To evaluate the safety and efficacy of adjunctive eslicarbazepine acetate (ESL) in adults with focal seizures, according to epilepsy etiology.

ESL is a once-daily (QD), oral antiepileptic drug (AED) for focal (partial-onset) seizures.

Data were pooled from three Phase III, randomized, double-blind, placebo-controlled trials
(2093-301, -302, -304). After an 8-week baseline period, adults with ≥4 focal seizures/month and taking 1–3 AEDs were randomized equally to receive placebo, ESL 400 mg (Studies 301 and 302 only; not reported here), ESL 800 mg or ESL 1200 mg QD (2-week titration; 12-week maintenance).

Epilepsy etiology categories (safety/efficacy analysis populations) included: other/unknown (n=526/520), idiopathic (n=255/239), cranial trauma/injury (n=166/164), congenital/hereditary disorders (n=109/106), and infectious disease (n=105/104). Responder (≥50% reduction from baseline in standardized seizure frequency) rates were dose-related for most etiologies. Patients with infectious disease (58.3%) and cranial trauma/injury (46.3%) etiologies had the highest responder rates with ESL 1200 mg; patients with congenital/hereditary disorders had the lowest (29.0%). Treatment-emergent adverse event (TEAE) incidences were generally higher with ESL than placebo but similar between ESL doses, across etiologies. Serious adverse events occurred in <10% of patients in most groups. Incidences of TEAEs leading to ESL discontinuation were dose-related. TEAEs leading to ESL discontinuation (32.4%) and psychiatric TEAEs (13.5%) were most frequent in patients with congenital/hereditary disorders receiving ESL 1200 mg.

The efficacy of ESL was generally comparable across epilepsy etiologies (responder rates: 23–58%). Responder rates were higher with ESL than placebo and dose-related. Responder rates were highest in patients with epilepsy caused by infectious disease or cranial trauma/injury, and lowest in those with congenital/hereditary disorders. Incidences of TEAEs leading to ESL discontinuation were dose-dependent. TEAEs leading to ESL discontinuation and psychiatric TEAEs occurred most frequently in patients with congenital/hereditary disorders.