A Study to Evaluate Efficacy and Safety of Perampanel Administered as an Adjunctive Therapy in Pediatric Participants With Childhood Epilepsy

Inclusion Criteria:

• Male or female participants. Cohort 1: age 1 month to less than 18 years; Cohort 2:age 1 month to less than 2 years at the time of informed consent/assent.Participants below the age of 1 year must have been at least 36 weeks of gestationalage at birth.

• Have a diagnosis of epilepsy with a pediatric epileptic syndrome (Cohort 1) orepilepsy with POS with or without secondary generalization (Cohort 2).

• Have had equal or greater than 4 seizures over the 4-week interval prior toenrollment visit.

• Absence of any progressive cause of epilepsy that has been confirmed clinically orbased on brain imaging (example, magnetic resonance imaging [MRI] scan or computedtomography [CT] or ultrasound [for less than 1 year old]).

• Currently maintained on stable doses of 1 to a maximum of 4 approved antiepilepticdrugs (AEDs). A prescription medical marijuana (including products containingcannabidiol) is counted as 1 of the maximum of 4 allowed AEDs; however, it cannot bethe only concomitant AED if this product is not an approved AED in the country wherethe study site is located. Doses must be stable for at least 4 weeks (at least 2weeks for participant less than [<] 6 months old) before Visit 1/Baseline orscreening; only 1 enzyme-inducing antiepileptic drug (EIAED) (defined ascarbamazepine, phenytoin, oxcarbazepine, or eslicarbazepine) out of the maximum of 4AEDs is allowed.

Exclusion Criteria:

• Current or history of pseudo-seizures (psychogenic nonepileptic seizures) withinapproximately 5 years before screening visit.

• Have a history of status epilepticus that required hospitalization within 6 monthsbefore screening visit.

• Have an unstable psychiatric diagnosis that may confound participant's ability toparticipate in the study or that may prevent completion of the protocol specifiedtests (example, significant suicide risk, including suicidal behavior and ideationwithin 6 months before screening visit 1, current psychotic disorder, acute mania).

• Any suicidal ideation with intent with or without a plan within 6 months beforeenrollment visit (answering "Yes" to questions 4 or 5 on the Suicidal Ideationsection of the C-SSRS) in participants aged 6 and above or based on the opinion ofthe Investigator for participants less than 6 years.

• Are scheduled or confirmed or both to have epilepsy surgery within 6 months afterscreening visit; however, those who have previously documented "failed" epilepsysurgery will be allowed.

• Have a progressive central nervous system (CNS) disease, including degenerative CNSdiseases and progressive tumors.

• Benzodiazepines for any indications other than epilepsy (example, anxiety/sleepdisorders) prohibited from 1 month before Visit 1/Baseline or screening and duringthe study. Benzodiazepines for seizure control and as rescue medication are allowed.

• A vagal nerve stimulator (VNS), responsive neurostimulator (RNS), or deep brainstimulator (DBS) implanted less than 5 months before screening visit or changes inparameter less than 4 weeks before screening visit (or thereafter during the study).

• Use of perampanel within 30 days before screening visit, or perampanel wasdiscontinued due to adverse reactions (perampanel-related) or lack of efficacy incase of previous exposure.

• Weight less than 4.0 kilogram (kg) at Visit 1 (Baseline or screening).