Ifosfamide vs cyclophosphamide in cancer therapy.

Ifosfamide is a newly available analog of cyclophosphamide in the oxazaphosphorine drug class. Cyclophosphamide has been marketed for 32 years, and it remains a highly effective agent for a wide cross-section of malignancies. Ifosfamide has a similar spectrum of antitumor activity but has different pharmacokinetics that could provide advantages in efficacy. Although ifosfamide has been substituted for cyclophosphamide in many therapeutic regimens, it has not been proven superior to cyclophosphamide in any cancer. Its current use in non-investigational therapy is for metastatic testicular carcinoma and sarcomas. Ifosfamide has a disadvantageous toxicity spectrum compared to cyclophosphamide and a greater financial cost and cost of patient inconvenience for administration. For most malignancies responsive to an oxazaphosphorine, the analog of choice will remain cyclophosphamide.