What is the primary focus of Phase 4?

• A. Post-marketing surveillance to monitor long-term safety.
• B. Initial dose-ranging in healthy volunteers.
• C. Global market launch.
• D. Animal toxicology.

Answer: (A)

Phase 4 focuses on post-marketing surveillance to monitor long-term safety and real-world effectiveness after a drug is approved and marketed. This phase aims to detect rare or long-term adverse events, safety signals, and how the drug behaves in broader, more diverse patient populations over extended periods. It uses pharmacovigilance, observational studies, and registries to gather data that aren’t fully captured in earlier trials.

Early-phase work, like initial dose-ranging in healthy volunteers, belongs to Phase 1. Launch of the product on the global market occurs after regulatory approval, not during Phase 4. Animal toxicology is preclinical work done before human trials.