Eribulin mesylate (Erib) plus capecitabine (X) for adjuvant treatment in post-menopausal estrogen receptor–positive (ER+) early-stage breast cancer: Phase II, multicenter, single-arm study.

Abstract

563 Background: Erib and X have both shown single agent activity in MBC; and X also has activity in ER+ adjuvant tx. This study was designed to evaluate the feasibility of the combination in the adjuvant setting. Methods: Female pts stage I-II, HER2 negative, ER+ BC received Erib at 1.4 mg/m2 iv D1 and D8 and X at 900 mg/m2 po bid on days 1-14 of 21 day cycle, for 4 cycles. The study was considered feasible if 80% of pts are able to achieve the target relative dose intensity (RDI) of at least 85% of the regimen and lower 95% confidence boundary (LCI) is above 70%. Results: Final results of 67pts enrolled are reported here. 88% pts completed 4 cycles of tx. Pt characteristics: Median age 62 yrs (range 28-80), ECOG 0(90%), stage 2(52%). 64/67 pts were evaluable for feasibility. The study met its primary endpoint demonstrating feasibility rate of 81%(95% LCI:71%) with average RDI of 91%. Results were mainly affected by X dose adjustments (Erib RDI-93%, X RDI-88%). X related dose reductions(24, (36%)), missed doses (57,(85%)) and discontinuations due to AE (11(16%)) were higher compared to that with Erib(14(21%), 5(8%) and 7(10%)), respectively. Most common AEs with dose reductions were gr 3/4 hand foot syndrome (HFS) (12%), neutropenia(8%), neuropathy(8%), and GI disorders(6%); and drug discontinuation were HFS(8%), neutropenia(3%), neuropathy(2%), and GI disorders(3%). Tx related AEs and SAE are reported in the Table. 14(21%) pts had an SAE with 12(18%) requiring hospitalization. Conclusions: Adjuvant tx with the Erib-X combination can be given safely with the majority of the patients able to achieve full dosing regimen. We plan to explore an alternative schedule of X(7wk on/off) with this regimen to see if it will further improve tolerability and the RDI. Clinical trial information: NCT01439282. [Table: see text]