Background: Eribulin (E) has been assessed in two phase 3, open-label trials in pts with locally recurrent or MBC progressing after an anthracycline (A) and taxane (T). E significantly increased overall survival (OS) compared with treatment of physician’s choice (TPC) in one study (EMBRACE) and there was a non-significant trend for improved OS with E vs capecitabine (cape) in the other (Study 301). We present an unplanned pooled analysis of these data. Methods: In the EMBRACE trial, women had received 2–5 lines of chemotherapy for advanced disease. In this ≥ 3rd line setting, pts were randomized 2:1 to E mesylate (1.4 mg/m² iv on days 1 and 8 every 21 days) or TPC. In study 301, pts who had received 0-2 prior chemotherapies for advanced disease were randomized 1:1 to either E (as above) or cape (1.25 g/m²orally b.i.d. days 1–14 every 21 days). We analysed OS by 2-sided stratified log-rank tests and Cox regression in the overall intent-to-treat population and in the HER2-, triple negative (TNBC) and HER2+ subgroups. Results: 1,864 pts (median age 54 yrs) were included; most had been treated in the 2nd (31.5%) or 3rd line (32.7%) MBC settings. Overall, E provided significantly improved OS vs control; this benefit was also significant in HER2− and TNBC, but not HER2+ pts (Table). E improved progression-free survival overall (4.0 vs 3.4 months, HR = 0.90, 95%CI = 0.81, 0.997, p = 0.046), in HER2– (3.7 vs 3.0 months, HR = 0.84, 95%CI = 0.74, 0.95, p = 0.006) and TNBC pts (2.8 vs 2.6 months, HR = 0.78, 95%CI = 0.63, 0.96, p= 0.018). As reported before, the E safety profile was similar in the studies. Conclusions: E significantly improved OS vs standard therapies in MBC pts with HER2− and TNBC in this pooled analysis; in pts with HER2+ disease the difference did not reach statistical significance but numbers were smaller. Clinical trial information: NCT00337103 and NCT00388726.

Abbreviations: Con, control; E, eribulin; HR, hazard ratio. ^aBased on survival curve adjusted by study; ^bStratified by geographic region, prior cape use and study (plus HER2 status [overall] and TNBC [HER2-]).