Progression-free survival (PFS) as a surrogate end point for overall survival (OS) in first-line treatment of advanced epithelial ovarian cancer (EOC).

Abstract

5081 Background: The duration and cost of clinical trials of first-line chemotherapy in advanced EOC could be reduced if a surrogate endpoint were used in place of OS. The consensus of the Gynecological Cancer Intergroup was that PFS is the preferred primary end point for these trials due to potential confounding of post-progression therapy on OS. We performed a systematic review to assess the extent to which treatment effect on PFS is predictive of OS in this patient population. Methods: Randomised trials of first-line chemotherapy comparing platinum containing regimens in advanced EOC were identified; trials with non-platinum backbone, maintenance strategies or biological containing therapies were excluded. Summary data (hazard ratios (HR), median PFS and OS and the ratios of medians between treatment arms) were extracted. Weighted least-square (WLS) R2 by trial sample size derived using linear regression was used to report correlation. Results: 15 eligible trials with 19 treatment comparisons were identified comprising a total of 16,598 patients. There was a good correlation between treatment effect on PFS and OS (correlation of HR: r, 0.88, WLS R2, 0.71; correlation of ratios of medians: r, 0.84, WLS R2, 0.72). Good correlation between treatment effect on PFS and OS was also observed in various prognostic subgroups (Table). Conclusions: In clinical trials of first-line platinum based chemotherapy without biological agents in advanced EOC, treatment effect on PFS and OS is highly correlated. PFS could be considered as a primary end point when evaluating future first line strategies in advanced EOC. [Table: see text]