Open-label, uncontrolled retrospective study of perampanel in adults with Lennox-Gastaut syndrome

Perampanel (PER) was added to the anticonvulsant regimen of 71 patients with Lennox-Gastaut Syndrome (LGS) to evaluate its efficacy against seizures and its tolerability.

We evaluated at 3-month intervals 62 with pure LGS and 9 with LGS-like epileptic encephalopathy (28 females, 43 males, mean age 40.1 ± 11.5 yrs, median 38, range 20-71) in whom PER was introduced by 2 mg steps at 2- to 4-week intervals up to 6 mg/day, with possible dose reduction or increases after that. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines were followed.

Mean PER exposure was 538.9 days ± 425 (median 429), with 44 patients (62 %) on PER at last follow-up. About 2/3 of patients were responders, including 35.2 % that had a ≥75 % decrease in their seizures. Among these 16.9 % had a ≥90 % decrease. No improvement was seen in 14 patients; 5 had a less than 50 % response, and 6 had seizure aggravation. Therefore, 25 (35.2 %) were considered non-responders. Half of the patients developed at least one side-effect. Significant negative changes in behavior were noted in 1/3 of the cases, including irritability (8.5 %) and aggressivity (7 %). Contrastingly, 4 patients reported positive behavioral and psychological well-being side-effects.

This retrospective, open-label study provides evidence that PER may significantly help in LGS. PER should be tried in LGS patients who are not satisfactorily controlled. Its use may be limited in some patients due to behavioral side-effects occurring, particularly at doses ≥ 6 mg/d.