Inappropriate use of progression-free survival in cancer drug approvals

The aim of cancer drugs is to prolong life or improve its quality. Yet only a third of cancer drugs entering the market in Europe and the US have evidence of overall benefits in survival or quality of life.1 Instead, regulators now routinely approve new cancer drugs on the basis of surrogate endpoints that measure disease progression or tumour shrinkage.

This was not always the case. Historically, regulators had little appetite to accept surrogate measures for approving cancer drugs. In the mid-1980s, the US Food and Drug Administration required (with some exceptions) that clinical trials to support new cancer drug approvals show an improvement in patient survival, symptoms, or quality of life. This requirement was based on evidence that the correlation between tumour response and clinical benefit was weak.2

Nevertheless, in 1996 the Clinton …