Excellent Tolerability of Ifosfamide and Mesna Via Continuous Infusion in a Pediatric Patient Population

Ifosfamide is an antitumor agent with activity against various malignancies in pediatric patients. As a prodrug, ifosfamide requires metabolic activation, which occurs via a saturable, multistep equilibrium-based process. Due to these metabolic characteristics, the method of administration can affect its therapeutic and toxic effects. This single-center, retrospective review describes the tolerability of continuous infusion and bolus administration of ifosfamide in 10 pediatric patients with Ewing sarcoma. The primary objective was to report the hematologic toxicities of patients with differing administration methods. Secondary objectives included collecting information on nonhematologic toxicities and incidence of treatment delays and dose reductions. Ultimately, 48 cycles of ifosfamide were administered as bolus administration and 24 as continuous infusion. Patients receiving bolus administration had lower hemoglobin and platelet nadirs resulting in more transfusions and treatment delays when compared proportionally to continuous infusion. With the results of this case series, continuous infusion ifosfamide appears to be safe and feasible for outpatient administration and may offer an advantage from a hematologic adverse event profile but would need to be confirmed in a larger cohort.