Progression-free survival as a primary end-point: Counting the cost

Abstract

For some time in cancer clinical trials, overall survival (OS) has been the gold standard in determining the endpoint of the drug's efficacy. However, in recent times, there has been a gradual shift in the endpoint of drug efficacy towards progression-free survival (PFS). PFS has its merits, especially being cost-effective, but not without associated shortcomings. PFS is not an ideal surrogate for OS, and in some cases, the correlation is low to medium in strength with heterogeneity in the methodologies used. There have also been cases where PFS is used as an endpoint in place of OS, which was achieved, but with increased reports of significant adverse events/reduced quality of life (QoL) index. Current realities make using OS as an endpoint in some cancer drug trials a difficult task to demonstrate. However, even if PFS is used, data must be thoroughly assessed for quality of life indices and drug safety. It is therefore important that stakeholders in the business of cancer drug evaluation and trials note the risks and benefits of such drugs for the target population. In so doing, patient’s QoL would be paramount in therapeutic decision-making.