Gynecologic Oncology Group studies with ifosfamide.

The Gynecologic Oncology Group has conducted a series of phase II studies with ifosfamide and mesna since 1985. Previously untreated patients received ifosfamide 1.5 g/m2 intravenously daily for 5 days. Mesna was given intravenously every 4 hours three times daily at 20% of the daily ifosfamide dose. Because of the toxic effects observed in previously treated patients with ovarian cancer, the ifosfamide dose was reduced to 1.2 g/m2/d in patients with prior chemotherapy or radiotherapy. In epithelial ovarian cancer, responses were observed in eight (20%) of 41 evaluable patients, with three (7%) complete responses. In patients with squamous carcinoma of the cervix, an 11.1% response rate (three of 27 patients) was observed in those who had received prior platinum therapy. In 51 previously untreated patients, the response rate was 15.7%. In nonsquamous cervical carcinomas, there were three partial responses among 25 patients (12%). An 8.6% response rate was observed among 23 patients with previously treated endometrial adenocarcinomas. In uterine sarcomas, response rates were 30.7% in mixed müllerian tumors, 17.2% in leiomyosarcomas, and 27.3% in endometrial stromal sarcomas. Patients with ovarian sarcomas responded in 27.8% of cases. Studies with ifosfamide combinations are currently under way by the Gynecologic Oncology Group.