Pitfalls in the Use of Progression-Free Survival as a Surrogate for Overall Survival in Cancer Clinical Trials

• Activity Number: 330
• Type: Topic Contributed
• Date/Time: Tuesday, August 5, 2014 : 10:30 AM to 12:20 PM
• Sponsor: Biopharmaceutical Section
• Author(s): Gregory Pond*+
• Companies: McMaster University
• Keywords: oncology ; clinical trials ; progression-free survival ; surrogate

Abstract

There is a trend to increased use of progression-free survival (PFS) as the primary outcome measure in phase III cancer clinical trials, despite the fact that PFS has only infrequently been formally validated as a surrogate for overall survival (OS). This is partly due to the stringent criteria required to formally validate PFS as a surrogate, but secondarily, also due to the fact that PFS is often a poor surrogate measure. PFS offers many advantages over overall survival (OS) as an outcome, including shorter follow-up, smaller sample sizes and reduced trial costs. Conversely, practical issues often add bias, including differential censoring, timing of response evaluations and non-centralized evaluations. This talk will provide an overview of these issues and discuss statistical and practical measures which can be utilized to reduce the potential biases when planning phase III oncology clinical trials.