Interim results of a real-world observational study of eribulin in soft tissue sarcoma including rare subtypes

Although eribulin is used to treat soft tissue sarcomas (STSs), treatment data for rare subtypes are limited. We conducted a post-marketing surveillance study to assess safety and efficacy of eribulin in STS patients stratified by subtype. Japanese patients (n = 256) with advanced or metastatic STS receiving eribulin treatment were monitored for treatment status, adverse events, diagnostic imaging, and clinical outcomes at 3 months and 1 year. Interim analysis was performed. Patients will be monitored up to 2 years. Interim analysis included 3-month (n = 255), imaging (n = 226), and 1-year (n = 105) data. STS subtype distribution was normal. Median number of eribulin cycles was 3.0 (range: 1-17 cycles). Among patients with imaging data, best overall tumor response (12 weeks) was partial response, 7.5% (n = 17); stable disease, 34.5% (n = 78); and stable disease ≥11 weeks, 10.2% (n = 23). Overall response rate (ORR), disease control rate (DCR), and clinical benefit rate (CBR) for all patients were 7.5%, 42.0% and 17.7%, respectively. ORR, DCR, and CBR were 10.3%, 32.0% and 16.5%, respectively, for patients with STS subtypes other than liposarcoma and leiomyosarcoma and included responses from patients with rare STS subtypes. Adverse drug reactions (ADRs) occurred in 211 (82.7%) patients (42 [16.5%] patients had serious ADRs), and none led to death. ADRs leading to drug withdrawal and dose reduction occurred in 27 (10.6%) and 55 (21.6%) patients, respectively. Eribulin was generally well tolerated and showed antitumor activity against STSs, including rare subtypes that currently have few treatment options. NCT03058406 (ClinicalTrials.gov).