A Suspected Unexpected Serious Adverse Reaction (SUSAR) is a serious adverse reaction that is unexpected based on reference safety information and suspected to be related to the investigational product.
SUSARs require expedited reporting to regulators and ethics committees within defined timelines, making them a central component of safety oversight. Determining SUSAR status depends on seriousness criteria, causality assessment, and expectedness evaluation against the Investigator Brochure or labeling. SUSAR reporting can trigger protocol changes, risk communications, and enhanced monitoring measures. High-quality SUSAR assessment protects participants and strengthens regulatory confidence in sponsor pharmacovigilance practices.