Which statement best describes the Per Protocol Set?

• A. All randomized subjects
• B. Valid cases, efficacy sample, evaluable subjects
• C. Includes only those with protocol deviations
• D. Used to assess safety only

Answer: (B)

The Per Protocol Set is the subset of randomized participants who followed the protocol without major deviations and have evaluable data for efficacy. This group is used to estimate the treatment effect under ideal protocol compliance, so it is narrower than the full randomized population and excludes those with protocol violations or incomplete efficacy data. That’s why the description “valid cases, efficacy sample, evaluable subjects” best fits. It’s not the group used for safety analyses (which typically relies on all treated or all randomized participants) and it’s not meant to include only those with protocol deviations.