Question

Design of clinical trial phases of clinical trials

Answer 1

The development of investigational new drugs (INDs) involves performing clinical trials (or studies) to assess the safety and efficacy of the IND in humans. These trials are usually classified into 4 phases of development (Phase 1 to 4), with each potentially lasting for several years. Successful completion of each phase and approval by the appropriate regulatory authority or authorities (the European Medicines Agency [EMA] in the European Union, Food and Drug Administration [FDA] in the United States, Health Canada in Canada, or the Ministry of Health, Labour and Welfare in Japan) is required for progression to the next phase.

Satisfactory completion and approval of Phases 1 to 3 is required for a drug to be approved for marketing. Phase 4 studies are conducted after a compound has been approved, for the primary purpose of post marketing surveillance.

In an attempt to both speed up the drug development process and to quickly identify safety issues, Phase 0 studies, also referred to as ‘human microdosing studies’ were introduced.