What is a SUSAR in clinical trials, and when must it be reported?

A SUSAR is a suspected unexpected serious adverse reaction: an adverse event in a clinical trial that is serious, is not expected from the reference safety information (in a US IND, the investigator's brochure), and carries a reasonable possibility that the investigational drug caused it. In the EU, Article 42 of the Clinical Trials Regulation (EU 536/2014) has the sponsor report a SUSAR to EudraVigilance within 7 days if it is fatal or life-threatening and within 15 days otherwise. US rules say serious and unexpected suspected adverse reaction: under 21 CFR 312.32 the IND safety report is due within 15 calendar days of the sponsor deciding a case qualifies, and within 7 calendar days of first receipt for an unexpected fatal or life-threatening reaction. Seriousness and severity are separate questions, so a CTCAE grade alone never makes an event a SUSAR. Burna AI generates FDA MedWatch 3500A, IRB and sponsor SAE reports. More: burna.ai/blog/ind-safety-reports-21-cfr-312-32.