Evaluation of epothilone B analog in advanced soft tissue sarcoma: A phase II study of the phase II consortium

Purpose: Epothilones are a new class of nontaxane tubulin polymerization agents that have activity in taxane-resistant tumors. Epothilone B (BMS-247550) is a semisynthetic analog of the natural product epothilone B. This study was performed to determine the activity of BMS-247550 in patients with soft tissue sarcomas (STSs) who had not received prior chemotherapy for metastatic disease. Patients and Methods: Patients with measurable, advanced, or metastatic STS with no prior chemotherapy for metastatic disease were treated with BMS-2457550 50 mg/m² intravenously during 1 hour every 21 days. All responses were confirmed 4 weeks later. Results: Thirty-one patients (median age, 54 years; range, 19 to 78 years; 48% female) were entered onto the trial and were assessable for response. All but one patient had an Eastern Cooperative Oncology Group performance score of 0% or 1 %, and 39% had received prior adjuvant chemotherapy. Mean follow-up was 22 months, with a confirmed response rate of 6% (95% CI, 0% to 17%). Median time to progression was 4.5 months (95% CI, 1.9 to 8.3 months), and 1 year progression-free survival was 17% (95% CI, 8% to 38%). Median survival was 16.4 months, with a 1-year survival of 61% (95% CI, 46% to 81%). Toxicity was mainly hematologic, with eight of 31 (26%) patients experiencing grade 3 to 4 leukopenia; 15 of 31 patients (48%) experienced grade 3 to 4 neutropenia. The grade 3 to 4 nonhematologic toxicities included neuropathies (26%), myalgia (13%), and fatigue (10%). Conclusion: BMS-247550 has limited activity against STSs when given in this dose and schedule. The clinical toxicity is similar to that of taxanes.