A phase I study of ifosfamide with Mesna given daily for 3 consecutive days to children with malignant solid tumors

The authors conducted a Phase I dose escalation trial of ifosfamide given daily for 3 consecutive days to 29 children with malignant solid tumors. Twenty-eight of these children had received prior chemotherapy.

Patients were assigned to dosage cohorts separately on the basis of prior exposure to the platinum alkylating agents cisplatin or carboplatin (n = 20) or the absence of such exposure (n = 9). At least three patients in each category were treated at a starting dosage of 2133 mg/m2/d for 3 days. This dosage represented 80% of the total dose delivered in the prior study of ifosfamide given daily over 5 days with dosage escalation of 20% in subsequent cohorts.

Myelosuppression was dose-limiting at the second dosage level (2560 mg/m2/d) for patients previously treated with platinum and at the third dosage level (3072 mg/m2/d) for those not previously treated with platinum. Dose-limiting neurotoxicity was seen at 2560 mg/m2/d for the former group, but was not encountered in the latter group.

Delivery of ifosfamide daily for 3 days is feasible and safe at recommended dosages of 2133 mg/m2/d for children with prior exposure to platinum and 3000 mg/m2/d for those without prior exposure.