Working Group on New TB Drugs

Preclinical Phase: A single promising anti-TB development candidate has been selected to advance into preclinical studies to determine if the agent is likely to be safe and effective for use in humans. Activities for candidates in this phase include: Animal model efficacy studies, GLP and non-GLP animal pharmacology, safety, PK/PD, ADME and toxicology studies to prepare documentation for regulatory submission; toxicity studies in two animal species (rodent and non-rodent) including dose-escalation, repeat dose and both short-term and long-term exposure studies; process development chemistry to ensure that production of the active agent can be scaled up; and stability testing of the agent.

Phase 1: A trial designed to assess the safety, tolerability, and pharmacokinetics of a candidate drug in a small (20-100) group of healthy volunteers.

Phase 2: A trial designed to assess safety and efficacy of a candidate drug on small groups of tuberculosis patients (20-300). Phase 2 studies are sometimes divided into Phase 2A and Phase 2B. Phase 2A is specifically designed to assess dosing requirements. Phase 2B is specifically designed to study efficacy at the prescribed dose(s).

Phase 3: A randomized controlled, multicenter trial on large patient groups (300-3,000 or more) that is aimed at being the definitive assessment of candidate drug efficacy, in comparison with the 'gold standard' treatment.