Phase 2 trial of single agent ifosfamide/mesna in patients with platinum/paclitaxel refractory ovarian cancer who have not previously been treated with an alkylating agent.

Ifosfamide has been shown to possess modest activity in patients with platinum/cyclophosphamide refractory ovarian cancer. Current standard initial chemotherapy for ovarian cancer does not include an alkylating agent (paclitaxel substituting for cyclophosphamide). To evaluate the activity of ifosfamide in patients with refractory ovarian cancer who had not previously received an alkylating agent, 21 patients with platinum/paclitaxel refractory disease were treated with the drug as a single agent (1.8 g/m2/day x 3 days, with treatment repeated every 28 days). Treatment was reasonably well tolerated in most patients, although 1 individual was removed from study secondary to neurotoxicity. One patient exhibited an objective response of measurable disease, while a second individual had a major decrease in CA-125 levels (no measurable disease present) following therapy. An additional patient experienced disappearance of severe pelvic pain following treatment but failed to meet the criteria for a partial response. We conclude that ifosfamide has modest activity in platinum/paclitaxel refractory ovarian cancer. However, the level of effectiveness does not appear to be increased in individuals who are alkylating-agent naive, compared to previously reported experience in patients with prior exposure to this class of cytotoxic drugs (10-15% response rate).