Abstract P3-06-09: Plasma biomarker analysis in patients with HER2-negative locally recurrent or metastatic breast cancer (LR/MBC) treated with first-line bevacizumab (A) and paclitaxel (T) without or with capecitabine (X)

Background The phase II ATX trial aimed at evaluating safety and efficacy of first-line AT or ATX for HER2-negative LR/MBC (NTR1348; BOOG 2006-06). Plasma samples were collected for investigation of circulating proteins involved in angiogenesis and their possible association with therapy outcome. We here report the prognostic value of plasma VEGF-A, soluble (s)VEGFR-2, ANG2, sTIE2, IL6, IL8 and CA9 at baseline (C1D1) and their changes after cycle 1 (C2D1). Methods 312 patients were randomized 1:1 to AT (T 90 mg/m 2 d1, 8, 15 & A 10 mg/kg d1, 15 q4w x 6 cycles → A 15 mg/kg d1 q3w for next cycles) or ATX (T 90 mg/m 2 d1, 8, A 15 mg/kg d1 & X 825 mg/m 2 bid d1–14 q3w x 8 cycles → A & X at same dose q3w for next cycles). Plasma proteins were measured by immunoassays (RD San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-06-09.