Pilot study of ambulatory infusional ifosfamide admixed with carboplatin

Ifosfamide and carboplatin are agents that have completed Phase I studies using a continuous infusion schedule for as long as 14 days. The in vitro compatibility of the two drugs allows for the simultaneous administration in an admixture, and a pilot study was undertaken to determine the feasibility and tolerability of the infusion schedule for the combination.

Ifosfamide at 500 mg/M2/day and carboplatin at 15 or 20 mg/M2/day were administered for 14-day cycles repeated at 28 days in 29 patients, with a total of 60 courses administered.

Total cumulative dose per cycle was: ifosfamide 7.0 g/M2 and carboplatin 210-280 mg/M2. Hematuria developed in five patients, four of whom had prior urologic disease, severe thrombocytopenia, or pelvic radiation. In all patients, the hematuria was transient and inconsequential despite the absence of mesna. Grade 3 or 4 leukopenia was observed in eight patients with or without thrombocytopenia and delayed subsequent treatment cycles. Thrombocytopenia was less frequent (Grade 3, 2 patients: Grade 4, 1 patient). No significant episodes of sepsis or hemorrhage were noted. Anemia requiring transfusion developed in 12 of 29 patients. Twenty-one of the 29 patients had received prior chemotherapy. Five of seven previously untreated patients with non-small cell lung cancer achieved a complete (1) or partial (4) response.

A continuous 14-day infusion of ifosfamide admixed with carboplatin is feasible in an ambulatory setting with no need for adding mesna for urologic protection and full dosage administration for each agent. Phase 2 studies in non-small cell lung cancer would be reasonable at the optimal doses of ifosfamide 500 mg/M2/day and carboplatin 15 mg/M2/day, and the potential exists for the introduction of additional agents, such as etoposide.