AESI
Adverse Event of Special Interest
What a definition is not
A definition is SPEQ’s plain-language decode of how a term is used in practice, cited to the documents that define it. It is a practitioner reference, not legal or regulatory advice, it does not replace the definition in the source, and where a regulator’s wording differs the regulator’s wording governs.
An adverse event, serious or non-serious, of scientific or medical importance specific to a sponsor’s product or program, for which ongoing monitoring and rapid communication to the sponsor is required, and which is tracked separately from routine adverse event collection. AESIs are pre-specified in the protocol and safety monitoring plan based on the product’s known or theoretical risks.
AESI lists are built from known class effects, the product’s mechanism of action, and findings in nonclinical toxicology studies — the point is to watch proactively for a specific theoretical or previously observed risk, rather than waiting to notice it in routine adverse event summaries.
Unlike a SUSAR, an AESI does not need to be serious to require enhanced monitoring and rapid internal reporting — a mild but mechanistically important finding can still be an AESI if it is scientifically informative about the product’s risk profile.
The AESI list is a living document, periodically reviewed and updated as clinical experience and new nonclinical data accumulate, and it typically drives a dedicated CRF page or targeted data collection instrument beyond standard adverse event capture.
- —Pre-specified in the protocol or safety monitoring plan based on known class effects, mechanism of action, or nonclinical findings.
- —Unlike a SUSAR, an AESI does not have to be serious to warrant enhanced monitoring and rapid reporting.
- —The AESI list is periodically reviewed and updated as accumulating clinical and nonclinical data emerge.
- —Drives targeted data collection instruments, such as a dedicated CRF page, beyond standard adverse event capture.
ICH E2A Clinical Safety Data Management: Definitions and Standards for Expedited Reporting; ICH E2F Development Safety Update Report
Frequently asked questions
What does AESI stand for?
AESI stands for Adverse Event of Special Interest.
What is AESI?
An adverse event, serious or non-serious, of scientific or medical importance specific to a sponsor’s product or program, for which ongoing monitoring and rapid communication to the sponsor is required, and which is tracked separately from routine adverse event collection. AESIs are pre-specified in the protocol and safety monitoring plan based on the product’s known or theoretical risks.
Which regulations cover AESI?
ICH E2A Clinical Safety Data Management: Definitions and Standards for Expedited Reporting; ICH E2F Development Safety Update Report