An endpoint is a targeted outcome of a clinical trial that is statistically analyzed to help determine the efficacy and safety of the therapy being studied. Endpoints for a clincial trial may include one or more clinical outcome assessment and/or surrogate endpoint. Clinical outcomes assessments measure direct clinical benefit to the participant where as surrogate endpoints, including biomarkers, predict clinical benefit. Endpoints may also be used to throughout a study to determine if a participant’s risk of continuing to be in a study is too great.
Endpoints must be validated prior to using in a clinical trial. Endpoint choice depends on the clinical trial design, the nature of the disorder or condition being treated, and the expected effect of the therapy being tested. Chosen endpoints are usually clearly defined prior to the start of a clinical trial. A clinical study may have one or more primary, secondary, and exploratory endpoints. Primary endpoints will be the basis for determining whether the study met its objective or, in the case of interventional clincal trials, will be the main data evaluated for regulatory approval. Secondary endpoints are those that may provide supportive information about a therapy’s effect on the primary endpoint or demonstrate additional effects on the disease or condition. Exploratory endpoints may include clinically important events that are expected to occur too infrequently to show a treatment effect or endpoints that for other reasons are thought to be less likely to show an effect but are included to explore new hypotheses.
U.S. Food and Drug Administration (FDA) Patient-Focused Drug Development Glossary
U.S. Food and Drug Administration (FDA): Multiple Endpoints in Clinical Trials Guidance for Industry
Surrogate Endpoint Resources for Drug and Biologic Development