GlaxoSmithKline and partner Valeant Pharmaceuticals International are celebrating after getting support from advisors to the US Food and Drug Administration for their new epilepsy treatment Potiga.

The agency’s Peripheral and Central Nervous System Drugs Advisory Committee has voted unanimously (13-0) to recommend approval of Potiga (ezogabine) as adjunctive treatment for adults with partial-onset seizures. The panel also voted 11-0, with two absentions, that the risk of urinary retention risk that has been associated with the drug “could be mitigated by patient monitoring."

The FDA had specifically asked the Committee to comment on the urinary retention risk because in pivotal trials, it occurred at a rate of 0.9% in patients receiving ezogabine compared to 0.5% on placebo. In all studies of patients with partial-onset seizures, including open-label trials, five patients required catheterisation (four on Potiga and one on placebo).

The panel recommended that patient monitoring for these events would be appropriate, with special attention given to specific groups that may be predisposed to urinary retention. However GSK and Valeant noted that the Committee “also voted unanimously that monitoring should not be instituted for infection and kidney stones”.

Atul Pande, of GSK North America’s Neurosciences Medicines Development Centre, said “we are encouraged by the advisory committee's assessment of the efficacy and safety of ezogabine and await a decision by the FDA". The Prescription Drug User Fee Act goal date for the agency to complete its review is August 30 and the product, known as retigabine outside the USA, is also under review by the European Medicines Agency.

Valeant, which is in the process of being acquired by Biovail Corp, was pretty pleased too. Head of neurology R&D, Susan Hall, noted that “there is a significant need for additional anti-epileptic drugs because approximately one-third of patients with epilepsy continue to experience seizures despite treatment”.

Analysts are confident the FDA will give the definitive thumbs-up later this month and peak sales estimates vary between $200-$800 million.