The drug, sodium stibogluconate (SSG), used in the past to treat leishmaniasis, a skin disorder found mostly in tropic and sub-tropic developing countries, is now in clinical trials as a treatment for cancers of the breast, prostate, bladder, and colon.
A phase I/II study in patients with refractory cancers has been initiated at the Cleveland Clinic. Patients who have failed to see improvement with previous cancer treatments will be dosed with SSG together with interferon for evaluation of its tolerance, safety, and dosing in such combination therapy. Extensive preclinical studies in animals have shown significant anti-tumor activity with SSG at lower comparable doses of the drug than used for leishmaniasis in humans.
VioQuest has partnered with investigators at the Cleveland Clinic Taussig Cancer Center, who have found that SSG reduces specific proteins called tyrosine phosphatases (PTPases). Researchers believe that inhibition of PTPases may, in fact, enhance the activity of certain interferons, thereby improving efficacy as anticancer agents.
“The preclinical data suggest this drug may be a prototype for a completely new form of cancer therapy,” said Dr Ernest Borden, principal investigator on the trials at the Cleveland Clinic.