Randomized Phase II Study of Trabectedin and Doxorubicin Compared With Doxorubicin Alone as First-Line Treatment in Patients With Advanced Soft Tissue Sarcomas: A Spanish Group for Research on Sarcoma Study

Abstract

Purpose Doxorubicin and trabectedin are considered active drugs in soft tissue sarcoma (STS). The combination of both drugs was hypothesized to be advantageous and safe on the basis of preclinical evidence and a previous phase I trial, respectively. The aim of this study was to compare the clinical outcome of trabectedin plus doxorubicin with doxorubicin as first-line treatment of advanced STS patients. Patients and Methods In this open-label randomized phase II trial, the main end point was progression-free survival (PFS). Trabectedin 1.1 mg/m2 in a 3-hour infusion plus doxorubicin 60 mg/m2 as the experimental arm and doxorubicin 75 mg/m2 as the control arm were administered for up to six cycles. Translational research was planned to correlate the expression of apoptotic and DNA repair genes with clinical outcome. Results In 115 randomly assigned patients, the median PFS was 5.5 months in the control arm and 5.7 months in the experimental arm (hazard ratio, 1.16; 95% CI, 0.79 to 1.71; P = .45) in the intent-to-treat analysis. The trial was stopped for futility after the interim analysis, because the results in the experimental arm showed the risk reduction for the main end point to be < 9.64%. The proportion of patients with grade 3 or 4 thrombocytopenia, asthenia, and liver toxicity was significantly higher in the experimental arm. FAS and p53 were shown to be prognostic factors for PFS (7.0 months if FAS+ and p53−; 3.4 months if FAS+/p53+ or FAS−/p53−; and 0.7 months if FAS− and p53+; P < .001) and for overall survival. Conclusion Trabectedin plus doxorubicin did not show superiority over doxorubicin alone as first-line treatment of advanced STS. The prognostic role of apoptotic key genes, FAS and p53, was shown to be robust enough to continue this research line.