Phase 1b-2 trial of eribulin in combination with cyclophosphamide in patients with advanced breast cancer

A phase 1b-2 trial evaluated the combination of eribulin and cyclophosphamide in patients with pretreated advanced breast cancer (aBC). No dose-limiting toxicities were identified in the dose escalation cohort. In the dose expansion cohort, clinical benefit rate was 79.5% and the median duration of response was 16.4 weeks. Median progression-free survival was 16.4 weeks. The most common grade 3 or 4 adverse event was neutropenia (47.7% of patients). Median PFS was shorter in patients who were CTC-positive (≥5 CTC/7.5 ml) at baseline (13.1 versus 30.6 weeks; p=0.011). The authors conclude that among pretreated aBC patients, eribulin plus cyclophosphamide resulted in encouraging CBR and PFS, with neutropenia as most common grade 3 or 4 toxicity.