Protocol Deviations in Clinical Trials

A protocol deviation (PD) is any change, divergence, or departure from the study design or procedures defined in the protocol, consent document, recruitment process, or study materials originally approved.

Protocol deviations are classified as major (e.g.: non-compliance with inclusion / exclusion criteria) if they increase risk and/or decrease the benefit to the participants or affect the subject’s rights, safety or welfare and/or the integrity of the research data or they can be classified as minor (e.g.: out-of-schedule visit dates) if they do not entail such risks. Depending on the study complexity, it may not be immediately apparent whether an action constitutes a PD and, in this case, an independent committee may be called upon to decide.

Why is Protocol Deviation tracking and reporting so important? 

Tracking and reporting PDs impacts the overall compliance to GCP and other regulations. While occasional PDs only impact the site’s reputation, systematic deviations that can be due to a variety of factors such as poorly written protocol or inadequate instructions to the sites can affect the validity of the study and be subject to health authorities’ warning letters.