Who determines AE causality?

• A. Sponsor.
• B. Ethics Committee.
• C. Investigator.
• D. Monitor.

Answer: (C)

In a clinical trial, the person caring for the patient at the site evaluates whether an adverse event is related to the investigational product. This attribution, called causality assessment, is done by the investigator because they have the full clinical picture, timing of the event relative to the drug, and the ability to assess alternate explanations such as underlying disease or other medications. They judge the relationship (related, possibly related, probably related, or not related) and record it in the case report form, guiding safety reporting within the trial and to regulators.

While the sponsor may conduct safety reviews and regulatory reporting, the formal determination of causality for an individual adverse event rests with the investigator. The ethics committee reviews risks and the consent process but does not assign causality for each AE. The monitor ensures data quality and safety processes but does not make the final causality judgment.