Two-thirds of cancer drugs approved based on surrogate endpoints

Many new cancer drugs receive their approval based on a surrogate endpoint, such as progression-free survival (PFS). When this happens, further study is needed to examine the drug's effect on overall survival.

Many new cancer drugs receive their approval based on a surrogate endpoint, such as progression-free survival (PFS). When this happens, further study is needed to examine the drug's effect on overall survival. Researchers investigated cancer drugs approved based on a surrogate endpoint to determine whether subsequent studies are reported and whether they improve overall survival. The analysis included 54 FDA marketing approvals issued in 2008–12. Of these drugs, 36 (67%) were approved based on a surrogate endpoint. Rate of response was the primary measure of efficacy for 19 surrogate-based approvals (53%), whereas PFS or disease-free survival was the basis for 17 (47%). During followup, 18 drugs failed to improve overall survival as primary or secondary outcomes, and 13 drugs either remained untested or had no reported survival results as primary or secondary outcome. According to the authors, Chul Kim, MD, of the National Cancer Institute, and Vinay Prasad, MD, of Knight Cancer Center, the "results suggest that the FDA may be approving many costly, toxic drugs that do not improve overall survival. Enforcement of postmarketing studies is therefore of critical importance."