Approaches to clinical trials of new anti-TB drugs

New drugs and drug combinations are urgently needed for shorter, more effective TB treatment. Standard regimens require treatment for at least 6 months and are difficult to complete in resource-constrained settings. Resistance to first- and second-line drugs is increasing in many areas and therefore drugs with new mechanisms of action are needed. These issues complicate clinical trials of new anti-TB drugs, which continue to require prolonged follow-up of 1 to 2 years after therapy and rely heavily on end points based on mycobacterial culture. Significant barriers to accelerated testing include the development and validation of biomarkers that can be used as surrogate end points to reliably predict long-term clinical outcomes in Phase II and III trials, designing trials to evaluate new drugs for drug-resistant TB, better approaches for selecting, optimizing and testing combination regimens, and expanding the infrastructure and sites to support registration trials in high-burden countries.