Abstracts

Rationale: Eslicarbazepine acetate (ESL) is a novel voltage-gated sodium channel blocker not approved for use in the United States. Two double-blind, placebo-controlled Phase III studies evaluated ESL once-daily (QD) as adjunct therapy in patients with partial-onset seizures. It is not known if the efficacy of adjunct ESL varies based on concomitant antiepileptic drug (con-AED). Methods: We studied patients (N=790) in the intent-to-treat population who received at least 1 dose of study medication (ESL 400 mg QD, 800 mg QD, 1200 mg QD or placebo) added to1-3 concomitant AEDs, and had at least 1 post-dose seizure assessment in the two studies. An exploratory analysis on the impact of con-AEDs on efficacy was conducted for the double-blind portion of these studies (BIA 2093-301 and BIA 2093-302). Log-transformed standardized seizure frequency per 4 weeks over the 12-week maintenance period was analyzed using ANCOVA model with fixed effects for treatment, study, baseline standardized seizure frequency and number of con-AEDs, and interaction of treatment with the 4 most commonly used con-AEDs. Results: The most commonly used con-AEDs were carbamazepine (58.7%), lamotrigine (23.5%), valproic acid (23.5%), and topiramate (16.7%). ESL 800 and 1200 mg QD significantly reduced seizure frequency compared to placebo. There was no significant interaction between type of con-AED and treatment effect. Conclusions: Adjunct treatment with ESL 800 and 1200 mg QD had a consistent effect in reducing seizure frequency compared to placebo independent of type of con-AEDs. The limitation of these analyses was that patients may have been on more than a single con-AED and the impact of these combinations could not be assessed.Studies supported by BIAL-Portela; analysis by Sunovion.