Surrogate Endpoint
A measurable marker, such as a lab value or imaging result, used in clinical trials as a stand-in for a direct clinical outcome like survival. Regulators may accept validated surrogates to support faster evaluation of a treatment's effect.
What is a surrogate endpoint?
A surrogate endpoint is a measurable marker used in a clinical trial as a substitute for a direct clinical outcome that matters to patients, such as survival or freedom from disease. Common surrogates include laboratory values, blood pressure, tumor shrinkage, or imaging findings that are expected to predict the true outcome.
Surrogates are useful because the true outcome may take years to observe, whereas a marker can change much sooner. A surrogate is only meaningful if evidence shows that changes in it reliably correspond to changes in the clinical result it represents.
Why do surrogate endpoints matter?
Surrogate endpoints can shorten trials and speed patient access to treatments by allowing earlier read-outs of whether a therapy is working. Regulators may accept a validated surrogate to support approval, sometimes with a requirement to confirm benefit on the true outcome afterward.
The trade-off is risk: if a surrogate does not truly track the clinical outcome, a treatment may appear effective on the marker while failing to help, or even harming, patients. For this reason, the strength of the link between surrogate and outcome is a central question in drug and device development.
- surrogate endpoint meaning
- what is a surrogate endpoint
- surrogate endpoint vs clinical endpoint
- surrogate marker clinical trial
- surrogate outcome definition
- validated surrogate endpoint