SRI International has regained from sanofi-aventis all rights to tirapazamine, a cancer drug that reached Phase III trials. The drug is a bioreductively activated, hypoxia-selective small molecule that acts primarily in hypoxic regions of tumors, wherein tirapazamine radicals cause double-stranded DNA breaks. Additive cell killing through this mechanism would be predicted in combination with other chemotherapeutics and antitumor regimens, including radiotherapy.
Tirapazamine was originally identified as an anticancer agent by SRI and Stanford University researchers investigating oxygen deficiency in solid tumors.
"Tirapazamine has been shown to be highly effective in experimental models, and we are interested in finding the right partner to continue clinical development of the drug," says Edward Spack, Ph.D., senior director of business development, SRI biosciences division. "To date it has been studied in patients with head and neck, non-small-cell-lung, ovarian, and other cancers, with mixed results. Clinical studies are continuing, including government and investigator-sponsored trials."