Reduction of ifosfamide toxicity using dose fractionation.

Ifosfamide was given in i.v. doses of 600 to 1200 mg/sq m/day for 5 days to 32 cancer patients, refractory to prior therapy, in an attempt to investigate the possibility of reducing toxicity by dose fractionation. Microscopic hematuria occurred in 14% and gross hematuria in only 10% of the patient trials. Azotemia did not occur in any patient on this study. Reversible myelosuppression was comparable to that found by other investigators. Other side effects such as nausea and mental confusion occurred infrequently. Ifosfamide produced antitumor effect in 7 of 27 evaluable patients. This study indicates that the renal and bladder toxicity of ifosfamide can be substantially reduced if the drug is administered in i.v. infusions of 1 to 2 hr daily for 5 days.