A Efficacy and Safety Study of Adjunctive Perampanel in Primary Generalized Tonic Clonic Seizures

This study is designed to evaluate the efficacy, safety, and pharmacokinetics (PK) of perampanel on Primary Generalized Tonic Clonic (PGTC) seizure frequency in adolescents and adults maintained on one to two stable antiepileptic drugs (AED).

This study is a multicenter, randomized, double-blind, placebo-controlled, parallel-group, adjunctive-therapy study with an open-label Extension Phase. The Core Study consists of 2 phases: Prerandomization and Randomization. The Prerandomization Phase consisted of 2 periods: Screening (up to 4 weeks) and Baseline (4 or 8 weeks, depending on the accuracy of diary-documented seizures during Screening), during which participants will be assessed for eligibility to participate in the study. The Randomization Phase consisted of 3 periods: Titration (4 weeks), Maintenance (13 weeks), and Follow-up (4 weeks; only for those participants not entering into the Extension Phase). At the start of the Randomization Phase, eligible participants will be randomized to the perampanel or placebo treatment groups in a 1:1 ratio. The extension phase consists of 142 weeks.

Eligibility Criteria:
Inclusion:

1. Clinical diagnosis of PGTC seizures (with or without other subtypes of primary generalized seizures) and experiencing greater than or equal to 3 PGTC seizures during the 8-week period prior to randomization
2. Have had a routine electroencephalogram (EEG) prior to or during the Baseline Period with electroencephalographic features consistent with primary generalized epilepsy; other concomitant anomaly should be explained by adequate past medical history
3. On a fixed dose of one to a maximum of three concomitant antiepileptic drugs (AEDs) for a minimum of 30 days prior to Baseline; only one inducer AED (i.e., carbamazepine, oxcarbazepine, or phenytoin) out of the maximum of two AEDs will be allowed
4. A vagal nerve stimulator (VNS) will be allowed, but it must have been implanted greater than or equal to 5 months prior to Baseline (stimulator parameters cannot be changed for 30 days prior to Baseline and for the duration of the study).
5. Have had a computed tomography (CT) or magnetic resonance imaging (MRI) within the last 10 years (for adults) and 5 years (for adolescents) that ruled out a progressive cause of epilepsy
6. A ketogenic diet will be allowed as long as the participant has been on this diet for 5 weeks prior to randomization

Exclusion:

1. A history of status epilepticus that required hospitalization within 12 months prior to Baseline
2. Seizure clusters where individual seizures cannot be counted
3. A history of psychogenic seizures
4. Concomitant diagnosis of Partial Onset Seizures (POS)
5. Progressive neurological disease
6. Clinical diagnosis of Lennox-Gastaut syndrome
7. If felbamate is used as a concomitant AED, participants must be on felbamate for at least 2 years, with a stable dose for 60 days prior to Baseline. They must not have a history of white blood cell (WBC) count below less than or equal to 2500/microL (2.50 1E+09/L), platelets less than 100,000/microL, liver function tests (LFTs) greater than 3 times the upper limit of normal (ULN), or other indication of hepatic or bone marrow dysfunction while receiving felbamate.
8. Concomitant use of vigabatrin: Participants who took vigabatrin in the past must be discontinued for approximately 5 months prior to Baseline, and must have documentation showing no evidence of a vigabatrin-associated clinically significant abnormality in an automated visual perimetry test
9. Concomitant use of barbiturates (except for seizure control indication) within 30 days prior to Baseline
10. Use of intermittent rescue benzodiazepines (i.e., one to two doses over a 24-hour period considered one-time rescue) two or more times within the 30 days prior to Baseline