Multivariate analysis (MVA) of progression-free survival (PFS) in two phase IIb, multinational, double-blind, randomized, placebo (PL)-controlled trials evaluating sorafenib (SOR) plus standard chemotherapy in patients (pts) with HER2-negative locally advanced or metastatic breast cancer (BC).

Abstract

1073 Background: Two phase IIb trials in pts with advanced BC demonstrated activity for SOR plus standard chemotherapy for the primary endpoint of PFS. In Study A, median PFS for SOR + capecitabine (CAP) versus PL+CAP was 6.4 versus 4.1 mo (hazard ratio [HR] 0.58; 1-sided p=0.0006). In Study B, median PFS for SOR + paclitaxel (PAC) versus PL+PAC was 6.9 versus 5.6 mo (HR 0.79; 1-sided p=0.09). In both studies, randomization was stratified by visceral status with slight imbalances in some covariates. We performed MVA to assess the impact of imbalances and prognostic factors on PFS. Methods: Study A: Pts (N=229) with ≤1 prior chemo regimen for advanced BC were randomized to CAP (1,000 mg/m2 po, twice daily [BID], 14 of 21 days) + SOR (400 mg po, BID) or PL. Study B: Pts (N=237) with no prior chemo for advanced BC were randomized to PAC (90 mg/m2/wk IV, 3 wk on/1 wk off) + SOR (400 mg po, BID) or PL. MVA: Cox proportional hazards models of PFS stratified by visceral status were used for each study. Additiona...