First-line bevacizumab in combination with weekly paclitaxel for metastatic breast cancer: efficacy and safety results from a routine oncology practice analysis

Abstract

Background: First-line bevacizumab plus paclitaxel therapy for human epidermal growth receptor factor 2 negative (HER2-) metastatic breast cancer (MBC) demonstrated a median progression-free survival (PFS) of around 11 months in few pivotal randomized phase 3 trials (E2100, TURANDOT, and CALGB 40502). However median overall survival (OS) did not significantly differ between treatment arms. Patients and methods: We analysed a series of MBC patients treated between 2008 and 2016 at our Department using bevacizumab plus paclitaxel regimen as first line (bevacizumab 10 mg/kg on days 1,15 q28 plus paclitaxel 90 mg/mq on days 1,8,15 q28). Primary endpoints were efficacy outcomes measured as PFS, overall response rate (ORR), clinical benefit rate (CBR), and OS on the whole series, and on selected subgroup of patients. CBR was defined as the percentage of patients who have achieved complete response, partial response or stable disease > =6 months. Toxicity profile of the treatment was recorded following the NCI CTCAE, version 4. Results: We overall evaluated a series of 97 patients. The median PFS was 9 months (range 2-68); no significant differences were shown in patients previously treated with taxanes in (neo)adjuvant setting (p = 0.42), and endocrine treatment for the MBC (p = 0.53). The best ORR was 25% (24/96 cases), and the CBR was 72.9% (70/96 cases). No significant difference emerged in terms of presence of visceral disease (9 vs 19 months; HR 1.1 95%CI 0.67 to 1.9; p = 0.63), triple negative (8 vs 13 months; HR 1.5 95%CI 0.74 to 4.67; p = 0.19), age (<65 vs > =65 years; p = 0.25), and time to failure from adjuvant treatment ( < =18 vs > 18 months; p = 0.12). The median OS was 26 months (range 2-111). Patients showing a PFS longer than 18 months evidenced a significant OS improvement (21 vs 75 months; p < 0.0001). Eleven grade 3 AE were reported: hypertension (5.1%), neutropenia (5.1%), and peripheral neuropathy (1%). Conclusions: In our experience bevacizumab plus paclitaxel regimen as first line chemotherapy for HER2- MBC confirmed the efficacy results of pivotal trials. The regimen is highly effective and overall well-tolerated. Patients with prolonged PFS (>18 months) resulted in a significant better OS. Therefore, there is a strong need for studies aiming to identify predictive factors for response to treatment.