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

Study drug will be administered three times a day in a double blind manner. The starting dose of retigabine will be 300 mg/day. This dose will be increased by 150 mg/day per week to reach the target dose of 900mg/day over a 4 week Titration Phase). The subject will then continue to receive 900mg/day for the next 12 weeks (Maintenance Phase). Eligible subjects will then be offered an opportunity to enter an open label extension (OLE) study. After a 4 week transition phase, eligible subjects will start the OLE on retigabine 900mg/day.

Study drug will be administered three times a day in a double blind manner. The starting dose of retigabine will be 300mg/day. This dose will be increased by 150 mg/day per week to reach the target dose of 600mg/day over 2 weeks. The subject will then continue to receive 600mg/day for the next 14 weeks (2 weeks of the Titration Phase and 12 weeks of the Maintenance Phase). Eligible subjects will then be offered an opportunity to enter an open label extension (OLE) study. After a 4 week Transition Phase (3 weeks on retigabine 600mg/day, 1 week on retigabine 750mg/day) eligible subjects will start the OLE on retigabine 900mg/day.

Study drug will be administered three times a day in a double blind manner. Subjects randomised to placebo will receive the same number, size and colour of tablets as the 600mg/day and 900mg/day treatment arms for the duration of the 4 week Titration Phase and the 12 week Maintenance Phase. Eligible subjects will then be offered an opportunity to enter an open label extension (OLE) study. The starting dose of retigabine will be 300 mg/day. This dose will be increased by 150 mg/day per week to reach dose of 750mg/day over the 4 weeks of the Transition Phase. On completion of the Transition Phase eligible subjects will start the OLE on retigabine 900mg/day.