Source: DGNews  |  Posted 2 years ago

By Ann Saul

FLORENCE, Italy -- September 17, 2009 -- The therapeutic usefulness of neuronal
potassium channel openers was validated in a clinical study showing the
effectiveness and tolerability of retigabine 1,200 mg/day in adults with
refractory partial-onset seizures.

Jacqueline A. French, MD, New York University Comprehensive Epilepsy Center,
New York, New York, presented the findings of the multicentre, randomised,
double-blind, placebo-controlled, parallel-group phase 3 study on September 14
here at the 13th Congress of the European Federation of Neurological Societies
(EFNS).

A previous phase 2 study demonstrated that retigabine 600 to 1,200 mg/day
improved seizure control as adjunctive therapy to other antiepileptic drugs
(AED) in patients with partial-onset seizures.

For the current study 305 patients were randomised to retigabine 1,200 mg/day
(n = 153) or placebo (n = 152) for 12 weeks, after an 8-week titration period.

Patients in the retigabine group were force-titrated to 1,200 mg/day over a
period of 6 weeks. If patients were unable to tolerate the dose escalation,
they were discontinued from the study. After a 12-week maintenance phase,
patients were transitioned either to an open-label extension study or a 3-week
taper phase.

Findings showed that those in the retigabine group had a higher response rate
than those in the placebo group.

The median percent reduction from baseline in 28-day total partial seizure
frequency during the double-blind phase of the study was 44.3% for retigabine
versus 17.5% for placebo. In the maintenance phase, the reduction was 54.5% for
retigabine versus 18.9% for placebo. These data represent a significant
reduction ([]P[] < .001) in seizure frequency from baseline.

There were 140 (92%) adverse events (AE) in the retigabine group and 120 (85%)
in the placebo group. However, most AEs were considered to be mild or moderate
in intensity. In the retigabine group, the 6 most commonly reported AEs were
dizziness, somnolence, fatigue, confusional state, headache, and dysarthria.
During the double-blind maintenance period, 31% of patients in the retigabine
group and 12% of those in the placebo group discontinued the study due to AEs.

Funding for this study was provided by Valeant Pharmaceuticals International.

[Presentation title: Retigabine 1200 mg/day as Adjunctive Therapy in
Adults With Refractory Partial-Onset Seizures. Abstract P2405]