First-line bevacizumab plus taxane-based chemotherapy for locally recurrent or metastatic breast cancer: Safety and efficacy in an open-label study in 2251 patients

Background: First-line bevacizumab combined with chemotherapy significantly improves efficacy versus chemotherapy alone in human epidermal growth factor receptor 2 (HER2)-negative locally recurrent or metastatic breast cancer (LR/mBC). This large, open-label study further assesses first-line bevacizumab with taxane-based chemotherapy in routine oncology practice. Patients and methods: Patients with HER2-negative LR/mBC, Eastern Cooperative Oncology Group (ECOG) performance status (PS) of zero to two and no prior chemotherapy for LR/mBC received bevacizumab 10 mg/kg every 2 weeks or 15 mg/kg every 3 weeks plus taxane-based chemotherapy (or other non-anthracycline chemotherapy) until disease progression, unacceptable toxicity or patient withdrawal. The primary end point was safety; time to progression (TtP) was a secondary end point. Results: Median follow-up in 2251 treated patients was 12.7 months. Median age was 53 years and 94% of patients had ECOG PS of zero or one. Bevacizumab was most commonly administered with single-agent paclitaxel (35%), single-agent docetaxel (33%) or taxane-based combination therapy (10%). The most frequent grade ≥3 adverse event (AE) was neutropenia (5.4%). Grade ≥3 AEs previously associated with bevacizumab included hypertension (4.4%), arterial/venous thromboembolism (3.2%), proteinuria (1.7%) and bleeding (1.4%). No new bevacizumab safety signals were observed. Median TtP was 9.5 months (95% confidence interval 9.1-9.9). Conclusions: The study population in ATHENA was more representative of general oncology practice than populations enrolled into randomised trials, although there may have been some bias towards younger, fitter patients. The safety and efficacy of bevacizumab-taxane therapy in this large study were consistent with results from randomised first-line trials.