Phase II study of oral trofosfamide as palliative therapy in pretreated patients with metastatic soft-tissue sarcoma

This phase II study investigated the activity of continuously administered oral trofosfamide in chemotherapy-pretreated patients with metastatic soft-tissue sarcoma (STS). Trosfosfamide is an oxazaphosphorine with ifosfamide as the predominant metabolite. Eighteen patients with a median age of 60 years were treated with trofosfamide given as continuous oral treatment. Starting dose was 300 mg/day for 7 days and subsequently 150 mg/day. All patients had previously received at least one chemotherapy regimen including doxorubicin and ifosfamide. Three patients achieved partial responses (18%) and nine a disease stabilization (53%) for an overall response rate of 18% (95% CI: 0.5-35%). Median progression-free interval was 4 months (0-17 months) and median overall survival was 10 months (4-39+) months. Toxicity was generally mild. Only one WHO grade III nausea, but no other non-hematologic WHO grade III/IV toxicity occurred. Leukopenia WHO grade III/IV was observed in four patients (22%). No thrombocytopenia <50,000/microl and no neutropenic infection was seen. Continuously administered oral trofosfamide is a well-tolerated palliative treatment in anthracycline/oxazaphosphorin-pretreated patients with advanced STS achieving responses and/or disease stabilization in up to 70% of patients.