Eribulin mesylate in pretreated breast cancer patients: a multicenter retrospective observational study.

Eribulin was recently approved in patients progressing after being treated with anthracyclines and taxanes and after two or more chemotherapy lines for advanced disease.This multicenter observational retrospective study was performed in order to evaluate activity and tolerability of eribulin in real-world patient population.133 advanced breast cancer patients pretreated with ≥ 2 chemotherapy lines for metastatic disease were retrospectively enrolled in the observational trial in 11 italian cancer centres.A median of 5 cycles of eribulin (range, 1-15) were administered. Twenty-eight partial responses were observed, for an overall response rate of 21.1\% (95\%CI,14.1-28.0). A stable disease was recorded in 57 patients (42.8\%), and a clinical benefit (response or stable disease lasting ≥ six months) was observed in 51 patients (38.3\%, 95\%CI, 30.1-46.6). The subgroup analysis showed that a significant improvement in term of partial response and clinical benefit was achieved when eribulin was administered in HER-2 negative tumors (p=0.01 and p=0.004, respectively) and when it is given as third-line (p=0.09 and p=0.02, respectively). Toxicity was manageable; fatigue is the most common side effect observed, usually of low-grade, and clearly cumulative-dose related.In this retrospective, observational analysis eribulin confirmed its efficacy and manageable tolerability even in real-world population and in heavily pretreated patients