Real‐life activity of eribulin mesylate among metastatic breast cancer patients in the multicenter national observational ESME program

Eribulin mesylate (EM) was recently approved for metastatic breast cancer (MBC) chemotherapy (CT) in late lines by the FDA, with debated results in second line. We evaluated outcomes in breast cancer patients receiving EM as second, third and fourth line in a national real‐life cohort of 16,703 consecutive MBC patients initiating their first metastatic therapeutic line between 2008 and 2014. Primary and secondary objectives were overall survival (OS) and progression‐free survival (PFS). An imbalance was seen for HER2+ tumors and concomitant anti‐HER2 targeted therapies use, we thus performed a subanalysis in HER2− patients. PFS and OS were significantly better in EM patients in third and fourth lines, compared to “Other chemotherapies” patients (PFS: 4.14 vs. 3.02 months, p = 0.0010; 3.61 vs. 2.53 months, p = 0.0102, third and fourth‐line; OS: 11.27 vs. 7.65 months, p = 0.0001; 10.91 vs. 5.95 months, p