Clinical trial end points relevant to patients and society for rare cancers

In solid tumors, end points such as progression-free survival are increasingly utilized as primary end points, as the use of overall survival can often be confounded by the growing use of multiple lines of therapy. In rare cancers, the choice of end points is further complicated by small and heterogeneous patient populations. In the absence of confirmed overall survival benefit, it remains unclear as to whether extending progression-free survival provides a discernible clinical benefit. Inclusion of robust patient-reported outcomes may provide valuable supporting evidence when making decisions regarding the clinical value of new costly agents. We discuss recent trials in pancreatic neuroendocrine tumors to exemplify some of the challenges faced in the trial design for rare cancers.