Adjunctive lamotrigine XR for primary generalized tonic–clonic seizures in a randomized, placebo-controlled study

Efficacy and tolerability of once-daily adjunctive lamotrigine extended-release (XR) for primary generalized tonic–clonic (PGTC) seizures in epilepsy were evaluated. Patients (n = 153) ≥ 13 years old diagnosed with epilepsy with PGTC seizures were randomized to once-daily adjunctive lamotrigine XR or placebo in a double-blind, parallel-group trial comprising a baseline phase, a 7-week double-blind escalation phase, and a 12-week double-blind maintenance phase. Lamotrigine XR was more effective than placebo with respect to median percentage reduction from baseline in weekly PGTC seizure frequency (primary endpoint—19-week treatment phase: 75.4% vs 32.1%, P < 0.0001; escalation phase: 61.9% vs 30.6%, P = 0.0016; maintenance phase: 89.7% vs 33.3%, P < 0.0001). Lamotrigine XR was more effective than placebo with respect to the percentage of patients with ≥ 50% reduction in PGTC seizure frequency. Significant separation from placebo for ≥ 50% reduction in PGTC seizures was observed beginning on treatment day 8. The most common adverse event was headache (lamotrigine XR 14%, placebo 16%).

Research Highlights
► PGTC seizures have been neglected relative to partial seizures in anticonvulsant clinical trials.
► This double-blind, placebo-controlled study helps to address this evidence deficit.
► Once-daily adjunctive lamotrigine XR controlled PGTC seizures and was well tolerated.