Efficacy of ifosfamide in refractory malignant diseases and uroprotection by mesna: results of a clinical phase II-study with 151 patients.

In a clinical phase II study 151 patients with refractory malignant diseases were treated with ifosfamide (60 mg/kg/day i.v. days 1-5, q 21-28 days). Altogether, 490 courses of treatment were given, 92 with conventional prophylactic measures (continuous infusion of 3-4 litre physiological saline plus alkalinization of the urine) and 398 with mesna prophylaxis (12 mg/kg i.v., 0, 4 and 8 h after administration of ifosfamide). The overall response rate (min. 25% tumor reduction) was 67/151 (44%) including four complete remissions in a fairly unfavourable patient group with testicular teratoma (39/87), soft tissue sarcoma (10/16), malignant melanoma (2/7), osteogenic sarcoma (3/6), Ewing's sarcoma (2/6), lymphoma and acute leukemia (5/7) or other histologies (6/22). The response rate in patients pretreated by cyclophosphamide containing regimen was 7/19 (36%) including one complete remission and one partial remission. Mesna was highly effective in reducing the frequency of hemorrhagic cystitis from 25/92 (27%) to 16/398 (4%) ifosfamide courses. The antitumor activity of ifosfamide in testicular cancer was not reduced by mesna. In conclusion, ifosfamide with the potent uroprotector mesna appears to compare favourably with the most active agents in the treatment of malignant diseases.