Long-term safety and efficacy of lacosamide and controlled-release carbamazepine monotherapy in patients with newly diagnosed epilepsy

Abstract

Objective: A large-scale, double-blind trial (SP0993; NCT01243177) demonstrated that lacosamide was noninferior to controlled-release carbamazepine (carbamazepine-CR) in terms of efficacy, and well tolerated as first-line monotherapy in patients (≥16 years of age) with newly diagnosed epilepsy. We report primary safety outcomes from the double-blind extension of the noninferiority trial (SP0994; NCT01465997) and post hoc analyses of pooled long-term safety and efficacy data from both trials.

Methods: Patients were randomized 1:1 to lacosamide or carbamazepine-CR. Doses were escalated (lacosamide: 200/400/600 mg/d; carbamazepine-CR: 400/800/1200 mg/d) based on seizure control. Eligible patients continued randomized treatment in the extension. Primary outcomes of the extension were treatment-emergent adverse events (TEAEs), serious TEAEs, and discontinuations due to TEAEs. Post hoc analyses of data from combined trials included 12- and 24-month seizure freedom and TEAEs by number of comorbid conditions.

Results: A total of 886 patients were treated in the initial trial and 548 in the extension; 211 of 279 patients (75.6%) on lacosamide and 180/269 (66.9%) on carbamazepine-CR completed the extension. In the extension, 181 patients (64.9%) on lacosamide and 182 (67.7%) on carbamazepine-CR reported TEAEs; in both groups, nasopharyngitis, headache, and dizziness were most common. Serious TEAEs were reported by 32 patients (11.5%) on lacosamide and 22 (8.2%) on carbamazepine-CR; 12 (4.3%) and 21 (7.8%) discontinued due to TEAEs. In the combined trials (median exposure: lacosamide 630 days; carbamazepine-CR 589 days), Kaplan-Meier estimated proportions of patients with 12- and 24-month seizure freedom from first dose were 50.8% (95% confidence interval 46.2%-55.4%) and 47.0% (42.2%-51.7%) on lacosamide, and 54.9% (50.3%-59.6%) and 50.9% (46.0%-55.7%) on carbamazepine-CR. Incidences of drug-related TEAEs and discontinuations due to TEAEs increased by number of comorbid conditions and were lower in patients on lacosamide.

Significance: Long-term (median ~2 years) lacosamide monotherapy was efficacious and generally well tolerated in adults with newly diagnosed epilepsy. Seizure freedom rates were similar with lacosamide and carbamazepine-CR.

Keywords: antiepileptic drug; comorbidity; lacosamide monotherapy; tolerability.