Long-term effectiveness of add-on perampanel in patients with Lennox-Gastaut syndrome: a multicenter retrospective study.

This retrospective study assessed long-term effectiveness of add-on perampanel (PER) in patients with Lennox-Gastaut syndrome (LGS). Outcomes included time to PER-failure and time to seizure-relapse in responders. Perampanel failure was defined as either discontinuation of PER or initiation of another treatment. Seizure relapse in responders was defined as occurrence of a seizure in seizure-free patients and increase of at least 50% in average monthly seizure frequency for those who were responders. Eighty-seven patients were included. Treatment failure occurred in 52 (59.8%) subjects at a median time of 12 months. Treatment failure was due to lack of efficacy in 27 (52.0%) patients, lack of tolerability in 14 (27.0%), and both reasons in 11 (21.0%). A slower titration was associated with a lower risk of PER failure compared to faster titration schedules and the occurrence of adverse events increased the risk of treatment failure. Thirty-six patients (41.4%) were responders during a median follow-up of 11 months. Seizure relapse occurred in 13/36 (36.1%) patients after a median time of 21 months. The overall rate of seizure responders was 23/87 (26.4%) at the end of follow-up. This study provides real-world evidence about the effectiveness of PER as adjunctive treatment in LGS patients.