Fig. 2. Metabolic pathway of cyclophosphamide. (Calabresi P, Parks RE Jr: Antiproliferative agents and drugs used for immunosuppression. In Gilman AG, Goodman LS, Gilman A [eds]: The Pharmacological Basics of Therapeutics, 6th ed, pp 1263–1368. New York, Macmillan, 1980)