Assessment of the Efficacy and Safety of 2 Doses of Retigabine Immediate Release (900 mg/Day and 600 mg/Day) Used as Adjunctive Therapy in Adult Asian Subjects With Drug-resistant Partial-onset Seizures

Epilepsy Clinical Trial

Official title: A Randomised, Double-blind, Placebo-controlled, Parallel-group, Multicentre Study to Determine the Efficacy and Safety of 2 Doses of Retigabine Immediate Release (900 mg/Day and 600 mg/Day) Used as Adjunctive Therapy in Adult Asian Subjects With Drug-resistant Partial-onset Seizures.

Status Terminated

Clinical Trial Summary

The immediate release (IR) formulation of retigabine has been shown to be superior to placebo as adjunctive therapy in 3 adequate and well-controlled studies in subjects with drug-resistant partial-onset seizures (POS) who had previously failed to respond to two or more antiepileptic drugs (AEDs) and were still having seizures despite current treatment with 1, 2, or 3 AEDs. However, of 1244 subjects randomly assigned to treatment in these 3 clinical studies, only 10 were Asian subjects and only 5 of these Asian subjects were randomly assigned to treatment with retigabine. Therefore, this Phase III study is being conducted to evaluate the efficacy, safety and tolerability, and health outcomes of retigabine, at doses of 900 mg/day and 600 mg/day, compared with placebo in adult Asian subjects with drug-resistant POS.

Clinical Trial Description

This is a Phase III study evaluating the efficacy, safety and tolerability, and health outcomes of 2 doses of retigabine immediate release (IR) (GW582892) compared with placebo in adult Asian subjects with drug-resistant partial-onset seizures (POS) who are already taking 1, 2, or 3 antiepileptic drugs (AEDs). This randomised, double-blind, placebo-controlled, parallel-group study will compare retigabine IR at doses of 900 mg/day and 600 mg/day taken in equally divided doses three times a day with placebo.

The study design includes an 8-week Screening/Baseline Phase, a 16-week Treatment Phase (4-week Titration Phase and 12-week Maintenance Phase), and a 4-week Transition or Taper/Follow-up Phase. Approximately 500 subjects will be screened and enrolled with approximately 354 subjects randomly assigned to 1 of 3 treatment groups in a ratio of 1:1:1 (retigabine 900 mg/day, retigabine 600 mg/day, or placebo). The total duration of the study for each subject will be approximately 28 weeks. At the end of the Maintenance Phase, eligible subjects will be given the opportunity to enrol in an open-label extension study.

The primary efficacy endpoint is the proportion of responders, defined as subjects with >/=50% reduction in 28 day total POS frequency, from the Baseline Phase to the Maintenance Phase, in subjects randomly assigned to retigabine 900 mg/day compared with placebo. The key secondary efficacy endpoint is the proportion of responders, defined as subjects with >/=50% reduction in 28 day total POS frequency, from the Baseline Phase to the Maintenance Phase, in subjects randomly assigned to retigabine 600 mg/day compared with placebo.

The safety and tolerability endpoints are incidence and severity of adverse events (AEs); proportion of subjects with AEs leading to discontinuation; change from Baseline in vital sign measurements and weight; change from Baseline in electrocardiogram parameters; change from Baseline in haematology, chemistry, and urinalysis parameters; changes from Baseline in American Urological Association Symptom Index and post-void residual bladder ultrasound volumes; and summary of the Columbia-Suicide Severity Rating Scale. ;

Related Conditions & MeSH terms

• Epilepsy
• Seizures

• NCT number: NCT01648101
• Study type: Interventional
• Source: GlaxoSmithKline
• Status: Terminated
• Phase: Phase 3
• Start date: August 29, 2012
• Completion date: December 23, 2013