The United States Food and Drug Administration (FDA) initiated the FDA Accelerated Approval Program in 1992 to allow faster approval of drugs for serious conditions that fill an unmet medical need. The faster approval relies on use of surrogate endpoints. Drug approval typically requires clinical trials with endpoints that demonstrate a clinical benefit, such as increased survival for cancer patients. Drugs with accelerated approval can initially be tested in clinical trials that use a surrogate endpoint, or something that is thought to predict clinical benefit. Surrogate endpoints typically require less time, and in the case of a cancer patient, it is much faster to measure a reduction in tumor size, for example, than overall patient survival.
Drugs approved under the FDA Accelerated Approval Program still need to be tested in clinical trials using endpoints that demonstrate clinical benefit, and those trials are known as phase 4 confirmatory trials. If the drug later proves unable to demonstrate clinical benefit to patients, the FDA may withdraw approval.