Pooled Analysis of Trabectedin Efficacy in Myxoid/Round Cell Liposarcoma from Three Prospective Clinical Trials

Background/Objectives: Trabectedin is a standard-of-care chemotherapy for recurrent/metastatic liposarcomas, including myxoid/round cell liposarcoma (MRCLS). This pooled analysis was performed to evaluate trabectedin efficacy in MRCLS across multiple trials to establish a standard-of-care efficacy baseline. Methods: The Yale University Open Data Access (YODA) Project was queried for prospective trabectedin trials. Data on patients with unresectable, locally advanced/metastatic MRCLS who received ≥ 1 trabectedin dose(s) (1.0–1.5 mg/m2 administered as a 24-h continuous infusion every 3 weeks) were extracted from three trials: NCT00060944, NCT00210665, and NCT01343277. The primary outcome was the objective response rate as per the Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Secondary outcomes included disease control rate and overall survival, defined as the time from first trabectedin administration to death. Responses were assessed using RECIST by investigators in NCT01343277 and by independent review in NCT00060944. In NCT00210665, tumor assessment followed institutional standards, so only overall survival was analyzed. Results: Sixty-three patients were included (42 from NCT01343277, 13 from NCT00060944, 8 from NCT00210665): 32% were female, the median age was 50 years, and 79% were White. The objective response rate was 16.3% (8/49) of patients (37 from NCT01343277, 12 from NCT00060944). The disease control rate was 77.6% (38/49). Overall survival data were available for 63 patients: the median overall survival was 22.51 months (95% CI: 16.99–34.33). Conclusions: This analysis represents one of the largest pooled populations to date of patients with advanced MRCLS treated with trabectedin in prospective clinical trials to be reported. Whilst limited by typical factors affecting pooled analyses, including cross-study heterogeneity, nevertheless the results estimate a trabectedin efficacy baseline against which to inform other therapies for MRCLS.