Veterinary Drug Might Work To Treat Human River Blindness

Researchers have discovered a possible human use for the drug closantel, currently used to treat sheep and cattle infected with liver flukes. Christian Gloeckner and Kim D. Janda of Scripps Research Institute and coworkers find that closantel might be effective against onchocerciasis, which is also known as river blindness (Proc. Natl. Acad. Sci. USA, DOI: 10.1073/pnas.0915125107). The tropical disease currently affects 18 million people worldwide, mostly in Africa, and is caused by a nematode that is transmitted to people via black flies. The sole practical treatment for river blindness is ivermectin, which Merck has donated freely to all who need it since 1988. However, resistance to ivermectin is emerging, and new medications are needed. The Scripps group screened a panel of approved drugs from the Johns Hopkins Clinical Compound Library for inhibitors of chitinase, an essential enzyme in the nematode’s life cycle. They identified closantel as a potent inhibitor of the enzyme and found that it had promising effects on treated worm larvae. The research team hopes to begin clinical testing of closantel for treating river blindness.