Efficacy and safety of trabectedin in patients with advanced or metastatic liposarcoma or leiomyosarcoma after failure of prior anthracyclines and ifosfamide: Results of a randomized phase II study of two different schedules

Purpose: To evaluate the safety and efficacy of trabectedin in a phase II, open-label, multicenter, randomized study in adult patients with unresectable/metastatic liposarcoma or leiomyosarcoma after failure of prior conventional chemotherapy including anthracyclines and ifosfamide. Patients and Methods: Patients were randomly assigned to one of two trabectedin regimens (via central venous access): 1.5 mg/m² 24-hour intravenous infusion once every 3 weeks (q3 weeks 24-hour) versus 0.58 mg/m² 3-hour IV infusion every week for 3 weeks of a 4-week cycle (qwk 3-hour). Time to progression (TTP) was the primary efficacy end point, based on confirmed independent review of images. Results: Two hundred seventy patients were randomly assigned; 136 (q3 weeks 24-hour) versus 134 (qwk 3-hour). Median TTP was 3.7 months versus 2.3 months (hazard ratio [HR], 0.734; 95% CI, 0.554 to 0.974; P = .0302), favoring the q3 weeks 24-hour arm. Median progression-free survival was 3.3 months versus 2.3 months (HR, 0.755; 95% CI, 0.574 to 0.992; P = .0418). Median overall survival (n = 235 events) was 13.9 months versus 11.8 months (HR, 0.843; 95% CI, 0.653 to 1.090; P = .1920). Although somewhat more neutropenia, elevations in AST/ALT, emesis, and fatigue occurred in the q3 weeks 24-hour, this regimen was reasonably well tolerated. Febrile neutropenia was rare (0.8%). No cumulative toxicities were noted. Conclusion: Prior studies showed clinical benefit with trabectedin in patients with sarcomas after failure of standard chemotherapy. This trial documents superior disease control with the q3 weeks 24-hour trabectedin regimen in liposarcomas and leiomyosarcomas, although the qwk 3-hour regimen also demonstrated activity relative to historical comparisons. Trabectedin may now be considered an important new option to control advanced sarcomas in patients after failure of available standard-of-care therapies.