Eslicarbazepine acetate: A double-blind, add-on, placebo-controlled exploratory trial in adult patients with partial-onset seizures

Objective: To explore the efficacy and safety of eslicarbazepine acetate (BIA 2-093), a new antiepileptic drug, as adjunctive therapy in adult patients with partial epilepsy. Methods: A multicenter, double-blind, randomized, placebo-controlled study was conducted in 143 refractory patients aged 18-65 years with ≥4 partial-onset seizures/month. The study consisted of a 12-week treatment period followed by a 1-week tapering off. Patients were randomly assigned to one of three groups: treatment with eslicarbazepine acetate once daily (QD, n = 50), twice daily (BID, n = 46), or placebo (PL, n = 47). The daily dose was titrated from 400 mg to 800 mg and to 1,200 mg at 4-week intervals. The proportion of responders (patients with a ≥50% seizure reduction) was the primary end point. Results: The percentage of responders versus baseline showed a statistically significant difference between QD and PL groups (54% vs. 28%; 90% CI = -∞, -14; p = 0.008). The difference between the BID (41%) and PL did not reach statistical significance (90% CI = -∞, -1; p = 0.12). A significantly higher proportion of responders in weeks 5-8 was found in the QD group than in the BID group (58% vs. 33%, respectively, p = 0.022). At the end of the 12-week treatment, the number of seizure-free patients in the QD and BID groups was 24%, which was significantly different from the PL group. The incidence of adverse events was similar between the treatment groups and no drug-related serious adverse events occurred. Conclusion: Eslicarbazepine acetate was efficacious and well tolerated as an adjunctive therapy of refractory epileptic patients.