Phase 2 study of eribulin in patients with previously treated advanced or metastatic soft tissue sarcoma

Objective: Eribulin, a microtubule dynamics inhibitor, is approved for the treatment of patients with breast cancer and soft tissue sarcoma. We investigated the efficacy and safety of eribulin in Japanese patients with soft tissue sarcoma. Methods: This open-label, multicenter, nonrandomized, Phase 2 study enrolled Japanese patients with measurable, advanced/metastatic soft tissue sarcoma of high/intermediate grade and ≥1 prior chemotherapy for advanced disease. Patients received eribulin mesilate 1.4 mg/m² intravenously over 2-5 minutes on Days 1 and 8 of a 21-day cycle. The primary endpoint was progressionfree rate at 12 weeks. Secondary endpoints included overall survival, progression-free survival and safety. Efficacy analyses were stratified by histology (liposarcoma or leiomyosarcoma, and other subtypes). Results: Overall, 52 patients were enrolled and 51 patients were treated. Patients with liposarcoma/ leiomyosarcoma (n = 35) had similar characteristics to those with other subtypes (n = 16), except for a higher proportion of women (63% vs 38%, respectively) and patients with Eastern Cooperative Oncology Group performance status 0 (57% vs 44%). Progression-free rate at 12 weeks was 60% in liposarcoma/leiomyosarcoma patients, 31% in other subtypes and 51% overall. Median progression-free survival was 5.5 months in liposarcoma/leiomyosarcoma patients, 2.0 months in other subtypes and 4.1 months overall. Median overall survival was 17.0 months in liposarcoma/leiomyosarcoma patients, 7.6 months in other subtypes and 13.2 months overall. The most common Grade 3-4 adverse events were neutropenia (86%), leukopenia (75%), lymphopenia (33%), anemia (14%) and febrile neutropenia (8%). Conclusion: Eribulin showed clinical activity with a manageable safety profile in previously treated Japanese patients with advanced/metastatic soft tissue sarcoma.