title: Oxazaphosphorines: new therapeutic strategies for an old class of drugs.
abstract: BACKGROUND
  The oxazaphosphorines (cyclophosphamide, ifosfamide and trofosfamide) are widely used in clinical practice for their antitumor and immunomodulatory activities. However, their use is associated with toxicities. The metabolism of oxazaphosphorines involves cytochrome P450 biotransformations, leading to highly reactive metabolites such as acrolein and chloroacetaldehyde responsible for urotoxicity, neurotoxicity and nephrotoxicity. While the mechanisms behind these toxicities remain under investigation, some advances have been made, as exemplified by the use of mesna to limit acrolein related urotoxicity.
  
  
  METHODS
  This review highlights potential strategies for limiting side effects commonly associated with the oxazaphosphorine drugs, through pharmacological or medicinal chemistry-based approaches.
  
  
  RESULTS
  The readers will gain a comprehensive review of these approaches to treatment in terms of: i) pharmacology: use of antidotes and modification of metabolism through inhibition/induction of CYP enzymes or use of gene therapy; and ii) medicinal chemistry: the design of new drugs to target cancer cells and avoid CYP biotransformation with pre-activated prodrugs or with side-chain substituted analogues.
  
  
  CONCLUSIONS
  An increased knowledge of oxazaphosphorines' metabolism and toxicity may allow the development of new anticancer drugs combined with drug delivery systems to circumvent drug toxicity, providing increased tumoral specificity and greater anticancer activity.
authors.affiliation: Paris XI University and Integrated Research Cancer Institute Villejuif , France.
authors.forename: Bérénice
authors.initials: B
authors.lastname: Giraud
authors.forename: Guillaume
authors.initials: G
authors.lastname: Hebert
authors.forename: Alain
authors.initials: A
authors.lastname: Deroussent
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: Veal
authors.forename: Gilles
authors.initials: G
authors.lastname: Vassal
authors.forename: Angelo
authors.initials: A
authors.lastname: Paci
mesh_terms: D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000009:adverse effects / Q000378:metabolism / Q000494:pharmacology; D003520:Cyclophosphamide / Q000009:adverse effects / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D016503:Drug Delivery Systems; D015195:Drug Design; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D007069:Ifosfamide / Q000009:adverse effects / Q000378:metabolism / Q000494:pharmacology*; D009369:Neoplasms / Q000188:drug therapy / Q000503:physiopathology
chemical_list: D018906:Antineoplastic Agents, Alkylating; D003520:Cyclophosphamide; D003577:Cytochrome P-450 Enzyme System; C003726:trofosfamide; D007069:Ifosfamide