Novel Epileptic Agent Found Safe and Effective

April 10, 2007

PHILADELPHIA -- The investigational epilepsy drug retigabine is safe and effective in reducing partial-onset seizures, according to researchers here.

PHILADELPHIA, April 10 -- The investigational epilepsy drug retigabine is safe and effective in reducing partial-onset seizures, according to researchers here.

In an international randomized double-blind trial that tested retigabine against placebo, the drug reduced the number of partial-onset seizures by up to 35%, depending on dose, reported Roger Porter, M.D., of the University of Pennsylvania, and colleagues, in the April 10 issue of Neurology.

The industry-sponsored study was a combined dose-ranging and efficacy study of the drug, which enhances the opening of potassium channels, said the investigators. Retigabine, they added, has activity in a wide variety of animal models of epilepsy, suggesting a broad spectrum of human antiepileptic activity.

In an eight-week baseline phase, volunteers -- all taking other anti-epileptic drugs -- were randomized to placebo or one of three doses of retigabine, 600, 900, or 1,200 mg/day.

The first eight weeks after randomization was a forced titration phase, in which volunteers began at 100 mg/day and had their dose increased by 150 mg/day weekly, so that, for example, those in the 600-mg arm reached the study dose at day 15.

At the end of the eight-week forced titration phase, patients were kept on a maintenance dose for a further eight weeks.

The study found:

  • Of 399 randomized patients, 279 (or 69.9%) completed double-blind treatment.
  • Median percent change in monthly total partial-seizure frequency from baseline -- the primary efficacy endpoint -- was a reduction of 13% for placebo, 23% for 600 mg/day, 29% for 900 mg/day, and 35% for 1,200 mg/day.
  • The trend was significant at P

"Some of the participants might have better tolerated a more flexible dosing schedule."

The data show that "retigabine is, in its first controlled efficacy trial, a drug with substantial efficacy for hard-to-treat partial seizures," the researchers said.

They concluded that the results of the trial warrant further development of retigabine in Phase III studies, as adjunct therapy for hard-to-control partial onset seizures.