Which statement correctly describes the Full Analysis Set?

• A. The Per Protocol Set includes only protocol-adherent subjects.
• B. The Safety Analysis Set focuses on adverse events.
• C. The Full Analysis Set is the analysis set that is as complete as possible and as close as possible to the intention-to-treat ideal of including all randomized subjects.
• D. The Primary Endpoint Set defines the main outcome.

Answer: (C)

The main idea is that the Full Analysis Set is the most inclusive population used for efficacy analysis, aiming to reflect the intention-to-treat principle. It is as complete as possible and as close as possible to including all randomized subjects, so the analysis stays true to the original randomization and minimizes bias from dropouts or deviations.

This is why it’s the best description: it prioritizes including as many randomized participants as feasible to preserve comparability between groups and to avoid bias that can arise from excluding subjects who didn’t strictly adhere to the protocol. Per Protocol Set, by contrast, excludes non-adherent or protocol-violating participants, which can bias results toward a subset of patients. The Safety Analysis Set focuses on safety data rather than efficacy and is not defined to mirror ITT. The Primary Endpoint Set is defined for the main outcome analysis and is not intended to be the most inclusive population.