A Double-blind, Randomized, Placebo-controlled, Multicenter Study to Evaluate the Efficacy and Safety of Adjunctive Perampanel in Primary Generalized Tonic Clonic Seizures

INTERVENTION: investigational material(s) Generic name etc : E2007 INN of investigational material : Perampanel Therapeutic category code : 113 Antiepileptics Dosage and Administration for Investigational material : Oral CONDITION: Primary Generalized Tonic Clonic Seizures (Epilepsy) PRIMARY OUTCOME: Percent change from baseline in PGTC seizure frequency per 28 days [ Time Frame: from baseline over the Titration and Maintenance Periods (17 weeks) ] INCLUSION CRITERIA: 1.Clinical diagnosis of PGTC seizures (with or without other subtypes of primary generalized seizures) and experiencing >/= 2 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 two 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 >/= 5 months prior to Baseline (stimulator parameters can not 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) w