Abstracts

Both weight gain and weight loss have been associated with many antiepileptic drugs (AEDs). AED-associated changes in weight appear slowly and over the long-term with therapy. Retigabine is a novel AED that enhances the potassium currents mediated by human KCNQ2/3 and KCNQ3/5 potassium channels and is currently undergoing global phase 3 studies as adjunctive treatment for partial-onset seizures in adults with refractory epilepsy. In this report data from Study 212, a long-term open-label extension of a double-blind phase 2 trial [1], were analyzed to characterize weight changes with long-term retigabine adjunctive therapy., 399 patients (age range: 16-70 years, baseline seizure frequency: [underline][gt][/underline]4 seizures/month) participated in a multicenter, randomized, double-blind, placebo-controlled phase 2 trial. Study design included an 8-week baseline and 16-week double-blind treatment period (8-week forced titration and 8-week maintenance). Patients received placebo or retigabine 600, 900, or 1200 mg/day and up to 2 approved AEDs. 279 patients completed the study and 222 enrolled in the open-label extension (Study 212). Patients could receive 600-1200 mg/day of retigabine. Body weight and adverse events were evaluated over time. Body weight changes and absolute body weight were calculated at various times during the treatment period., Of the 222 patients included in the analysis, 56.8% were male, and mean age was 36.1 years (range: 14-66 years). 47.3% of patients received retigabine 900 mg/day and 23.4% received 1200 mg/day as their maximum dosage. The mean duration of therapy was 352.5 days (range: 5-682 days). Body weight remained stable throughout the long-term extension study (Table). The mean difference in weight at 1 year was 2.2 kg (73.4-75.6 kg). Increased body weight was reported as a treatment-emergent adverse event (TEAE) by 3 patients (1.4%), while 2 patients discontinued the study due to increased weight, although in 1 patient this was not considered to be a TEAE.[table1], Long-term adjunctive therapy with retigabine 600 to 1200 mg/day is not associated with weight gain.
Reference
1. Porter P, Alves W, Nohria V, et al. World Congress of Neurology, 2005 (Sydney, Australia)., (Supported by Valeant Pharmaceuticals International.)