Prognostic and Predictive Value of Tumor Vascular Endothelial Growth Factor Gene Amplification in Metastatic Breast Cancer Treated with Paclitaxel with and without Bevacizumab; Results from ECOG 2100 Trial

Abstract

Abstract Purpose: Clinically validated biomarkers for anti-angiogenesis agents are not available. We have previously reported associations between candidate VEGFA single-nucleotide polymorphisms (SNP) and overall survival (OS) in E2100. The associations between tumor VEGFA amplification and outcome are evaluated here. Experimental Design: E2100 was a phase III trial comparing paclitaxel with or without bevacizumab for patients with metastatic breast cancer. FISH to assess gene amplification status for VEGFA was conducted on paraffin-embedded tumors from 363 patients in E2100. Evaluation for association between amplification status and outcomes was conducted. Results: Estrogen receptor (ER)+ or progesterone receptor (PR)+ tumors were less likely to have VEGFA amplification than ER/PR− tumors (P = 0.020). VEGFA amplification was associated with worse OS (20.2 vs. 25.3 months; P = 0.013) in univariate analysis with a trend for worse OS in multivariate analysis (P = 0.08). There was a significant interaction between VEGFA amplification, hormone receptor status, and study arm. Patients with VEGFA amplification and triple-negative breast cancers (TNBC) or HER2 amplification had inferior OS (P = 0.047); amplification did not affect OS for those who were ER+ or PR+ and HER2−. Those who received bevacizumab with VEGFA amplification had inferior progression-free survival (PFS; P = 0.010) and OS (P = 0.042); no association was seen in the control arm. Test for interaction between study arm and VEGFA amplification with OS was not significant. Conclusion: VEGFA amplification in univariate analysis was associated with poor outcomes; this was particularly prominent in HER2+ or TNBCs. Additional studies are necessary to confirm the trend for poor OS seen on multivariate analysis for patients treated with bevacizumab. Clin Cancer Res; 19(5); 1281–9. ©2012 AACR.</jats:p