Treatment-Emergent Adverse Event
An adverse event that occurs for the first time or worsens in severity after the start of study treatment. This definition helps distinguish events caused or exacerbated by the drug from pre-existing conditions. Treatment-emergent adverse events are the standard safety reporting metric in clinical trials.
Technical Context
TEAE definition: any AE with onset on or after first dose of study medication, or any pre-existing condition that worsens in severity or frequency after first dose. TEAEs are distinguished from pre-treatment AEs (events occurring before first dose, captured during screening/run-in) and post-treatment AEs (events occurring after the last dose + a defined follow-up period, typically 5 half-lives). TEAE tables in clinical study reports show: overall incidence, incidence by System Organ Class and preferred term, severity breakdown, relationship to study drug assessment, and events leading to discontinuation. For regulatory review, TEAE data are compared between treatment and control groups using exposure-adjusted incidence rates to account for different treatment durations.