MISSISSAUGA, Ontario, LONDON, and RESEARCH TRIANGLE PARK, N.C., June 13, 2011 /PRNewswire via COMTEX/ -- Valeant Pharmaceuticals International, Inc. and GlaxoSmithKline (NYSE: GSK) announced today that the U.S. Food and Drug Administration (FDA) has approved Potiga(TM) (ezogabine) Tablets, a potassium channel opener, as adjunctive treatment of partial-onset seizures in patients aged 18 years and older.

This is the first step in final approval. The FDA has recommended that ezogabine be scheduled as a controlled substance under the Controlled Substances Act (CSA). Final classification is still under review by the Federal Drug Enforcement Administration (DEA) and ezogabine will not be available until this process is complete.

"We are so pleased to reach such an important milestone with the U.S. approval of Potiga by the FDA," stated Susan Hall, Ph.D., head of research and development at Valeant. "We believe this product will play a needed role in the management of partial onset seizures in appropriate patients who are uncontrolled on their current medications."

The efficacy of ezogabine as adjunctive therapy in partial onset seizures was established in three controlled clinical studies involving 1,239 adult patients. The primary endpoint was percent change in seizure frequency from baseline in the double-blind treatment phase.

The FDA has determined that a Risk Evaluation and Mitigation Strategy (REMS) will be necessary for ezogabine, with the goal of informing health care professionals of the risk of urinary retention and the symptoms of acute urinary retention. Ezogabine caused urinary retention in clinical trials. Urinary retention was reported as an adverse event in 29 out of 1,365 (approximately 2 percent) patients treated with ezogabine. In all studies of patients with partial-onset seizures, including open-label studies, five patients required catheterization (four on ezogabine and one on placebo).

In three controlled clinical studies, 25 percent of patients receiving ezogabine (199/813) and 11 percent of patients receiving placebo (45/427) discontinued treatment because of treatment-emergent adverse reactions.

The most frequently reported adverse reactions in patients receiving ezogabine vs placebo were dizziness, somnolence, fatigue, confusional state, vertigo, tremor, abnormal coordination, double vision, disturbance in attention, memory impairment, blurred vision, gait disturbance and balance disorder.

Ezogabine is expected to be available in U.S. pharmacies by the end of the year. Full Prescribing Information and a Medication Guide will be available at http://www.gsk.com once scheduling is complete.

Outside of the U.S., ezogabine is known as retigabine (brand name Trobalt(TM)), and received marketing authorization in the European Union (EU) on March 28, 2011.

For more information on Potiga, please refer to the podcast on this drug with Dr. Carl Bazil found below.

Joseph Sirven, M.D.
Editor-in-Chief, epilepsy.com 
Last Reviewed: 6/15/11