Phase II study of eribulin with trasutuzumab for pretreated locally advanced or metastatic HER2-positive breast cancer.

Abstract

e12505 Background: Eribulin mesylate demonstrated a survival benefit in patients with locally recurrent or metastatic breast cancer who previously received 2 or more chemotherapy regimens. There are limited studies reported about the efficacy of eribulin with trastuzumab as first-line therapy for locally advanced or metastatic HER2-positive breast cancer. The aim of this study was to assess the efficacy and safety of eribulin with trastuzumab as late-line therapy for locally advanced or metastatic HER2-positive breast cancer. Methods: In this multicenter, phase II, single-arm study, patients with locally advanced or metastatic HER2 positive breast cancer who previously received at least one chemotherapeutic regimen, received eribulin at 1.4 mg/m2 intravenously (I.V.) on days 1 and 8 of each 21-day cycle with an initial trastuzumab dose of 8 mg/kg I.V. on day 1, followed by 6 mg/kg of trastuzumab on day 1 of each subsequent cycle. The primary end point was ORR, and secondary end points included PFS and safety. Results: Thirty-six patients (median age: 60.5 years) were enrolled. The median number of prior treatment regimens was 4 (range, 1‐8). Twenty-two patients (61.1%) had received prior pertuzumab treatment, 10 patients (27.8%) had prior T-DM1. Patients received a median of 6 cycles of eribulin with trastuzumab (2-13 cycles). The ORR was 17% (CR 0, PR 6) with median PFS of 4.6 months (3.3-7.0 months). The clinical benefit rate was 33%. The most common Grade 3/4 treatment-emergent adverse events were neutropenia in 22 (61%) patients, peripheral neuropathy in 3 (8%; all Grade 3) patients, fatigue in 1 (3%) patients. Five (13.9%) patients had asymptomatic LVEF decline. However, no grade 3 LVEF decline or symptomatic congestive heart failure was observed. The reasons for treatment discontinuation were disease progression in 27 (75%) patients and adverse events in 8 (22%) patients. Conclusions: Eribulin with trastuzumab is an acceptable option in late-line treatment for locally advanced or metastatic HER2-positive breast cancer. Clinical trial information: 000012350.