Induction therapy with paclitaxel and bevacizumab followed by switch maintenance therapy with eribulin in Japanese patients with HER2-negative metastatic breast cancer: a multicenter, collaborative, open-label, phase II clinical study for the SBCCSG 35 investigators

BACKGROUND: To examine the efficacy and safety of induction therapy with paclitaxel and bevacizumab followed by switch maintenance therapy with eribulin (ISMT) in Japanese patients with HER2-negative metastatic breast cancer (MBC). METHODS: Patients, who had previously undergone a maximum of 2 regimens of chemotherapy, received 3 cycles of induction therapy with paclitaxel (90 mg/m(2) intravenously on days 1, 8, and 15 followed by 1-week drug holiday) and bevacizumab (10 mg/kg intravenously after the completion of paclitaxel administration on days 1 and 15). Patients who had complete response, partial response, or stable disease underwent switch maintenance therapy with eribulin (1.4 mg/m(2) intravenously on days 1 and 8 followed by 1-week drug holiday). The primary endpoint was time to treatment failure (TTF) for ISMT. RESULTS: Fifty-one eligible patients (median age: 66 years; range: 35–74) were enrolled: 19 (37.3%) and 32 (62.7%) had stage IV and recurrence, respectively, 42 (82.4%) had visceral metastases, and 45 (88.2%) received eribulin—38 of whom showed disease progression, and 40 (78.4%) underwent post therapy. Median TTF was 9.2 months (95% confidence interval [CI]: 7.3–11.1), median progression-free survival was 10.7 months (95% CI: 9.6–11.8), and median overall survival was 20.0 months (95% CI: 16.0–24.0). Relative dose intensity was 97.7% (range: 33.3–100.0) for induction therapy and was 83.3% (range: 49.3–100.6%) for eribulin maintenance therapy. The most common adverse event was alopecia (51 [100%]) in induction therapy and was peripheral sensory neuropathy (37 [82.2%]) in eribulin maintenance therapy. Eribulin was effective with manageable tolerability. CONCLUSIONS: ISMT may be a promising therapeutic option for patients with MBC. TRIAL REGISTRATION: UMIN000015971. Registration date: January 1, 2015.