9403 Eribulin mesylate (E7389) in patients with leiomyosarcoma (LMS) and other (OTH) subtypes of soft tissue sarcoma (STS): a Phase II study from the European Organisation for Research and Treatment of Cancer – Soft Tissue and Bone Sarcoma Group (EORTC 62052)

Abstract

The efficacy and safety of continuing multiple anti-HER2 therapies in advanced breast cancer (ABC) patients remains unclear. This study investigated eribulin in combination with pertuzumab and trastuzumab for both taxane- and trastuzumab-pretreated HER2-positive ABC patients.In a single-institute, single-arm, open-label, phase II trial, HER2-positive ABC patients who had previously received taxanes and trastuzumab were treated with eribulin in combination with pertuzumab and trastuzumab. The pharmacokinetics of eribulin in this combination were assessed in 6 patients. Tumor assessments were conducted every 6 weeks for the first 6 cycles and every 12 weeks thereafter. The primary endpoint was objective response rate (ORR).A total of 30 patients (median age, 58 years; range, 31–76) were enrolled, with a median number of previous chemotherapy regimens of 3.5 (range: 1–9) in the metastatic setting. Pharmacokinetic parameters of eribulin in this combination were similar to previous reports of eribulin monotherapy. ORR was 34.8% (95% CI: 16.4–57.3, n = 23), and median progression-free survival was 42.6 weeks (95% CI: 20.3–51.9, n = 30). Clinical benefit rate was 60.9% (95% CI: 16.4–57.3). The most common grade 3/4 adverse event was neutropenia in 20 patients (66.7%). A dose reduction of eribulin was required in 27 patients due to adverse events, particularly grade 3 neutropenia.Eribulin in combination with pertuzumab and trastuzumab was well tolerated in heavily pretreated patients. Eribulin may be a viable treatment option when used in combination with pertuzumab and trastuzumab for HER2-positive ABC patients (UMIN Clinical Trial Registry identification number, UMIN000012375).