NCI Drug Dictionary

The NCI Drug Dictionary contains technical definitions and synonyms for drugs/agents used to treat patients with cancer or conditions related to cancer. Each drug entry includes links to check for clinical trials listed in NCI's List of Cancer Clinical Trials.

fosbretabulin tromethamine
The tromethamine salt form of prodrug fosbretabulin, a water-soluble phosphate derivative of a stilbenoid phenol derived from the African bush willow (Combretum caffrum) with antineoplastic activities. Upon administration, fosbretabulin is dephosphorylated to its active metabolite, combretastatin A4, which targets and binds to tubulin dimers and prevents microtubule polymerization, thereby resulting in mitotic arrest and apoptosis in endothelial cells. As apoptotic endothelial cells detach from their substrata, tumor blood vessels collapse; the acute disruption of tumor blood flow may result in tumor necrosis. Check for active clinical trials using this agent. (NCI Thesaurus)

Synonym:combretastatin A4 phosphate
US brand name:Zybrestat
Chemical structure:
  • 1,3-dihydroxy-2-(hydroxymethyl)propan-2-aminium 2-methoxy-5-((1z)-2-(3,4,5-trimethoxyphenyl)ethenyl)phenyl hydrogen phosphate
  • 1,3-propanediol, 2-amino-2-(hydroxymethyl)-, compd. with 2-methoxy-5-((1z)-2-(3,4,5-trimethoxyphenyl)ethenyl)phenyl dihydrogen phosphate (1:1)