| 2021 | Four-Month Rifapentine Regimens with or without Moxifloxacin for Tuberculosis. | N Engl J Med | Rifapentine-based regimens have potent antimycobacterial activity that may allow for a shorter course in patients with drug-susceptible pulmonary tuberculosis.In an open-label, phase 3, randomized, controlled trial involving persons with newly diagnosed pulmonary tuberculosis from 13 countries, we compared two 4-month rifapentine-based regimens with a standard 6-month regimen consisting of rifampin, isoniazid, pyrazinamide, and ethambutol (control) using a noninferiority margin of 6.6 percentage points. In one 4-month regimen, rifampin was replaced with rifapentine; in the other, rifampin was replaced with rifapentine and ethambutol with Moxifloxacin. The primary efficacy outcome was survival free of tuberculosis at 12 months.Among 2516 participants who had undergone randomization, 2343 had a culture positive for that was not resistant to isoniazid, rifampin, or fluoroquinolones (microbiologically eligible population; 768 in the control group, 791 in the rifapentine-Moxifloxacin group, and 784 in the rifapentine group), of whom 194 were coinfected with human immunodeficiency virus and 1703 had cavitation on chest radiography. A total of 2234 participants could be assessed for the primary outcome (assessable population; 726 in the control group, 756 in the rifapentine-Moxifloxacin group, and 752 in the rifapentine group). Rifapentine with Moxifloxacin was noninferior to the control in the microbiologically eligible population (15.5% vs. 14.6% had an unfavorable outcome; difference, 1.0 percentage point; 95% confidence interval [CI], -2.6 to 4.5) and in the assessable population (11.6% vs. 9.6%; difference, 2.0 percentage points; 95% CI, -1.1 to 5.1). Noninferiority was shown in the secondary and sensitivity analyses. Rifapentine without Moxifloxacin was not shown to be noninferior to the control in either population (17.7% vs. 14.6% with an unfavorable outcome in the microbiologically eligible population; difference, 3.0 percentage points [95% CI, -0.6 to 6.6]; and 14.2% vs. 9.6% in the assessable population; difference, 4.4 percentage points [95% CI, 1.2 to 7.7]). Adverse events of grade 3 or higher occurred during the on-treatment period in 19.3% of participants in the control group, 18.8% in the rifapentine-Moxifloxacin group, and 14.3% in the rifapentine group.The efficacy of a 4-month rifapentine-based regimen containing Moxifloxacin was noninferior to the standard 6-month regimen in the treatment of tuberculosis. (Funded by the Centers for Disease Control and Prevention and others; Study 31/A5349 ClinicalTrials.gov number, NCT02410772.). |
| 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 | 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 | 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. |
| 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. |
| 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. |
| 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. |
| 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 | 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 | 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. |
| 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. |
| 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. |
| 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 | 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. |
| 2015 | A novel inhibitor of gyrase B is a potent drug candidate for treatment of tuberculosis and nontuberculosis mycobacterial infections. | Antimicrob Agents Chemother | New drugs to treat drug-resistant tuberculosis are urgently needed. Extensively drug-resistant and probably the totally drug-resistant tuberculosis strains are resistant to fluoroquinolones like Moxifloxacin, which target gyrase A, and most people infected with these strains die within a year. In this study, we found that a novel aminobenzimidazole, VXc-486, which targets gyrase B, potently inhibits multiple drug-sensitive isolates and drug-resistant isolates of Mycobacterium tuberculosis in vitro (MICs of 0.03 to 0.30 μg/ml and 0.08 to 5.48 μg/ml, respectively) and reduces mycobacterial burdens in lungs of infected mice in vivo. VXc-486 is active against drug-resistant isolates, has bactericidal activity, and kills intracellular and dormant M. tuberculosis bacteria in a low-oxygen environment. Furthermore, we found that VXc-486 inhibits the growth of multiple strains of Mycobacterium abscessus, Mycobacterium avium complex, and Mycobacterium kansasii (MICs of 0.1 to 2.0 μg/ml), as well as that of several strains of Nocardia spp. (MICs of 0.1 to 1.0 μg/ml). We made a direct comparison of the parent compound VXc-486 and a phosphate prodrug of VXc-486 and showed that the prodrug of VXc-486 had more potent killing of M. tuberculosis than did VXc-486 in vivo. In combination with other antimycobacterial drugs, the prodrug of VXc-486 sterilized M. tuberculosis infection when combined with rifapentine-pyrazinamide and bedaquiline-pyrazinamide in a relapse infection study in mice. Furthermore, the prodrug of VXc-486 appeared to perform at least as well as the gyrase A inhibitor Moxifloxacin. These findings warrant further development of the prodrug of VXc-486 for the treatment of tuberculosis and nontuberculosis mycobacterial infections. |
| 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 | 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 | A rifapentine-containing inhaled triple antibiotic formulation for rapid treatment of tubercular infection. | Pharm Res | The potential for rifapentine-containing oral therapeutic regimens to significantly shorten the current six-month anti-tubercular treatment regimen is confounded by high plasma protein binding of rifapentine. Inhaled aerosol delivery of rifapentine, a more potent anti-tubercular antibiotic drug, in combination with other first-line antibiotics may overcome this limitation to deliver a high drug dose at the pulmonary site of infection.A formulation consisting of rifapentine, Moxifloxacin and pyrazinamide, with and without leucine, was prepared by spray-drying. This formulation was assessed for its physico-chemical properties, in vitro aerosol performance and antimicrobial activity.The antibiotic powders, with and without leucine, had similar median aerodynamic diameters of 2.58 ± 0.08 μm and 2.51 ± 0.06 μm, with a relatively high fine particle fraction of 55.5 ± 1.9% and 63.6 ± 2.0%, respectively. Although the powders were mostly amorphous, some crystalline peaks associated with the δ polymorph for the spray-dried crystalline pyrazinamide were identified.Stabilisation of the powder with 10% w/w leucine and protection from moisture ingress was found to be necessary to prevent overt crystallisation of pyrazinamide after long-term storage. In vitro biological assays indicated antimicrobial activity was retained after spray-drying. Murine pharmacokinetic studies are currently underway. |
| 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. |
| 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 | 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. |
| [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 | 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 | 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 | 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. |
| 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 | 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. |
| [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 | 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. |
| 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 | 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. |
| 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 | 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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. |
| 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 | 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. |