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

This study will consist of a Core Study, Extension Phase A and Extension Phase B. 1. Core Study will consist of the following 2 phases: Pretreatment (4 weeks screening or baseline period) and Treatment Period. The Treatment Period (23 weeks) of Core study include Titration period (10 weeks) and Maintenance period (13 weeks). 2. Extension Phase A will consist of a Treatment Period (33 weeks) and a Follow-up Period (4 weeks). All participants who will complete the Core Study will be eligible to participate in Extension Phase A of the study. 3. Extension Phase B will only be for participants who reside in countries where perampanel (oral tablets or oral suspension) is not commercially available or an extended access program (EAP) is not yet implemented, participants have completed Extension Phase A, and who, in the opinion of the investigator, will continue to benefit from treatment with perampanel.