Efficacy results from a multicenter phase II noncomparative two-arm pilot trial of bevacizumab with anastrozole or fulvestrant as first-line endocrine therapy for metastatic breast cancer

1091 Background: Estrogen modulates angiogenesis via effects on endothelial cells with subsequent induction of vascular endothelial growth factor (VEGF). VEGF promotes tumor growth and is associated with poor response to antiestrogen therapy. This trial was designed to evaluate the progression-free survival (PFS) of bevacizumab (B) in combination with anastrozole (A) or fulvestrant (F) as first-line endocrine therapy (ET) in metastatic breast cancer (MBC). Methods: Eligibility criteria: no prior hormonal or chemotherapy for MBC, measurable or evaluable disease, normal LVEF, post-menopausal. Treatment: Arm A: anastrozole 1 mg po QD in pts who were a) ET naive, b) ≥ 12 months from adjuvant ET, and c) intolerant of or progressed on prior tamoxifen. Arm B: fulvestrant 500 mg D1 and 250 mg D15 IM loading dose followed by 250 mg q28 days in pts who were a) < 12 months from adjuvant aromatase inhibitors (AIs), b) intolerant of or progressed on AIs, and c) MD's discretion. Bevacizumab 10 mg/kg IV D1 q2 weeks was ...