Pharmacokinetic Study With an Oral Suspension of Perampanel as Adjunctive Therapy in Pediatric Subjects With Epilepsy

This is a multicenter, open-label study comprised of pretreatment, treatment (core study),
and extension phases that is designed to evaluate the PK of an oral suspension of perampanel
(target dose of 12 milligrams per day [mg /day] for non-enzyme-inducing antiepileptic drug
[non-EIAED] or 16 mg/day for EIAED) when given as an adjunctive therapy in participants
ranging from 1 month to less than 24 months (<2 years) of age with epilepsy. The Pretreatment
Phase will last up to 2 weeks, during which participants will be assessed for their
eligibility to participate in the study. The Treatment Phase will consist of 3 periods:
Titration (12 to 16 weeks), Maintenance (4 weeks), and Follow-Up (4 weeks; only for those
participants who complete the Maintenance Period but do not continue into the Extension Phase
and those participants who discontinue study participation). The Extension Phase will consist
of 2 periods: Maintenance (32 to 36 weeks) and Follow-Up (4 weeks).

The maximum total duration of treatment for each participant will be 52 weeks, and the
maximum total duration of the study for each participant will be 58 weeks (52 weeks of
treatment + 2 weeks of pretreatment + 4 weeks of follow-up).

Inclusion Criteria:

- Male or female, from 1 to less than 24 months (<2 years) of age (and of at least 36
weeks gestational age) at the time of consent

- Have a minimum weight of 4 kilograms (kg) (8.8 pounds [lb])

- Have a diagnosis of epilepsy with any type of seizure according to the International
League Against Epilepsy's (ILAE) Classification of Epileptic Seizures (1981).
Diagnosis should have been established at least 2 weeks (≤6 months of age) or 4 weeks
(>6 months of age) before Visit 1, by clinical history and an electroencephalogram
(EEG) that is consistent with epilepsy; normal interictal EEGs will be allowed
provided that the participant meets the other diagnosis criterion (i.e., clinical
history)

- Have had brain imaging (computed tomography [CT] or magnetic resonance imaging [MRI])
before Visit 1 that ruled out a progressive cause of epilepsy

- Have had 1 or more seizure(s) before Visit 1

- Currently being treated with a stable dose (i.e., unchanged for at least 5 half-lives)
of 1 to a maximum of 3 antiepileptic drugs (AEDs) (at least 6, but not more than 8,
participants will be taking 1 enzyme-inducing AED [EIAEDs] out of the maximum of 3
AEDs allowed. The remaining participants cannot be taking any EIAEDs).

- Have been on their current concomitant AED regime with a stable dose for at least 2
weeks (≤6 months of age) or 4 weeks (>6 months of age) before Visit 1

- Must have discontinued all restricted medications at least 2 weeks or 5 half-lives
(whichever is longer) before Visit 1

- If entering the Extension Phase, must have completed the last visit of the Maintenance
Period of the Core Study

Exclusion Criteria:

- Have a history of status epilepticus that required hospitalization during the 3 months
before Visit 1

- Have seizures due to treatable medical conditions, such as those arising due to
metabolic disturbances, toxic exposure, or an active infection

- Have epilepsy secondary to progressive central nervous system (CNS) disease or any
other progressive neurodegenerative disease, including tumors

- Have had epilepsy surgery within 1 year of Visit 1

- Are scheduled and/or confirmed to have epilepsy surgery within 6 months after Visit 1

- Used intermittent rescue benzodiazepines (i.e., 1 to 2 doses over a 24-hour period
considered one-time rescue) 2 or more times in the 2 weeks before Visit 1

- Prior use of felbamate

- Prior use of vigabatrin

- Are on ketogenic diet regimen that has not been stable for at least 4 weeks before
Visit 1

- Have used other drugs known to influence the CNS, where the dose has not been
stabilized for at least 2 weeks (≤6 months of age) or 4 weeks (>6 months of age)
before Visit 1

- Have any concomitant illnesses/co-morbidities that could severely affect the
participant's safety or study conduct

- Have evidence of clinically significant disease (e.g., cardiac, respiratory,
gastrointestinal, renal disease) that in the opinion of the investigator(s) could
affect the participant's safety or study conduct

- Have clinically significant laboratory abnormalities or any clinically acute or
chronic disease

- Have evidence of significant active hepatic disease. Stable elevation of liver
enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) due to
concomitant medication(s), will be allowed if they are less than 3 times the upper
limit of normal (ULN)

- Have clinical evidence of significant active hematological disease; white blood cell
(WBC) count ≤2500/ microliter (μL) (2.50 x 10^9/Liter [L]) or an absolute neutrophil
count ≤1000/μL (1.00 x 10^9/L)

- Have conditions that may interfere with their participation in the study and/or with
the PK of study drug

- Have participated in a study involving administration of an investigational drug or
device within 4 weeks before Visit 1, or within approximately 5 half-lives of the
previous investigational compound, whichever is longer

- Have previously participated in a clinical trial involving perampanel

- Have a clinically significant ECG abnormality, including prolonged corrected QT
interval (QTc) defined as >450 milliseconds (msec)

- Have had multiple drug allergies or a severe drug reaction to an AED(s), including
dermatological (e.g., Stevens-Johnson syndrome), hematological, or organ toxicity
reactions