sq-109 and Extensively-Drug-Resistant-Tuberculosis

The emergence of drug resistance continues to afflict TB control where drug resistant strains have become a global health concern. Contrary to drug-sensitive TB, the treatment of MDR/XDR-TB is more complicated requiring the administration of second-line drugs that are inefficient than the first line drugs and are associated with greater side effects. The emergence of drug resistant Mtb strains had coincided with an innovation void in the field of drug discovery of anti-mycobacterials. However, the approval of bedaquiline and delamanid recently for use in MDR/XDR-TB has given an impetus to the TB drug discovery. The review discusses the drug discovery efforts in the field of tuberculosis with a focus on the strategies adopted and challenges confronted by TB research community. Here, we discuss the diverse clinical candidates in the current TB drug discovery pipeline. There is an urgent need to combat the current TB menace through multidisciplinary approaches and strategies making use of the recent advances in understanding the molecular biology and pathogenesis of Mtb. The review highlights the recent advances in drug discovery, with the host directed therapeutics and nanoparticles-drug delivery coming up as important tools to fight tuberculosis in the future.

Topics: Antitubercular Agents; Diarylquinolines; Drug Therapy, Combination; Ethambutol; Extensively Drug-Resistant Tuberculosis; Humans; Isoniazid; Mycobacterium tuberculosis; Nitroimidazoles; Oxazoles; Pyrazinamide; Rifampin

The United Nations Millennium Development Goal of reversing the global spread of tuberculosis by 2015 has been offset by the rampant re-emergence of drug-resistant tuberculosis, in particular fluoroquinolone-resistant multidrug-resistant and extensively drug-resistant tuberculosis. After decades of quiescence in the development of antituberculosis medications, bedaquiline and delamanid have been conditionally approved for the treatment of drug-resistant tuberculosis, while several other novel compounds (AZD5847, PA-824, SQ109 and sutezolid) have been evaluated in phase II clinical trials. Before novel drugs can find their place in the battle against drug-resistant tuberculosis, linezolid has been compassionately used with success in the treatment of fluoroquinolone-resistant multidrug-resistant tuberculosis. This review largely discusses six novel drugs that have been evaluated in phase II and III clinical trials, with focus on the clinical evidence for efficacy and safety, potential drug interactions, and prospect for using multiple novel drugs in new regimens.

Topics: Adamantane; Antitubercular Agents; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Diarylquinolines; Drug Therapy, Combination; Ethylenediamines; Extensively Drug-Resistant Tuberculosis; Female; Follow-Up Studies; Humans; Male; Nitroimidazoles; Oxazoles; Oxazolidinones; Treatment Outcome; Tuberculosis, Multidrug-Resistant

Tuberculosis is a major global health problem. In the middle of the last century several laboratories identified, developed and synthesized several substances which were active against Mycobacterium tuberculosis, the causative agent of the disease. In the 1980s the standard oral treatment regimen was introduced with isoniazid, rifampicin, pyrazinamide, and ethambutol. In combination with the DOTS strategy it was possible treat TB within 6-8 months. But with the emergence of drug resistant strains, the formerly successful regiment became ineffective for MDR and XDR TB patients. Even more alarming, the rapidly increasing HIV epidemic also increases the number of HIV-related TB. Facing these facts, it became evident that novel strategies and antibiotics were needed to treat the new forms of TB. But over the last 60 years no novel TB drug was developed or even in the drug pipeline. But during the last ten years several novel substances have been developed to combat the deadly disease. For the first time in decades the TB drug pipeline is filled again with several promising compounds and many of them have reached Phase II and Phase III clinical trials. Several laboratories and companies all over the world currently are developing and evaluating these substances. This review presents novel substances, which were for the first time exclusively developed for TB such as bedaquilines, nitroimidazoles and the diamine SQ109. We also summarize the present knowledge about enzymes and biosynthesis pathways which offer potential targets for drug discovery against M. tuberculosis.

Topics: Adamantane; Antitubercular Agents; Cyclic GMP-Dependent Protein Kinases; Diarylquinolines; Enzymes; Ethylenediamines; Extensively Drug-Resistant Tuberculosis; Humans; Molecular Targeted Therapy; Mycobacterium tuberculosis; Nitroimidazoles; Quantitative Structure-Activity Relationship

The current 6-month tuberculosis (TB) therapy is suboptimal with significant side effects and a poor patient compliance problem that frequently selects drug-resistant organisms. The increasing drug-resistant TB problem highlights the need to develop new and more effective drugs. Significant progress has been made recently with several new drug candidates currently in clinical trials. Improved understanding of persister biology and development of persister drugs are likely to be important for developing a more effective therapy.

Topics: Adamantane; AIDS-Related Opportunistic Infections; Animals; Anti-Bacterial Agents; Antitubercular Agents; Drug Administration Schedule; Drug Resistance, Bacterial; Drug Therapy, Combination; Drugs, Investigational; Ethylenediamines; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Isoniazid; Mycobacterium tuberculosis; Nitroimidazoles; Oxazoles; Pyrazinamide; Rifampin; Treatment Refusal; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary

There presently is no rapid method to assess the bactericidal activity of new regimens for tuberculosis. This study examined PNU-100480, TMC207, PA-824, SQ109, and pyrazinamide, singly and in various combinations, against intracellular M. tuberculosis, using whole blood culture (WBA). The addition of 1,25-dihydroxy vitamin D facilitated detection of the activity of TMC207 in the 3-day cultures. Pyrazinamide failed to show significant activity against a PZA-resistant strain (M. bovis BCG), and was not further considered. Low, mid, and high therapeutic concentrations of each remaining drug were tested individually and in a paired checkerboard fashion. Observed bactericidal activity was compared to that predicted by the sum of the effects of individual drugs. Combinations of PNU-100480, TMC207, and SQ109 were fully additive, whereas those including PA-824 were less than additive or antagonistic. The cumulative activities of 2, 3, and 4 drug combinations were predicted based on the observed concentration-activity relationship, published pharmacokinetic data, and, for PNU-100480, published WBA data after oral dosing. The most active regimens, including PNU-100480, TMC207, and SQ109, were predicted to have cumulative activity comparable to standard TB therapy. Further testing of regimens including these compounds is warranted. Measurement of whole blood bactericidal activity can accelerate the development of novel TB regimens.

Topics: Adamantane; Antitubercular Agents; Diarylquinolines; Drug Monitoring; Drug Therapy, Combination; Ethylenediamines; Extensively Drug-Resistant Tuberculosis; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Nitroimidazoles; Oxazolidinones; Pyrazinamide; Quinolines; Reproducibility of Results; Time Factors