Relationship between OS and PFS in metastatic breast cancer (MBC): Review of FDA submission data.

Abstract

1035 Background: An improvement in overall survival (OS) in a randomized controlled study is the gold standard endpoint for the regular approval of new treatments in MBC. Progression-free survival (PFS) has been used for approval of second and third-line indications or accelerated approval of first-line indications. We have further explored the relationship between OS and PFS in MBC. Methods: We reviewed 12 randomized clinical trials in 8,431 patients with MBC. The trials led to new drug approvals or were presented at an ODAC meeting. All of these trials had PFS as a primary or secondary endpoint. Due to important limitations (e.g., lack of endpoint definitions, inconsistent PFS definitions, or insufficient information on trial statistical design) with some published trials, we limited our evaluation and endpoints correlation to data reviewed by the FDA. The relationship between PFS and OS in MBC was investigated using a weighted linear regression model, where each trial was weighted by the sample size. T...