Phase III is intended to provide an adequate basis for what?

• A. To explore endpoints in healthy volunteers
• B. To confirm long-term safety in animal studies
• C. To provide an adequate basis for marketing approval
• D. To conduct post-marketing surveillance

Answer: (C)

Phase III trials are designed to provide robust evidence of a drug’s efficacy and safety in a broad patient population to support regulatory approval. This is the best fit because these trials are the pivotal studies that confirm that the therapy works in the intended population and that its benefits outweigh risks, sufficiently to justify marketing authorization. They are typically large, randomized trials with diverse participants, clinically meaningful endpoints, longer follow-up, and careful safety monitoring, all aimed at producing data strong enough for labeling decisions.

The other options reflect activities outside the Phase III purpose: exploring endpoints in healthy volunteers is a Phase I activity focused on safety and pharmacokinetics; long-term safety in animal studies occurs in preclinical work before human trials; post-marketing surveillance happens after approval in phase IV to monitor long-term safety in routine use.