Under what circumstances are interim results appropriate to include in the clinical study report?

• A. Always
• B. Never
• C. Only when mandated and with appropriate caveats and DSMB input
• D. Only if they show favorable results

Answer: (A)

Interim results belong in the clinical study report only when they are planned and required by the protocol or regulatory authorities, and their inclusion is accompanied by clear caveats and input from the Data Safety Monitoring Board (DSMB). This ensures transparency about how the trial progressed, how safety monitoring influenced decisions, and how interim findings affect the interpretation of the final results. You should describe the timing and methods of the interim analyses, the pre-specified decision rules, and any DSMB recommendations, while noting that interim findings are exploratory and subject to multiplicity concerns. Interim results should not be included simply because they look favorable, nor should they be included automatically in every CSR; their inclusion hinges on mandate, proper context, and DSMB input.