Adherex Technologies Inc, a biopharmaceutical company with a broad portfolio of products under development, announced that is has received orphan drug designation for sodium thiosulfate (STS) from the U.S. Food and Drug Administration (FDA). The designation was granted for the prevention of platinum-induced ototoxicity in pediatric patients.

"FDA orphan drug designation for STS is a major milestone for both children with cancer and for the Company," said Dr. William P. Peters, CEO and chairman of Adherex. "Hearing loss among children receiving platinum-based chemotherapy is frequent, permanent and severely disabling and affects nearly a third of all children with cancer. Orphan drug designation for STS makes development commercially viable and provides multiple incentives for Adherex to undertake further clinical trials to potentially solve this significant clinical problem."

The FDA orphan-drug designation, administered by the Office of Orphan Products Development, encourages companies to develop treatments for diseases that affect fewer than 200,000 patients, or, as in this case, for preventative drugs that will be administered to fewer than 200,000 patients per year. The designation provides potential incentives such as funding for clinical studies, study design assistance, waiver of FDA user fees, substantial tax credits and, most importantly, up to seven years of market exclusivity upon regulatory approval.

STS is currently FDA approved for use in humans as part of a treatment for cyanide poisoning. Adherex obtained the intellectual property rights directed to the use of this compound as a chemoprotectant, including protection against hearing loss, through a licensing agreement with Oregon Health & Science University (OHSU). Pre-clinical investigations using animal ototoxicity models have demonstrated that STS is an effective otoprotective agent with platinum administration. Two clinical Phase I and Phase II studies have been completed by OHSU and confirm the efficacy and safety of STS as an otoprotectant for platinum-induced ototoxicity.

Dr. Edward Neuwelt of OHSU said, "Our data thus far has shown protection against platinum-induced hearing loss not only in animal models but also in human Phase I and Phase II clinical studies involving more than 100 patients. The need for hearing aids to correct high frequency hearing loss in these patients was reduced from about 50 per cent to less than 5 per cent. There is major interest in conducting a prospective, randomized trial using the Adherex drug, which would serve as a potential drug registration trial for this important clinical problem."