Ifosfamide and etoposide in the treatment of advanced soft tissue sarcomas

Ifosfamide is an active chemotherapeutic agent in the treatment of soft tissue sarcoma. This Phase II study attempted to evaluate the efficacy of the addition of etoposide to ifosfamide administered to patients with recurrent or metastatic soft tissue sarcoma. Treatment consisted of etoposide 100 mg/m2, followed by ifosfamide 2.0 g/m2, daily, for 4 consecutive days. Mesna was administered for uroprotection. Cycles were repeated at 21-day intervals or upon recovery from toxicity. Two partial responses were observed in 19 evaluable patients (response rate 10.5%, 95% confidence interval, 7% to 14%). Response durations were brief at 2 and 6 months. In a subset of 10 patients with gastrointestinal leiomyosarcoma, no responses were observed. Toxicity was generally mild, consisting primarily of myelosuppression and controllable nausea and emesis. No episodes of hematuria were observed. Overall survival for all eligible patients was 10 months (range: 0.2 to 34.7+ months). Etoposide, in this dose and schedule, failed to enhance the activity of ifosfamide in adult soft tissue sarcoma. Additionally, this experience and a review of the literature, suggest that ifosfamide has little activity against gastrointestinal leiomyosarcomas. Continued efforts are needed to identify novel agents with efficacy against these resistant tumors.