What constitutes "protocol deviation"?

A protocol deviation refers to any instance where the conduct of a clinical trial does not align with the approved protocol. This can include variations that may compromise the integrity of the trial or impact participant safety. The key element of a protocol deviation is that it diverges from what was initially outlined and approved in the study protocol, which is designed to ensure consistency, safety, and data integrity throughout the trial.

In this context, the most appropriate definition encompasses those deviations which have a potential significance, either for the safety of participants or for the validity of the trial data. Such deviations could include unauthorized changes to dosing, different methods of administration, or failure to follow specific procedures as outlined in the protocol. Recognizing what constitutes a protocol deviation is crucial for ensuring compliance with Good Clinical Practice (GCP) guidelines and maintaining the integrity of clinical research.