What criteria classify an event as "unexpected" in the context of serious adverse events?

In the context of serious adverse events, an event is classified as "unexpected" when it is not consistent with the nature or frequency of events that have previously been documented in relation to the study drug. This typically involves considering the known safety profile established through prior research, clinical trials, or detailed information in the Investigator's Brochure.

When an event is not found in the study drug's known profile, it indicates that the event has not been documented or anticipated based on existing data. This suggests that the occurrence of the event might be of particular concern, prompting further investigation into a potential causal relationship between the event and the drug.

In contrast, events that are listed in the Investigator's Brochure could be considered expected, as they are already documented and understood within the context of the drug's profile. Similarly, events that are well known and frequently observed within the general population do not render themselves unexpected, since these occurrences can be anticipated and may not indicate a new or unforeseen risk associated with the investigational therapy. An event occurring without prior indication does not automatically qualify as unexpected unless it aligns with the specific context of the study drug's safety data.