A category of adverse events that can particularly occur with cancer or autoimmune condition treatments during a clinical trial is the treatment emergent adverse event. This is an often unexpected adverse (negative) outcome or event that arises during the course of treatment that did not appear to exist beforehand or appears to be worsening a pre-existing condition or problem. Whereas adverse events may or may not be related to a treatment, a TEAE is distinguished by its appearing specifically while treatment is ongoing or very soon thereafter, often with an infusion therapy or a treatment that requires multiple visits over time.
