Efficacy and toxicity of 4-(2-sulfonatoethylthio)-cyclophosphamide cyclohexylamine salt (ASTA Z 7557, INN mafosfamide) after intraperitoneal administration to mice.

4-(2-sulfonatoethylthio)-cyclophosphamide cyclohexylamine salt (AZ; ASTA Z 7557) is a cyclophosphamide (CP) analog designed to be without acute bladder toxicity and to undergo spontaneous activation yielding phosphoramide mustard (PM). Studies in murine systems with intraperitoneal (i.p.) administration suggest that AZ may have a therapeutic index favorable to CP without an associated risk of bladder toxicity. Pericapsular hepatic fibrosis after i.p. administration suggests that regional AZ therapy may cause local toxicity. Further study of this compound, especially with intravenous (i.v.) administration, will be of interest.