Which adverse drug reactions (ADRs) require expedited reporting to all concerned investigators/institutions, IRBs/IEC(s) where required, and regulatory authorities?

• A. Any adverse drug reaction (ADR) regardless of seriousness or unexpectedness
• B. Only ADRs that are serious but expected
• C. ADRs that are both serious and unexpected
• D. ADRs that occur only at the sponsor's site

Answer: (C)

Expedited reporting is required when an adverse drug reaction is both serious and unexpected. In clinical trials, these SUSARs (Serious, Unexpected Adverse Reactions) must be reported quickly to all investigators/institutions, IRBs/IEC(s), and regulatory authorities so safety oversight can assess the new risk and take timely action if needed. The urgency exists because the event reveals a risk not anticipated by the protocol or the Investigator’s Brochure, affecting the risk–benefit evaluation for participants.

If an ADR is serious but expected, it’s already anticipated and documented, so it’s handled through routine SAE reporting rather than urgent regulatory reporting. Non-serious ADRs don’t trigger expedited reporting. The requirement isn’t about where the event occurs (sponsor’s site vs others); it’s about the event’s seriousness and whether it is unexpected.