CTCAE is the US National Cancer Institute terminology used to describe and grade the severity of adverse events in clinical trials, particularly oncology studies. The current CTCAE v6.0 was released in 2025 and is based on MedDRA terminology.
Relationship with MedDRA
CTCAE and MedDRA overlap in medical concepts but are not interchangeable. CTCAE adds standard severity grades for trial adverse events, whereas MedDRA is the broader international regulatory terminology used for coding and analysis across clinical and post-marketing safety activities.
The NCI resource page provides the current version, prior versions, mappings and adverse-event reporting resources.