Safety and tolerability of eribulin mesylate in patients with pretreated metastatic breast cancer

Purpose. The safety and tolerability of eribulin mesylate for the treatment of metastatic breast cancer (MBC) are examined. Methods. This retrospective analysis used pooled safety and tolerability data from three Phase II trials and one Phase III trial of eribulin in patients with MBC. In these studies, patients with pretreated MBC received eribulin mesylate 1.4 mg/m² as a two- to five-minute i.v. infusion on days 1 and 8 of a 21-day cycle. Adverse events were assessed according to the Common Terminology Criteria for Adverse Events, version 3.0. Results. Across the four trials, 908 patients received eribulin and were assessed for safety. Aside from anthracyclines and taxanes, the most common prior chemotherapy agents were capecitabine, vinorelbine, and gemcitabine. Patients had received a mean of 3.7 (range, 1-11) prior chemotherapeutic regimens. Dose delays, reductions, and interruptions due to treatment-emergent adverse events occurred in 35.0%, 17.3%, and 2.9% of patients, respectively. Treatment was discontinued in 12.3% of patients due to adverse events, regardless of whether the adverse event was considered treatment related. The most common grade 3 or 4 treatment-related adverse events were neutropenia (52.4%) and leukopenia (19.3%). Serious adverse events occurred in 26.1% of patients, with the most common being febrile neutropenia (3.6%) and pyrexia (2.3%). Peripheral neuropathy was seen in 30.6% of patients, with 6.6% experiencing grade 3 or 4 reactions. Conclusion. Despite heavy pretreatment with anthracyclines, taxanes, and capeci-tabine, eribulin was well tolerated in this pooled analysis of patients with MBC.