RE:How does Accelerated Approval work Which Types of Surrogate Endpoints Are Used for Accelerated Approval?
The FDA accepts surrogate endpoints for clinical studies of pharmaceutical products in several instances. Approval decisions through the traditional review pathway can be based on a validated surrogate endpoint, if one is available. The FDA can deem a surrogate endpoint to be validated if it is “supported by a clear mechanistic rationale and clinical data providing strong evidence that an effect on the surrogate endpoint predicts a specific clinical benefit”.
However, the Accelerated Approval Process (AAP) does not use validated surrogate endpoints. It was designed to consider surrogate endpoints that meet a lower standard of being “reasonably likely to predict clinical benefit.” The FDA describes a reasonably likely surrogate endpoint as one with a “strong mechanistic and/or epidemiologic rationale such that an effect on the surrogate endpoint is expected to be correlated with an endpoint intended to assess clinical benefit in clinical trials, but without sufficient clinical data to show that it is a validated surrogate endpoint.” This is the only difference between a surrogate endpoint that is considered validated and one that is not validated but can be used for accelerated approval.