ABSTRACT
Typically, phase II cancer clinical trials use response rate as the primary endpoint, where in the solid tumor setting, response usually involves a reduction in the dimensions of the measurable disease. However, there are shortcomings to using response rate as the primary endpoint for evaluating efficacy: (1) Response has not been shown to be strongly correlated with survival across most disease sites, (2) there are challenges to
evaluating response, and (3) there are new classes of agents that are being tested that are not expected to be cytotoxic (tumor reducing) but instead are cytostatic; that is, the agents may delay disease progression but not reduce the tumor size. For these reasons, other endpoints such as survival or progression-free survival should be considered as the primary endpoint for evaluating phase II drugs.
