of current therapy. The rifamycin activity could be improved by increasing the dose size of rifampicin or by daily dosing with long acting Rifapentine. Increasing the dose size of pyrazinamide is limited by toxicity but an alternative approach is to use inhalation with pyrazinoic acid, as an adjunct to standard oral therapy. This would acidify pulmonary lesions, thus increasing the bactericidal activity of the orally administered pyrazinamide. Because pyrazinoic acid is the active moiety, it should also increase overall pyrazinamide activity and, because most resistance arises in the pncA gene that converts pyrazinamide to pyrazinoic acid, it should act on most pyrazinamide resistant strains. Inhalation technology allows delivery of drug to lesions rapidly and without first pass toxicity. The properties of drug containing microparticles and nanoparticles during inhalation and storage are reviewed. Spray-dried larger Trojan particles in which the smaller encapsulated particles can reside should be able to improve localisation within alveoli and avoid some storage problems. |
| 2010 | Rifamycins--obstacles and opportunities. | Tuberculosis (Edinb) | With nearly one-third of the global population infected by Mycobacterium tuberculosis, TB remains a major cause of death (1.7 million in 2006). TB is particularly severe in parts of Asia and Africa where it is often present in AIDS patients. Difficulties in treatment are exacerbated by the 6-9 month treatment times and numerous side effects. There is significant concern about the multi-drug-resistant (MDR) strains of TB (0.5 million MDR-TB cases worldwide in 2006). The rifamycins, long considered a mainstay of TB treatment, were a tremendous breakthrough when they were developed in the 1960's. While the rifamycins display many admirable qualities, they still have a number of shortfalls including: rapid selection of resistant mutants, hepatotoxicity, a flu-like syndrome (especially at higher doses), potent induction of cytochromes P450 (CYP) and inhibition of hepatic transporters. This review of the state-of-the-art regarding rifamycins suggests that it is quite possible to devise improved rifamycin analogs. Studies showing the potential of shortening the duration of treatment if higher doses could be tolerated, also suggest that more potent (or less toxic) rifamycin analogs might accomplish the same end. The improved activity against rifampin-resistant strains by some analogs promises that further work in this area, especially if the information from co-crystal structures with RNA polymerase is applied, should lead to even better analogs. The extensive drug-drug interactions seen with rifampin have already been somewhat ameliorated with rifabutin and rifalazil, and the use of a CYP-induction screening assay should serve to efficiently identify even better analogs. The toxicity due to the flu-like syndrome is an issue that needs effective resolution, particularly for analogs in the rifalazil class. It would be of interest to profile rifalazil and analogs in relation to rifampin, Rifapentine, and rifabutin in a variety of screens, particularly those that might relate to hypersensitivity or immunomodulatory processes. |
| 2010 | Resistance to rifampicin: at the crossroads between ecological, genomic and medical concerns. | Int J Antimicrob Agents | The first antibiotic of the ansamycin family, rifampicin (RIF), was isolated in 1959 and was introduced into therapy in 1962; it is still a first-line agent in the treatment of diseases such as tuberculosis, leprosy and various biofilm-related infections. The antimicrobial activity of RIF is due to its inhibition of bacterial RNA polymerase (RNAP). Most frequently, bacteria become resistant to RIF through mutation of the target; however, this mechanism is not unique. Other mechanisms of resistance have been reported, such as duplication of the target, action of RNAP-binding proteins, modification of RIF and modification of cell permeability. We suggest that several of these alternative resistance strategies could reflect the ecological function of RIF, such as autoregulation and/or signalling to surrounding microorganisms. Very often, resistance mechanisms found in the clinic have an environmental origin. One may ask whether the introduction of the RIF analogues rifaximin, rifalazil, Rifapentine and rifabutin in the therapeutic arsenal, together with the diversification of the pathologies treated by these molecules, will diversify the resistance mechanisms of human pathogens against ansamycins. |
| [On the way to shortening tuberculosis treatments: clinical trials of the Unitat d' Investagació en Tuberculosi de Barcelona supported by the Centers for Disease Control and Prevention]. | Gac Sanit | New treatment guidelines are required to improve the tuberculosis control strategies that have been used for 30 years. Seven centers of the Barcelona Tuberculosis Research Unit (BTRU) (Unitat d'Investigació en Tuberculosi de Barcelona) are collaborating with the Division of Tuberculosis Elimination of the United States Centers for Disease Control and Prevention in a series of clinical trials on latent tuberculosis infection and tuberculosis disease. BTRU participation began in 2004 with Study 26, an evaluation of the efficacy and tolerability of Rifapentine plus isoniazid administered once weekly for 3 months compared with the standard treatment for latent tuberculosis infection. The BTRU centers together enrolled 246 patients (3% of the total). General enrollment was completed in February, 2008. HIV-infected patient and child enrollment continues. Treatment with 12 doses instead of 270 doses is expected to be a clear success. However, the analysis will be completed in 2010. Study 28 (started in 2006), designed for the treatment of pulmonary tuberculosis, compared standard treatment with an experimental regimen substituting moxifloxacin for isoniazid. BTRU centers together enrolled 15 patients (3.5% of the total). The provisional results (presented at the 47th Interscience Conference on Antimicrobial Agents and Chemotherapy in Chicago, 2007) showed no difference between the sputum conversion rate of each regimen at week 8 of treatment. Study 29 is currently underway, in which Rifapentine was introduced in the experimental regimen for active tuberculosis treatment. |
| 2010 | An interesting case of rifampicin-dependent/-enhanced multidrug-resistant tuberculosis. | Int J Tuberc Lung Dis | We report a case of rifampicin (RMP) dependent/enhanced multidrug-resistant (MDR-TB) from a patient who had been treated with the World Health Organization optional thrice-weekly treatment and document the clinical and bacteriological features. RMP-enhanced tubercle bacilli that grew poorly without RMP but grew better in its presence were isolated from the patient with treatment failure. The bacteria grown without RMP consisted of mixed morphologies of short rod-shaped acid-fast bacteria and poorly stained coccoid bacteria, but stained normally as acid-fast rods when grown in the presence of RMP. The isolated RMP-enhanced bacteria harbored the common S531L mutation and a novel mutation F584S in the rpoB gene. Treatment containing RMP or replacement of RMP with more powerful Rifapentine paradoxically aggravated the disease, but its removal led to successful cure of the patient. This study highlights the potential dangers of continued treatment of MDR-TB with rifamycins that can occur due to delayed or absent drug susceptibility results and calls for timely detection of RMP-dependent/-enhanced bacteria in treatment failure patients by including RMP in culture media and removal of RMP from treatment regimen upon detection. |
| 2010 | Neglected diseases caused by bacterial infections. | Curr Med Chem | Bacterial infections represent a major health problem, especially in third world countries. In endemic regions, large populations of people are greatly affected, but the medical care is very limited. In this review, the neglected diseases buruli ulcer and trachoma are elucidated. Buruli ulcer is caused by Mycobacterium ulcerans which produces an outstanding immunosuppressive toxin mycolactone that induces an ulcerative, necrotic skin disease. Until today, only the combination of rifampin/streptomycin is used to treat buruli ulcer. However, this therapy is ineffective and expensive. Here, we report new findings that suggest pharmaceutical formulations such as Rifapentine, in combination with clarithromycin or moxifloxacin that have shown promising results in mice footpad trials. Moreover, alternative treatment options such as heat therapy, nitric oxide cremes and French clay show bactericidal effects. The genotyping of M. ulcerans also promises new ways of finding drug targets and vaccines. Trachoma, induced by the bacterium Chlamydia trachomatis, is the primary infectious cause of blindness worldwide. Recurrent infections lead to chronic inflammation of the upper tarsal conjunctiva. As a consequence, scarring and distortion of the eye lids occur, eventually resulting in blindness. First-line medications for trachoma treatment are bacteriostatic agents such as topically applied tetracylines and systematically administered azithromycin. Surgery, environmental improvements and personal hygiene are further crucial factors in controlling trachoma. Moreover, efforts are being undertaken towards the development of vaccine systems, with the major outer membrane protein and the polymorphic membrane protein acting as attractive candidates. |
| 2010 | Experimental and clinical studies on Rifacinna--the new effective antituberculous drug (review). | Recent Pat Antiinfect Drug Discov | A new rifamycin derivative 3-(4-cinnamyl-piperazinyl iminomethyl) rifamycin SV (T9) and its sodium salt (T11, Rifacinna((R))) were in vitro, in vivo, toxicologically and clinically investigated in comparison with rifampicin, Rifapentine, rifabutin, rifalazil. Our experiments showed that Rifacinna exhibits excellent in vitro activity against Gram(+), Gram (-) aerobic, anaerobic pathogens and mycobacteria. Rifacinna is active against Staphylococcus, Streptococcus spp. including MRSA, with MIC90- 0.06-0.5 mg/L; against Gram(+), Gram (-) anaerobes with MIC90 0.5 - 1 mg/L; against Mycobacterium tuberculosis (MTB) with MIC90 0.062 mg/L; against MDR resistant MTB (25%-30 %) and Mycobacterium avium complex (MAC) strains with MICs 0.6-1.0 mg/L. It shows high intraphagocytic activity against MAC strains (0.06 0.125mg/L). Single daily dose 10 mg/kg provides complete erradication of mycobacteria in experimental generalized tuberculosis. Pharmacological studies established: excellent pharmacokinetic profile following single oral dose 10mg/kg Tmax 5-6 h, C(max) 5-9 mg/L, T1/2 33-34 h; low toxicity; no teratogenic and embryotoxic effects. The clinical study of Rifacinna shows higher therapeutic efficacy than Rifampicin in patients with infiltrative, disseminated and cavitary form of pulmonary tuberculosis, good tolerability and safety profile. Some of the recent patents related to the treatment of tuberculosis are discussed in this review article. |
| 2009 | Short-course therapy with daily rifapentine in a murine model of latent tuberculosis infection. | Am J Respir Crit Care Med | Regimens recommended to treat latent tuberculosis infection (LTBI) are 3 to 9 months long. A 2-month rifampin+pyrazinamide regimen is no longer recommended. Shorter regimens are highly desirable. Because substituting Rifapentine for rifampin in the standard regimen for active tuberculosis halves the treatment duration needed to prevent relapse in mice, we hypothesized daily Rifapentine-based regimens could shorten LTBI treatment to 2 months or less.To improve an existing model of LTBI chemotherapy and evaluate the efficacy of daily Rifapentine-based regimens.Mice were immunized with a more immunogenic recombinant Bacille Calmette-Guérin strain (rBCG30) and received very low-dose aerosol infection with Mycobacterium tuberculosis to establish a stable lung bacterial burden below 10(4) CFU without drug treatment. Mice received a control (isoniazid alone, rifampin alone, rifampin+isoniazid, rifampin+pyrazinamide) or test (Rifapentine alone, Rifapentine+isoniazid, Rifapentine+pyrazinamide, Rifapentine+isoniazid+pyrazinamide) regimen for 8 weeks. Rifamycin doses were 10 mg/kg/d, analogous to the same human doses. Outcomes were biweekly lung CFU counts and relapse after 4 to 8 weeks of treatment.M. tuberculosis CFU counts remained stable around 3.65 log(10) in immunized, untreated mice. Isoniazid or rifampin left all or most mice culture-positive at week 8. Rifampin+isoniazid cured 0 and 53% of mice and rifampin+pyrazinamide cured 47 and 100% of mice in 4 and 8 weeks, respectively. Rifapentine-based regimens were more active than rifampin+isoniazid and indistinguishable from rifampin+pyrazinamide.In this improved murine model of LTBI chemotherapy with very low lung burden, existing regimens were well represented. Daily Rifapentine-based regimens were at least as active as rifampin+pyrazinamide, suggesting they could effectively treat LTBI in 6 to 8 weeks. |
| 2009 | Rifapentine vs. rifampicin for the treatment of pulmonary tuberculosis: a systematic review. | Int J Tuberc Lung Dis | To evaluate the efficacy and safety of Rifapentine (RPT) vs. rifampicin (RMP) for the treatment of pulmonary tuberculosis (PTB).Systematic review of randomised controlled trials (RCTs) that compared combination drug regimens containing RPT with those containing RMP for the treatment of drug-susceptible or previously untreated PTB.Nine RCTs were identified. Statistically significant differences were not found in the cure rates, severe adverse effects, severe hepatotoxicity or bacteriological relapse rates between the regimens containing once- or twice-weekly RPT and those containing daily RMP for human immunodeficiency virus (HIV) negative patients, but were found in the bacteriological relapse rates between regimens containing once-weekly or less frequent RPT and those containing twice- or thrice-weekly RMP: the pooled relative risks in the two subgroups were respectively 1.71 (95%CI 1.13-2.58, P = 0.01) and 2.44 (95%CI 1.15-5.18, P = 0.02). The trial for HIV-positive patients did not show significant differences in the sputum conversion rate, severe adverse effects or bacteriological relapse rate between the RPT- and RMP-containing regimens; four of the five relapses were associated with the RPT-containing regimen, but none of the three relapses with the RMP-containing regimen produced monoresistance to rifamycin (RIF).Once- or twice-weekly RPT and daily RMP have similar efficacy and safety for the treatment of HIV-negative PTB, but once-weekly or less frequent use of RPT, in comparison with twice- or thrice-weekly RMP, increases the risk of bacteriological relapse. RPT might increase the risk of resistance to RIF in HIV-positive patients. |
| 2009 | Costs and cost-effectiveness of four treatment regimens for latent tuberculosis infection. | Am J Respir Crit Care Med | Isoniazid given daily for 9 months is the standard treatment for latent tuberculosis infection (LTBI), but its effectiveness is limited by poor completion rates. Shorter course regimens and regimens using directly observed therapy result in improved adherence but have higher upfront costs.To evaluate the costs and cost-effectiveness of regimens for the treatment of LTBI.We used a computerized Markov model to estimate total societal costs and benefits associated with four regimens for the treatment of LTBI: self-administered isoniazid daily for 9 months, directly observed isoniazid twice-weekly for 9 months, directly observed isoniazid plus Rifapentine once weekly for 3 months, and self-administered rifampin daily for 4 months. In the base-case analysis, subjects were assumed to have newly positive tuberculin skin tests after recent exposure to infectious tuberculosis.We determined the costs of treatment, quality-adjusted life-years gained, and cases of active tuberculosis prevented. In the base-case analysis, rifampin dominated (less costly with increased benefits) all other regimens except isoniazid plus Rifapentine, which was more effective at a cost $48,997 per quality-adjusted life year gained. Isoniazid plus Rifapentine dominated all regimens at a relative risk of disease 5.2 times the baseline estimate, or with completion rates less than 34% for isoniazid or 37% for rifampin. Rifampin could be 17% less efficacious than self-administered isoniazid and still be cost-saving compared with this regimen.In our model, rifampin is cost-saving compared with the standard therapy of self-administered isoniazid. Isoniazid plus Rifapentine is cost-saving for extremely high-risk patients and is cost-effective for lower-risk patients. |
| 2008 | [Effects of two treatment regimens for drug-resistant tuberculosis in tuberculosis control project areas: a comparative study]. | Zhonghua Yi Xue Za Zhi | To search for an ideal therapeutic regimen for multidrug resistant tuberculosis conforming to the situation of China.One hundred and fifty-four patients with rifampin-resistant tuberculosis, 114 multi-drug resistant (MDR-TB) and 40 resistant to other drugs, in Heilongjiang, Zhejiang, and Shenzhen, 107 males and 47 females, aged 39 (19-77), were randomly divided into 2 groups: 85 patients in the group of drug-resistant regimen, 3RFT AM Ofx Pto PAS-INH/5RFT Ofx Pto PAS-INH regimen, including Rifapentine (RFT), amikacin (Am), ofloxacin (Ofx), protionamide (Pto), para-aminosalicylic acid-isoniazid (PAS-INH) for 3 months and then RFT, Ofx, Pto, and PAS-INH for 5 months, and 69 in the retreatment regimen group undergoing 3 H3R3Z3E3S3/5 H3R3E3, including isoniazid (H), rifampin (R), pyrazinamide (Z), ethambutol (E), and streptomycin (S) for 3 months and then H, R, and E for 5 months. Sputum smear was checked and the sputum smear conversion rate was calculated as an effective treatment indicator 3, 6, and 8 months later.One hundred and fourteen of the 154 patients were treated for a good 8 months. The sputum smear conversion rate 8 months after treatment of the drug-resistant regimen group was 65.9% (56/85), significantly higher than that of the retreatment regimen group [40.6% (28/69), chi2 = 9.834, P = 0.002]. Eighty-five of the 114 MDR-TB patients had been treated for a good 8 months with a sputum smear conversion rate of 61.8% (42/68), significantly higher than that of the retreatment regimen group [39.1% (18/46), chi2 = 5.638, P = 0.018]. Sputum smear conversion at the end of the 8th month was related to age, course of disease, therapeutic regimen, and the type of drug-resistance (all P < 0.05). The side-effect rate of the drug-resistant regimen group was 23.9% (17/71), higher than that of the retreatment regimen group [18.6% (8/43)], but not significantly (chi2 = 0.446, P = 0.504).The drug-resistant regimen recommended above is more effective than the retreatment regimen and should be considered in the areas where the WHO guideline fails to be followed or drug sensitivity test (DST) cannot be conducted and adjusted according to the results of DST and treatment. |
| 2009 | A once-weekly R207910-containing regimen exceeds activity of the standard daily regimen in murine tuberculosis. | Am J Respir Crit Care Med | R207910 (TMC207 or J) is a member of the diarylquinolines, a new family of antituberculous drugs with high bactericidal activity when given daily in the murine model of tuberculosis. R207910 exhibits a long half-life and thus is a good candidate for once-weekly therapy of tuberculosis.To study the activity of once-weekly R207910 monotherapy and combinations of R207910 with other antituberculous agents (isoniazid, Rifapentine, moxifloxacin, and pyrazinamide).The established infection model of murine tuberculosis was used. Colony counts were determined in the lungs.Eight weeks of monotherapy reduced the bacillary load by 3 to 4 log(10) for Rifapentine and by 5 to 6 log(10) for R207910 (P < 0.05). The addition of Rifapentine and isoniazid or moxifloxacin did not improve the bactericidal activity of R207910 monotherapy. In contrast, the triple combination of R207910 plus Rifapentine plus pyrazinamide given once weekly for 2 months (i.e., a total of only eight administrations), was significantly (P < 0.05) more active than R207910 monotherapy or other R207910 combinations, and led to lung culture negativity in 9 of 10 mice, whereas all lungs were culture positive in the groups treated with other drug combinations. Moreover, R207910 plus Rifapentine plus pyrazinamide given once weekly was more active than the current standard regimen of rifampin plus isoniazid plus pyrazinamide given five times per week.The unprecedented activity of the triple combination of R207910 plus Rifapentine plus pyrazinamide suggests that it may be feasible to develop a fully intermittent once-weekly regimen. |
| 2008 | New approaches to the treatment of latent tuberculosis. | Semin Respir Crit Care Med | It is estimated that one third of the global population is infected with MYCOBACTERIUM TUBERCULOSIS. Treatment of M. TUBERCULOSIS infection is an important strategy for tuberculosis elimination, but the effectiveness of this strategy is limited by poor adherence to therapy, which is due at least in part to the long duration of treatment. A 9-month course of isoniazid is the currently preferred treatment regimen for M. TUBERCULOSIS infection, due to the extensive data regarding the effectiveness and tolerability of isoniazid, and limited data on the effectiveness and tolerability of alternative shorter-course regimens. This review covers all currently available regimens, including less established alternative treatment regimens (e.g., rifampin for 4 months and isoniazid + rifampin for 3 months), as well as regimens that are currently under investigation (e.g., isoniazid + Rifapentine for 3 months). Potential future regimens and experimental approaches are also discussed. |
| 2008 | Isoniazid or moxifloxacin in rifapentine-based regimens for experimental tuberculosis? | Am J Respir Crit Care Med | Recent studies have demonstrated that combined substitutions of Rifapentine for rifampin and moxifloxacin for isoniazid in the standard, daily, short-course regimen of rifampin, isoniazid, and pyrazinamide produces stable cure in 12 weeks or less. This study was designed to more precisely evaluate the contribution of moxifloxacin and isoniazid to Rifapentine-based regimens.We compared bactericidal activity and treatment-shortening potential between regimens consisting of isoniazid or moxifloxacin plus Rifapentine and pyrazinamide administered either thrice-weekly or daily.Using a mouse model of tuberculosis, we assessed bactericidal activity by performing quantitative cultures of lung homogenates over the first 12 weeks of treatment. Relapse rates were assessed after completing 8, 10, and 12 weeks of treatment to determine the duration of treatment necessary for stable cure.After 4 weeks of treatment, daily and thrice-weekly therapy with Rifapentine, moxifloxacin, and pyrazinamide was significantly more active than treatment with Rifapentine, isoniazid, and pyrazinamide. By 8 weeks of treatment, all mice receiving the moxifloxacin-containing regimens were lung culture negative, whereas those mice receiving the isoniazid-containing regimens continued to be lung culture positive. However, the duration of treatment necessary to achieve stable cure was 10 weeks for daily regimens and 12 weeks for thrice-weekly regimens, regardless of whether isoniazid or moxifloxacin was used. All mice receiving standard daily therapy with rifampin, isoniazid, and pyrazinamide relapsed after 12 weeks of treatment.These results suggest that regimens consisting of isoniazid or moxifloxacin plus Rifapentine and pyrazinamide may dramatically shorten the duration of treatment needed to cure human tuberculosis. |
| 2008 | The value of end-of-treatment chest radiograph in predicting pulmonary tuberculosis relapse. | Int J Tuberc Lung Dis | Patients with cavitary pulmonary tuberculosis (TB) on baseline chest radiograph (CXR) who remain culture-positive after 8 weeks of treatment are at high risk of relapse. The role of end-of-treatment (EOT) CXR in predicting relapse is unclear.To determine whether EOT CXR independently predicts TB relapse.We conducted a secondary analysis of a randomized trial of intermittent treatment using Rifapentine in the continuation phase of TB treatment among 1004 human immunodeficiency virus seronegative adults with culture-proven pulmonary TB.Relapse occurred in 17.3% of subjects with persistent cavity on EOT CXR, in 7.6% of subjects with a cavity that resolved by EOT, and 2.5% (P=0.002 for trend) of subjects who never had a cavity. In multivariable analysis, patients with persistent cavity on EOT CXR were significantly more likely to relapse than patients with no cavity on baseline or 2-month CXR (hazard ratio [HR] 4.22, 95%CI 2.00-8.91), and were more likely to relapse than subjects whose early cavity had resolved by EOT CXR (HR 1.92, 95%CI 1.09-3.39).A persistent cavity after 6 months of TB treatment was independently associated with disease relapse after controlling for other variables. EOT CXR may help predict those likely to relapse. |
| 2008 | [The effect of interventional therapy in multimodality treatment on multi-drug resistant pulmonary tuberculosis]. | Zhonghua Jie He He Hu Xi Za Zhi | To evaluate the effect of interventional therapy with antituberculous drug instillation to the lesions in the treatment of multi-drug resistant pulmonary tuberculosis (MDR-PTB) on conventional therapy.Sixty-one cases of MDR TB were included from January 2001 to October 2002 in five hospitals. Pasiniazide, Rifapentine levofloxacin, ethambutol, ethionamide, amikacin and clarithromycin were used as the basic chemotherapy regimen. In addition, M. vaccac and interventional therapy were used, and chemotherapy was continued for a total of 18 months.The sputum negative conversion rate (including sputum smear and culture) was 50.8% (31/61) after 3 months of interventional therapy. The rate increased to 83.6% (51/61) after 18 months of therapy. Chest X-ray showed that, the foci were markedly absorbed in 50.8% (31/61), and the effective rate was 93.4% (57/61) after 3 months of therapy. The foci were markedly absorbed in 78.7% (48/61) after 18 months of treatment. The effective rate was 96.7%. The rate of cavity closure was 21.3% (13/61) after 3 months of interventional therapy and it increased to 49.2% (30/61) after 18 months of treatment. The rate of symptom disappearance was 73.2%-94.4%, including fever, hemoptysis and dyspnea.For the treatment of MDR-TB, interventional therapy is effective in improving sputum negative conversion, lesion absorption and cavity closure. |
| 2008 | Bactericidal and sterilizing activities of several orally administered combined regimens against Mycobacterium ulcerans in mice. | Antimicrob Agents Chemother | Treatment with rifampin-clarithromycin or moxifloxacin-clarithromycin for 8 weeks displayed promising bactericidal activity against Mycobacterium ulcerans in mice; none of the mice treated with rifampin-clarithromycin relapsed, whereas 59% of those treated with moxifloxacin-clarithromycin relapsed after treatment was stopped. The bactericidal and sterilizing activities of the five-times-weekly (5/7) administration of 5 mg of Rifapentine/kg of body weight, either alone or in combination, were virtually identical to those of the corresponding regimens with 10 mg of rifampin/kg of body weight; however, because of the long half-life of Rifapentine, accumulation of the drug after 5/7 administration is a concern. The bactericidal activity of 20 mg/kg Rifapentine in monotherapy or 20 mg/kg Rifapentine in combination with 150 mg/kg streptomycin or 200 mg/kg moxifloxacin administered twice weekly was as effective as the corresponding regimens containing 10 mg/kg rifampin administered 5/7, suggesting that Buruli ulcer might be treated with intermittently administered Rifapentine-containing combinations. |
| 2007 | Daily dosing of rifapentine cures tuberculosis in three months or less in the murine model. | PLoS Med | Availability of an ultra-short-course drug regimen capable of curing patients with tuberculosis in 2 to 3 mo would significantly improve global control efforts. Because immediate prospects for novel treatment-shortening drugs remain uncertain, we examined whether better use of existing drugs could shorten the duration of treatment. Rifapentine is a long-lived rifamycin derivative currently recommended only in once-weekly continuation-phase regimens. Moxifloxacin is an 8-methoxyfluoroquinolone currently used in second-line regimens.Using a well-established mouse model with a high bacterial burden and human-equivalent drug dosing, we compared the efficacy of Rifapentine- and moxifloxacin-containing regimens with that of the standard daily short-course regimen based on rifampin, isoniazid, and pyrazinamide. Bactericidal activity was assessed by lung colony-forming unit counts, and sterilizing activity was assessed by the proportion of mice with culture-positive relapse after 2, 3, 4, and 6 mo of treatment. Here, we demonstrate that replacing rifampin with Rifapentine and isoniazid with moxifloxacin dramatically increased the activity of the standard daily regimen. After just 2 mo of treatment, mice receiving Rifapentine- and moxifloxacin-containing regimens were found to have negative lung cultures, while those given the standard regimen still harbored 3.17 log10 colony-forming units in the lungs (p < 0.01). No relapse was observed after just 3 mo of treatment with daily and thrice-weekly administered Rifapentine- and moxifloxacin-containing regimens, whereas the standard daily regimen required 6 mo to prevent relapse in all mice.Rifapentine should no longer be viewed solely as a rifamycin for once-weekly administration. Our results suggest that treatment regimens based on daily and thrice-weekly administration of Rifapentine and moxifloxacin may permit shortening the current 6 mo duration of treatment to 3 mo or less. Such regimens warrant urgent clinical investigation. |
| 2007 | Overview of anti-tuberculosis (TB) drugs and their resistance mechanisms. | Mini Rev Med Chem | One-third of the world's population is infected with Mycobacterium (M.) tuberculosis. Tuberculosis continues to be the most common infectious cause of death and still has a serious impact, medically, socially and financially. Multidrug-resistant tuberculosis (MDR-TB), caused by tubercle bacilli that are resistant to at least isoniazid and rifampin, is among the most worrisome elements of the pandemic of antibiotic resistance because TB patients for whom treatment has failed have a high risk of death. Drugs used to treat tuberculosis are classified into first-line and second-line agents. First-line essential anti-tuberculosis agents are the most effective, and are a necessary component of any short-course therapeutic regimen. The drugs in this category are isoniazid, rifampin, ethambutol, pyrazinamide and streptomycin. Second-line anti-tuberculosis drugs are clinically much less effective than first-line agents and elicit severe reactions much more frequently. These drugs include para-aminosalicylic acid (PAS), ethionamide, cycloserine, amikacin and capreomycin. New drugs, which are yet to be assigned to the above categories, include Rifapentine, levofloxacin, gatifloxacin and moxifloxacin. Recently there has been much development in the molecular pharmacology of anti-tuberculosis drugs. This review summarizes information for isoniazid, rifampicin, ethambutol, pyrazinamide, and fluoroquinolones, and describes their resistance mechanisms. |
| 2006 | [Development of antituberculous drugs: current status and future prospects]. | Kekkaku | Worldwide, tuberculosis (TB) remains the most frequent and important infectious disease causing morbidity and death. One-third of the world's population is infected with Mycobacterium tuberculosis (MTB), the etiologic agent of TB. The World Health Organization estimates that about eight to ten million new TB cases occur annually worldwide and the incidence of TB is currently increasing. In this context, TB is in the top three, with malaria and HIV being the leading causes of death from a single infectious agent, and approximately two million deaths are attributable to TB annually. In particular, pulmonary TB, the most common form of TB, is a highly contagious and life-threatening infection. Moreover, enhanced susceptibility to TB in HIV-infected populations is another serious health problem throughout the world. In addition, multidrug-resistant TB (MDR-TB) has been increasing in incidence in many areas, not only in developing countries but industrialized countries as well, during the past decade. These situations, particularly the global resurgence of TB and the rapid emergence of MDR-TB, underscore the importance of the development of new antituberculous drugs and new protocols for efficacious clinical control of TB patients using ordinary antimycobacterial drugs. Concerning the development of new antituberculous drugs, the following points are of particular importance. (1) Development of drugs which display lasting antimycobacterial activity in vivo is desirable, since they can be administered with long intervals and consequently facilitate directly observed therapy and enhance patient compliance. (2) Development of novel antituberculosis compounds to combat MDR-TB is urgently needed. (3) The eradication of slowly metabolizing and, if possible, dormant populations of MTB organisms that cause relapse, using new classes of anti-TB drugs is very promising for prevention of TB incidence, because it will markedly reduce the incidence of active TB from persons who are latently infected with MTB. Unfortunately, no new drugs except rifabutin and Rifapentine has been marketed for TB in the US and other countries during the 40 years after release of rifampicin. There are a number of constraints that have deterred companies from investing in new anti-TB drugs. The research is expensive, slow and difficult, and requires specialized facilities for handling MTB. There are few animal models that closely mimic the human TB disease. Development time of any anti-TB drug will be long. In fact, clinical trials will require the minimum six-month therapy, with a follow-up period of one year or more. In addition, it is hard to demonstrate obvious benefit of a new anti-TB agents over pre-existing drugs, since clinical trials involve multidrug combination therapy using highly effective ordinary anti-TB drugs. Finaly, there is the perceived lack of commercial return to companies engaged in the development of new anti-TB drugs, because over 95% of TB cases worldwide are in developing countries. In this symposium, we reviewed the following areas. 1. Critical new information on the entire genome of MTB recently obtained and increasing knowledge of various mycobacterial virulence genes are greatly promoting the identification of genes that code for new drug targets. In this context, Dr. Namba reviewed the status of new types of compounds which are being developed as anti-TB drug. He also discussed the development of new antimycobacterial drugs according to new and potential pharmacological targets and the best clinical development plans for new-TB drugs in relation to corporate strategy. 2. Using such findings for mycobacterial genomes, bioinformatics/genomics/proteomics-based drug design and drug development using quantitative structure-activity relationships may be possible in the near future. In this context, Dr. Suwa and Dr. Suzuki reviewed the usefulness of chemical genomics in searching novel drug targets for development of new antituberculous drugs. The authors reviewed (1) the history and present status of chemical genomics that is defined as the systemic search for a selective small molecular modulator for each function of all gene products, (2) recent studies of the authors on profiles of the interactions between various kinds of human proteins and small molecule modulators using the new technology devised by Reverse Proteomics Research Institute, and (3) future prospects of the development of new antituberculous drugs based on chemical genomics. 3. It appears also promising to develop new types of drug administration systems using drug vehicles, which enable efficacious drug delivery to their target in vivo. Dr. Izumikawa, Dr. Ohno and Dr. Kohno reviewed the usefulness of liposome- and polymer-based technologies, which enable efficacious delivery of encapsulated drugs at required doses for prolonged periods of time with only a single shot without toxicity, and also enable highly targeted delivery of drugs to their target in vivo. They indicated that the applications of drug delivery system using conventional anti-mycobacterial agents are challenging to improve the compliance of treatment and better clinical outcome. 4. Immunoadjunctive therapy appears to be promising in improving outcome of clinical control of refractory mycobacterial infections, including MDR-TB and M. avium complex infection. Dr. Shimizu, Dr. Sato and Dr. Tomioka reviewed the present status of immunotherapy of mycobacterial infections in combination with antimycobacterial drugs. They indicated that the development of new classes of immunomodulators other than cytokines (IL-2, IFN-gamma, GM-CSF, IL-12, etc.) particularly those with no severe side-effects, are urgently needed. Their review dealed with some promising immunoadjunctive agents, especially ATP and its analogues, which potentiate macrophage antimycobacterial activity via purinergic P2 receptors. The aim of this symposium is to address the future prospects of the development of new drugs and drug regimens for anti-TB chemotherapy. There are a number of difficulties in drug-design for the development of new drug formulations with increased potential for antimycobacterial effects, excellent pharmacokinetics, and tolerability. It should be emphasized that the most urgent goal of chemotherapy of TB and MAC infections, especially that associated with HIV infection, is to develop highly active, low-cost drugs which can be used not only in industrialized countries but also in developing countries, since the incidences of AIDS-associated intractable TB and MAC infections are rapidly increasing in the latter. We strongly wish a great advance of fundametal and practical studies in developing such kinds of new anti-TB drugs in the near future. 1. Prospects for non-clinical or clinical development of new antituberculous drugs in relation to corporate strategy: Kenji NAMBA (New Product Research Laboratories I, Daiichi Pharmaceutical Co., Ltd.) Tuberculosis (TB) remains one of the deadliest threats to public health. No new anti-TB drugs have been brought into the clinic in the past 40 years. Current non-clinical works with progressed technology and Global Alliance for TB Drug Development, a non-profit organization established in 2000, accelerate research and development of faster-acting anti-TB compounds. We reviewed the status of new types of compounds which are being developed as anti-TB drug, such as diarylquinoline (TMC 207), nitroimidazole (PA-824 and OPC-67683), and moxifloxacin (MFLX). We also discussed the best clinical development plans for new-TB drugs in relation to corporate strategy. 2. Exploring novel drug targets through the chemical genomics approach and its possible application to the development of anti-tuberculosis drugs: Yorimasa SUWA (Reverse Proteomics Research Institute Co., Ltd.), Yohji SUZUKI (Teijin Ltd.) Recently, chemical genomics approach has been focused as an emerging technology for the drug discovery. In advance to a very large scale national project in US started last year, Reverse Proteomics Research Institute Co., Ltd. (REPRORI) has developed the core technologies for chemical genomics. Here we describe the outline of chemical genomics study, especially that of REPRORI, and discuss about its possible application to the development of anti-tuberculosis drugs. 3. Anti-mycobacterial agents and drug delivery: Koichi IZUMIKAWA, Hideaki OHNO, Shigeru KOHNO (Second Department of Internal Medicine, Nagasaki University School of Medicine) Mycobacterium infection is a major clinical concern in whole world. Since the newly developed anti-mycobacterial agents are few and still unavailable in clinical settings, the applications of drug delivery system using conventional anti-mycobacterial agents are challenging to improve the compliance of treatment and better efficacy. The efficacy of anti-mycobacterial agents modified by liposome or polymer based technology have been investigated and reported using various animal models. Drug delivery system increased and prolonged the drug concentrations at the blood and targeted organs and the duration of sustained drug release, respectively. These effects lead to decrease in the frequency of drug administrations dramatically and better efficacy rates. The studies, however, were performed only in animal models, the further investigations and evaluations in human are required for practical use. 4. Adjunctive immunotherapy of mycobacterial infections: Toshiaki SHIMIZU, Katsumasa SATO, Haruaki TOMIOKA (Department of Microbiology and Immunology, Shimane University School of Medicine) There is an urgent need to develop new antimicrobials and protocols for the administration of drugs that are potently efficacious against intractable mycobacterial infections. Unfortunately, development of the new drugs for solving this problem is not progressing. (ABSTRACT TRUNCATED) |
| 2006 | Rifapentine for the treatment of pulmonary tuberculosis. | Clin Infect Dis | Rifapentine is a recently approved antituberculosis drug that has not yet been widely used in clinical settings. Clinical data support intermittent use of Rifapentine with isoniazid during the continuation phase of tuberculosis treatment. Patients with culture-positive, noncavitary, pulmonary tuberculosis whose sputum smear is negative for acid-fast bacilli at the end of the 2-month intensive treatment phase are eligible for Rifapentine therapy. Rifapentine should not be used in human immunodeficiency virus-infected patients, given their increased risk of developing rifampin resistance with currently recommended dosages. Rifapentine is not currently recommended for children aged <12 years, pregnant or lactating women, or individuals with culture-negative or extrapulmonary tuberculosis. Rifapentine (600 mg) is administered once weekly with isoniazid (900 mg) during the continuation phase of treatment. This combination should only be given under direct observation. As with rifampin, drug-drug interactions are common, and regular patient monitoring is required. Ease of administration makes this regimen attractive both for tuberculosis-control programs and for patients. |
| 2006 | [A controlled clinical trial of long course chemotherapy regimens containing rifabutin in the treatment of multi-drug resistant pulmonary tuberculosis]. | Zhonghua Jie He He Hu Xi Za Zhi | To evaluate the curative effect and safety of a long course regimen containing Chinese-made rifabutin as compared to the regimen containing Rifapentine in the treatment of multi-drug resistant pulmonary tuberculosis.During 18 month treatment, 130 patients with multi-drug resistant pulmonary tuberculosis were divided into a treatment group (rifabutin, pasiniazide, levofloxacin, ethambutol, ethionamide, amikacin for 3 months, rifabutin, pasiniazide, levofloxacin, ethambutol, ethionamide for 6 months, rifabutin, pasiniazide, levofloxacin, ethambutol for 9 months), and a control group (Rifapentine, pasiniazide, levofloxacin, ethambutol, ethionamide, amikacin for 3 months, rifabutin, pasiniazide, levofloxacin, ethambutol, ethionamide for 6 months, rifabutin, pasiniazide, levofloxacin, ethambutol for 9 months) with proportion 1:1 random, and parallel compared method.After intensive phase, the sputum negative conversion rates (smear negative, culture negative) of the treatment group and the control group were 41.54% (27/65) and 35.94% (23/65), chi(2) = 2.42, P > 0.05, respectively. The remarkable effective rates in chest X-ray of the two groups were all 10.77% (7/65), chi(2) = 0.01, P > 0.05, and the effective rates were 67.69% (44/65) and 56.92% (37/65), chi(2) = 1.44, P > 0.05, respectively. At the end of the treatment, the sputum negative conversion rate (smear negative, culture negative) of the treatment group was 75.0% (48/65), and of the control group was 65.08% (41/65), chi(2) = 1.88, P > 0.05. The remarkable effective rates in chest X-ray of the two groups were 46.15% (30/65) and 44.62% (29/65), chi(2) = 0.02, P > 0.05, and the effective rates were 76.92% (50/65) and 73.85% (48/65), chi(2) = 0.19, P > 0.05, respectively. The cavity closure rates were 23.64% (13/55) and 33.33% (17/51), chi(2) = 0.00, P > 0.05, respectively.Regimens containing rifabutin or Rifapentine. are very effective in sputum negative conversion rate, lesion absorption and cavity closing for the treatment of multi-drug resistant pulmonary tuberculosis, with good safety and tolerance. |
| 2006 | Antituberculosis drugs and hepatotoxicity. | Respirology | Isoniazid, pyrazinamide and rifampicin have hepatotoxic potential, and can lead to such reactions during antituberculosis chemotherapy. Most of the hepatotoxic reactions are dose-related; some are, however, caused by drug hypersensitivity. The immunogenetics of antituberculosis drug-induced hepatotoxicity, especially inclusive of acetylaor phenotype polymorphism, have been increasingly unravelled. Other principal clinical risk factors for hepatotoxicity are old age, malnutrition, alcoholism, HIV infection, as well as chronic hepatitis B and C infections. Drug-induced hepatic dysfunction usually occurs within the initial few weeks of the intensive phase of antituberculosis chemotherapy. Vigilant clinical (including patient education on symptoms of hepatitis) and biochemical monitoring are mandatory to improve the outcomes of patients with drug-induced hepatotoxicity during antituberculosis chemotherapy. Some fluoroquinolones like ofloxacin/levofloxacin may have a role in constituting non-hepatotoxic drug regimens for management of tuberculosis (TB) in the presence of hepatic dysfunction. Isoniazid administration is currently the standard therapy for latent TB infection. Rifamycins like rifampicin or Rifapentine, alone or in combination with isoniazid, may also be considered as alternatives, pending accumulation of further clinical data. During treatment of latent TB infection, regular follow up is essential to ensure adherence to therapy and facilitate clinical monitoring for hepatic dysfunction. Monitoring of liver chemistry is also required for those patients at risk of drug-induced hepatotoxicity. |
| 2006 | [Preparation, characterization, and pulmonary delivery of rifapentine liposomes modified by lauric diethanolamide]. | Yao Xue Xue Bao | To prepare Rifapentine (RIF) liposomes modified by surfactants for studying their the water-solubility, drug loading effeciency, release rate and pulmonary drug delivery.The film method was used to prepare RIF liposomes. Of verious RIF liposomes morphology by lauric diethanolamide (LDEA), Tween 80 and azone, the properties were studied, envolving morphology, entrapment drug release rate and dissected lung-membrance penetration rate of swine. Pulmonary delivery study was carried out through bronchoscope.The particle size of RIF-LDEA liposomes was between 15 - 50 nm. The top entrapment efficiency reached 83.0%. The apparent coefficient of membrane penetration (Kp) was 44.29. LD50 was 675 mg x kg(-1) by iv.LDEA increased the water-solubility, loading effeciency and release rate of RIF liposomes. The prepared RIF-LDEA liposomes were suitable for the treatment of pulmonary tubrculosis through bronchoscope. |
| 2006 | Dosing schedules of 6-month regimens and relapse for pulmonary tuberculosis. | Am J Respir Crit Care Med | The optimal approach for reducing tuberculosis relapse is open.We examined the possibility of reducing relapse by increasing dosing schedules.We conducted a systematic review of published clinical trials involving adult cohorts with pulmonary tuberculosis treated using 6-mo rifamycin-containing regimens, which were grouped under seven categories ordered by dosing schedules. Assuming cavitation and positive 2-mo culture were the driving forces for relapse, a static deterministic model apportioned observed numbers with and without relapse in each cohort into eight subgroups. Combining subgroups stratified by cavitation, 2-mo culture, and regimens enabled estimation of adjusted relapse risks. chi2 Tests for trend and logistic regression analysis examined the relationship between relapse and dosing schedules.We identified 200 cases of bacteriologic relapse out of 5,208 patients in 32 cohorts. A logistic risk model showed a significant dose-response relationship between dosing schedules and relapse, with the following odds (95% confidence intervals) of relapse relative to daily regimens: 1.6 (0.6-4.1) for daily initial phase (IP) plus thrice-weekly continuation phase (CP), 2.8 (1.3-6.1) for daily IP plus twice-weekly CP, 2.8 (1.4-5.7) for thrice-weekly, 5.0 (2.4-10.5) for daily IP plus once-weekly Rifapentine, and 7.1 (3.3-15.3) for thrice-weekly IP plus once-weekly Rifapentine. In the presence of cavitation, only 6-mo daily or daily IP plus thrice-weekly CP attained best-estimated relapse risks below 5%; they reached 6% when 2-mo culture was also positive.Cavitary tuberculosis is best treated with 6-mo regimens comprising daily IP and thrice-weekly CP, which may be extended when 2-mo culture is positive. |
| 2006 | Pharmacokinetics of rifapentine in children. | Pediatr Infect Dis J | Rifapentine is a rifamycin antibiotic approved for the treatment of pulmonary infections caused by Mycobacterium tuberculosis. Although the pharmacokinetics of Rifapentine has been investigated in adolescents and adults, no studies have assessed the pharmacokinetics of this drug in children or infants.Twenty-four children (7.1 +/- 3.3 years; mean +/- 1 SD, 27.9 +/- 11.9 kg) were enrolled in this open label study. Children received a single oral dose (10 to <30 kg body weight received 150 mg; 30 to <60 kg body weight received 300 mg), followed by repeated blood sampling (n = 11) for 32 hours. Rifapentine and 25-desacetyl Rifapentine were quantitated by a validated high-pressure liquid chromatography method. Pharmacokinetic parameters were determined using a model-independent approach.A significant difference in dose-normalized area under the curves (AUC0-n and AUC0-infinity) was observed between children receiving the 150 and 300 mg doses, which was accounted for by differences in age between the dosing arms. In separate analyses, including data from adults, further age-dependence in total body exposure (reflected by AUC) and elimination was observed. Adverse events associated with Rifapentine were mild and included gastric distress (n = 1) and vomiting (n = 2).Given a comparable weight-normalized dose, Rifapentine exposure estimates are lower in children than those reported in adults, suggesting that a larger weight-normalized (ie, mg/kg) dose of Rifapentine is needed in children. |
| 2006 | Study of the interaction between rifapentine and isoniazid under acid conditions. | J Pharm Biomed Anal | A well-known problem of anti-tuberculosis fixed-dose combination (FDC) products containing rifampicin (R) and isoniazid (H) is the fall in bioavailability, in particular of R, when two or more drugs are present together. The same has been ascribed to hydrolysis of R to 3-formylrifamycin (3-RIF) under stomach acid conditions and reaction of the latter with H to form isonicotinyl hydrazone (HYD). The objective of present study was to explore whether the same reaction occurred when H was present along with Rifapentine (Rp), a newer long acting rifamycin, which is structurally similar to R. Clinical trials are currently undergoing for co-administration of Rp with H in patients who had completed 2 months of standard chemotherapy. For the purpose, first a validated HPLC method was developed for the separation of Rp and H, and the same was used for the study of interaction between the two drugs. Like R, Rp was also found to convert to 3-RIF in acid conditions, which reacted further with H to form HYD. The pH-rate profile was also similar in shape to that established with the combination of R and H; maximum decomposition occurred at pH 2, where Rp loss was to an extent of approximately 30%, while corresponding decomposition of H was approximately 9%. These values were similar to those reported for the combination of R (approximately 33%) and H (approximately 10%). Hence, the study suggests that co-administration of Rp and H should be avoided, like in case of R and H, and the two drugs should not be formulated directly into a single dosage form. |
| 2006 | Potent twice-weekly rifapentine-containing regimens in murine tuberculosis. | Am J Respir Crit Care Med | Recent studies have demonstrated that intermittent administration of rifamycin-based regimens results in higher rates of tuberculosis relapse and treatment failure compared with daily therapy. Twice-weekly treatment with rifampin, isoniazid, and pyrazinamide may be improved by increasing Mycobacterium tuberculosis exposure to rifamycin by substituting Rifapentine for rifampin.To test this hypothesis, we compared the activities of standard daily and twice-weekly rifampin plus isoniazid-based regimens to those of twice-weekly Rifapentine plus isoniazid- or moxifloxacin-containing regimens in the murine model of tuberculosis. Relapse rates were assessed after 4, 5, and 6 mo of treatment to assess stable cure. Single- and multiple-dose pharmacokinetics of rifampin and Rifapentine were also determined.After 2 mo of treatment, twice-weekly therapy with Rifapentine (15 or 20 mg/kg), moxifloxacin, and pyrazinamide was significantly more active than standard daily or twice-weekly therapy with rifampin, isoniazid, and pyrazinamide. Stable cure was achieved after 4 mo of twice-weekly Rifapentine plus isoniazid- or moxifloxacin-containing therapy, but only after 6 mo of standard daily therapy. Twice-weekly Rifapentine (15 mg/kg) displayed more favorable pharmacodynamics than did daily rifampin (10 mg/kg).By virtue of the enhanced rifamycin exposure, twice-weekly regimens containing Rifapentine (15 or 20 mg/kg) may permit shortening the current treatment duration by 2 mo. Such regimens warrant clinical investigation. |
| 2006 | Bactericidal activities of R207910 and other newer antimicrobial agents against Mycobacterium leprae in mice. | Antimicrob Agents Chemother | As measured by a proportional bactericidal technique in the mouse footpad system, the bactericidal activity against Mycobacterium leprae of R207910 was equal to that of Rifapentine, rifampin, or moxifloxacin and significantly greater than those of minocycline, PA-824, and linezolid. These data suggest that R207910 may play an important role in treatment of leprosy. |
| 2006 | Advances in the diagnosis and treatment of tuberculosis. | Proc Am Thorac Soc | Although truly major advances that would revolutionize tuberculosis (TB) diagnosis and treatment have not been realized, we are beginning to see the innovations that have been prompted by the recognition of the economic potential of the market for new diagnostic tests and treatments for TB and considerably increased public and private funding. Despite the enormous global burden of TB and the overall low rates of case detection worldwide, conventional approaches to diagnosis have, until recently, relied on tests that have major limitations. In this review of advances in diagnosis, we focus on strengths and limitations of newer tests that are available for the diagnosis of latent and active tuberculosis and rapid detection of drug resistance, specifically, tests that measure release of IFN-gamma in response to stimulation by Mycobacterium tuberculosis antigens, nucleic acid amplification for identification of M. tuberculosis complex, and rapid tests for detecting drug resistance. Standard regimens for treating TB have not changed for more than 30 yr and still require a minimum of 6 mo to have a high likelihood of a lasting cure. In this article, we focus on important changes in the philosophy of treatment, emphasizing the responsibility of the provider to assure successful completion of treatment, and on the roles of existing anti-TB agents and newer drugs such as rifabutin, Rifapentine, and fluoroquinolones. |
| 2006 | Weekly rifapentine/isoniazid or daily rifampin/pyrazinamide for latent tuberculosis in household contacts. | Am J Respir Crit Care Med | Treatment of latent tuberculosis (TB) infection with weekly Rifapentine and isoniazid is a potentially effective alternative to current therapies.To compare the efficacy of weekly Rifapentine/isoniazid to daily rifampin/pyrazinamide in preventing TB in household contacts of patients with pulmonary TB in Brazil.Contacts of patients with TB were randomized to Rifapentine 900 mg/isoniazid 900 mg once weekly for 12 wk or rifampin 450-600 mg/pyrazinamide 750-1,500 mg daily for 8 wk and followed for at least 2 yr.TB rates, adverse events, and adherence to therapy.A total of 399 household contacts were enrolled, 206 in the Rifapentine/isoniazid arm and 193 in the rifampin/pyrazinamide arm. The median age was 34 yr, median weight was 63 kg, 60% of participants were female, and only one patient was HIV infected. Rifapentine/isoniazid was well tolerated, but the trial was halted by the investigators before completion because of unanticipated hepatotoxicity in the rifampin/pyrazinamide arm. Twenty of 193 participants (10%) receiving rifampin/pyrazinamide experienced grade 3 or 4 hepatotoxicity, compared with 2 of 206 participants (1%) on Rifapentine/isoniazid (p<0.001). There were no hospitalizations or deaths due to hepatotoxicity, and all participants' liver enzyme levels returned to normal during follow-up. During follow-up, four cases of active TB developed, three in the Rifapentine/isoniazid group and one in the rifampin/pyrazinamide group (1.46 vs. 0.52%; difference, 0.94%; 95% confidence interval, -1.6 to 3.7%).Rifapentine/isoniazid was better tolerated than rifampin/pyrazinamide and was associated with good protection against TB. Rifapentine/isoniazid weekly for 12 wk is likely a promising therapy for latent TB infection. |
| 2006 | Monitoring the ingestion of anti-tuberculosis drugs by simple non-invasive methods. | Int J Pharm | This investigation retrospectively assessed inexpensive non-invasive qualitative methods to monitor the ingestion of anti-tuberculosis drugs isoniazid, rifampicin and Rifapentine. Results showed that commercial test strips detected the isoniazid metabolites isonicotinic acid and isonicotinylglycine as efficiently as the isonicotinic acid method in 150 urine samples. The presence of rifamycins in urine samples (n=1085) was detected by microbiological assay techniques and the sensitivity compared to the n-butanol extraction colour test in 91 of these specimens. The proportions detected by the two methods were significantly different and the sensitivity of the n-butanol procedure was only 63.8% (95% CL 51.2-76.4%) as compared to that of the superior microbiological method. Final validation (n=691) showed that qualitative assays measure isoniazid and rifamycin ingestion with an efficiency similar to high-performance liquid chromatography. The qualitative procedures may therefore be valuable in clinical trials and in tuberculosis clinics to confirm drug ingestion. |
| 2005 | Population pharmacokinetics of rifapentine and its primary desacetyl metabolite in South African tuberculosis patients. | Antimicrob Agents Chemother | This study was designed to describe the population pharmacokinetics of Rifapentine (RFP) and 25-desacetyl RFP in a South African pulmonary tuberculosis patient population. Special reference was made to studying the influence of previous exposure to rifampin (RIF) and the variability in pharmacokinetic parameters between patients and between occasions and the influence of different covariates. Patients were included in the study if they had been receiving first-line antimycobacterial therapy (rifampin, isoniazid, pyrazinamide, and ethambutol) for not less than 4 weeks and not more than 6 weeks and were divided into three RFP dosage groups based on weight: 600 mg, <45 kg; 750 mg, 46 to 55 kg; and 900 mg, >55 kg. Participants received a single oral dose of RFP together with concomitant antimycobacterial agents, excluding RIF, on study days 1 and 5 after they ingested a soup-based meal. The RFP and 25-desacetyl RFP concentration-time data were analyzed by nonlinear mixed-effect modeling using NONMEM. The pharmacokinetics of the parent drug were modeled separately, and the individual pharmacokinetic parameters were used as inputs for the 25-desacetyl RFP pharmacokinetic model. A one-compartment disposition model was found to best describe the data for both the parent and the metabolite, and the metabolite was assumed to be formed only from the central compartment of the parent drug. Prior treatment with RIF did not alter the pharmacokinetics of RFP but appeared to increase the excretion of 25-desacetyl RFP in a nonlinear fashion. The RFP oral clearance and volume of distribution were found to increase by 0.049 liter/h and 0.691 liter, respectively, with a 1-kg increase from the median weight of 50 kg. The oral clearance of 25-desacetyl RFP was found to be 35% lower in female patients. The model developed here describes the population pharmacokinetics of RFP and its primary metabolite in tuberculosis patients and includes the effects of prior administration with RIF and covariate factors. |
| 2005 | Efficient intermittent rifapentine-moxifloxacin-containing short-course regimen for treatment of tuberculosis in mice. | Antimicrob Agents Chemother | Long-half-life drugs raise the hope of once-a-week administration of antituberculous treatment. In a previous study with the murine model of tuberculosis, the most active intermittent regimen which contained Rifapentine (RFP), isoniazid (INH), and moxifloxacin (MXF) given once a week during 5.5 months, preceded by 2 weeks of daily treatment with INH, rifampin (RIF), pyrazinamide (PZA), and MXF, was less active than the standard 6-month daily RIF-INH-PZA regimen. We evaluated with the same model similar regimens in which we increased the dosing of Rifapentine from 10 to 15 mg/kg of body weight and of moxifloxacin from 100 to 400 mg/kg. Mice infected intravenously by 6.2 x10(6) CFU of Mycobacterium tuberculosis H37Rv were treated 2 weeks later when infection was established. After 6 months of treatment, all mice had negative lung culture. After 3 months of follow-up, no relapse occurred in the two groups that received moxifloxacin at 400 mg/kg, whatever the dosage of RFP, and in the group receiving the standard RIF-INH-PZA control regimen. In contrast, in the two groups receiving moxifloxacin at a lower dosage, the relapse rate was significantly higher (13% in mice receiving RFP at 15 mg/kg and 27% in those receiving RFP at 10 mg/kg). Finally, the fully intermittent once-a-week regimen (26 drug ingestions) of INH, RFP (15 mg/kg), and MXF (400 mg/kg) led to a relapse rate of 11%. In conclusion, when used at high dosage, Rifapentine and moxifloxacin are very efficient when combined with isoniazid in a once-a-week treatment in mouse tuberculosis. |
| 2005 | Rifapentine, moxifloxacin, or DNA vaccine improves treatment of latent tuberculosis in a mouse model. | Am J Respir Crit Care Med | Priorities for developing improved regimens for treatment of latent tuberculosis (TB) infection include (1) developing shorter and/or more intermittently administered regimens that are easier to supervise and (2) developing and evaluating regimens that are active against multidrug-resistant organisms.By using a previously validated murine model that involves immunizing mice with Mycobacterium bovis bacillus Calmette-Guérin to augment host immunity before infection with virulent Mycobacterium tuberculosis, we evaluated new treatment regimens including Rifapentine and moxifloxacin, and assessed the potential of the Mycobacterium leprae heat shock protein-65 DNA vaccine to augment the activity of moxifloxacin.Quantitative spleen colony-forming unit counts, and the proportion of mice with culture-positive relapse after treatment, were determined.Three-month, once-weekly regimens of Rifapentine combined with either isoniazid or moxifloxacin were as active as daily isoniazid for 6-9 mo. Six-month daily combinations of moxifloxacin with pyrazinamide, ethionamide, or ethambutol were more active than pyrazinamide plus ethambutol, a regimen recommended for latent TB infection after exposure to multidrug-resistant TB. The combination of moxifloxacin with the experimental nitroimidazopyran PA-824 was especially active. Finally, the heat shock protein-65 DNA vaccine had no effect on colony-forming unit counts when given alone, but augmented the bactericidal activity of moxifloxacin.Together, these findings suggest that Rifapentine, moxifloxacin, and, perhaps, therapeutic DNA vaccination have the potential to improve on the current treatment of latent TB infection. |
| 2005 | Weekly moxifloxacin and rifapentine is more active than the denver regimen in murine tuberculosis. | Am J Respir Crit Care Med | Treatment of tuberculosis with an efficacious once-weekly regimen would be a significant achievement in improving patient adherence. Currently, the only recommended once-weekly continuation phase regimen of isoniazid plus Rifapentine (10 mg/kg) is inferior to standard twice-weekly therapy with isoniazid plus rifampin and is, therefore, restricted to non-high-risk patients. The substitution of moxifloxacin, a new 8-methoxyfluoroquinolone, for isoniazid and an increase in the dose of Rifapentine could augment the activity of once-weekly regimens.To test this hypothesis we evaluated the sterilizing activity of improved once-weekly Rifapentine-based continuation phase regimens in a murine model that mimics the treatment of high-risk patients with tuberculosis. The bactericidal activity of standard daily therapy and standard intermittent therapy ("Denver" regimen) was also assessed to evaluate the effect of intermittent drug administration during the initial phase of therapy.After 2 mo of treatment, lung colony-forming unit counts were 1 log(10) lower in mice treated with standard daily therapy than with the Denver regimen. During the continuation phase, the sterilizing activity of once-weekly moxifloxacin plus Rifapentine (15 mg/kg) was significantly greater than that of the predominantly twice-weekly Denver regimen of isoniazid plus rifampin. No significant difference in sterilizing activity was detected between once-weekly isoniazid plus Rifapentine (15 mg/kg) and the Denver regimen.These results suggest that the efficacy of the once-weekly isoniazid plus Rifapentine continuation phase regimen can be increased by substituting moxifloxacin for isoniazid and by increasing the dose of Rifapentine to a clinically acceptable level of 15 mg/kg. |
| 2005 | [In vitro study on cross resistance of rifampin and rifapentine for Mycobacterium tuberculosis]. | Zhonghua Jie He He Hu Xi Za Zhi | To study the bactericidal effect of Rifapentine and its cross-resistance with rifampin for Mycobacterium tuberculosis and to determine the critical concentration of Rifapentine for laboratory drug susceptibility test and therefore to provide the laboratory data for using Rifapentine in the treatment of tuberculosis, particularly rifampin resistant tuberculosis.We detected the minimal inhibitory concentrations (MICs) of rifampin and Rifapentine to H(37) Rv and isolated strains of rifampin susceptible and resistant Mycobacterium tuberculosis by using Middlebrook 7H9, Sauton and Lowenstein-Jensen media.The MICs of rifampin were > or = 0.32 microg/ml for 80% of the 19 rifampin susceptible strains on Middlebrook 7H9 and the MICs of Rifapentine ranged from 0.02 microg/ml to 0.32 microg/ml for most of the strains (84%). The MICs of Rifapentine were 2 - 4 times lower than those of rifampin to H(37) Rv and most clinical isolates. The Rifapentine susceptible isolates were mostly separated from resistant strains at MICs 5-10 microg/ml.Our results demonstrate the cross resistance of rifampin and Rifapentine and the stronger bactericidal potency of Rifapentine than rifampin. Some rifampin resistant strains still show susceptibility to Rifapentine, which suggests Rifapentine may be effective in the treatment of rifampin resistant tuberculosis. Our results also determined a critical resistant concentration of Rifapentine for routine drug susceptibility test. |
| 2005 | Cross-resistance of Escherichia coli RNA polymerases conferring rifampin resistance to different antibiotics. | J Bacteriol | In this study we further defined the rifampin-binding sites in Escherichia coli RNA polymerase (RNAP) and determined the relationship between rifampin-binding sites and the binding sites of other antibiotics, including two rifamycin derivatives, rifabutin and Rifapentine, and streptolydigin and sorangicin A, which are unrelated to rifampin, using a purified in vitro system. We found that there is almost a complete correlation between resistance to rifampin (Rif(r)) and reduced rifampin binding to 12 RNAPs purified from different rpoB Rif(r) mutants and a complete cross-resistance among the different rifamycin derivatives. Most Rif(r) RNAPs were sensitive to streptolydigin, although some exhibited weak resistance to this antibiotic. However, 5 out of the 12 Rif(r) RNAPs were partially resistant to sorangicin A, and one was completely cross-resistant to sorangicin A, indicating that the binding site(s) for these two antibiotics overlaps. Both rifampin and sorangicin A inhibited the transition step between transcription initiation and elongation; however, longer abortive initiation products were produced in the presence of the latter, indicating that the binding site for sorangicin A is within the rifampin-binding site. Competition experiments of different antibiotics with (3)H-labeled rifampin for binding to wild-type RNAP further confirmed that the binding sites for rifampin, rifabutin, Rifapentine, and sorangicin A are shared, whereas the binding sites for rifampin and streptolydigin are distinct. Because Rif(r) mutations are highly conserved in eubacteria, our results indicate that this set of Rif(r) mutant RNAPs can be used to screen for new antibiotics that will inhibit the growth of Rif(r) pathogenic bacteria. |
| 2005 | The early bactericidal activities of rifampin and rifapentine in pulmonary tuberculosis. | Am J Respir Crit Care Med | Comparison of the early bactericidal activity (EBA) of Rifapentine and its pharmacokinetics with those of rifampin to determine the cause of poor clinical response and regrowth between doses, leading to rifamycin monoresistance at relapse.Determination of the dose size of Rifapentine that gives sufficient drug exposure to prevent regrowth.EBA study over initial 5 days of treatment of 123 patients, half at Durban and half at Cape Town, who received single Rifapentine doses of 300, 600, 900, or 1,200 mg Rifapentine or five daily doses of 150, 300, or 600 mg rifampin, with a pharmacokinetic study on 58 patients measuring standard parameters for each dose size of rifamycin and their desacetyl metabolites.The EBAs for both rifamycins were similar, with a linear relationship to log dose at lower doses and a curvilinear response at higher doses giving a plateau at 1,136 mg Rifapentine. The area under the concentration-time curve (AUC) divided by the minimal inhibitory concentration (MIC) agreed well for both rifamycins on the assumption that the only free 2% of free Rifapentine and the 14% of free rifampin after plasma binding were active in the lesions.Only the free proportions of the rifamycins were active in lesions. From consideration of the pulse size and the duration of the postantibiotic lag, a 1,200-mg dose of Rifapentine seemed necessary to improve response and to prevent regrowth between doses, and hence rifamycin monoresistance. |
| 2004 | In vitro and in vivo activities of new rifamycin derivatives against mycobacterial infections. | Curr Pharm Des | Several rifamycin derivatives have been developed during the last 15 years for the treatment of mycobacterial infections. For tuberculosis, rifabutin (RFB) showed strong activity and seemed to be suitable when tuberculosis patients were also treated for their AIDS infection. Rifapentine (RPT) was evaluated in patients with or without AIDS for its intermittent use. It displayed promising activity but must be strengthened in situations, such as AIDS or patients without AIDS but with cavities. Rifalazil (RLZ) has been evaluated in mice but the dosages used were much higher than those tolerated by patients. Regarding Mycobacterium avium infections, RFB showed significant prophylactic activity in humans, RPT displayed some activity in mice and RLZ showed modest activity in mice. |
| 2004 | Consecutive-dose pharmacokinetics of rifapentine in patients diagnosed with pulmonary tuberculosis. | Int J Tuberc Lung Dis | To characterise the pharmacokinetics of two consecutive doses of Rifapentine (RPT) in patients diagnosed with pulmonary tuberculosis at a South African hospital.Forty-five patients received RPT doses of 600, 750 and 900 mg, based on body weight, after receiving a soup-based meal. Doses were administered to each subject on study days 1 and 5. All patients had already received not less than 4 weeks and not more than 6 weeks of standard antimycobacterial therapy (including isoniazid, rifampicin, pyrazinamide and ethambutol). Serial blood samples were collected between 0 and 72 h post-dose. RPT and 25-desacetyl-RPT concentrations were determined using validated high performance liquid chromatography methods. The plasma concentration-time data were analysed using a noncompartmental approach and compared to healthy volunteer data from a previous study.Median peak plasma concentrations for RPT in the patient cohort were 15.19 and 15.48 microg/ml on study days 1 and 5, respectively. Time to reach these concentrations was 5.00 and 5.08 h and plasma elimination half-lives were 11.63 and 12.03 h, respectively. Areas under the plasma concentration-time curve (0-72 h) were 355.81 and 371.89 microg x h/ml on the two occasions, respectively.A 15 mg/kg dose of RPT was well absorbed and well tolerated. The variability observed between individuals and between occasions was small, and similar to that seen in data from previous studies in healthy volunteers. |
| 2004 | Pharmacokinetics of rifapentine at 600, 900, and 1,200 mg during once-weekly tuberculosis therapy. | Am J Respir Crit Care Med | The pharmacokinetics of Rifapentine at 600, 900, and 1,200 mg were studied during once-weekly continuation phase therapy in 35 patients with tuberculosis. Mean area under the plasma concentration-time curve (AUC(0-infinity)) increased significantly with dose (Rifapentine AUC(0- infinity): 296, 410, and 477 microg.hour/ml at 600, 900, and 1,200 mg, respectively; p = 0.02 by linear regression). In multivariate stepwise regression analyses, AUC(0-infinity) values for Rifapentine and the active 25-desacetyl metabolite were associated with drug dose and plasma albumin concentration, and were lower among men and among white individuals. Fifty-four percent of patients had total (free and protein-bound) plasma concentrations of Rifapentine and of desacetyl Rifapentine detected for more than 36 hours after clearance of concurrently administered isoniazid. Serious adverse effects of therapy in these study patients were infrequent (1 of 35 cases; 3%) and not linked with higher Rifapentine AUC(0-infinity) or peak concentration. The present pharmacokinetic study supports further trials to determine the optimal Rifapentine dose for treatment of tuberculosis. |
| 2004 | In vitro postantibiotic effects of rifapentine, isoniazid, and moxifloxacin against Mycobacterium tuberculosis. | Antimicrob Agents Chemother | Postantibiotic effects (PAEs) of Rifapentine, isoniazid, and moxifloxacin against Mycobacterium tuberculosis ATCC 27294 were studied using a radiometric culture system. Rifapentine at 20 mg/liter gave the longest PAE (104 h) among the drugs used alone. The combinations of Rifapentine plus isoniazid, Rifapentine plus moxifloxacin, and isoniazid plus moxifloxacin gave PAEs of 136.5, 59.0, and 8.3 h, respectively. |
| 2003 | [A study on the clinical efficacy of a combination regimen with levofloxacin and capreomycin in the treatment of multi-drug resistant pulmonary tuberculosis]. | Zhonghua Jie He He Hu Xi Za Zhi | To study the clinical efficacy of a combination therapy with levofloxacin (LVFX), capreomycin (CPM) and other second-line antituberculosis drugs in the treatment of multi-drug resistant pulmonary tuberculosis (MDR-TB).177 patients with MDR-TB were assigned to a study group (88 cases), treated with LVFX, CPM, pyrazinamide (PZA), Rifapentine (RFT) and pasiniazid (PSZ); or a control group, treated with streptomycin (SM), ethambutol (EMB), PZA, RFT and PSZ. The course of treatment was 21 months.82 cases in the study group and 79 cases in the control group completed the treatment. The sputum negative conversion rate in the study group (83%) was significantly higher than that in the control group (58%) (P < 0.01). The radiographic improvement rate was 50% in the study group, significantly higher than that in the control group (28%) (P < 0.01). The closure rate of the lung cavities in the study group (63%) was higher than that in the control group (42%) (P < 0.05). No significant difference was found in side-effects between the two groups (31% in the study group, and 35% in the control group respectively) (P > 0.05).The regimen including LEVX, CPM and other second-line anti-TB drugs was effective and safe for patients with MDR-TB. |
| 2003 | Rapid detection of rifampin resistance in Mycobacterium tuberculosis isolates by heteroduplex analysis and determination of rifamycin cross-resistance in rifampin-resistant isolates. | J Clin Microbiol | Direct heteroduplex analysis and a universal heteroduplex generator assay were performed to detect rifampin resistance rapidly in Turkish Mycobacterium tuberculosis isolates. Cross-resistance to Rifapentine, rifabutin, and rifalazil was investigated. A relationship between specific mutations and resistance patterns, which can guide the choice of an appropriate therapeutic regimen for tuberculosis patients, was identified. |
| 2003 | Low isoniazid concentrations and outcome of tuberculosis treatment with once-weekly isoniazid and rifapentine. | Am J Respir Crit Care Med | To understand why once-weekly isoniazid/Rifapentine therapy for tuberculosis was less effective than twice-weekly isoniazid/rifampin, we studied human immunodeficiency virus-seronegative patients with either failure (n = 4), relapse (n = 35), or cure (n = 94), recruited from a comparative treatment trial. In multivariate analyses that were adjusted for severity of disease, low plasma concentrations of isoniazid were associated with failure/relapse with once-weekly isoniazid/Rifapentine (median isoniazid area under the concentration-time curve for 12 hours after the dose [AUC(0-12)] was 36 microg x hour/ml in failure/relapse versus 56 microg x hour/ml in control cases p = 0.005), but not with twice-weekly isoniazid/rifampin. Furthermore, two patients who relapsed with Mycobacterium tuberculosis monoresistant to rifamycin had very low concentrations of isoniazid. Finally, isoniazid acetylator status determined by N-acetyltransferase type 2 genotype was associated with outcome with once-weekly isoniazid/Rifapentine (p = 0.03) but not twice-weekly isoniazid/rifampin. No rifamycin pharmacokinetic parameter was consistently and significantly associated with outcome (p > 0.10). Because low isoniazid concentrations were associated with failure/relapse, a drug with consistently greater area under the concentration-time curve than isoniazid may be needed to achieve highly active once-weekly therapy with Rifapentine. |
| 2002 | Therapeutic drug monitoring in the treatment of tuberculosis. | Drugs | Therapeutic drug monitoring (TDM) is a standard clinical technique used for many disease states, including many infectious diseases. As for these other conditions, the use of TDM in the setting of tuberculosis (TB) allows the clinician to make informed decisions regarding the timely adjustment of drug therapy. Such adjustments may not be required for otherwise healthy individuals who are responding to the standard, four-drug TB regimens. However, some patients are slow to respond to treatment, have drug-resistant TB, are at risk of drug-drug interactions or have concurrent disease states that significantly complicate the clinical situation. Such patients may benefit from TDM and early interventions may preclude the development of further drug resistance. It is not possible to collect multiple blood samples in the clinical setting for logistical and financial reasons. Therefore, one typically is limited to one or two time points. When only one sample can be obtained, the 2-hour post-dose concentrations of isoniazid, rifampin, pyrazinamide and ethambutol are usually most informative. Unfortunately, low 2-hour values do not distinguish between delayed absorption (late peak, close to normal range) and malabsorption (low concentrations at all time points). A second sample, often collected at 6-hour post-dose, can differentiate between these two scenarios. The second time point can also provide some information about clearance and half-life, assuming that drug absorption was nearly completed by 2 hours. TDM requires that samples are promptly centrifuged, and that the serum is promptly harvested and frozen. Isoniazid and ethionamide, in particular, are not stable in human serum at room temperature. Rifampin is stable for more than 6 hours under these conditions. During TB treatment, isoniazid causes the greatest early reduction in organisms and is considered to be one of the two most important TB drugs, along with rifampin. Although isoniazid is highly active against TB, low isoniazid concentrations were associated with poorer clinical and bacteriological outcomes in US Public Health Services (USPHS) TB Trial 22. Several earlier trials showed a clear dose-response for rifampin and pyrazinamide, so low concentrations for those two drugs also may correlate with poorer treatment outcomes. At least in USPHS TB Trial 22, the rifampin pharmacokinetic parameters were not predictive of the outcome variables. In contrast, low concentrations of unbound Rifapentine may have been responsible, in part, for the worse-than-anticipated performance of this drug in clinical trials. The 'second-line' TB drugs, including p-aminosalicylic acid, cycloserine and ethionamide, are relatively weak TB drugs. Under the best conditions, treatment with these drugs takes over 2 years, as opposed to 6 to 9 months with isoniazid- and rifampin-containing regimens. Therefore, TB centres such as National Jewish Medical and Research Center in Denver, CO, USA, measure serum concentrations of the 'second-line' TB drugs early in the course of treatment. That way, poor drug absorption can be dealt with in a timely manner. This helps to minimise the time that patients are sputum smear- and culture-positive with multidrug-resistant TB, and may prevent the need for even longer treatment durations. Patients with HIV are at particular risk for drug-drug interactions. Because the published guidelines typically reflect interactions only between two drugs, these guidelines are of limited value when the patient is treated with three or more interacting drugs. Under such complicated circumstances, TDM often is the best available tool for sorting out these interactions and placing the patient the necessary doses that they require. TDM is only one part of the care of patients with TB. In isolation, it is of limited value. However, combined with clinical and bacteriological data, it can be a decisive tool, allowing the clinician to successfully treat even the most complicated TB patients. |
| 2002 | Rifapentine and isoniazid once a week versus rifampicin and isoniazid twice a week for treatment of drug-susceptible pulmonary tuberculosis in HIV-negative patients: a randomised clinical trial. | Lancet | Rifapentine has a long half-life in serum, which suggests a possible treatment once a week for tuberculosis. We aimed to compare Rifapentine and isoniazid once a week with rifampicin and isoniazid twice a week.We did a randomised, multicentre, open-label trial in the USA and Canada of HIV-negative people with drug-susceptible pulmonary tuberculosis who had completed 2 months of a 6-month treatment regimen. We randomly allocated patients directly observed treatment with either 600 mg Rifapentine plus 900 mg isoniazid once a week or 600 mg rifampicin plus 900 mg isoniazid twice a week. Primary outcome was failure/relapse. Analysis was by intention to treat.1004 patients were enrolled (502 per treatment group). 928 successfully completed treatment, and 803 completed the 2-year 4-month study. Crude rates of failure/relapse were 46/502 (9.2%) in those on Rifapentine once a week, and 28/502 (5.6%) in those given rifampicin twice a week (relative risk 1.64, 95% CI 1.04-2.58, p=0.04). By proportional hazards regression, five characteristics were independently associated with increased risk of failure/relapse: sputum culture positive at 2 months (hazard ratio 2.8, 95% CI 1.7-4.6); cavitation on chest radiography (3.0, 1.6-5.9); being underweight (3.0, 1.8-4.9); bilateral pulmonary involvement (1.8, 1.0-3.1); and being a non-Hispanic white person (1.8, 1.1-3.0). Adjustment for imbalances in 2-month culture and cavitation diminished the association of treatment group with outcome (1.34; 0.83-2.18; p=0.23). Of participants without cavitation, rates of failure/relapse were 6/210 (2.9%) in the once a week group and 6/241 (2.5%) in the twice a week group (relative risk 1.15; 95% CI 0.38-3.50; p=0.81). Rates of adverse events and death were similar in the two treatment groups.Rifapentine once a week is safe and effective for treatment of pulmonary tuberculosis in HIV-negative people without cavitation on chest radiography. Clinical, radiographic, and microbiological data help to identify patients with tuberculosis who are at increased risk of failure or relapse when treated with either regimen. |
| 2002 | [Prospects for development of new antituberculous drugs]. | Kekkaku | Tuberculosis (TB) is a growing international health concern, since it is the leading infectious cause of death in the world today. Moreover, the resurgence of TB in industrialized countries and the worldwide increase in the prevalence of Mycobacterium avium complex (MAC) infections in immunocompromised hosts have prompted the quest for new antimycobacterial drugs. In particular, the appearance of multidrug-resistant (MDR) strains of M. tuberculosis, which exhibit in vitro resistance to at least two major antituberculous drug (usually INH and RFP) and cause intractable TB, has greatly contributed to the increased incidence of TB. Because of the global health problems of TB, the increasing rate of MDR-TB and the high rate of a co-infection with HIV, the development of potent new antituberculous drugs without cross-resistance with known antimycobacterial agents is urgently needed. In this article, I reviewed the following areas. First, I briefly reviewed some new findings (mainly reported after 2000) on the pharmacological status of rifamycin derivatives (rifabutin, Rifapentine, and rifalazil), fluoroquinolones (ciprofloxacin, ofloxacin, sparfloxacin, levofloxacin, gatifloxacin, sitafloxacin, moxifloxacin, and others), and new macrolides (clarithromycin, azithromycin, and roxithromycin). Second, I described other types of agents which are being developed as antimycobacterial drugs. Some of the agents discussed are already under preliminary clinical investigation, and others appear to be promising candidates for future development. In this review, the status of the development of new antimycobacterial, especially antituberculous agents including oxazolidinone (PNU-100480), 5'-nitroimidazole (CGI 17341), 2-pyridone (ABT-255), new riminophenazines, nitroimidazopyran (PA-824), new ketolides (ABT-773, telithromycin) and defensins (human neutrophil peptide-I), was examined. Third, the development of new antitubercular drugs was discussed according to the potential pharmacological target. New critical information on the whole genome of M. tuberculosis recently elucidated and increasing knowledge on various mycobacterial virulence genes will promote the progression in the identification of genes that code for new drug targets. Using such findings on mycobacterial genomes, drug development using quantitative structure-activity relationship may be possible in the near future. In this review, I described the screening of drugs that have an inhibitory activity against dTDP-rhamnose synthesis of M. tuberculosis, as a new drug target of the organism. In addition, I discussed the usefulness of antisense oligo DNAs specific to mycobacterial genes encoding certain metabolic enzymes or virulence factors that play roles in the bacterial escape from antimicrobial mechanisms of host macrophages. Fourth, I reviewed the drug vehicles which enable efficacious drug delivery to their target in vivo. The usefulness of poly (DL-lactide-co-glycolide) microsphere technology, which enables the encapsulated drugs to deliver the requested doses of them for prolonged time periods by a single shot without causing any toxicity and, moreover, enables the highly targeted delivery of the drugs to host macrophages, was discussed. Fifth, I described adjunctive immunotherapy for the management of patients with mycobacterial infections by giving certain immunomodulators in combination with antimycobacterial drugs. Adjuvant clinical trials using IL-2 or GM-CSF have been found to be efficacious to some extent in improving patients with tuberculosis or disseminated MAC infections. However, it seems that these immunopotentiating cytokines as well as IFN-gamma and IL-12 are not so promising for the therapeutic agents of mycobacterial infections because of the possible induction of immunosuppressive cytokines during adjuvant therapy and, in some cases, severe side-effect. Thus, the development of new classes of immuno-modulators other than cytokines, particularly those with no severe side-effect, is needed. This review dealt with ATP and its analogues which potentiate macrophage antimycobacterial activity via a purinergic P2X7 receptor. Finally, I described the roles of type II alveolar epithelial cells in the establishment of mycobacterial infections in the host lungs and the profiles of drug susceptibilities of M. tuberculosis and MAC organisms replicating within the type II pneumocytes. These findings are useful to precisely assess or predict the in vivo therapeutic activity of a given antimycobacterial drug from its in vitro activity. In this article, I have thoroughly reviewed the status of the development of new antimycobacterial drugs. There are a number of difficulties in the drug-design for the development of new drug formulations with increased potential for antimycobacterial effects, excellent pharmacokinetics, and tolerability. It should be emphasized that the most urgent goal of chemotherapy of tuberculosis and MAC infections, especially that associated with HIV infection, is to develop highly active, low-cost drugs which can be used not only in industrialized countries but also in developing countries, since the incidences of AIDS-associated intractable tuberculosis is rapidly increasing in the latter. |
| 2002 | A prospective, randomized, double-blind study of the tolerability of rifapentine 600, 900, and 1,200 mg plus isoniazid in the continuation phase of tuberculosis treatment. | Am J Respir Crit Care Med | Once-weekly Rifapentine 600 mg plus isoniazid (INH) during the continuation phase treatment of tuberculosis is associated with a relapse rate higher than that of twice-weekly rifampin plus INH. The safety and tolerability of higher Rifapentine doses need to be determined. We conducted a prospective, randomized, double-blind trial of Rifapentine at three doses (600, 900, and 1,200 mg) plus INH 15 mg/kg once weekly in the continuation phase treatment of culture-positive tuberculosis in 150 human immunodeficiency virus-seronegative adults. Outcome measures were discontinuation of therapy for any reason and adverse events on therapy. Treatment was discontinued in 3 of 52 (6%), 2 of 51 (4%), and 3 of 47 (6%) in the Rifapentine 600-, 900-, and 1,200-mg treatment arms, respectively. Only one discontinuation, in the Rifapentine 1,200-mg arm, was due to an adverse event possibly associated with study therapy. There was a trend toward more adverse events, possibly associated with study therapy, in the highest-dose arms (p = 0.051). Rifapentine 900-mg, once-weekly dosing appears to be safe and well tolerated and is being evaluated in Phase III efficacy trials of treatment of latent tuberculosis. Further evaluation of the safety and tolerability of Rifapentine 1,200 mg is warranted. |
| 2002 | Rifapentine and isoniazid in the continuation phase of a 6-month regimen. Final report at 5 years: prognostic value of various measures. | Int J Tuberc Lung Dis | Clinical trial in 672 patients with newly diagnosed pulmonary tuberculosis in Hong Kong. After an initial 2 months of a four-drug intensive phase consisting of thrice-weekly streptomycin, isoniazid, rifampicin and pyrazinamide (SHRZ), a random allocation was made to a continuation phase of once-weekly 600 mg Rifapentine + 15 mg/kg isoniazid (HRp1), HRp1 given in 2 of every 3 weeks (HRp1.2/3), or to thrice-weekly isoniazid + rifampicin (HR3), the standard treatment in Hong Kong.Final report evaluating adverse events (46 relapses and one failure) after 5 years and the prognostic influence of various factors.Kaplan-Meier analysis of adverse events and Cox proportional hazards analysis of prognostic factors.The two Rifapentine regimens, HRp1 and HRp1.2/3 had similar final rates of adverse events of 10.8% and 11.7%, respectively, compared to 4.2% for the HR3 regimen (P = 0.02 and 0.009, respectively). In the initial univariate proportional hazards analysis, adverse events were significantly related to the regimen, age, sex, pretreatment radiographic extent of disease and cavitation, and also to sputum culture at 2 months. In the final multivariate analysis, after step-wise removal of non-significant factors, adverse events were related only to the regimen, patients' sex and pretreatment radiographic extent of disease. Elderly male patients were more at risk of an adverse event, as were those with more severe disease. Adverse events occurred at life table rates of 9.0% in patients with drug-sensitive strains and in 8.9% of those with initially isoniazid-resistant organisms at 5 years.The two Rifapentine regimens were unsatisfactory because of their high incidence of adverse events. Isoniazid appeared not to contribute to preventing relapse. Further studies with increased Rifapentine dosage are necessary. |
| 2002 | Acquired rifamycin resistance in persons with advanced HIV disease being treated for active tuberculosis with intermittent rifamycin-based regimens. | MMWR Morb Mortal Wkly Rep | Rifamycin drugs (i.e., rifampin, rifabutin, and Rifapentine) are essential for short-course chemotherapy in persons with active tuberculosis (TB). However, adverse drug-drug interactions complicate the concurrent use of rifamycins and protease inhibitor drugs in persons with active TB who also are infected with human immunodeficiency virus (HIV-TB). CDC has recommended use of rifabutin in place of rifampin in multidrug regimens for the treatment of active TB in HIV-TB because rifabutin can be administered with antiretroviral treatment regimens that include protease inhibitors (1,2). These recommendations included twice-weekly intermittent therapy. Because intermittent rifabutin-based regimens had not been evaluated in clinical trials of HIV-TB, CDC's TB Trials Consortium (TBTC) initiated TBTC Study 23, a single-arm trial of twice-weekly rifabutin-based therapy for treatment of HIV-TB. |
| 2000 | Prospects for development of new antimycobacterial drugs. | J Infect Chemother | In this article, I have thoroughly reviewed the status of development of new antimycobacterial drugs, particularly fluoroquinolones (ciprofloxacin, ofloxacin, sparfloxacin, levofloxacin, gatifloxacin, sitafloxacin, and moxifloxacin), new macrolides (clarithromycin, azithromycin, and roxithromycin), rifamycin derivatives (rifabutin, Rifapentine, and KRM-1648), and others. The main purpose of this review was to describe the in-vitro and in-vivo activities of these drugs against Mycobacterium tuberculosis and Mycobacterium avium complex. In addition, the therapeutic efficacy of these drugs in the clinical treatment of mycobacterial infections has also been briefly mentioned. |
| 2001 | Newer drugs in leprosy. | Int J Lepr Other Mycobact Dis | During the last 15 years, new drugs active against Mycobacterium leprae have been identified. All of them belong to the fluoroquinolone, cycline and macrolide drug families. In the mouse model and in humans, minocycline, ofloxacin, and clarithromycin have demonstrated, individually or in combination, antileprosy activities much superior to those of the standard drugs dapsone and clofazimine. In humans, a single dose of the combination ofloxacin 400 mg + minocycline 100 mg was able to kill 68% to 98% of viable M. leprae and a single dose of ROM, a three-drug combination of rifampin 600 mg + ofloxacin 400 mg + minocycline 100 mg, was killing more than 99% of viable M. leprae. As a result of a double-blind, control, clinical trial, the Seventh Report of the WHO Expert Committee on Leprosy recommended in 1997 the use of single-dose ROM for the treatment of patients with single-lesion paucibacillary leprosy. Recently moxifloxacin, a new fluoroquinolone, and Rifapentine, a long-lasting rifamycin derivative, have demonstrated in the mouse model highly promising antileprosy activities, justifying their assessment in humans. |
| 2001 | Effectiveness of once-weekly rifapentine and moxifloxacin regimens against Mycobacterium tuberculosis in mice. | Antimicrob Agents Chemother | Mice infected with 1.6 x 10(7) CFU of Mycobacterium tuberculosis were treated 14 days later for 6 months with a regimen of once-weekly 10 mg of Rifapentine and 75 mg of isoniazid per kg of body weight supplemented with either 150 mg of streptomycin per kg or 100 mg of moxifloxacin per kg during either both the 2-week daily initial and once-weekly continuation phases or only in the daily 2-week initial phase. On completion of treatment, all lung cultures were negative, except for three mice, each with a single colony: two whose Rifapentine-isoniazid regimen was supplemented with streptomycin during the whole course of therapy and one whose Rifapentine-isoniazid regimen had no initial daily phase, but was supplemented with streptomycin and moxifloxacin during the whole course of therapy. After 3 months of follow-up, positive lung cultures were obtained from 61 and 56% of mice supplemented with streptomycin during either the full course of therapy or only the daily 2-week initial phase, respectively, and 15 and 50% of mice supplemented with moxifloxacin during either the full course of therapy or only the daily 2-week initial phase, respectively. These results suggest that moxifloxacin has sterilizing activity against M. tuberculosis. |
| 2001 | Comparative pharmacokinetics and pharmacodynamics of the rifamycin antibacterials. | Clin Pharmacokinet | The rifamycin antibacterials, rifampicin (rifampin), rifabutin and Rifapentine, are uniquely potent in the treatment of patients with tuberculosis and chronic staphylococcal infections. Absorption is variably affected by food; the maximal concentration of rifampicin is decreased by food, whereas Rifapentine absorption is increased in the presence of food. The rifamycins are well-known inducers of enzyme systems involved in the metabolism of many drugs, most notably those metabolised by cytochrome P450 (CYP) 3A. The relative potency of the rifamycins as CYP3A inducers is rifampin > Rifapentine > rifabutin; rifabutin is also a CYP3A substrate. The antituberculosis activity of rifampicin is decreased by a modest dose reduction from 600 to 450mg. This somewhat surprising finding may be due to the binding of rifampicin to serum proteins, limiting free, active concentrations of the drug. However, increasing the administration interval (after the first 2 to 8 weeks of therapy) has little effect on the sterilising activity of rifampicin, suggesting that relatively brief exposures to a critical concentration of rifampicin are sufficient to kill intermittently metabolising mycobacterial populations. The high protein binding of Rifapentine (97%) may explain the suboptimal efficacy of the currently recommended dose of this drug. The toxicity of rifampicin is related to dose and administration interval, with increasing rates of presumed hypersensitivity with higher doses combined with administration frequency of once weekly or less. Rifabutin toxicity is related to dose and concomitant use of CYP3A inhibitors. The rifamycins illustrate the complexity of predicting the pharmacodynamics of treatment of an intracellular pathogen with the capacity for dormancy. |
| 1998 | [Controlled clinical trial on efficacy of 5-month regimens and whole course intermittent 6-month regimens in treating bacillary pulmonary tuberculosis]. | Zhonghua Jie He He Hu Xi Za Zhi | To assess the therapeutic efficacy of Rifapentine (L), to reduce the duration of treatment and the frequency of drug administration, and to observe the influence on efficacy and adverse reactions of using pyrazinamide (Z) through whole-course.Two 5-month regimens respectively including rifampin (R) and L and two whole course intermittent regimens were designed as following: I: 2SHRZ/3R2H2Z2; II: 2SHRZ/3L1H2Z2; III: 2S3H3R3Z3/4L1H2Z2; IV: 2S3H3R3Z3/4L1H2E2. A total of 366 newly-diagnosed bacillary pulmonary tuberculosis patients were admitted and randomly allocated.339 cases completed the prescribed short course chemotherapy. The sputum conversion rates at the end of the treatment of groups I, II, III and IV were 97.0%, 94.1%, 100.0% and 97.2% respectively. X-ray resolution rates were 96.0%, 97.6%, 100.0% and 94.4% respectively. Cavity-close rates of the 5-month regimens and the 6-month regimens were 77% and 76%. Comparing the results among groups, there were no statistically significant differences (P > 0.05), and no obvious side-effect was found. 305 patients have been followed up for 3 years since completion of the chemotherapy. The bacteriological relapse and bacteriological relapse with deterioration on chest X-ray in groups I, II, III and IV were seen in 2,3,6 and 3 cases respectively.Domestic-made Rifapentine is a long-acting, highly effective antituberculosis drug. It is unnecessary to use Z in continuation phase, and it is possible to shorten the duration to 5 months with the appropriate combination of essential drugs, which is worthwhile for further study. |
| 2001 | Treatment alternatives for Mycobacterium kansasii. | J Antimicrob Chemother | Mycobacterium kansasii was administered intravenously to congenitally athymic (nude) mice. Beginning 1 week later, Rifapentine, azithromycin, ethambutol or combined therapy was initiated orally. All three drugs were highly active individually. Although there was no evidence of antagonism, combined therapy was not more effective than either component used alone. |
| 2000 | Combination of rifapentine-moxifloxacin-minocycline (PMM) for the treatment of leprosy. | Lepr Rev | To further the development of a multidrug regimen for treatment of leprosy that is suitable for monthly administration and fully supervisable, the bactericidal activities against Mycobacterium leprae of HMR 3647 (HMR), moxifloxacin (MXFX) and Rifapentine (RPT) were measured by the proportional bactericide technique in the mouse footpad system, and compared with those of the established antileprosy drugs clarithromycin (CLARI), ofloxacin (OFLO) and rifampicin (RMP). Administered in five daily doses of 100 mg per kg body weight, HMR appeared slightly more bactericidal than CLARI, but the difference did not attain statistical significance. Administered as single doses, MXFX in a dosage of 150 mg per kg was more active than OFLO in the same dosage, and displayed the same level of activity as RMP in a dosage of 10 mg per kg; the combination MXFX-minocycline (MINO) (MM) was more bactericidal than the combination OFLO-MINO (OM); RPT in a dosage of 10 mg per kg was more bactericidal than RMP administered in the same dosage, and even more active than the combination RMP-OFLO-MINO (ROM); the combination RPT-MXFX-MINO (PMM) killed 99.9% of viable M. leprae, and was slightly more bactericidal than was RPT alone, indicating that the combination PMM showed an additive effect against M. leprae. These promising results justify a clinical trial among lepromatous patients, in which MM is being compared with OM, and PMM with ROM, in terms of efficacy and tolerance. |
| 1999 | Recent Developments in Epidemiology, Treatment, and Diagnosis of Tuberculosis. | Curr Infect Dis Rep | The resurgence in cases of active tuberculosis in North America in the past decade has prompted increases in funding for tuberculosis treatment, research, and education. As a result, the number of new cases of tuberculosis has declined and cases occur in smaller pockets of well-characterized populations, such as communities of foreign-born persons and socioeconomically disadvantaged groups. New strategies for the treatment of both active and latent tuberculosis may soon include the newly licensed, long-acting rifamycin, Rifapentine, but further studies are needed to determine optimal dosing regimens for this agent. Experts in tuberculosis and HIV infection have made headway in defining the optimal therapy for each current therapeutic option, and recently published guidelines are a useful document for clinicians. Rifabutin-based regimens are one approach toward achieving the optimal treatment of both diseases simultaneously. Finally, newly licensed molecular diagnostic tests for direct use on clinical specimens are intriguing, but their clinical utility remains to be defined. |
| 2000 | Comparison of the in vitro activities of rifapentine and rifampicin against Mycobacterium tuberculosis complex. | J Antimicrob Chemother | The in vitro activity of Rifapentine for 44 clinical isolates of Mycobacterium tuberculosis complex was compared with that of rifampicin using the Bactec radiometric method and the absolute concentration method for susceptibility testing. Twenty-nine M. tuberculosis, 11 Mycobacterium bovis and four Mycobacterium africanum strains were studied. Control tests showed that Rifapentine was stable for 14 days in 7H9 broth and for 3 weeks in 7H10 agar medium. The 44 M. tuberculosis complex strains were more susceptible to Rifapentine than to rifampicin, irrespective of the testing method. In the radiometric system, the MIC50 and MIC90 of Rifapentine for M. tuberculosis complex strains were one or two two-fold dilutions lower than those of rifampicin (0.06-0.125 mg/L versus 0.25 mg/L, respectively). By the absolute concentration method, the MIC50 and MIC90 of Rifapentine for M. tuberculosis complex strains were two two-fold dilutions lower than those of rifampicin (0.125-0.25 mg/L versus 0.5-1 mg/L, respectively). The MIC90 of Rifapentine for the 44 M. tuberculosis complex strains was always 0.25 mg/L, irrespective of the method used, but the radiometric method was more reliable and more reproducible than the agar 7H10 method. |
| 2000 | Activity of rifapentine and its metabolite 25-O-desacetylrifapentine compared with rifampicin and rifabutin against Mycobacterium tuberculosis, Mycobacterium africanum, Mycobacterium bovis and M. bovis BCG. | J Antimicrob Chemother | The in vitro activity of Rifapentine and its metabolite, 25-O:-desacetylRifapentine, as compared with that of rifampicin and rifabutin, was determined against Mycobacterium tuberculosis, Mycobacterium africanum, Mycobacterium bovis and M. bovis BCG. MICs were determined radiometrically and by the 1% proportional method using Middlebrook 7H11 agar. The bactericidal effect of the drugs was determined in parallel at selected concentrations. For drugsusceptible isolates of M. tuberculosis, the Bactec MICs of Rifapentine and 25-O:-desacetylRifapentine were 0.03-0.06 mg/L and 0. 125-0.25 mg/L, respectively. Similar MICs were obtained for M. africanum (0.03-0.125 and 0.125-0.50 mg/L, respectively), and M. bovis (0.063-0.25 and 0.125-1.0 mg/L, respectively), but MICs were considerably lower for M. bovis BCG (0.008-0.063 mg/L for Rifapentine and 0.016-0.125 mg/L for its metabolite). In general, MICs determined using 7H11 agar medium were usually one or two dilutions higher than those obtained using Bactec broth. When compared with rifampicin and rifabutin, the inhibitory activity of Rifapentine for drug-susceptible isolates was roughly equal to that of rifabutin, and the inhibitory activity of 25-O:-desacetylRifapentine was comparable to that of rifampicin; however, Rifapentine was somewhat more bactericidal than rifabutin at equal concentrations. Clinical isolates of M. tuberculosis with a high degree of resistance to rifampicin (MIC >/= 32 mg/L) were also highly resistant to rifabutin, Rifapentine and 25-O:-desacetylRifapentine, although the MICs of rifabutin in this case were somewhat lower than the MICs of Rifapentine. |
| 2000 | Construction and characterization of a Mycobacterium tuberculosis mutant lacking the alternate sigma factor gene, sigF. | Infect Immun | The alternate RNA polymerase sigma factor gene, sigF, which is expressed in stationary phase and under stress conditions in vitro, has been deleted in the virulent CDC1551 strain of Mycobacterium tuberculosis. The growth rate of the DeltasigF mutant was identical to that of the isogenic wild-type strain in exponential phase, although in stationary phase the mutant achieved a higher density than the wild type. The mutant showed increased susceptibility to rifampin and Rifapentine. Additionally, the DeltasigF mutant displayed diminished uptake of chenodeoxycholate, and this effect was reversed by complementation with a wild-type sigF gene. No differences in short-term intracellular growth between mutant and wild-type organisms within human monocytes were observed. Similarly, the organisms did not differ in their susceptibilities to lymphocyte-mediated inhibition of intracellular growth. However, mice infected with the DeltasigF mutant showed a median time to death of 246 days compared with 161 days for wild-type strain-infected animals (P < 0.001). These data indicate that M. tuberculosis sigF is a nonessential alternate sigma factor both in axenic culture and for survival in macrophages in vitro. While the DeltasigF mutant produces a lethal infection of mice, it is less virulent than its wild-type counterpart by time-to-death analysis. |
| 2000 | Bactericidal activities of HMR 3647, moxifloxacin, and rifapentine against Mycobacterium leprae in mice. | Antimicrob Agents Chemother | Bactericidal activities of HMR 3647 (HMR), moxifloxacin (MXFX), and Rifapentine (RPT) against Mycobacterium leprae, measured by the proportional bactericidal technique in the mouse footpad system, were compared with those of the established antileprosy drugs clarithromycin (CLARI), ofloxacin (OFLO), and rifampin (RMP). Administered in five daily doses of 100 mg/kg of body weight, HMR appeared slightly more bactericidal than CLARI. In a single dose, MXFX at 150 mg/kg was more active than the same dose of OFLO and displayed exactly the same level of activity as RMP at 10 mg/kg; the combination MXFX-minocycline (MINO) (MM) was more bactericidal than the combination OFLO-MINO (OM); RPT at 10 mg/kg was more bactericidal than the same dose of RMP and even more active than the combination RMP-OFLO-MINO (ROM); the combination RPT-MXFX-MINO (PMM) killed 99.9% of viable M. leprae and was slightly more bactericidal than RPT alone, indicating that the combination PMM showed an additive effect against M. leprae. |
| 2000 | [Evaluation of modern antibiotics efficacy at experimental Northern Asia rickettsiosis]. | Antibiot Khimioter | Comparative investigation of antibiotics therapy efficacy at experimental murine Northern Asia rickettsiosis was performed. The efficacy was evaluated by the determination of protective activity in per cent and by the pathogen erradication. The investigated antibiotics may be ranged in the following order (by the diminishing efficacy): ansamycins (azorif, Rifapentine, rifampicin), tetracyclines (doxycycline), macrolides (azitromycin, sumamed), carbapenems (imipenem/cilastatin), fluoroquinolones (lomefloxacin, pefloxacin). Rifampicin and its derivatives--azorif, Rifapentine, along with doxycycline and azitromycm can be recommended for clinical trials at experimental rickettsiosis profilaxy and treatment in natural infection focus. |
| 2000 | Role of individual drugs in the chemotherapy of tuberculosis. | Int J Tuberc Lung Dis | During the course of chemotherapy, certain drugs are predominant in their bactericidal activities. Isoniazid is responsible for an initial kill of about 95% of organisms during the first 2 days of treatment. Its bactericidal role is then replaced by rifampicin and pyrazinamide during the intensive phase. In the continuation phase with an isoniazid/rifampicin regimen, rifampicin is the only effective drug against persisters, as shown by the similarity of response by patients with initially isoniazid-resistant or sensitive strains. If the continuation phase regimen does not contain rifampicin but does contain isoniazid, the dominant bactericidal drug is isoniazid. In this case, the response of patients with initial isoniazid resistance is appreciably less good than in those with sensitive organisms. The review suggests exploration in randomised control trials of a continuation phase of rifampicin (or Rifapentine) alone. It also suggests the importance of the dose size of rifampicin and the need for exploring a higher dose. Finally, it emphasises the importance of finding drugs that act on persisting organisms that are phenotypically but not genetically resistant to rifampicin. |
| 2000 | Prospects for development of new antimycobacterial drugs, with special reference to a new benzoxazinorifamycin, KRM-1648. | Arch Immunol Ther Exp (Warsz) | In this article, I have thoroughly reviewed the status of development of new antimycobacterial drugs, in particular, rifamycin derivatives (rifabutin, Rifapentine, and a new benzoxazinorifamycin, KRM-1648), fluoroquinolones (ciprofloxacin, ofloxacin, sparfloxacin, levofloxacin, gatifloxacin, sitafloxacin, moxifloxacin, and others), new macrolides (clarithromycin, azithromycin, roxithromycin), and others. In this review, I have mainly described the in vitro and in vivo activities of these drugs against Mycobacterium tuberculosis and atypical mycobacteria, especially Mycobacterium avium complex. In addition, therapeutic efficacy of these drugs in cases of clinical treatment of mycobacterial infections have also been briefly mentioned. |
| 2000 | Antituberculosis activity of once-weekly rifapentine-containing regimens in mice. Long-term effectiveness with 6- and 8-month treatment regimens. | Am J Respir Crit Care Med | The effectiveness of various once-weekly 10 mg/kg Rifapentine (P)- containing regimens for treatment of tuberculosis was assessed in mice infected intravenously with 4.3 x 10(6) colony-forming units (cfu) of Mycobacterium tuberculosis H37Rv, and treated 14 d later with various combinations of rifampin (R), P, isoniazid (H), pyrazinamide (Z), ethambutol (E), or streptomycin (S). Control mice treated daily with either 2-mo HRZ + 4-mo HR or 2-mo HRZ + 6-mo HE were rendered spleen and lung culture-negative at 6 mo and 8 mo, respectively. Treatment failure with emergence of R-resistant bacilli occurred in all mice given once-weekly monotherapy with P for 6 mo. Once-weekly PH treatment was successful at 6 mo when it was preceded by a 2-mo daily phase with HRZ. When the initial daily phase was reduced to 2 wk, once-weekly PH-containing treatment was successful, at 6 mo, only if it was supplemented with S during the initial daily and the once-weekly phases, and at 8 mo if it was supplemented with daily H during the once-weekly phase. Without these supplements, once-weekly treatment failed in some mice with selection of R-resistant or H-resistant mutants. |
| 2000 | Rifapentine and isoniazid in the continuation phase of a 6-month regimen. Interim report: no activity of isoniazid in the continuation phase. | Int J Tuberc Lung Dis | Clinical trial amongst 762 patients with newly diagnosed pulmonary tuberculosis in Hong Kong. After an initial 2 months of a four-drug intensive phase consisting of streptomycin, isoniazid, rifampicin and pyrazinamide (SHRZ), a random allocation in continuation to once-weekly Rifapentine + isoniazid (HRp1), HRp1 given in 2 of every 3 weeks (HRp1.2/3), or to three times weekly isoniazid + rifampicin (HR3).Interim report evaluating progress of study and the role of isoniazid in the continuation phase.Kaplan-Meier analysis and response of patients related to susceptibility of pretreatment organisms to isoniazid and to rate of isoniazid acetylation determined by NAT2 genotyping.In the 30-month follow-up, rates for adverse treatment events (failure and relapse) were 4.2% in the HR3, 10.2% in the HRp1 and 11.2% in the HRp1.2/3 series (P = 0.02 for HR3 vs HRp1 and P = 0.01 for HR3 vs HRp1.2/3). Occurrence of adverse events was not related to initial susceptibility to isoniazid nor to the rate of acetylation of isoniazid.The two Rifapentine regimens had similar final rates of adverse events which were unsatisfactory. Isoniazid had little or no activity in the continuation phase, indicating that no improvement of the continuation regimen is likely to be obtained by alteration of the isoniazid dosage. |
| 2000 | Single-dose intrapulmonary pharmacokinetics of rifapentine in normal subjects. | Antimicrob Agents Chemother | The intrapulmonary pharmacokinetics of Rifapentine were studied in 30 volunteers who received a single, oral dose of Rifapentine (600 mg). Subgroups of five subjects each underwent bronchoscopy and bronchoalveolar lavage (BAL) at timed intervals following drug administration. Drug concentrations, including the concentration of the primary metabolite 25-desacetyl Rifapentine, were determined in plasma, BAL fluid, and alveolar cells (AC) by high-pressure liquid chromatography. The concentrations in epithelial lining fluid (ELF) were calculated by the urea diffusion method. The concentration-time data were fit to two-compartment (plasma) or one-compartment (AC and ELF) models. The peak concentrations in plasma, ELF, and AC, 26.2, 3. 7, and 5.3 microg/ml, respectively, occurred at 5, 5, and 7 h after drug administration, respectively. The half-lives and areas under the curve for plasma, ELF, and AC were 18.3 h and 520 microg. h/ml, 20.8 h and 111 microg. h/ml, and 13.0 h and 133 microg. h/ml, respectively. Although the intrapulmonary Rifapentine concentrations were less than the plasma Rifapentine concentrations at all time periods, they remained above the proposed breakpoint for M. tuberculosis (0.5 microg/ml) for the 48-h observation period. These data provide a pharmacokinetic rationale for extended-interval dosing. The optimum dosing regimen for Rifapentine will have to be determined by controlled clinical trials. |
| 1999 | Rifapentine: its role in the treatment of tuberculosis. | Ann Pharmacother | To review the pharmacokinetics, efficacy, adverse effects, and cost of the newest antitubercular drug, Rifapentine.A MEDLINE search using key terms such as Rifapentine, rifampin, isoniazid, Mycobacterium tuberculosis, and pyrazinamide was conducted for the time period 1966-November 1998.Animal data were used for basic information and human studies were selected for inclusion if they were randomized, controlled studies assessing efficacy, or if they were single- or multiple-dose studies assessing the pharmacokinetics of Rifapentine. Background articles on the pathophysiology of tuberculosis and cost of care and noncontrolled studies assessing drug interactions were also included.Compared with an oral solution, the relative bioavailability of Rifapentine is 70% following oral admninistration of tablets. Food increased bioavailability by 55%. Rifapentine accumulated significantly in human macrophages and its elimination half-life was longer than that of rifampin. Comparative studies of Rifapentine and rifampin in humans during intensive- and continuation-phase treatment of tuberculosis suggest that at currently accepted doses, Rifapentine was slightly less effective than rifampin. The most significant drug interaction with Rifapentine involves indinavir: the maximum concentration and AUC of indinavir are reduced by 55% and 70%, respectively, when Rifapentine is coadministered with indinavir. Adverse events of Rifapentine may occur less frequently at the currently recommended 600-mg dose as compared with rifampin; however, the difference was not statistically significant. If only drug costs were evaluated during the six-month treatment of tuberculosis, Rifapentine is more expensive than rifampin.Rifapentine can be administered twice weekly during the intensive phase of tuberculosis treatment and then once weekly during the continuation phase of treatment. This may improve patient adherence over some other treatments and possibly reduce costs of treatment by preventing development of resistant tubercular strains due to nonadherence. Rifapentine is well tolerated, with most patients experiencing adverse effects at a similar rate as rifampin. Rifapentine induces cytochrome P450 somewhat less than rifampin, although few drug interaction studies have been done with Rifapentine. Its efficacy at the currently approved dosage of 600 mg may be slightly lower than that of rifampin. Studies are needed to determine if equal or greater efficacy can be achieved with higher doses of Rifapentine. Rifampin is less expensive than Rifapentine. Further pharmacoeconomic studies are needed to evaluate costs of relapse and failure in patients receiving these agents. |
| 1999 | Molecular characterization of rpoB mutations conferring cross-resistance to rifamycins on methicillin-resistant Staphylococcus aureus. | Antimicrob Agents Chemother | Mutations of the rpoB gene conferring resistance to rifampin were analyzed in 40 methicillin-resistant Staphylococcus aureus isolates obtained from six countries. Interestingly, the majority of clinical isolates showed multiple mutations within rpoB. The amino acid substitution 481His-->Asn was the most prevalent one, capable of conferring low-level resistance on its own. Cross-resistance to rifampin, rifabutin, and Rifapentine was demonstrated for all mutants identified. The level of resistance to rifamycins correlated with both the mutation position and type of amino acid substitution. |
| 1999 | Rifapentine pharmacokinetics in adolescents. | Pediatr Infect Dis J | Determination of Rifapentine pharmacokinetics in healthy adolescent children.Prospective Phase II clinical trial.Clinical research center within a university children's hospital.Twelve subjects ranging in age from 12 to 15 years, male and female.A single oral dose of Rifapentine was administered to healthy adolescent volunteers, 450 mg if <45 kg or 600 mg if > or =45 kg. Blood was collected at serial intervals (0, 2, 3, 4, 5, 6, 8, 12, 18, 24, 48 and 72 h postdose). Subjects were observed for adverse effects during the period of study.High pressure liquid chromatography was used to measure the plasma concentration of Rifapentine and 25-desacetyl Rifapentine in each blood sample. For each subject a plot of mean plasma concentration vs. time data for Rifapentine and its metabolite (i.e. 25-desacetyl Rifapentine) were created. Subsequently model-independent methods were used to determine the pharmacokinetic profiles for each subject.All subjects tolerated Rifapentine without adverse effects. The 2-h postdose plasma concentrations of Rifapentine (6.59 to 9.05 microg/ml) and 25-desacetyl Rifapentine (0.57 to 2.64 microg/ml) far exceeded the MIC of Mycobacterium tuberculosis to Rifapentine (approximately 0.12 microg/ml). The combination of a high Cmax (Rifapentine, 9.95 to 18.63 microg/ml; 25-desacetyl Rifapentine, 3.73 to 7.46 microg/ml) and lengthy terminal elimination phase t1/2 (Rifapentine, 10 to 23 h; 25-desacetyl Rifapentine, 14 to 35 h) resulted in potentially effective plasma concentrations of both compounds that persisted for at least 48 h in most subjects.A well-tolerated oral Rifapentine dose produced rapid and sustained plasma drug concentrations in adolescents that should effectively treat infections caused by M. tuberculosis. Rifapentine pharmacokinetics appears to be similar in adolescent and adult populations. |
| 1999 | Evaluation of rifapentine in long-term treatment regimens for tuberculosis in mice. | Antimicrob Agents Chemother | Besides direct bactericidal activity, long-term effectiveness is one of the most important features to consider when developing new drugs for chemotherapy. In this study, we evaluated the ability of Rifapentine (RFP), in monotherapy and combination therapy, to completely eradicate a Mycobacterium tuberculosis infection and to prevent relapse posttreatment in a Swiss mouse model. The combination of RFP, isoniazid (INH), and pyrazinamide (PZA) administered daily resulted in an apparent clearance of M. tuberculosis organisms in the lungs and spleens of infected mice after 10 weeks of treatment. However, 3 months after the cessation of therapy, bacterial regrowth occurred in mice treated for a 12-week period, indicating a relapse of infection. In intermittent treatment regimens of RFP in combination with INH and PZA, sterilization was achieved when mice were treated two to five times per week for 9 weeks. Bacterial growth was still observed in the once-weekly treatment group. Our results show that mouse models can predict important parameters for new drugs. We stress the necessity for long-term posttreatment observation in animal models for the routine evaluation of new drugs for antituberculosis chemotherapy. |
| 1999 | Analysis of rifapentine for preventive therapy in the Cornell mouse model of latent tuberculosis. | Antimicrob Agents Chemother | Rifapentine is a long-acting rifamycin which may be useful for intermittent drug therapy against tuberculosis. In this study we measured the efficacies of Rifapentine-containing intermittent drug regimens for preventive therapy using the Cornell mouse model of latent tuberculosis. We infected groups of mice intravenously with Mycobacterium tuberculosis and then treated them with isoniazid and pyrazinamide for 12 weeks according to the Cornell latency development protocol. After a 4-week interval of no treatment, experimental preventive therapy was administered by esophageal gavage for 12 or 18 weeks. After equilibration and dexamethasone amplification treatment, mouse organs were analyzed by quantitative colony counts to measure the effectiveness of therapy. Our results showed that once-weekly isoniazid plus Rifapentine combination therapy for 18 weeks was an effective preventive regimen with sterilizing potency and bacillary load reduction comparable to those of daily isoniazid therapy for 18 weeks. Monotherapy with Rifapentine weekly or fortnightly or with rifampin twice weekly for up to 18 weeks did not offer advantages in reducing bacillary load or in sterilizing organs compared to the effects of a placebo. These results with the Cornell mouse model indicate that once-weekly, short-course preventive therapy with isoniazid plus Rifapentine is effective and may warrant investigation in humans with latent tuberculosis infection. |
| 1999 | Acquired rifamycin monoresistance in patients with HIV-related tuberculosis treated with once-weekly rifapentine and isoniazid. Tuberculosis Trials Consortium. | Lancet | Rifapentine is a cyclopentyl-substituted rifamycin whose serum half-life is five times that of rifampin. The US Public Health Service Study 22 compared a once-weekly regimen of isoniazid and Rifapentine with twice weekly isoniazid and rifampin in the continuation phase (the last 4 months) of treatment for pulmonary tuberculosis in HIV-seropositive and HIV-seronegative patients. This report concerns only the HIV-seropositive part of the trial, which has ended. The HIV-seronegative part will stop follow-up in 2001.Adults with culture-positive, drug-susceptible pulmonary tuberculosis who completed 2 months of four-drug (isoniazid, rifampin, pyrazinamide, ethambutol) treatment (induction phase) were randomly assigned 900 mg isoniazid and 600 mg Rifapentine once weekly, or 900 mg isoniazid and 600 mg rifampin twice weekly. All therapy was directly observed. Statistical analysis used univariate, Kaplan-Meier, and logistic and proportional hazards regression methods.71 HIV-seropositive patients were enrolled: 61 completed therapy and were assessed for relapse. Five of 30 patients in the once-weekly isoniazid/Rifapentine group relapsed, compared with three of 31 patients in the twice-weekly isoniazid/rifampin group (log rank chi2=0.69, p=0.41). However, four of five relapses in the once-weekly isoniazid/Rifapentine group had monoresistance to rifamycin, compared with none of three in the rifampin group (p=0.05). Patients who relapsed with rifamycin monoresistance were younger (median age 29 vs 41 years), had lower baseline CD4 cell counts (median 16 vs 144 microL), and were more likely to have extrapulmonary involvement (75% vs 18%, p=0.03) and concomitant therapy with antifungal agents (75% vs 9%, p=0.006). No rifamycin monoresistant relapse has occurred among 1004 HIV-seronegative patients enrolled to date.Relapse with rifamycin monoresistant tuberculosis occurred among HIV-seropositive tuberculosis patients treated with a once-weekly isoniazid/Rifapentine continuation-phase regimen. Until more effective regimens have been identified and assessed in clinical trials, HIV-seropositive people with tuberculosis should not be treated with a once-weekly isoniazid/Rifapentine regimen. |
| 1999 | Single and multiple dose pharmacokinetics of rifapentine in man: part II. | Int J Tuberc Lung Dis | To characterize the pharmacokinetics of Rifapentine following single, multiple, and intermittent doses.Twenty-three healthy male volunteers were randomized in a two-period, incomplete block, crossover design to receive two of four possible treatments: single daily oral Rifapentine doses of 150, 300, or 600 mg given on day 1 and again on days 4-10, or a single oral 600 mg dose given on days 1, 4, 7, and 10.Maximum Rifapentine plasma concentrations were observed in 4-5 hours. Mean Rifapentine t(1/2) ranged from 13.2-14.1 hours and was similar across the 150-600 mg dose range. The changes in Rifapentine Cmax (R = 0.86) and AUC(0-->infinity) (R + 0.90) were dose linear. The active 25-desacetyl metabolite appeared slowly in plasma, with mean Tmax of 14.4-17.8 hours. Mean t(1/2) for 25-desacetyl-Rifapentine ranged from 13.3-24.3 hours. Disproportionate, dose-dependent increases in Rifapentine and 25-desacetyl-Rifapentine AUC were observed as single doses of Rifapentine increased from 150 to 600 mg. At steady state, however, the magnitude of dose dependency was much less.Maximum plasma Rifapentine concentrations were well above minimum inhibitory concentrations for Mycobacterium tuberculosis and M. avium following single 600 mg doses. In addition, the extended t(1/2) of Rifapentine and its active metabolite support clinical investigation of once or twice-weekly Rifapentine dosage regimens of Rifapentine for the management of tuberculosis. |
| 1999 | Enzyme induction observed in healthy volunteers after repeated administration of rifapentine and its lack of effect on steady-state rifapentine pharmacokinetics: part I. | Int J Tuberc Lung Dis | To determine the effects of Rifapentine on hepatic mixed function oxidase activity and to assess the effect of enzyme induction on the steady-state pharmacokinetics of Rifapentine.Twenty-three healthy males were randomized to receive two of the following treatments in a two-period, four-treatment, incomplete block, crossover design: single daily oral Rifapentine doses of 150 mg (group A), 300 mg (group B), or 600 mg (group C) on study days 1 and 4-10, or single oral Rifapentine 600 mg doses given every 3 days for a total of four doses (group D). Serial blood samples were collected after the first and last Rifapentine dose and assayed for Rifapentine and its active metabolite, 25-desacetyl-Rifapentine. Urine was collected for determination of cortisol and 6-hydroxycortisol concentrations.The ratio of 6beta-hydroxycortisol:cortisol increased during Rifapentine administration (+229%, +317%, and +357% on day 10 for groups A, B, and C, respectively). Ratios returned to baseline 2 weeks after the last dose. The per cent increase in the ratio of 6beta-hydroxycortisol:cortisol following daily doses (+357%) was much higher compared with every 72-hour dosing (+236%). Single-dose and steady-state comparisons of AUCss(0-24) and AUC(0-->infinity) for both Rifapentine and 25-desacetyl-Rifapentine were similar (P = NS) at corresponding doses of Rifapentine. Mean t(1/2) at steady-state was 84-98% of corresponding single-dose values.Rifapentine is a potent inducer of CYP3A activity. However, single-dose pharmacokinetics of Rifapentine predict steady-state exposure, indicating no autoinduction of Rifapentine metabolism with repeated administration. Enzyme activity returns to predose levels within 2 weeks of the last daily dose of Rifapentine. |
| 1999 | Pulmonary tuberculosis. | Curr Opin Pulm Med | Pulmonary tuberculosis is a major cause of morbidity and mortality worldwide, resulting in the greatest number of deaths due to any one single infectious agent. This trend is due, at least in part, to increasing numbers of individuals co-infected with HIV and Mycobacterium tuberculosis (MTB). Concerted efforts between the World Health Organization and other agencies, therefore, are underway to improve tuberculosis control worldwide. These include basic research in tuberculosis diagnostics and vaccine development, institution of preventive therapy in individuals dually infected with HIV and MTB, and directly observed short-course antituberculous therapy in developing countries with a high prevalence of MTB infection. Further, newer, longer-acting antituberculous therapeutic agents such as Rifapentine, which allow twice-weekly dosing in the continuation phase of anti-MTB therapy, have recently been released and are undergoing clinical trials. This review provides a synopsis of recent developments in these areas and serves as a reference source for interested readers. |
| 1999 | Pharmacokinetics of rifapentine in subjects seropositive for the human immunodeficiency virus: a phase I study. | Antimicrob Agents Chemother | Rifapentine is undergoing development for the treatment of pulmonary tuberculosis. This study was conducted to characterize the single-dose pharmacokinetics of Rifapentine and its 25-desacetyl metabolite and to assess the effect of food on the rate and extent of absorption in participants infected with human immunodeficiency virus (HIV). Twelve men and four women, mean age, 38.6 +/- 6.9 years, received a single 600-mg oral dose of Rifapentine in an open-label, randomized two-way, complete crossover study. Each volunteer received Rifapentine following a high-fat breakfast or during a fasting period. Serial blood samples were collected for 72 h and both Rifapentine and its metabolite were assayed by a validated high-performance liquid chromatography method. Pharmacokinetics of Rifapentine and 25-desacetylRifapentine were determined by noncompartmental methods. Mean (+/- the standard deviation) maximum concentrations of Rifapentine in serum and areas under the curve from time zero to infinity following a high-fat breakfast were 14.09 +/- 2.81 and 373.63 +/- 78.19 micrograms/ml, respectively, and following a fasting period they were 9.42 +/- 2.67 and 256.10 +/- 86.39 micrograms. h/ml, respectively. Pharmacokinetic data from a previously published healthy volunteer study were used for comparison. Administration of Rifapentine with a high-fat breakfast resulted in a 51% increase in Rifapentine bioavailability, an effect also observed in healthy volunteers. Although food increased the exposure of these patients to Rifapentine, the infrequent dosing schedule for the treatment of tuberculosis (e.g., once- or twice-weekly dosing) would be unlikely to lead to accumulation. Additionally, autoinduction has been previously studied and has not been demonstrated with this compound, unlike with rifabutin and rifampin. Rifapentine was well tolerated by HIV-infected study participants. The results of our study suggest that no dosage adjustments may be required for Rifapentine in HIV-infected patients (Centers for Disease Control and Prevention classification A1, A2, B1, or B2) undergoing treatment for tuberculosis. |
| Cloning of genes that have environmental and clinical importance from rhodococci and related bacteria. | Antonie Van Leeuwenhoek | Generalised and specialised transduction systems were developed for Rhodococcus by means of bacteriophage Q4. The latter was used in conjunction with DNA from an unstable genetic element of R. rhodochrous to construct resistance plasmids which replicate in strains of R. equi, R. erythropolis and R. rhodochrous. One of the plasmids, pDA21, was joined with Erythropolis coli suicide vector pEcoR251 to obtain shuttle plasmids maintained in both rhodococci and E. coli. Conjugation between these rhodococcal strains demonstrated all were interfertile with each other and that some of the determinants for this were located on the unstable genetic element. Plasmids derived from this element, such as pDA21, carried the conjugative and self-incompatibility capacities; deletion analysis revealed that DNA necessary for self-incompatibility overlapped with that for arsenic resistance. Rifampicin is one of the principal chemotherapeutic agents used to treat infections by rhodococci and related organisms. The genes responsible for two types of inactivation have been cloned. The sequence of the R. equi DNA responsible for decomposition of the antibiotic strongly resembled those of monooxygenases acting upon phenolic compounds, consistent with the presence of a naphthalenyl moiety in the rifampicin molecule. Antibiotic resistance conferred by the gene was surprisingly specific to the semisynthetic compounds rifampicin (150-fold increase) and Rifapentine (70-fold). Similar specificity was observed with the other inactivation gene cloned, which ribosylates rifampicin at the 23-hydroxyl position. A 60-bp sequence upstream of the monooxygenase and ribosylation genes is strikingly similar suggesting a shared pattern of regulation. Rhodococcal arsenic resistance and azo dye degradation genes have been cloned and characterised. |
| 1999 | [Current status and perspectives on the development of rifamycin derivative antibiotics]. | Kekkaku | Rifampicin (RFP) was developed as one of the anti-tuberculosis drugs in 1966 and has been used for almost 30 years. Establishment of combination therapy using RFP has been contributing to the treatment/eradication of tuberculosis. A number of rifamycin derivatives, as post RFPs, have been synthesized/developed over the the years. Chemical modification of rifamycins has largely been concentrated on the moiety of naphthalene ring because modification of the ansa chain moiety reduces the activity. In 1992, rifabutin was approved as a preventive drug for MAC infection in AIDS patients in the United States and in European countries. It is noteworthy that Rifapentine (RPT) was approved as an anti-tuberculosis drug in 1998 by FDA in the United States. A newly synthesized rifamycin derivative (KRM-1648, rifalazil) possesses a potent activity against both M. Tuberculosis and MAC, and it is now under clinical trial for the treatment of Tuberculosis in the United States. KRM-1648 is metabolized to 30-hydroxy KRM and 25-deacetyl KRM in the body, and its 30-hydroxylation is caused by liver cytochrome P450 3A. It is well known that RFP, RFB and RPT induce liver cytochrome P450 in animals and human, and these accelerate the metabolism of concomitant drugs such as HIV protease inhibitors resulting in lowering their blood levels. While KRM-1648 did not induce liver P450 in animals, but it is not examined yet in human. Clinical study of DOT with intermittent therapy of RPT in combination with INH resulted in the preferable therapeutic effect comparable to the RFP therapy. Since KRM-1648 has a potent activity, a high tissue distribution and a long half-life, it may be also suitable for intermittent therapy. For the future novel anti-tuberculosis drugs and therapy for tuberculosis, it is prerequisite to develop new drugs with a preferable antimicrobial activity, to shorten further the treatment period, and to be effective against multi-drug resistant bacilli. It is expected that more effective novel rifamycin derivatives can be developed with the above view points. |
| 1999 | Determination of rifampicin and its main metabolite in plasma and urine in presence of pyrazinamide and isoniazid by HPLC method. | J Pharm Biomed Anal | A reversed phase HPLC method is described for the simultaneous estimation of rifampicin and its major metabolite desacetyl rifampicin, in the presence of isoniazid and pyrazinamide, in human plasma and urine. The assay involves simple liquid extraction of drug, metabolite and internal standard (Rifapentine) from biological specimens and their subsequent separation on a C18 reversed phase column and single wavelength UV detection. In plasma as well as in urine samples, all the three compounds of interest eluted within 17 min. Using methanol-sodium phosphate buffer (pH 5.2; 0.01 M) (65:35, v/v) as mobile phase under isocratic conditions, it was established that isoniazid, pyrazinamide and ascorbic acid (added to prevent oxidative degradation of analytes) did not interfere with the analyte peaks. Recoveries (extraction efficiency) for drug were greater than 90% in both plasma and urine, whereas for metabolite the values were found to be 79 and 86% in plasma and urine, respectively. The plasma and urine methods were precise (total coefficient of variation ranged from 5 to 23%) and accurate (-7 to 5% of the nominal values) for both the analytes. Individual variance components, their estimates and their contribution to the total variance were also determined. Using the same method, unknown samples supplied by WHO were assayed and good correlations were obtained between the found and intended values. The method developed proved to be suitable for simultaneous estimation of rifampicin and desacetyl rifampicin in plasma and urine samples. |
| 1999 | Development of rifapentine susceptibility tests for Mycobacterium tuberculosis. | Antimicrob Agents Chemother | Two methods for testing the susceptibility of Mycobacterium tuberculosis to Rifapentine have been developed: the agar proportion method and the radiometric BACTEC technique. A critical concentration of 0.5 microg of Rifapentine per ml is proposed for both methods since it provides a reliable means of distinguishing between susceptible and resistant M. tuberculosis isolates. It is recommended that two quality control M. tuberculosis strains be used at the introduction of these tests in a clinical laboratory: one that is pansusceptible (H37Rv) and one that is resistant to Rifapentine. The resistant strain can be obtained from the American Type Culture Collection, where it is deposited under the number ATCC 700457. |
| 1998 | Rifapentine. | Drugs | Rifapentine is a rifamycin antibiotic with antimycobacterial activity. Rifapentine is generally more active against Mycobacterium tuberculosis than rifampicin (rifampin), although strains resistant to rifampicin are usually cross-resistant to Rifapentine. Sputum culture conversion rates were slightly higher after 6 months of Rifapentine- versus rifampicin-based therapy in patients with pulmonary tuberculosis in a Western study; however, relapse rates were higher in Rifapentine recipients during follow-up. The excess relapses in the Rifapentine group appeared to be related to poor compliance with nonrifamycin antituberculosis drugs during the intensive phase (first 2 months) of therapy. Rifapentine- and rifampicin-containing regimens produced similar sputum culture conversion rates with low rates of relapse in 2 randomised clinical trials in patients with smear-positive tuberculosis in China. In one trial, there was no difference in sputum culture conversion rates in patients treated with Rifapentine once weekly or rifampicin twice weekly in combination with isoniazid and ethambutol during the continuation phase of treatment. Hyperuricaemia, which was reported only during the intensive phase, elevated ALT and AST levels and neutropenia were the most common treatment-related adverse events reported in patients receiving Rifapentine- or rifampicin-containing regimens for tuberculosis in 1 Western study. |
| 1998 | Evaluation of once-weekly therapy for tuberculosis using isoniazid plus rifamycins in the mouse aerosol infection model. | Antimicrob Agents Chemother | Once-weekly therapy with combinations of isoniazid plus a rifamycin was tested in the mouse low-dose aerosol infection model against two strains of Mycobacterium tuberculosis. Combinations of isoniazid and rifalizil and isoniazid and Rifapentine were both highly effective. These animal model data thus support the evaluation of these regimens under clinical conditions. |
| 1998 | Single-dose pharmacokinetics of rifapentine in women. | J Pharmacokinet Biopharm | Gender can be an important variable in the absorption and disposition of some drugs. In this open-label study, 15 healthy, nonsmoking women received a single 600-mg oral dose of Rifapentine. Plasma samples were obtained at frequent intervals for up to 72 hr after the dose to determine the pharmacokinetic (PK) parameters of Rifapentine and its active metabolite, 25-desacetyl-Rifapentine. Peak plasma Rifapentine concentrations (Cmax) were observed 5.9 hr after ingestion of the single dose. The mean area under the Rifapentine plasma concentration-time curve [AUC(0-->infinity)] was 325 micrograms.hr ml and the mean elimination half-life (t1/2) was 16.3 hr. Plasma concentrations for the 25-desacetyl metabolite peaked at 15.4 hr after the Rifapentine dose and declined with a terminal half-life of 17.3 hr. These Rifapentine and 25-desacetyl-Rifapentine PK data in women were compared to data generated previously in healthy men. Striking similarities in the PK profiles of parent drug and metabolite were found in the two populations. Mean differences in Rifapentine CL/F (12%) and t1/2 (2%) were small. The only adverse event reported in the female subjects was discoloration of the urine. Based on these PK and safety data, no dosage adjustments for Rifapentine based on gender are recommended. |
| 1998 | Single-dose pharmacokinetics of rifapentine in elderly men. | Pharm Res | This study was undertaken to characterize the pharmacokinetic profiles of Rifapentine and its active metabolite, 25-desacetlyl Rifapentine, in elderly men.Fourteen healthy, nonsmoking male volunteers between the ages of 65 and 82 years received a single oral 600 mg dose of Rifapentine. Plasma samples were collected at frequent intervals for up to 72 hours postdose. The control group consisted of 20 healthy, young (18-45 years) males volunteers from a previous, single-dose (600 mg) Rifapentine pharmacokinetic study.Plasma Rifapentine concentrations above the minimum inhibitory concentration for M. tuberculosis were observed at 2 hours after dosing. Disposition of Rifapentine was monophasic with a mean terminal half-life of 19.6 hours. The peak plasma concentration of 25 desacetyl-Rifapentine was found 21.7 hours, on average, after the Rifapentine dose; the mean 25-desacetyl-Rifapentine t1/2 was 22.9 hours. Compared to the younger subjects, apparent oral clearance of Rifapentine (24%) was lower in the elderly male (p < 0.05), and Cmax (28%) was higher. The only adverse event reported in both the older and younger subjects in these single-dose studies was discoloration of the urine.Because the aged-related changes in the pharmacokinetic profile of Rifapentine observed in this study were modest and unlikely to be associated with toxicity, no dosage adjustments for this antibiotic are recommended in elderly patients. |
| 1998 | Disposition and metabolism of 14C-rifapentine in healthy volunteers. | Drug Metab Dispos | Rifapentine is a long-acting cyclopentyl-derivative of rifampin. This study was designed to investigate the mass balance and biotransformation of 14C-Rifapentine in humans. Four healthy male volunteers received a single 600-mg oral dose of 14C-Rifapentine in a hydroalcoholic solution. Whole blood, urine, and fecal samples were collected before and at frequent intervals after drug administration. Amount of radioactivity recovered in urine and feces was assessed for up to 18 days postdose. Metabolite characterization in urine and feces was conducted using high-performance liquid chromatography with radiometric detection and liquid chromatography/mass spectroscopy. The total recovery of radioactive dose was 86.8%, with the majority of the radioactive dose recovered in feces (70.2%). Urine was a minor pathway for excretion (16.6% of the dose recovered). More than 90% of the excreted radioactivity was profiled as 14C chromatographic peaks and 50% was structurally characterized. These characterized compounds found in feces and urine were Rifapentine, 25-desacetyl-Rifapentine, 3-formyl-Rifapentine, and 3-formyl-25-desacetyl-Rifapentine. The 25-desacetyl metabolite, formed by esterase enzymes found in blood, liver, and other tissues, was the most abundant compound in feces and urine, contributing 22% to the profiled radioactivity in feces and 54% in urine. The 3-formyl derivatives of Rifapentine and 25-desacetyl-Rifapentine, formed by nonenzymatic hydrolysis, were also prominent in feces and, to a lesser extent, in urine. In contrast to the feces and urine, Rifapentine and 25-desacetyl-Rifapentine accounted for essentially all of the plasma radioactivity (99% of the 14C area under the concentration-time curve), indicating that 25-desacetyl-Rifapentine is the primary metabolite in plasma. It appears, therefore, that the nonenzymatic hydrolysis of Rifapentine to 3-formyl byproducts occurs primarily in the gut and the acidic environment of the urine. |
| 1998 | Disposition and metabolism of rifapentine, a rifamycin antibiotic, in mice, rats, and monkeys. | Drug Metab Dispos | Rifapentine is a cyclopentyl derivative of rifampin under development for the treatment of Mycobacterium tuberculosis and Mycobacterium avium complex infections. These studies were designed to investigate the disposition and biotransformation of single iv and oral doses of 14C-Rifapentine in mice, bile duct-cannulated and uncannulated rats, and monkeys. Mass balance studies included 14C analyses of urine, feces, bile, cage wash, carcasses, and cage air collected for up to 120 hr postdose. Separation of radioactive compounds extracted from urine, bile, and feces was conducted using high-performance liquid chromatography and radioisotope detection. The mass spectra of selected chromatographic peaks were obtained. Disposition results were similar for all three species. Less than 5% of the radioactive dose of 14C-Rifapentine was recovered in urine, indicating that renal excretion is a minor route of elimination in these species. The major route of elimination of radioactivity was into the feces, where more than 75% of the radioactivity was recovered. Biliary excretion was the major route of elimination of radioactivity in bile duct-cannulated rats dosed either po or IV. Radiochromatograms were similar for fecal samples from animals dosed by IV or orally. Ten regions of radioactivity were observed in mouse and rat fecal sample radiochromatograms, and seven regions of radioactivity were observed in monkey fecal sample radiochromatograms. The most abundant compound identified in feces was usually intact Rifapentine (27%-41% of dose in mouse, 3%-35% of dose in rat, and 17%-29% of dose in monkey). Other peaks identified or characterized in feces based on liquid chromatography/ultraviolet/14C and/or liquid chromatography/mass spectrometry methods included 25-desacetyl-Rifapentine, 3-formyl-25-desacetyl-Rifapentine, and 3-formyl-Rifapentine. The compounds Rifapentine, 25-desacetyl-Rifapentine, and 3-formyl-Rifapentine were present in rat bile samples. These studies show that the metabolism and disposition of Rifapentine in mice, rats, and monkeys were similar. |
| 1998 | Contribution of rpoB mutations to development of rifamycin cross-resistance in Mycobacterium tuberculosis. | Antimicrob Agents Chemother | The contributions of 23 insertion, deletion, or missense mutations within an 81-bp fragment of rpoB, the gene encoding the beta-subunit of the DNA-dependent RNA polymerase of Mycobacterium tuberculosis, to the development of resistance to rifamycins (rifampin, rifabutin, Rifapentine, and KRM-1648) in 29 rifampin-resistant clinical isolates were defined. Specific mutant rpoB alleles led to the development of cross-resistance to all rifamycins tested, while a subset of mutations were associated with resistance to rifampin and Rifapentine but not to KRM-1648 or rifabutin. To further study the impact of specific rpoB mutant alleles on the development of rifamycin resistance, mutations were incorporated into the rpoB gene of M. tuberculosis H37Rv, contained on a mycobacterial shuttle plasmid, by in vitro mutagenesis. Recombinant M. tuberculosis clones containing plasmids with specific mutations in either codon 531 or 526 of rpoB exhibited high-level resistance to all rifamycins tested, whereas clones containing a plasmid with a mutation in codon 516 exhibited high-level resistance to rifampin and Rifapentine but were susceptible to both rifabutin and KRM-1648. These results provided additional proof of the association of specific rpoB mutations with the development of rifamycin resistance and corroborate previous reports of the usefulness of rpoB genotyping for predicting rifamycin-resistant phenotypes. |
| 1998 | Pharmacokinetics of rifapentine in patients with varying degrees of hepatic dysfunction. | J Clin Pharmacol | In this open-label investigation, the pharmacokinetics of Rifapentine and its active metabolite, 25-desacetyl-Rifapentine, were characterized in patients with varying degrees of hepatic dysfunction. Eight patients with mild-to-moderate chronic, stable hepatic dysfunction and seven patients with moderate-to-severe hepatic dysfunction received single oral 600-mg doses of Rifapentine. Maximum plasma concentration of Rifapentine was lower, time to maximum plasma concentration (tmax) was greater, and elimination half-life (t 1/2) was longer in the patients with moderate-to-severe hepatic dysfunction than in those with mild-to-moderate dysfunction. However, mean area under the concentration-time curve extrapolated to infinity (AUC0-infinity) for the two groups was similar. AUC0-infinity values in patients with hepatic dysfunction were 19% to 25% higher than values previously reported for healthy volunteers. The 25-desacetyl metabolite appeared in plasma slowly after the single oral dose of Rifapentine. Similar to findings for the parent drug, comparable plasma exposures of 25-desacetyl-Rifapentine based on AUC0-infinity were found in the two groups of patients with mild-to-moderate and moderate-to-severe hepatic dysfunction. Rifapentine was well tolerated in this patient population, irrespective of the etiology or severity of hepatic dysfunction. These safety and pharmacokinetic results suggest that no dosage adjustments for Rifapentine are needed in patients with hepatic impairment. |
| 1998 | Rifapentine and isoniazid in the continuation phase of treating pulmonary tuberculosis. Initial report. | Am J Respir Crit Care Med | A randomized comparison has been made of three times weekly rifampin plus isoniazid (HR3) with Rifapentine plus isoniazid given once weekly (HRp1) or on 2 of 3 wk (HRp1.2/3) in the continuation phase of 6-mo regimens (each starting with an initial 2 mo of 4-drug therapy) for the treatment of pulmonary tuberculosis in 672 Chinese patients in Hong Kong. Because of poor bioavailability of the Rifapentine used (produced in China), its dose size was increased from 600 mg initially to about 750 mg in the last third of patients to obtain serum concentrations similar to those with Rifapentine of Western origin; all doses were given after a meal promoting absorption. After initial exclusions, an intent to treat analysis, done on the remaining 592 patients, showed 45 adverse treatment events in 7 of 190 HR3 patients, in 17 of 199 HRp1 patients, and in 21 of 203 HRp1.2/3 patients; of these, 42 were bacteriological or radiographic relapses after the end of treatment (HR3 versus HRp1, p = 0.04; HR3 versus HRp1.2/3, p = 0.01). Patients with organisms initially sensitive or resistant to isoniazid or streptomycin had similar relapse rates. The high relapse rate in the HRp1 regimen suggests that the Rifapentine dose should be increased. Similarity of relapse rates, 8.9% and 10.4%, after the HRp1 and HRp1.2/3 regimens, respectively, indicates that irregularity in taking Rifapentine/isoniazid could be tolerated. The few adverse side effects in the continuation phase in the Rifapentine regimens were less frequent than in the HR3 regimen. |
| 1998 | Susceptibilities of Legionella spp. to newer antimicrobials in vitro. | Antimicrob Agents Chemother | The in vitro activities of 13 antimicrobial agents against 30 strains of Legionella spp. were determined. Rifapentine, rifampin, and clarithromycin were the most potent agents (MICs at which 90% of isolates are inhibited [MIC90s], < or = 0.008 microgram/ml). The ketolide HMR 3647 and the fluoroquinolones levofloxacin and BAY 12-8039 (MIC90s, 0.03 to 0.06 microgram/ml) were more active than erythromycin A or roxithromycin. The MIC90s of dalfopristin-quinupristin and linezolid were 0.5 and 8 micrograms/ml, respectively. Based on class characteristics and in vitro activities, several of these agents may have potential roles in the treatment of Legionella infections. |
| 1998 | Once-weekly rifapentine-containing regimens for treatment of tuberculosis in mice. | Am J Respir Crit Care Med | The bactericidal activities of several once-weekly Rifapentine (P)-containing combination regimens against Mycobacterium tuberculosis, and their ability to prevent the selection of rifampin (R)-resistant mutants, were compared with those of the standard six-times-weekly regimen consisting of R, isoniazid (H), and pyrazinamide (Z) in a mouse experiment. Mice were infected intravenously with 1.3 x 10(7) cfu of M. tuberculosis strain H37Rv, and 8 wk of treatment began on Day 14 after infection, when mice were randomly allocated to an untreated control group and nine treatment groups of 30 mice each. At the end of 8 wk of treatment, all the tested regimens showed promising bactericidal activities. Once-weekly P alone was less bactericidal than six-times-weekly R alone; likewise, the once-weekly P-containing combined regimens were less bactericidal than the six-times-weekly standard regimen. However, the difference in killing was about 1 log10, which represented only a fraction of the overall 4 log10 to 5 log10 magnitude of killing effects. The addition of streptomycin (S) improved the bactericidal effect of once-weekly PHZ, and the effect of once-weekly PHZS was further enhanced when it was preceded by 2 wk of daily HZS. The latter regimen achieved the same level of activity as the standard six-times-weekly regimen. All of the once-weekly P-containing combined regimens were able to prevent the selection of R-resistant mutants, whereas monotherapy with R or P selected resistant mutants in approximately 50% of animals. |
| 1998 | In vitro susceptibilities of aerobic and facultative non-spore-forming gram-positive bacilli to HMR 3647 (RU 66647) and 14 other antimicrobials. | Antimicrob Agents Chemother | The comparative in vitro activity of the ketolide HMR 3647 (RU 66647) and those of structurally related macrolide-lincosamide-streptogramin compounds (erythromycin, roxithromycin, azithromycin, clarithromycin, josamycin, lincomycin, pristinamycin, and quinupristin-dalfopristin) as well as those of benzylpenicillin, doxycycline, vancomycin, teicoplanin, levofloxacin, and Rifapentine against 247 aerobic and facultative non-spore-forming gram-positive bacilli were determined by an agar dilution method. The ketolide was active against most organisms tested except Corynebacterium striatum, coryneform CDC group 12, and Oerskovia spp. The frequency of resistance to erythromycin and other macrolides as well as that to lincomycin was high. Pristinamycin and, to a lesser extent, quinupristin-dalfopristin were very active, but resistance to these agents was present in some strains of Rhodococcus equi, Listeria spp., C. striatum, Erysipelothrix rhusiopathiae, and Oerskovia spp. HMR 3647 was very active against all erythromycin-sensitive and many erythromycin-nonsusceptible strains, especially Corynebacterium minutissimum, Corynebacterium pseudodiphtheriticum, Corynebacterium amycolatum, and Corynebacterium jeikeium. In vitro resistance to benzylpenicillin was common, but doxycycline, vancomycin, and teicoplanin were very active against most organisms tested except E. rhusiopathiae, against which glycopeptide antibiotics were not active. The in vitro activity of levofloxacin was remarkable, but resistance to this agent was common for C. amycolatum, Corynebacterium urealyticum, C. jeikeium, and Oerskovia spp. strains. Rifapentine was also very active in vitro against many organisms, but resistance to this agent was always present in E. rhusiopathiae and was very common in C. striatum and C. urealyticum. |
| 1998 | In vitro susceptibilities of Bordetella pertussis and Bordetella parapertussis to two ketolides (HMR 3004 and HMR 3647), four macrolides (azithromycin, clarithromycin, erythromycin A, and roxithromycin), and two ansamycins (rifampin and rifapentine). | Antimicrob Agents Chemother | When tested by agar dilution on Mueller-Hinton agar supplemented with 5% horse blood, the ketolides HMR 3004 and HMR 3647 were slightly more active (MIC at which 90% of the isolates were inhibited [MIC90], 0.03 microg/ml) against Bordetella pertussis than azithromycin, clarithromycin, erythromycin A, and roxithromycin. Azithromycin (MIC90, 0.06 microg/ml) was the most active compound against B. parapertussis. Rifampin and Rifapentine were considerably less active. |
| 1998 | [Nontuberculous mycobacteriosis; the present status and in the future. 3--(1). The view of development of new drugs against nontuberculous mycobacterial infections]. | Kekkaku | It is obvious that the number of patients with pulmonary nontuberculous mycobacterial infections is increasing gradually in Japan. Of these infections, M. avium complex (MAC) is the most common cause, and is known to be resistant to many antimicrobial drugs. At present, no standard regimen which is able to control MAC infections completely is established. For these reasons, the development of new drugs with strong antimycobacterial activity which are not cross-resistant to conventional antimycobacterial drugs is urgently desired. Thus, we studied in vitro activities of various drugs which are expected to be a new promising drug against nontuberculous mycobacterial infections, and reviewed clinical impact of these drugs. 1) New quinolones New quinolones including ofloxacin, ciprofloxacin, levofloxacin and sparfloxacin (SPFX), are considered to be active against M. tuberculosis, M. kansasii, M. fortuitum, but are inactive against MAC, M. chelonae, M. abscessus, M. scrofulaceum. Both AM-1155 and Du-6859a, newer quinolones, seemed to be comparable to or more active than SPFX which is considered to be most active now. 2) New macrolides Clarithromycin (CAM) has in vitro activities against various nontuberculous mycobacteria including MAC, and also has proven to have clinical potential not only for disseminated MAC infections in AIDS but also for pulmonary MAC infections. Therefore, CAM seems to be a candidate for one of the key drugs in the treatment of MAC infections. 3)Rifamycins Rifabutin (RBT) and Rifapentine exhibited more potent in vitro and in vivo antimycobacterial activities than rifampicin. RBT has already demonstrated clinical effect against intractable tuberculosis and MAC infections. Thus, RBT is recommended for the prophylaxis of M. tuberculosis and MAC infections in AIDS patients in US. KRM-1648 displayed much more potent in vitro and in vivo activities than rifampicin against both M. tuberculosis and MAC. It is needed an effort to confirm its therapeutic efficacies. Now clinical phase study is going on in US. 4) Phenazines Clofazimine (CFZ), an effective antileprosy drug, is known to be active in vitro against various mycobacteria including MAC, and often used as a component of combination chemotherapy for disseminated MAC infections in AIDS patients in US. Recently, CFZ new analogs have been developed, and it is necessary to evaluate its activities against nontuberculous mycobacteria. |
| 1997 | Bioavailability of Chinese rifapentine during a clinical trial in Hong Kong. | Int J Tuberc Lung Dis | A clinical trial of Rifapentine in Hong Kong.Assessment of the bioavailability of the Chinese Rifapentine used in the trial.The content of Rifapentine in serum samples taken from 287 patients during the administration of four batches of the drug was measured by microbiological assay.An initial comparison of areas under curve obtained in a random allocation to 40 patients of Rifapentine either of Western or Chinese origin indicated that the bioavailability of the Chinese drug was 74% of the Western drug. The bioavailability of the second batch was found to be about 66% of the Western drug. The dose of the last two batches of Rifapentine was therefore increased from the planned 600 mg to 750 mg, or briefly to 900 mg; serum concentrations were then similar to those obtained with the Western drug. Bioavailability did not change during the use of each drug batch.A comparison of the results obtained in the trial with the initial two batches and the final batches will estimate the effects of Rifapentine dose size on its efficacy and toxicity. |
| 1997 | Primary human hepatocytes as a tool for the evaluation of structure-activity relationship in cytochrome P450 induction potential of xenobiotics: evaluation of rifampin, rifapentine and rifabutin. | Chem Biol Interact | In our laboratory, primary human hepatocytes are being investigated as an in vitro experimental system for the evaluation of pharmacokinetic drug-drug interactions. Our study here represents the first reported study that directly compares the cytochrome P450 isozyme 3A (CYP3A) induction potential of three antimicrobials derived from rifamycin B, namely, rifampin, Rifapentine and rifabutin. Two endpoints of CYP3A activity, testosterone 6 beta-hydroxylation and midazolam 1-hydroxylation have been used. Results obtained with hepatocytes from four different human donors show consistently that rifampin and Rifapentine are potent inducers of CYP3A, while a significantly lower induction potential is observed for rifabutin. The relative induction potency of the three antimicrobials (rifampin > Rifapentine >> rifabutin) is consistent with the available human in vivo data. For CYP1A measured as ethoxyresorufin O-deethylase activity, CYP2C8/9 measured as tolbutamide 4-hydroxylation activity, CYP2D6 measured as dextromethorphan O-demethylation, and AZT glucuronidation, there is either no effect or, where induction is found to be statistically significant in these other endpoints, the maximum induction values are consistently < 100% of the control. Our results suggest that CYP3A is the major CYP induced by these rifamycin B derivatives. These studies illustrate the application of human hepatocytes in the evaluation of the structure-activity relationships in CYP induction for this class of chemicals and as an in vitro screen for drug-drug interaction potential via CYP induction. |
| 1997 | Comparison of biological and chemical assays for the quantitation of rifapentine in human plasma. | Diagn Microbiol Infect Dis | The purpose of this study was to establish the correlation between biological and chemical assays for the quantification of Rifapentine in human plasma. The bioassay was found to overestimate antibiotic plasma concentration when compared to the high-performance liquid chromatography (HPLC) assay for Rifapentine (r = 0.9538, n = 220). This was because of the presence of varying amounts of the biologically active 25-O-desacetyl metabolite in the test samples. A better correlation (r = 0.9804, n = 220) was observed when the bioassay data were compared to combined parent-metabolite HPLC values. Such correlative data are necessary adjuncts in the establishment of antibiotic susceptibility test breakpoints. |
| 1996 | Low-dose aerosol infection model for testing drugs for efficacy against Mycobacterium tuberculosis. | Antimicrob Agents Chemother | As a paradigm for chronic infectious diseases, tuberculosis exhibits a variety of clinical presentations, ranging from primary pulmonary tuberculosis to reactivation tuberculosis and cavitary disease. To date, the animal models used in evaluating chemotherapy of tuberculosis have been high-dose intravenous models that mimic the disseminated forms of the disease. In the present study, we have used a low-dose aerosol exposure model which we feel better reflects newly diagnosed tuberculosis in patients converting to tuberculin positivity. As appropriate examples of chemotherapy, four rifamycins (rifampin, rifabutin, Rifapentine, and KRM-1648) were tested, first in an in vitro murine macrophage model and then in the low-dose aerosol infection model, for their activity against Mycobacterium tuberculosis. In both models, KRM-1648 had the highest level of activity of the four compounds. In the infected-lung model, rifabutin, Rifapentine, and KRM-1648 all had sterilizing activity when given orally at 5 mg/kg of body weight per day. When given at 2.5 mg/kg/day, KRM-1648 had the highest level of activity of the four drugs, reducing the bacterial load by 2.7 logs over 35 days of therapy. |
| 1996 | Comparative antimycobacterial activities of rifampin, rifapentine, and KRM-1648 against a collection of rifampin-resistant Mycobacterium tuberculosis isolates with known rpoB mutations. | Antimicrob Agents Chemother | A collection of 24 rifampin-resistant clinical isolates of Mycobacterium tuberculosis with characterized RNA polymerase beta-subunit (rpoB) gene mutations was tested against the antimycobacterial agents rifampin, Rifapentine, and KRM-1648 to correlate levels of resistance with specific rpoB genotypes. The results indicate that KRM-1648 is more active in vitro than rifampin and Rifapentine, and its ability to overcome rifampin resistance in strains with four different genetic alterations may prove to be useful in understanding structure-function relationships. |
| 1996 | High-performance liquid chromatography assay of rifapentine in human serum. | J Chromatogr B Biomed Appl | A high-performance liquid chromatographic method for the determination of Rifapentine in human serum was developed. The method utilized a Spherisorb C18 column, ultraviolet detection (336 nm), rifampin as internal standard and a calibration curve (C = 7.010 As/Ain +/- 0.156, r = 0.999) with reproducibility studies which yield a coefficient of variation (C.V.) of intra-day and inter-day assays lower than 10%. The average recovery of Rifapentine from serum in the concentration range of 0.5 to 30 micrograms/ml was 92.93 +/- 9.704%. |
| 1996 | Rifapentine is active in vitro and in vivo against Toxoplasma gondii. | Antimicrob Agents Chemother | Rifapentine, a derivative of rifamycin, was examined for its in vitro and in vivo activities against the protozoan parasite Toxoplasma gondii. The drug inhibited the intracellular replication of parasites and was not cytotoxic for the host cells at inhibitory concentrations. Mice infected either intraperitoneally with tachyzoites of the RH strain or orally with tissue cysts of the C56 strain were protected against death by treatment with Rifapentine. The degree of protection was similar to that induced by atovaquone and apparently higher than that induced by rifabutin. Rifapentine may be a useful drug for the treatment of toxoplasmosis in immunocompromised individuals. |
| 1995 | New drugs for tuberculosis. | Eur Respir J Suppl | Since the late 1960s, tuberculosis has been successfully cured with antibiotics. With the introduction of rifampin, "short course" regimens using isoniazid and rifampin together with either streptomycin, ethambutol or pyrazinamide, for 6-9 months, have been successfully adopted. The spread of drug resistant M. tuberculosis strains in large urban areas has made this armamentarium of drugs insufficient, calling for the development of new drugs. Among rifamycin derivatives, rifabutin is more active than rifampin in vitro and in experimental animals, and allows sputum conversion rats of 95-100%. It is effective in treating multidrug-resistant tuberculosis. Rifapentine is more active than rifampin in vitro and has a longer half-life, but it is not active against rifampin-resistant strains. Fluoroquinolones concentrate within macrophages, are effective against M. tuberculosis and act synergistically with rifampin and isoniazid. Ofloxacin, ciprofloxacin, sparfloxacin and lomefloxacin have been evaluated as antimycobacterial agents, and no cross-resistance with major antituberculous drugs has been found. Several other drugs, including new inhibitors of beta-lactamase and new beta-lactamase-resistant antibiotics, the aminoglycoside antibiotic, paromomycin, and the new nitroimidazole, 2-ethyl-5-intro-2.3-dihydro imidazo-oxazole, have been found to be active in vitro against M. tuberculosis. |
| 1995 | Comparison of activities of rifapentine and rifampin against Mycobacterium tuberculosis residing in human macrophages. | Antimicrob Agents Chemother | The activities of Rifapentine and rifampin against Mycobacterium tuberculosis residing in human monocyte-derived macrophages were determined. The MICs and MBCs of Rifapentine for intracellular bacteria were two- to fourfold lower than those of rifampin. For extracellular bacteria, this difference was less noticeable. Nevertheless, the more favorable pharmacokinetics of Rifapentine over rifampin was addressed in other experimental models. These models showed substantial differences after short pulsed exposures of the infected macrophages to the drugs and when the infected macrophages were exposed to changing drug concentrations that imitated the pharmacokinetic curves observed in blood. Once-a-week exposures to Rifapentine concentrations equivalent to those attained in blood after one 600-mg dose resulted during the first week in a dramatic decline in the number of bacteria, and this decline was maintained at a minimal level for a period of four weeks. The results of this study have shown the suitability of Rifapentine for intermittent-treatment regimens. The prolonged effect of Rifapentine found in this study may be associated with high ratios of intracellular accumulation, which were four- to fivefold higher than those found for rifampin. Further studies on the intracellular distribution of rifamycins and on the sites of actual interaction between the drugs and bacteria residing in macrophages are necessary. |
| 1994 | Preventive therapy of tuberculosis with rifapentine in immunocompetent and nude mice. | Am J Respir Crit Care Med | The effectiveness of intermittent administration of Rifapentine (RPT), with or without isoniazid (INH), for preventive therapy of tuberculosis was evaluated in immunocompetent (normal) and nude mice. After infection with a small inoculum of Mycobacterium tuberculosis H37Rv, normal mice developed a chronic and nonfatal infection, and the bacterial population became relatively stable after an initial period of limited multiplication. On the other hand, nude mice developed an acute and fatal infection, and all untreated mice died within 5 wk, with very high colony-forming-unit (CFU) counts in their organs. Various degrees of bactericidal activity were shown in normal mice after daily treatment with rifampin (RMP) plus pyrazinamide (PZA) for 13 wk, INH daily for 26 wk, or RPT once weekly for 13 or 26 wk or once fortnightly for 26 wk. The activity of RPT was significantly enhanced when INH was added at the same dosing frequency. In nude mice the response of M. tuberculosis infection to certain regimens was less favorable than that in normal mice, suggesting that preventive therapy may be less effective in severely immunodeficient hosts even during treatment. After chemotherapy was stopped, virtually all nude mice relapsed within 12 wk regardless of the regimen administered, whereas no or very few relapses were observed in normal mice that had been treated with RMP+PZA daily for 13 wk, or RPT alone or RPT+INH once weekly for 26 wk. The latter three regimens and RPT+INH once weekly for 13 wk may be applied for fixed-duration preventive therapy in human immunodeficiency virus (HIV)-negative subjects.(ABSTRACT TRUNCATED AT 250 WORDS) |
| 1994 | Intermittent azithromycin for treatment of Mycobacterium avium infection in beige mice. | Antimicrob Agents Chemother | The activity of azithromycin (AZI) was evaluated in the beige mouse model of disseminated Mycobacterium avium infection. Mice were infected intravenously with approximately 10(7) viable avium ATCC 49601. AZI at 50, 100, or 200 mg/kg of body weight or clarithromycin (CLA) at 200 mg/kg was given by gavage 5 days per week for 4 weeks. Groups of treated mice were compared with untreated control animals. A dose-related reduction in cell counts in organs was observed with AZI treatment. AZI at 200 mg/kg was more active than CLA at 200 mg/kg against organisms in spleens. The activities of these two agents at 200 mg/kg were comparable against organisms in lungs. In a second study, AZI at 200 mg/kg was given daily for 5 days; this was followed by intermittent AZI treatment for the next 3 weeks. The activities of AZI given on a three-times- and five-times-per-week basis in the continuation phase were comparable. AZI given on a once-weekly basis was less active. The regimen of AZI given in combination with Rifapentine on a once-weekly basis for 8 weeks showed promising activity. Clinical evaluation of AZI and Rifapentine will help to define the roles of these agents in the treatment of disseminated M. avium complex infection. |
| 1994 | Antimycobacterial drugs. | Semin Respir Infect | This review consists of the following three sections: (1) General principles in selecting antimycobacterial drugs for the treatment regimens, (2) The antimicrobial activity in vitro with an emphasis on inhibitory and bactericidal potency of various agents, and (3) Drug susceptibility testing including methodology and interpretation of the test results. Each of these sections addresses three groups of antimycobacterial agents: (1) against tuberculosis, (2) against Mycobacterium avium complex infections, and (3) against infections caused by M. fortuitum and M chelonae. The following are the drugs examined in the sections and subsections of this review: isoniazid, ethionamide, thiacetazone, rifampin, rifabutin, Rifapentine, KRM-1648, pyrazinamide, streptomycin, kanamycin, amikacin, capreomycin, gentamicin, tobramycin, ethambutol, para-aminosalicylic acid, D-cycloserine, ofloxacin, levofloxacin, ciprofloxacin, sparfloin, clofazimine, clarithromycin, azithromycin, erythromycin, cefoxitin, cefmetazole, imipenem, sulfamethoxazole, sulfisoxazole, sulfadiazine, sulfathiazole, trimethoprim, and doxycycline. |
| 1994 | Comparative in vivo activities of rifabutin and rifapentine against Mycobacterium avium complex. | Antimicrob Agents Chemother | The dose-response activity of rifabutin and the comparative activities of rifabutin and Rifapentine were evaluated in the beige mouse model of disseminated Mycobacterium avium complex (MAC) infection. In the dose-response study, mice were infected intravenously with approximately 10(7) viable M. avium ATCC 49601. Treatment with rifabutin at 10, 20, or 40 mg/kg of body weight was started 7 days postinfection and was administered daily for 10 days. The mice were sacrificed 3 to 5 days after the last dose. Spleens, livers, and lungs were homogenized, and viable cell counts were determined by serial dilution and plating onto Middlebrook 7H10 agar. A dose-related reduction in MAC cell counts in the organs was noted for this MAC isolate. The comparative activities of rifabutin and Rifapentine were determined against a total of five MAC isolates in the beige mouse model. Rifabutin or Rifapentine (20 mg/kg each) was administered to infected mice for 10 days. Groups of treated mice were compared with untreated control animals. Despite favorable in vitro susceptibility results, rifabutin and Rifapentine had activities in the spleens against only two of the five MAC isolates. For these two MAC isolates, rifabutin was more active than Rifapentine. These agents had activities in the lungs against three of five isolates. Further study of rifabutin or Rifapentine against a broader range of clinical isolates in a murine infection model may be useful as part of the continuing development of newer rifamycins as anti-MAC agents. |
| 1994 | Comparison of Chinese and Western rifapentines and improvement of bioavailability by prior taking of various meals. | Int J Antimicrob Agents | Bioavailability was measured by Rifapentine (RPE) serum concentrations and by the urinary ratio between RPE and creatinine, in specimens obtained 4-50 h after 600 mg RPE preceded by food. The bioavailabilities of RPEs manufactured in China and by a Western manufacturer were similar after a standard English breakfast, and serum concentrations were also similar to those obtained in an earlier Italian study following a complex meal. Although absorption of RPE was unsatisfactory after lipid-rich biscuits or shortbread, absorption after egges and toast was excellent and was nearly as good after a fast-food sandwich. The urinary measure of bioavailability at 26 h appeared as efficient as peak serum estimations at 6, 8 and 26 h. Fast-food sandwiches are being taken before RPE in a current clinical trial of Chinese RPE in Hong Kong. |
| 1993 | Effectiveness of rifampin, rifabutin, and rifapentine for preventive therapy of tuberculosis in mice. | Am Rev Respir Dis | To identify alternative regimens for preventive therapy of tuberculosis, the pharmacokinetics and antimicrobial activities of rifampin (RMP), rifabutin (RBT), and Rifapentine (RPT) were compared in BCG-vaccinated and M. tuberculosis-infected immunocompetent mice. RPT showed the highest serum peak level (Cmax) and the longest half-life (t1/2), whereas RBT displayed the lowest Cmax and the shortest t1/2. On weight-to-weight basis, both RPT and RBT were more bactericidal than RMP. The activity of RMP was significantly reduced when the frequency of administration was reduced from six to three times weekly, whereas significant bactericidal activity was still observed in mice treated with RPT, 10 mg/kg up to once fortnightly, or RBT, 10 mg/kg twice weekly. Because the bactericidal activity of RBT, 10 mg/kg six times/wk for 6 wk, or RPT, 10 mg/kg two times/wk for 12 wk, was comparable to that of RMP, 10 mg/kg six times/wk for 12 wk in mice, the two regimens are appropriate for clinical trials of preventive therapy of tuberculosis. |
| 1993 | In vitro activities of new macrolides and rifapentine against Brucella spp. | Antimicrob Agents Chemother | We have tested the in vitro activities of streptomycin, rifampin, tetracyclines, trimethoprim-sulfamethoxazole, erythromycin, four new macrolides (roxithromycin, azithromycin, clarithromycin, and dirithromycin), and Rifapentine against 62 strains of Brucella spp. Azithromycin and clarithromycin were, respectively, eight- and twofold more active than erythromycins (MIC for 90% of strains = 2, 8, and 16 micrograms/ml, respectively). The activity of Rifapentine was similar to that of rifampin (MIC for 90% of strains = 1 microgram/ml). |
| 1993 | Azithromycin, rifabutin, and rifapentine for treatment and prophylaxis of Mycobacterium avium complex in rats treated with cyclosporine. | Antimicrob Agents Chemother | Azithromycin, rifabutin, and Rifapentine were used to treat or prevent disseminated Mycobacterium avium complex (MAC) infections produced in rats immunosuppressed with cyclosporine. Animals with bacteremic infections were treated 1 week after intravenous inoculation with 10(7) CFU of MAC with azithromycin, 100 mg/kg of body weight administered subcutaneously for 5 days and then 75 mg/kg on Monday, Wednesday, and Friday, or with rifabutin or Rifapentine, 20 mg/kg administered intraperitoneally on Monday through Friday. All three drugs showed efficacy after 1 and 2 months. Rifabutin cleared the organisms from tissues more rapidly than azithromycin or Rifapentine. To approximate prophylaxis, treatment was started 2 weeks before intravenous inoculation with 10(4) organisms. MAC infections were undetectable in treated animals after 4 months, while control animals had disseminated infections. These findings support the rationale for clinical trials of treatment and prophylaxis with these agents. The cyclosporine-treated rat appears to be a useful model in which to evaluate compounds for the treatment and prophylaxis of disseminated MAC infections. |
| 1993 | [A comparative study of rifapentine treatment and three years follow-up on initial pulmonary tuberculous]. | Zhonghua Jie He He Hu Xi Za Zhi | A clinical study about the efficacy of Rifapentine in the treatment and 3 years' follow up on initial pulmonary tuberculous patient. Altogether 267 patients of initial pulmonary tuberculosis with positive smears were randomly divided into 3 groups; Group I with DL473 twice-weekly (2HE+L2/7H2L2), Group IIARFp twice-weekly (2HE+R2/7H2R2) and Group IIBRFP daily (2HRE/7HR) for controls. Results are: the conversion rate to smear negative are 96.0%, 96.4% and 97.1% respectively (P > 0.05); the sputum conversion rate by cultures are 98.0%, 95.7% and 96.4% respectively (P > 0.05). From X-Ray pictures, the treatment effect of Group I are similar to that of Group IIB. But in Group I with less side action were observed. The relapse rate of the three groups are 2.6%, 3.8% and 3.1% respectively (P > 0.05). From this investigation, we can draw a conclusion that the twice-weekly of Rifapentine has at least an effect similar to rifampicin given daily. Further investigation of DL473 once weekly will soon be followed. |
| 1992 | Postantibiotic effect of amikacin and rifapentine against Mycobacterium avium complex. | J Infect Dis | Postantibiotic effect (PAE) has received little attention in the therapy of chronic intracellular infections, such as those caused by mycobacteria. Amikacin is active therapeutically against Mycobacterium avium complex, even though serum levels exceed the MIC for only a few hours. To determine the PAE of amikacin and Rifapentine for M. avium, bacteria were exposed to concentrations of 1x, 4x, and 10x the MIC of each drug for up to 120 min. Regrowth of M. avium was compared with similarly diluted untreated cultures. No PAE was observed on an inoculum of 10(4) bacteria when Rifapentine was used at 5x MIC, although a slight inhibition of growth was obtained at 10x MIC for 2 h. For amikacin, PAE was observed up to 48 h at concentrations of 4x and 8x MIC and exposure times of 30-120 min. A PAE of 22 h was seen with 10(7) cfu of M. avium during incubation for 30 min with amikacin at 4x MIC. These results show that amikacin, unlike Rifapentine, has a long PAE against M. avium. |
| 1992 | Epithelial cells in culture as a model for the intestinal transport of antimicrobial agents. | Antimicrob Agents Chemother | The bioavailabilities of orally administered drugs depend to a great extent on their capability of being transported across the intestinal mucosa. In an attempt to develop an in vitro model for studying the intestinal transport of drugs, we used an intestinal epithelial cell line (Caco 2) derived from a human colon adenocarcinoma. A renal epithelial cell line (MDCK) was also used to determine the tissue specificity of drug transport. These cell lines, which were grown on filters, form a monolayer of well-polarized cells coupled by tight junctions and can be used for transcellular transport experiments. We studied the transport of nine antimicrobial agents with different physicochemical and pharmacokinetic characteristics using these epithelial cell monolayers to determine whether this model could be predictive of oral bioavailability. The transepithelial passage was assayed from the apical (AP) to the basolateral (BL) side and in the opposite direction (BL to AP) in both cell lines. Radioactively labeled mannitol was used to monitor the intactness of the cell monolayer during drug passage. The results indicated that all antimicrobial agents tested tended to behave in vitro generally according to their known in vivo absorptive characteristics. In addition, the use of epithelia from different tissues enabled us to divide the drugs into four groups according to their behaviors and suggested the existence of different transport mechanisms. In particular, two antibiotics, gentamicin and teicoplanin, showed no passage in either direction or cell line, in accordance with their very poor in vivo absorbances after oral administration. In contrast, Rifapentine, rifampin, and nalidixic acid passed very efficiently at similar rates in both directions and cell lines in a concentration-dependent, nonsaturable manner, which is suggestive of passive diffusion down a concentration gradient. Of the remaining drugs, isoniazid and novobiocin sodium showed some differences in passage between the two cell lines and, given their ionized state at the pH that was used, may use the paracellular route. Finally, trimethoprim and D-cycloserine exhibited differences in passage both with respect to polarity and cell line; in particular, trimethoprim had a faster rate of passage only in Caco 2 cells and in the BL to AP direction, while D-cycloserine was exclusively transported by Caco 2 cells in the AP to BL direction. In both cases it is possible that active transport mechanisms are involved. |
| 1992 | TLC G-65 in combination with other agents in the therapy of Mycobacterium avium infection in beige mice. | J Antimicrob Chemother | The activity of TLC G-65 (a liposomal gentamicin preparation), alone and in combination with Rifapentine, clarithromycin, clofazimine and ethambutol, was evaluated in the beige mouse (C57BL/6J--bgj/bgj) model of disseminated Mycobacterium avium infection. TLC G-65 was found to be more active than amikacin. The combination of Rifapentine and TLC G-65 was more active than either agent alone. The activity of clarithromycin in combination with TLC G-65 was similar to that of either agent alone. Clofazimine improved the activity of TLC G-65 with respect to the spleen, while ethambutol improved the activity with respect to the liver. Clofazimine and ethambutol enhanced the activity of TLC G-65 against bacteria in the lungs. TLC G-65 in combination with Rifapentine appears to be an attractive regimen for the treatment of infections caused by bacteria in the M. avium complex. |
| 1992 | Activity of rifapentine against Mycobacterium avium infection in beige mice. | J Antimicrob Chemother | The activity of Rifapentine (MDL 473) was evaluated in the beige (C57BL/6J-bgj/bgj) mouse model of disseminated Mycobacterium avium infection. Approximately 10(7) cfu of M. avium, serotype 1, were given iv. Seven days later treatment was started with intraperitoneal Rifapentine at 20 mg/kg of body weight. Treatment was given daily for five days followed by twice weekly for three weeks. The mice were killed two days after the last dose. Spleens, livers and lungs were homogenized and cfu/organ determined. Analysis of variance and Tukey honestly significant difference tests indicated that Rifapentine reduced cfu in each of the organs compared with untreated controls. A dose-response experiment was performed with a daily Rifapentine dose of 10, 20 or 40 mg/kg administered intraperitoneally. Dose-related reductions in cfu counts were observed in each of the organs. The activity of oral Rifapentine at 20 mg/kg was demonstrated in a comparative experiment with rifampicin at 20, 40 or 60 mg/kg. Rifapentine significantly reduced cfu counts in organs compared with rifampicin. Rifapentine should be considered for further evaluation in the treatment of M. avium complex infection in humans. |
| 1992 | Activity of two long-acting rifamycins, rifapentine and FCE 22807, in experimental murine tuberculosis. | Tuber Lung Dis | The efficacy of the long-acting rifamycins, Rifapentine (RPE) and FCE 22807 (FCE) in experimental murine tuberculosis was studied by counting viable bacilli in spleens. At 2 weeks after infection with Mycobacterium tuberculosis, strain H37Rv, treatment with isoniazid 25 mg/kg, rifampicin 10 mg/kg and pyrazinamide 150 mg/kg was given daily for 6 weeks. The mice were then divided into groups given RPE or FCE at intervals of 1, 2 or 3 weeks with spleen counts after 18 and 24 weeks of chemotherapy. The first experiment showed the great effect of the size of the dose of RPE, which, in once-weekly regimens, caused rapid sterilization at 16 mg/kg, less rapid sterilization at 10 mg/kg and incomplete activity at 6.25 mg/kg. Regimens of RPE given every 2 or 3 weeks were less effective, though 16 mg/kg fortnightly was as good as 6 mg/kg once-weekly. The second experiment compared RPE and FCE each given at 12 or 8 mg/kg. The results were similar though, at 8 mg/kg every 2 or 3 weeks, FCE was slightly more effective than RPE. Serum assays showed that the levels with 8 and 12 mg/kg FCE were lower than those produced even by 6.25 mg/kg RPE, suggesting that FCE would be a better drug than RPE if its bioavailability could be improved, and that the levels following 16 mg/kg RPE were similar to those found in man after 8 mg/kg RPE taken with a fat-rich meal, suggesting good prospects for effective once-fortnightly human treatment. The potential for long-acting rifamycins in the management of pulmonary tuberculosis is discussed. |
| 1992 | Activity of antimicrobial agents against Mycobacterium avium-intracellulare complex (MAC) strains isolated in Italy from AIDS-patients. | Zentralbl Bakteriol | Twenty-five strains of Mycobacterium avium-intracellulare (MAC) isolated from acquired immunodeficiency syndrome (AIDS) patients in three medical centres in Italy have been studied. Serotyping performed on eighteen strains showed various serovars within either M. avium or M. intracellulare serotypes and with serovars 1 and 21 being the most prevalent (four strains for each serovar). Among fourteen drugs used for testing the antibiotic sensitivity, Rifapentine, rifabutin and clofazimine showed to have the best in vitro activity. In an ex vivo model of infection using peritoneal resting macrophages from the C57BL/6 mouse, the intracellular viability of a strain of M. avium (strain 489, serovar 3) was reduced by clofazimine, amikacin, ciprofloxacin, rifabutin and clarithromycin (99, 98, 93, 89 and 69%, respectively), thus indicating for clofazimine a good correlation between in vitro and ex vivo activity. |
| 1992 | High-performance liquid chromatographic determination of rifapentine in serum using column switching. | J Chromatogr | A high-performance liquid chromatographic method with column switching has been developed for the determination of Rifapentine in serum. The serum samples were injected onto a precolumn packed with Corasil RP C18 (37-50 microns) after simple dilution with an internal standard in a 1% ascorbic acid solution. Polar serum components were washed out using 0.05 M phosphate buffer. After valve switching, the concentrated drugs were eluted in the back-flush mode and separated by a mu Bondapak C18 column with acetonitrile-tetrahydrofuran-0.05 M phosphate buffer (pH 7.0) (42:5:53, v/v/v) as the mobile phase. The method showed excellent precision with good sensitivity and speed, and a detection limit of 0.1 microgram/ml. The total analysis time was less than 25 min and the mean coefficients of variation for intra- and inter-assay were less than 4.8%. The method has been successfully applied to serum samples from dogs after the oral administration of Rifapentine. |
| 1992 | Activity in vitro of rifabutin, FCE 22807, rifapentine, and rifampin against Mycobacterium microti and M. tuberculosis and their penetration into mouse peritoneal macrophages. | Am Rev Respir Dis | The activities of the rifamycins, rifabutin, FCE 22807, Rifapentine, and rifampin, were studied within unstimulated peritoneal macrophages infected with Mycobacterium microti and in cultures of M. microti and M. tuberculosis in 7H-9 medium without Tween 80. In macrophage cultures, serial rifamycin concentrations were added after a 2.5 h phagocytosis period, and viable counts were done after incubation for 5 to 6 days. To ensure comparability with the daily drug replacements in the macrophage experiments, the period of exposure to serial rifamycin concentrations in 7H-9 medium was kept to only 3 days. The MICs of M. microti and M. tuberculosis were similar. The MICs of rifabutin and FCE 22807 were 2.5 times lower and that of Rifapentine 1.7 times lower than the MIC of rifampin. None of the rifamycins were concentrated in macrophages, the MICs being higher in the macrophages than in vitro by a factor of 2-fold for rifabutin, 6.7-fold for rifampin, 20-fold for FCE 22807, and 26-fold for Rifapentine. |
| 1991 | In vivo activities of newer rifamycin analogs against Mycobacterium avium infection. | Antimicrob Agents Chemother | The comparative activities of newer rifamycin analogs and the activity of rifabutin or Rifapentine in combination with other antimycobacterial agents was evaluated in the beige (C57BL/6J; bgj/bgj) mouse model of disseminated Mycobacterium avium infection. Rifabutin and Rifapentine at 20 mg/kg of body weight had comparable activities. P/DEA and CGP 7040 at 20 mg/kg were less active. The combination of ethambutol at 125 mg/kg and rifabutin at 20 mg/kg resulted in a slight increase in activity beyond that seen with rifabutin alone against organisms in the spleens. The combination of ethambutol and Rifapentine at 20 mg/kg resulted in a modest increase in activity beyond that seen with Rifapentine alone against organisms in the lungs. The combination of ethionamide at 125 mg/kg and Rifapentine resulted in a decrease in activity compared with that for Rifapentine alone. The combination of clofazimine at 20 mg/kg and Rifapentine resulted in increased activity in the mouse model. The combination of clofazimine and Rifapentine (or rifabutin) appears to be an attractive regimen that should be evaluated for the treatment of human infections due to M. avium complex. |
| 1991 | High-performance liquid chromatographic determination of rifapentine and its metabolite in human plasma by direct injection into a shielded hydrophobic phase column. | J Chromatogr | A simple high-performance liquid chromatographic method for determination of Rifapentine, a cyclopentyl semisynthetic analogue of rifamycin belonging to the class of piperazinyl hydrazone derivatives of 3-formylrifamycin SV, and its metabolite, 25-desacetylRifapentine, in human plasma was developed using direct injection of the sample onto a Supelco LC HISEP column. The mean recovery was 100.3% for Rifapentine and 99.7% for the metabolite and the precision of the assays was 3% and 7%, respectively. The limit of determination was 0.2 micrograms/ml and the method was validated for concentrations up to 64 micrograms/ml for Rifapentine and 32 micrograms/ml for the metabolite. The results correlated well with those of the microbiological assay with Sarcina lutea as test organism. |
| 1991 | Activities of sparfloxacin, azithromycin, temafloxacin, and rifapentine compared with that of clarithromycin against multiplication of Mycobacterium avium complex within human macrophages. | Antimicrob Agents Chemother | The activities of sparfloxacin, azithromycin, temafloxacin, and Rifapentine against two virulent strains of the Mycobacterium avium complex isolated from patients with AIDS were evaluated in a model of intracellular infection and were compared with that of clarithromycin. Human monocyte-derived macrophages were infected with the M. avium complex at day 6 of culture. The intracellular CFU was counted 60 min after inoculation. The intracellular and supernatant CFU was counted on days 4 and 7 after inoculation. The concentrations used, which were equal to peak levels in serum, were 10 micrograms of Rifapentine per ml (MICs for the two strains, 4 and 16 micrograms/ml), 4 micrograms of clarithromycin per ml (MICs, 8 and 4 micrograms/ml), 1 microgram of azithromycin per ml (MICs, 32 and 16 micrograms/ml), 4 micrograms of temafloxacin per ml (MICs, 2 and 16 micrograms/ml), and 1 microgram of sparfloxacin per ml (MICs, 0.5 and 2 micrograms/ml). Compared with controls on day 7 after inoculation, clarithromycin (P less than 0.001), sparfloxacin (P less than 0.001), and azithromycin (P less than 0.001 for the first strain, P less than 0.02 for the second) slowed intracellular replication. Rifapentine (P less than 0.001) and temafloxacin (P less than 0.001) slowed intracellular replication of the first strain but not of the second strain. Azithromycin plus sparfloxacin was as effective as sparfloxacin alone. In this macrophage model, sparfloxacin or clarithromycin (difference not significant) exhibited a better efficacy than Rifapentine, azithromycin, or temafloxacin against intracellular M. avium complex infection. |
| 1991 | Effect of various antibiotics on Listeria monocytogenes multiplying in L 929 cells. | Infection | Various antibiotics were evaluated as to their effect on Listeria monocytogenes SLCC 4013 multiplying within L 929 mouse fibroblast cells. Antibiotics were employed in concentrations above the MIC value. However, there was no measurable effect of some drugs on intracellular listeriae (azlocillin, mezlocillin, cephalothin, ciprofloxacin, chloramphenicol). With other drugs an inhibition of intracellular growth was observed (penicillin, ampicillin, rifampicin, Rifapentine, erythromycin, doxycycline, co-trimoxazole, coumermycin). Notably, with none of the antibiotics a complete eradication of the listeriae was achieved. There is a good correlation of these results with animal experiments. Therefore, the cell culture system might be useful for the screening of new antibiotics. |
| 1990 | Inductive effects of rifapentine on mice hepatic mixed function oxidase system. | Methods Find Exp Clin Pharmacol | Rifapentine (R773, DL473) is a long-acting antituberculous drug used in China. In our experiments we have found some manifestations of induction of hepatic mixed function oxidase system in mice following pretreatment with Rifapentine or phenobarbital. Both Rifapentine and phenobarbital significantly increased the rate of antipyrine and pentobarbital metabolism in vivo. They also increased liver weight, the content of liver microsomal protein and cytochrome P-450, the activity of NADPH-cytochrome C reductase and NADPH oxidase. SDS-polyacylamide gel electrophoresis showed that the relative proportions of some polypeptide bands in mice microsomal fraction were significantly changed following Rifapentine or phenobarbital pretreatment. The results indicate that Rifapentine, like phenobarbital, is a potent inducer of hepatic mixed function oxidase system in mice and that it should be used carefully in clinical therapy, when combined with other drugs. |
| 1990 | Bactericidal activity in vitro of various rifamycins against Mycobacterium avium and Mycobacterium tuberculosis. | Am Rev Respir Dis | Minimal inhibitory and bactericidal concentrations (MICs and MBCs) of rifampin (RMP), rifabutin (RBT), Rifapentine (RPT), CGP-7040, and P-DEA, were determined for 50 M. avium strains in 7H12 liquid medium radiometrically under various pH conditions. Half were isolated from patients with AIDS and the other half from patients without AIDS but with pulmonary disease. The MICs and MBCs were also determined in 7H12 broth for M. tuberculosis strains. The MIC results obtained with M. tuberculosis strains, and the serum peak levels in humans, were used as standards for interpretation of the MICs and MBCs of the rifamycins for M. avium. The bactericidal activity of all rifamycins for M. avium was substantially lower than for M. tuberculosis. The majority of M. avium strains was within the "susceptible" category, e.g., comparable to susceptible M. tuberculosis strains, when tested with CGP-7040 and RPT, and all of them were "moderately susceptible" when tested with P-DEA. On the basis of in vitro bacteriostatic and bactericidal activity, it seems that three agents, RPT, P-DEA, and CGP-7040 have more potential than do RMP and RBT against M. avium disease. |
| 1989 | [In vitro activity of clofazimine alone and in combination with amikacin, roxithromycin, rifampicin and rifapentine against Mycobacterium avium-intracellulare]. | Enferm Infecc Microbiol Clin | The activity of clofazimine, amikacin, roxithromycin, rifampicin and Rifapentine was tested, alone and in association, against Mycobacterium avium intracellulare. Clofazimine, amikacin and Rifapentine were shown to be very active. With all established associations, the MIC observed for each drug alone was appreciably reduced. |
| 1989 | The activity of rifampin and analogs against Staphylococcus epidermidis biofilms in a CAPD environment model. | Am J Nephrol | Rifampin has been noted to exhibit exceptional antimicrobial activity against Staphylococcus epidermidis biofilms as compared to commonly used antibiotics. To further explore this unique effect of rifampin, we evaluated the antimicrobial activity of three commercially available preparations of rifampin, two rifampin analogs (CGP29861 and Rifapentine) and the parent compound rifamycin SV. These were tested against standardized S. epidermidis biofilms in various milieus. All six members of the rifamycin group tested demonstrated marked antimicrobial activity but with minor foci of resisters when tested in a peptone water environment. The microscopy of the exposed biofilms showed profound lysis and morphological distortion of the remaining cells. The synergistic elimination of the foci of resistance was achieved in an environment of fresh peritoneal dialysis (PD) solution or by the addition of vancomycin. Neither vancomycin nor fresh PD solution demonstrated significant antimicrobial activity when tested alone with biofilm preparations. Spent PD fluid markedly antagonized the activity of the rifamycins with the exception of the rifampin analogs, an effect primarily of pH. The synergistic effect of vancomycin with the rifamycins was not affected either by protein content or pH, leaving the antagonistic properties of spent PD fluid unexplained. The variable activity of the different members of the rifamycin group underlines the importance of structural differences in determining their interaction with bacterial biofilms. Further precision of the nature of these structural interactions is seen to have considerable potential for therapeutic advancement of catheter-associated sepsis. |
| 1987 | In vitro and ex vivo influence of rifamycins on human phagocytes. | Chemioterapia | We studied the effects of rifamycin SV, rifampicin and Rifapentine on human phagocyte functions. Rifamycins inhibited in vitro neutrophil chemotaxis in the range of their therapeutic levels, and they significantly affected the survival of a rifamycin-sensitive strain of Staphylococcus aureus inside human monocytes. Both effects were related to the intraphagocytic penetration of these antibiotics. For the ex vivo studies, 600 mg of rifampicin were orally administered to five subjects with defective S. aureus killing. A significant reduction of neutrophil chemotaxis and increased activity against S. aureus were shown 150 and 210 min after administration of the drug. |
| 1987 | In vitro observations on the suitability of new rifamycins for the intermittent chemotherapy of tuberculosis. | Tubercle | The bactericidal activity of six new rifamycin derivatives--rifabutin (RBU), FCE 22250 (F22), Rifapentine (RPE), CGP 29861 (C29), CGP 7040 (C70) and CGP 27557 (C27) and rifampicin (RMP)--have been measured against log phase and, as a better test of sterilising activity, against stationary phase cultures of Mycobacterium tuberculosis, H37Rv. The order of activity of 1.0 and 0.2 mg/l rifamycin against log phase cultures was RMP greater than RPE & C27 greater than RBU & C29 greater than C70. The order of activity of 1.0 and 0.4 mg/l, adjusted for stability of the rifamycin, against stationary phase cultures was F22 & RMP greater than RBU greater than RPE greater than C27 & C29 greater than C70. Viable counts were done during and after pulsed exposures of 6, 24 or 96 h to C29 and RMP. The curves were similar though C29 was less bactericidal and the lag period before recovery was 1-2 days longer. F22, having high bactericidal activity against stationary organisms and a long half-life, was considered likely to be the most effective sterilising drug. |
| 1987 | In vitro activity of new rifamycins against rifampicin-resistant M. tuberculosis and MAIS-complex mycobacteria. | Tubercle | Comparisons were made of the in vitro activity of rifampicin, and the rifamycin derivatives, Rifapentine, rifabutin, CGP 29861, CGP 7040 and CGP 27557, against rifampicin-sensitive and rifampicin-resistant strains of Mycobacterium tuberculosis and against the Mycobacterium avium/intracellulare/scrofulaceum (MAIS) complex. The new rifamycins had MICs four to eight times lower than those of rifampicin against sensitive M. tuberculosis strains. Of the 35 rifampicin-resistant strains of M. tuberculosis, 31% were sensitive to rifabutin but only 3-11% to the other rifamycins. The proportions of the MAIS strains found to be sensitive were 35% for rifampicin, 50-60% for CGP 27557, Rifapentine and rifabutin and 85-92% for CGP 29861 and CGP 7040. |
| 1987 | In vitro properties of rifapentine (MDL473) relevant to its use in intermittent chemotherapy of tuberculosis. | Tubercle | In a comparison of in vitro properties of Rifapentine (RIF) and rifampicin (RMP), the minimal inhibitory concentration of RIF against Mycobacterium tuberculosis in Tween-albumin liquid medium was usually 0.02 micrograms/ml, 2-3 times lower than for RMP; the bactericidal activity against a log phase culture was slightly less than that of RMP and the recovery after pulsed exposures to 1 microgram/ml of RIF or RMP lasting 6, 24 and 96 h was identical for the two rifamycins. These findings are used to interpret published data from the chronic experimental murine tuberculosis model and support the view that in the mouse, the efficacy of RIF in widely spaced intermittent chemotherapy is the result of its long half-life. |
| 1987 | Uptake and activity of rifapentine in human peritoneal macrophages and polymorphonuclear leukocytes. | Eur J Clin Microbiol | Rifapentine uptake by human peritoneal macrophages and polymorphonuclear leukocytes was evaluated and its activity against intracellular Staphylococcus aureus and Staphylococcus epidermidis in both types of phagocytes was compared to that of rifampin, teicoplanin and clindamycin. Uptake of radiolabeled Rifapentine by peritoneal macrophages (intracellular/extracellular ratio 61.4 +/- 5.8) and polymorphonuclear leukocytes (intracellular/extracellular ratio 87.6 +/- 3.9) was significantly higher than that of teicoplanin (intracellular/extracellular ratio 40.8 +/- 3.6 and 52.3 +/- 3.2 respectively) and clindamycin (intracellular/extracellular ratio 6.9 +/- 0.4 and 8.3 +/- 0.5 respectively). Rifapentine and rifampin showed the highest activity against intracellular staphylococci in both peritoneal macrophages and polymorphonuclear leukocytes. Clindamycin also showed efficient intracellular activity. In contrast, teicoplanin, which achieved high cellular levels with both types of phagocytes, failed to produce a significant reduction in viable intraphagocytic Staphylococcus epidermidis. On the basis of these findings it is suggested that Rifapentine may play a future role in the treatment of certain types of staphylococcal infection. |
| 1987 | Comparative in vitro activity of CI934, a new fluoroquinolone, alone and in combination with coumermycin, against gram-positive bacteria. | Drugs Exp Clin Res | The in vitro activity of Cl934, a new quinolone antimicrobial agent, was studied against 314 strains of Gram-positive bacteria representing 6 genera: Staphylococcus aureus, Streptococcus faecalis, S. agalactiae, S. pyogenes, S. pneumoniae, S. milleri, viridans streptococci, Listeria monocytogenes, Corynebacterium JK, Mycobacterium fortuitum and Bacillus spp.; and compared with that of enoxacin, ciprofloxacin, penicillin G, ampicillin, coumermycin, oxacillin, vancomycin, teicoplanin, rifampin, Rifapentine, LM 427, erythromycin, minocycline, tetracycline and clindamycin. The agar dilution method was used. Cl934 was very active in vitro, with MIC90 less than or equal to 0.5 mg/l against most species tested, except for S. faecalis and M. fortuitum. It was usually 2 to 8-fold more active than ciprofloxacin. Cl934 was also tested by the killing curve method, alone and in combination with coumermycin. It was rapidly bactericidal against most species tested, including S. faecalis. A synergistic interaction was observed with coumermycin against S. aureus, S. agalactiae, S. milleri and S. faecalis. The only antagonistic interaction occurred against L. monocytogenes exposed to 8 X MIC of Cl934 with 2 X MIC of coumermycin. |
| 1986 | Induction of mixed function oxidase activity in man by rifapentine (MDL 473), a long-acting rifamycin derivative. | Br J Clin Pharmacol | The effects of Rifapentine (MDL 473) administration on hepatic mixed function oxidase activity in man have been investigated in six healthy volunteers. Administration of Rifapentine (600 mg 48 h-1) for 10 days resulted in a significant reduction in antipyrine half-life (from 13.2 +/- 1.0 h to 7.7 +/- 0.4 h) and a corresponding increase in its total body clearance (from 41.8 +/- 5.5 ml min-1 to 67.4 +/- 5.6 ml min-1). Twelve days after stopping Rifapentine administration, these values had largely returned to base-line. 24-Hour excretion of 6 beta-hydroxycortisol was significantly increased, by approximately three-fold, following administration of Rifapentine for 10 days. Again, 12 days after stopping drug administration, 6 beta-hydroxycortisol excretion had returned to pretreatment values. Clearance of antipyrine to its three oxidative metabolites was increased by Rifapentine administration, although the increase for 3-hydroxymethylantipyrine was not significant. The greatest increase (+140%) was observed for norantipyrine. Twelve days after the last dose of Rifapentine, all values had returned to control levels. It is concluded that, like rifampicin, Rifapentine is a potent inducer of mixed function oxidase activity in man and that the possibility of clinically significant drug interactions should be anticipated in the therapeutic use of this compound. |
| 1985 | In vitro activities of rifapentine and rifampin, alone and in combination with six other antibiotics, against methicillin-susceptible and methicillin-resistant staphylococci of different species. | Antimicrob Agents Chemother | The antistaphylococcal activity of Rifapentine, a new rifamycin SV derivative, was evaluated in vitro and compared with that of rifampin. A total of 313 staphylococcal strains freshly isolated from clinical material and including representatives of all currently recognized Staphylococcus species of human origin were used. The susceptibility to methicillin of all the test strains was determined preliminarily. Despite minor differences with some species, the MICs of Rifapentine were found to be substantially similar to those of rifampin. Methicillin-resistant strains of all species were most resistant to Rifapentine and rifampin than were their methicillin-susceptible counterparts. For most strains tested, the MBCs of both rifamycins exceeded by twofold the respective MICs. Both the checkerboard dilution and time-kill methods were used to determine the interactions of Rifapentine or rifampin with six different antibiotics: cefamandole, vancomycin, teicoplanin, gentamicin, erythromycin, and fusidic acid. No significant differences between the two rifamycins in the combinations were observed against either methicillin-susceptible or methicillin-resistant strains. Minor differences were noted depending on the second antibiotic tested or the staphylococcal species examined. Antagonism was never observed, and indifference was the prevalent response. Cases of synergism were observed occasionally with the checkerboard method and slightly more often with the time-kill method. |
| 1984 | Pharmacokinetics of rifapentine, a new long lasting rifamycin, in the rat, the mouse and the rabbit. | J Antibiot (Tokyo) | A study on the pharmacokinetics of Rifapentine, a new long-lasting rifamycin, has been carried out in the rat, the mouse and the rabbit. The investigation was made using either radioactive or unlabelled Rifapentine and both the total 14C and the unchanged compound were assayed. In the rat, the overall evidence obtained was: the oral absorption of Rifapentine into central compartment, due to its poor water solubility, appears to be dose-dependent with a satisfactory oral absorption (84%) after a dose of 3 mg/kg, lower (65%) after 10 mg/kg; the antibiotic undergoes rapid liver uptake while it diffuses into the tissue compartment more slowly, with particular affinity for the adrenals, pancreas and kidneys; concentrations higher than in plasma were also measured in the lungs; elimination of Rifapentine from the blood and tissue compartments suggests a non linear capacity-limited kinetics where the terminal elimination phase has monoexponential course. Terminal plasma half-life ranged between 14 and 18 hours; the compound is eliminated mainly via the bile with the feces (92% of dose). In mice Rifapentine shows a kinetic profile resembling that obtained in rats, whereas in rabbits is metabolized and/or eliminated much more rapidly with a half-life of only 1.8 hours. |
| 1984 | Comparative uptake of rifampicin and rifapentine (DL473) by human neutrophils. | J Antimicrob Chemother | Rifapentine, a new cyclopentyl rifamycin, was weight for weight less active than rifampicin against Staphylococcus aureus. It was, however, equally effective at reducing the survival of Staph. aureus within human neutrophils even at concentrations below the conventionally determined MIC. The intracellular survival of antibiotic-resistant Staph. aureus was affected by neither agent. The bactericidal activity of neutrophil sonicates after exposure to both antibiotics showed that Rifapentine was concentrated three-fold more than rifampicin. Uptake was temperature dependent and rapidly reached a plateau within 10 min. Uptake of rifampicin was unaffected by pH whereas that of Rifapentine was reduced when the pH was lowered from 7.3 to 5. Studies with the metabolic inhibitors, sodium cyanide and potassium fluoride, suggested a minor role for both oxidative and glycolytic metabolism in this process. However, neither inhibitor had any demonstrable effect on the intracellular killing of Staph. aureus by either Rifapentine or rifampicin. |
| 1984 | Rifampicin and rifapentine in treatment of experimental listeriosis in normal mice and athymic (nude) mice. | Chemotherapy | Rifampicin and Rifapentine were used in the treatment of Listeria monocytogenes infections in normal mice and congenitally athymic (nude) mice. Results were compared with untreated controls and with the results obtained from a previous study of ampicillin in which this model was used. Low doses of rifampicin or Rifapentine were adequate to cure normal mice. The efficacy of these antibiotic treatment schedules was lost in nude mice. Prolonged antibiotic treatment schedules with increased dosages were also unsuccessful. These studies show that rifampicin and Rifapentine , two antimicrobial agents being capable of destroying intracellular bacteria, were not effective in curing the Listeria infection in mice with impaired host defenses. |