Evaluation of formulation-associated ifosfamide neurotoxicity.

Abstract

e23562 Background: Ifosfamide, an alkylating agent used commonly in both hematologic and solid tumor malignancies, carries a notable risk for neurotoxicity/encephalopathy. Ifosfamide is available as both a reconstituted powder formulation and a solution for injection. Literature has shown that there may be higher rates of ifosfamide neurotoxicity/encephalopathy (INT/E) with the solution compared to the reconstituted powder. The primary objective of this study was to compare the rates of neurotoxicity/encephalopathy in association with the two available pharmaceutical formulations of ifosfamide. Methods: We performed a retrospective study of adult patients receiving at least one dose of either available pharmaceutical formulation of ifosfamide. The primary outcome was the incidence of formulation-associated INT/E. Secondary outcomes included additional risk factors for development of INT/E. Results: Of 218 patients evaluated, 212 were included in the study with 56 patients receiving the reconstituted powder formulation and 156 patients receiving the solution for injection formulation of ifosfamide. Baseline characteristics were similar between the two groups, including dose of ifosfamide received, use of INT/E prophylaxis, and renal and hepatic function. INT/E occurred in 4 patients (7.1%) receiving the reconstituted powder formulation vs 32 patients (20.5%) receiving the solution for injection (p = 0.022) Evaluation and analysis of additional risk factors for development of INT/E are ongoing, including the impact of baseline demographics, ifosfamide dosing, renal and hepatic function, and concomitant medications. Conclusions: In this study, hematology/oncology patients who were treated with ifosfamide had significantly lower rates of INT/E with the reconstituted powder formulation compared to the solution for injection. Further analysis regarding additional risk factors for INT/E development is ongoing.[Table: see text]