Phase II trial of ifosfamide and cisplatin in the treatment of metastatic sarcomas: a Southwest Oncology Group study.

The Southwest Oncology Group (SWOG) performed a phase II trial of a combination of ifosfamide/mesna/cisplatin in patients with metastatic soft-tissue sarcoma who had previously received one chemotherapeutic regimen. A total of 39 patients were registered in the study, including 7 treated during a limited-institution pilot phase; 38 patients were fully eligible and evaluable. During the pilot phase, patients were treated with 2.5 g/m2 ifosfamide daily on days 1-3, 2.5 g/m2 mesna daily on days 1-4, and 100 mg/m2 cisplatin on days 2 and 9. Due to excessive myelosuppression, the day-9 cisplatin dose was dropped when the study was opened groupwide, and the subsequent 32 patients were treated at 3- to 4-week intervals with 2.5 g/m2 ifosfamide daily on days 1-3, 2.5 g/m2 mesna daily on days 1-4, and 100 mg/m2 cisplatin on day 2. Myelosuppression was severe, with granulocytopenia (< 0.5 x 10(9)/l) being observed in 26 of 38 patients. Three cases of National Cancer Institute grade 3 or 4 nephrotoxicity (serum creatinine, > 3 times the normal value) and three cases of grade 3 or 4 central nervous system toxicity were reported. Overall, three complete and five partial responses were achieved, for a major response rate of 21%. The median survival of all patients was 11 months. We conclude that ifosfamide-based chemotherapy can produce objective responses in previously treated patients with metastatic soft-tissue sarcoma but that cisplatin increases the toxicity of therapy. Phase II trials of new agents are needed to identify drugs with clinical activity in the treatment of soft-tissue sarcomas.