"There is a clear need for the development of antiepileptic drugs with new mechanisms of action to improve the management of patients whose epilepsy is not controlled by current medications," said Phase 2 study investigator and lead author Roger J. Porter, M.D., University of Pennsylvania. "This new molecule clearly acts by way of a different neuronal mechanism and if approved, would meet a market need. The Phase 2 data published in Neurology indicate that retigabine was efficacious for these hard-to-treat partial seizures in this study."
"We are pleased that these important findings have been published in Neurology," said Wesley P. Wheeler, president, North America and research and development. "Valeant is committed to developing innovative drugs for neurological disorders. We believe that potassium-channel openers with their unique mechanisms of action will advance the treatment of epilepsy."
In the study, investigators found that during the 8-week dose-escalation and 8-week maintenance periods, the addition of retigabine 600, 900 or 1,200 mg per day significantly reduced median monthly seizure frequency compared to baseline by 23, 29 and 35 percent, respectively. The reductions in the 900 and 1,200 mg groups were significantly greater than in the placebo group (13 percent vs. base line). Additionally, the percent of "responders" - those who had a 50 percent or greater reduction in seizure frequency - was significantly greater for the 900 and 1,200 mg groups than placebo (32 and 33 percent vs. 16 percent, respectively).
The double-blind study involved 73 centers in 19 countries (Europe, Australia and the United States), and included 396 patients who were 16 to 70 years of age with partial-onset seizures refractory to current treatment. After an initial 8-week baseline period, patients were randomly assigned to receive retigabine (600, 900 or 1,200 mg/day) or placebo, while maintaining their current therapies. Dosing of retigabine was increased gradually over a period of 8 weeks and then maintained for an additional 8 weeks.
It is currently estimated that 30 percent of those affected by epilepsy are not adequately controlled by existing medications. Retigabine is believed to act primarily by opening neuronal potassium-channels resulting in a hyperpolarizing shift that modulates the excitability of the neuronal cells. This mechanism of action (MOA) is different than other antiepileptic drugs.
Retigabine is an investigational compound that has not been found by the Food and Drug Administration (FDA) or any other regulatory agency to be safe or effective in the diagnosis, mitigation, treatment or cure of any disease or illness. It may not be sold or promoted in the United States unless and until the FDA has approved a New Drug Application. Similar restrictions apply in other countries.
Retigabine is currently being investigated in the Retigabine Efficacy and Safety Trials for Partial Onset Epilepsy (RESTORE), two large, pivotal Phase 3 trials that will evaluate the safety and efficacy of retigabine in refractory epilepsy patients who are receiving one, two or three antiepileptic drugs (AEDs).
At the completion of these trials, retigabine will have been studied in more than 1,300 patients, mor e than 300 of which have taken the investigational product for a minimum of 12 months.
The most common side effects associated with retigabine to date include somnolence, dizziness, confusion, speech disorder, vertigo, tremor, amnesia, abnormal thinking, abnormal gait, paresthesia, diplopia, incoordination, nervousness, abnormal vision, asthenia, headache, nausea and diarrhea.
Epilepsy is one of the most common neurological diseases, affecting more than 50 million people worldwide, and 2.7 million Americans of all ages. It is estimated that approximately 200,000 new cases of seizures and epilepsy occur each year, with 10 percent of the American population experiencing a seizure in their lifetime.
Valeant Pharmaceuticals International (NYSE:VRX) is a global specialty pharmaceutical company that develops, manufactures and markets a broad range of pharmaceutical products primarily in the areas of neurology, infectious disease and dermatology. More information about Valeant can be found at www.valeant.com.
Jeff Misakian, 949-461-6184