Cancer immunotherapy using trabectedin and nivolumab in advanced soft tissue sarcoma: A retrospective analysis.

40Background: To restore innate tumor surveillance that is lost in cancer patients, a tumoricidal agent may have synergistic activity with an immune checkpoint inhibitor. Herein, we report on a retrospective analysis of our clinical experience using trabectedin, an alkylating agent, and nivolumab, a PD-1 inhibitor in advanced soft tissue sarcoma. Methods: Twenty previously treated STS patients received trabectedin (1.5 mg/m2 continuous intravenous infusion, CIV, for 24 hours) every 3 weeks, and nivolumab (3 mg/kg IV over 30 minutes) every 2 weeks. Safety/toxicity was analyzed using the NIH/NCI CTCAE v.4.03. Tumor responses were assessed by RECIST v1.1 and immune-related response criteria (irRECIST). Results: Histologic subtypes in 20 patients include undifferentiated pleomorphic sarcoma (UPS; n = 7), leiomyosarcoma (n = 5), synovial sarcoma (n = 2), myxoid liposarcoma (n = 4) and chondrosarcoma (n = 2). All patients had metastatic disease and a median of 4 lines of prior chemotherapy. Safety analysis (n =...