Compound for treating epilepsy; Valeant Pharmaceuticals; U.S. Pat. No. 7,786,146

U.S. Patent No. 7,786,146, issued on August 31, 2010 to Valeant Pharmaceuticals International of Aliso Viejo, CA, discloses chemical compounds that serve as potassium channel modulators for treating epileptic seizures.

According to the ’164 patent, about 3% of people suffer from epilepsy, and about 30% of these people do not respond to currently available treatments.  One drug, retigabine (or ezogabine) (N-(2-amino-4-(4-flourobezylamino) phenyl carbamic acid, ethyl ester], has shown promise in treating a broad range of seizure disorders, such as epilepsy, presumably by modulating the transport of potassium ions across the neuron’s membrane.  This realization has been motivation to find additional potassium channel modulators.  Some of the compounds disclosed by the ’164 patent are purported to be potassium channel modulators which “display a 40- to 400-fold improvement over retigabine.”

According to its website, Valeant Pharmaceuticals is a multinational specialty pharmaceutical company with specializations in developing treatments in neurology and dermatology, and had $830.5 million in revenues in 2009.  Valeant’s neurology pipeline includes retigabine, which “has been evaluated in two large Phase III trials conducted in patients with refractory epilepsy receiving treatment with up to three antiepileptic drugs,” and is the subject of a exclusive worldwide collaboration agreement between Valeant and GlaxoSmithKline.  According to a recent press release, the FDA has recently extended the goal date for its regulatory review of ezogabine by three months to November 30, 2010.

Beyond treatment of epileptic seizures, retigabine is also being evaluated for treating “post-herpetic neuralgia (PHN), a painful and common complication of shingles.”  According to the company’s 2009 annual report, Valeant has a number of patents and pending patent applications covering various forms of retigabine, and the ’164 patent appears to be the result of Valeant’s efforts to find still more effective drugs.