Efficacy and tolerability of perampanel in ten patients with Lafora disease

Lafora disease (LD) is a fatal intractable adolescence-onset progressive myoclonus epilepsy. Recently, two single-case studies reported drastic reductions in seizures and myoclonus with the AMPA antagonist perampanel and improved activities of daily living. We proceeded to study the effect of perampanel on 10 patients with genetically confirmed LD with disease duration ranging from 2 to 27 years. Open-label perampanel was added to ongoing medications to a mean dose of 6.7 mg/day. Seizures, myoclonus, functional disability, and cognition scores were measured for the third and ninth months following initiation and compared with those of the month prior to the start of therapy. Three patients withdrew because of inefficacy or side effects. Four had significant reduction in seizures of greater than 74% from baseline. Seven had major improvement in myoclonus with group-adjusted sum score of myoclonus intensity reduced from 7.01 at baseline to 5.67 and 5.18 at 3 and 9 months, respectively. There was no significant improvement in disability and cognition. While not universal, perampanel adjunctive therapy appears to confer particular benefit not commonly seen with other antiepileptic drugs on seizures and myoclonus in LD. Improvement in the extremely disabling myoclonus of LD is a major benefit in this devastating disease.