First-line bevacizumab and eribulin combination therapy for HER2-negative metastatic breast cancer: Efficacy and safety in the GINECO phase II ESMERALDA study

Purpose: Combining bevacizumab with paclitaxel significantly improves progression-free survival (PFS) versus paclitaxel alone in HER2-negative metastatic breast cancer (MBC). Eribulin is active and tolerable in pretreated MBC. To assess whether eribulin may offer a more tolerable yet effective combination partner for bevacizumab, we evaluated a bevacizumab/eribulin combination regimen as first-line therapy for MBC.

Methods: In this single-arm phase II study, patients with histologically confirmed HER2-negative MBC and no prior chemotherapy for MBC received eribulin 1.23 mg/m² on days 1 and 8 every 3 weeks for ≥6 cycles plus bevacizumab 15 mg/kg on day 1 every 3 weeks until disease progression. The primary endpoint was non-progression rate at 1 year. Secondary endpoints included objective response rate (ORR), PFS, and safety.

Results: The median age of the 61 treated female patients was 59 years, 16% had triple-negative MBC, 30% had ≥3 metastatic sites, and 71% had received prior (neo)adjuvant chemotherapy. Patients received a median of six eribulin and nine bevacizumab cycles. The non-progression rate at 1 year was 32% (95% confidence interval [CI]: 20-43%), ORR was 47% (95% CI: 34-60%), and median PFS was 8.3 months (95% CI: 7.0-9.6 months). The only grade ≥3 clinical adverse events in >5% of patients were hypertension (39%), neutropenia (26%), thrombosis (10%), and paresthesia/dysesthesia (7%).

Conclusion: First-line eribulin/bevacizumab combination therapy showed interesting activity in MBC with an acceptable safety profile, including a particularly low incidence of high-grade neuropathy.