Potent and highly selective hypoxia-activated achiral phosphoramidate mustards as anticancer drugs

J Med Chem. 2008 Apr 24;51(8):2412-20. doi: 10.1021/jm701028q. Epub 2008 Feb 8.


A series of achiral hypoxia-activated prodrugs were synthesized on the basis of the DNA cross-linking toxin of the prodrug, ifosfamide. The hypoxia-selective cytotoxicity of several of the compounds was improved over previously reported racemic mixtures of chiral bioreductive phosphoramidate prodrugs. Prodrugs activated by 2-nitroimidazole reduction demonstrated up to 400-fold enhanced cytotoxicity toward H460 cells in culture under hypoxia versus their potency under aerobic conditions. Compounds were further assessed for their stability to cytochrome P450 metabolism using a liver microsome assay. The 2-nitroimidazole containing lead compound 3b (TH-302) was selectively potent under hypoxia and stable to liver microsomes. It was active in an in vivo MIA PaCa-2 pancreatic cancer orthotopic xenograft model as a monotherapy and demonstrated dramatic efficacy when used in combination with gemcitabine, extending survival with one of eight animals tumor free at day-44. Compound 3b has emerged as a promising antitumor agent that shows excellent in vivo efficacy and is currently being evaluated in the clinic.

MeSH terms

  • Amides / chemistry
  • Amides / pharmacology*
  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Cell Hypoxia*
  • Cell Line, Tumor
  • Drug Evaluation, Preclinical
  • Humans
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Mice
  • Microsomes, Liver / drug effects
  • Phosphoric Acids / chemistry
  • Phosphoric Acids / pharmacology*
  • Solubility


  • Amides
  • Antineoplastic Agents
  • Phosphoric Acids
  • phosphoramidic acid