Abstracts

Rationale: Limited treatment options are available for patients with PGTC seizures, thus treatment with a narrow range of antiepileptic drugs (AEDs) is often the only option for these patients. Therefore, it is essential to continue to investigate AEDs with novel mechanisms of action to improve treatment outcomes for patients with PGTC seizures. Perampanel is a once-daily oral AED for partial-onset seizures and PGTC seizures. Perampanel has demonstrated efficacy and tolerability for PGTC seizures in the randomized, double-blind, placebo-controlled, Phase III Study 332 (French et al. Neurology 2015;85:950-957). Patients completing the Double-blind Phase of Study 332 could enter an OLEx Phase (NCT02307578). This post hoc analysis investigated PGTC seizure-free status rates during adjunctive treatment with perampanel =12 mg/day in patients aged =12 years with PGTC seizures from the OLEx Phase of Study 332 to determine if responses obtained during the Double-blind Phase were maintained in the OLEx. Methods: The OLEx Phase of Study 332 included a 6-week blinded Conversion Period and a =136-week Maintenance Phase (perampanel =12 mg/day). This post hoc analysis included patients with PGTC seizures who participated in the OLEx Phase of Study 332 and achieved PGTC seizure-free status during the Double-blind Phase or the Perampanel Treatment Duration (defined as the OLEx Phase for patients randomized to placebo during the Double-blind Phase, or the Double-blind and OLEx Phases for patients randomized to perampanel during the Double-blind Phase). Seizure-free status rates were assessed at 6, 12, 18, and 24 months in patients who achieved PGTC seizure-free status during the Double-blind Phase. Patients were also assessed for PGTC seizure freedom for =6 and =12 months at any time during the Perampanel Treatment Duration. Results: During the Double-blind Phase of Study 332, a total of 35 out of 162 patients (21.6%; 10 receiving placebo, 25 receiving perampanel) achieved PGTC seizure-free status (mean age 30.5 [standard deviation 13.6] years; 62.9% female; 48.6% Caucasian). Of the 25 patients who received perampanel and were seizure free during the Double-blind Phase, 21/25 (84.0%), 14/25 (56.0%), 11/24 (45.8%), and 6/19 (31.6%) of these patients remained PGTC seizure free for 6, 12, 18, and 24 months, respectively (Table 1).Of 138 patients treated with perampanel during the Perampanel Treatment Duration (70 received prior placebo and 68 received prior perampanel during the Double-blind Phase), PGTC seizure-free status was achieved for =6 or =12 months in 73 (52.9%) and 41 (29.7%) patients, respectively (Table 2). PGTC seizure-free status rates were similar irrespective of prior treatment during the Double-blind Phase (Table 2). Conclusions: These data are encouraging given the refractory nature of generalized seizure types and suggest adjunctive perampanel may offer a long-term treatment option for patients with PGTC seizures. Funding: Eisai Inc.