Prospective audit with adjunctive perampanel: Preliminary observations in focal epilepsy

Perampanel (PER) was first licensed in the United Kingdom in 2012 for the adjunctive treatment of focal seizures with or without secondary generalization in adults and children over 12years of age. It has recently also been approved for use as add-on therapy for patients with primary generalized tonic-clonic seizures. This prospective audit reports preliminary outcomes with adjunctive PER in patients with focal-onset seizures in everyday clinical practice using a standard design.

To date, 54 patients (38 males, 16 females; 21-65years, median: 48years) have completed the study. The median monthly seizure frequency was 4 (range: 1-60). At baseline, patients were taking a median of 2 other antiepileptic drugs (range: 1-4 drugs), with their seizures having previously failed to improve on a median of 3 schedules (range: 1-15 schedules). After 12weeks of stable dosing, PER was added, aiming at a target range of 6-12mg/daily. Review took place every 6-8weeks until one of 4 endpoints was reached: seizure freedom for ≥6months on a given PER dose, ≥50% (responder) or <50% (marginal effect) seizure reduction over 6months, compared with the prospective baseline, on the highest tolerated PER dose, or withdrawal of PER due to a lack of efficacy or side effects.

Three (5.6%) patients have remained seizure-free, with 8 (14.8%) demonstrating a ≥50% response and a further 17 (31.5%) reporting a marginal effect. Of the 26 (48.1%) dropping out of PER treatment, 21 (38.9%) did so because of side effects. The commonest problems were nausea, vomiting, ataxia, dizziness, and sedation. Overall, 6 (11%) patients developed neuropsychiatric problems, with 3 reporting irritability and/or aggression. Two patients had substantial weight gain, and another patient suffered recurrent falls. Treatment with enzyme-inducing AEDs had no effect on PER dosing in patients responding to PER or withdrawing due to side effects.

These data support the value of adjunctive PER in some patients with pharmacoresistant epilepsy in everyday clinical practice.