Trial Outcomes & Findings for Pharmacokinetic Study With an Oral Suspension of Perampanel as Adjunctive Therapy in Pediatric Subjects With Epilepsy (NCT NCT02914314)

Last Updated: 2024-03-15

Results Overview

Dose normalized AUCtau,ss was calculated as AUCtau,ss/maintenance dose, where AUCtau,ss is the area under the curve during a dosing interval (tau, 24 hours) at steady state calculated using population pharmacokinetic (PK) model. PK sparse sampling was performed. One sample was collected at anytime between 1 to 5 hours post-dose on Days 99 and 113 (Cohort 1, Cohort 2, Cohort 3) and two samples were collected, one at pre-dose and other at anytime between 1 to 5 hours post-dose on Days 99 and 113 (Cohort 4). Plasma concentrations of perampanel were measured and concentration data were summarized. Plasma concentrations of perampanel were quantified using a validated liquid chromatography mass spectrometry (LC MS/MS) analytical method.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

26 participants

Primary outcome timeframe

Maintenance Period of the Core Phase- Days 99 and 113: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 99 and 113: Pre-dose, 1-5 hours post-dose (Cohort 4)

Results posted on

2024-03-15

Participant Flow

Participants took part in the study at 8 investigative sites in the United States and Latvia from 20 February 2017 to 25 April 2023.

A total of 26 participants were screened and enrolled, of which 5 were screen failure and 21 participants received the study treatment.

Participant milestones

Participant milestones
Measure	Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from greater than or equal to (\>=) 1 month to less than or equal to (\<=) 6 months received perampanel 0.5 milligrams (mg), oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 milligram per day (mg/day) (for participants who are not taking any EIAED\]), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from greater than (\>) 6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to less than (\<) 24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Core Phase (Up to 20 Weeks) STARTED	4	5	9	3
Core Phase (Up to 20 Weeks) Participants Who Did Not Take EIAED	4	3	5	1
Core Phase (Up to 20 Weeks) Participants Who Took EIAED	0	2	4	2
Core Phase (Up to 20 Weeks) COMPLETED	4	5	8	1
Core Phase (Up to 20 Weeks) NOT COMPLETED	0	0	1	2
Extension Phase (Up to 36 Weeks) STARTED	4	5	8	1
Extension Phase (Up to 36 Weeks) COMPLETED	4	5	6	1
Extension Phase (Up to 36 Weeks) NOT COMPLETED	0	0	2	0

Reasons for withdrawal

Reasons for withdrawal
Measure	Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to less than (\<) 24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Core Phase (Up to 20 Weeks) Lost to Follow-up	0	1
Core Phase (Up to 20 Weeks) Withdrawal by Subject	0	1
Core Phase (Up to 20 Weeks) Inadequate Therapeutic Effect	1	0
Extension Phase (Up to 36 Weeks) Withdrawal by Subject	1	0
Extension Phase (Up to 36 Weeks) Participant choice	1	0

Baseline Characteristics

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

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Cohort 1, Age >=1 to <=6 Months: Perampanel n=4 Participants Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Cohort 2, Age >6 to <=12 Months: Perampanel n=5 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Cohort 3, Age >12 to <24 Months: Perampanel n=9 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Cohort 4, Age >=24 to <48 Months: Perampanel n=3 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. All participants who completed Core Phase, entered Extension Phase, and continued their optimal perampanel dose in extension phase for up to Week 52. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants, and total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Total n=21 Participants Total of all reporting groups
Age, Continuous	5.5 months STANDARD_DEVIATION 0.58 • n=5 Participants	10.2 months STANDARD_DEVIATION 0.84 • n=7 Participants	18.8 months STANDARD_DEVIATION 3.73 • n=5 Participants	31.3 months STANDARD_DEVIATION 4.16 • n=4 Participants	16.0 months STANDARD_DEVIATION 8.76 • n=21 Participants
Sex: Female, Male Female	2 Participants n=5 Participants	3 Participants n=7 Participants	7 Participants n=5 Participants	1 Participants n=4 Participants	13 Participants n=21 Participants
Sex: Female, Male Male	2 Participants n=5 Participants	2 Participants n=7 Participants	2 Participants n=5 Participants	2 Participants n=4 Participants	8 Participants n=21 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	1 Participants n=5 Participants	0 Participants n=7 Participants	2 Participants n=5 Participants	1 Participants n=4 Participants	4 Participants n=21 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	3 Participants n=5 Participants	5 Participants n=7 Participants	7 Participants n=5 Participants	2 Participants n=4 Participants	17 Participants n=21 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants
Race (NIH/OMB) Asian	1 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	1 Participants n=21 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants	0 Participants n=7 Participants	2 Participants n=5 Participants	0 Participants n=4 Participants	2 Participants n=21 Participants
Race (NIH/OMB) White	3 Participants n=5 Participants	5 Participants n=7 Participants	7 Participants n=5 Participants	2 Participants n=4 Participants	17 Participants n=21 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	1 Participants n=4 Participants	1 Participants n=21 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants	0 Participants n=21 Participants

PRIMARY outcome

Timeframe: Maintenance Period of the Core Phase- Days 99 and 113: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 99 and 113: Pre-dose, 1-5 hours post-dose (Cohort 4)

Population: The PK Analysis Set was the group of participants with at least 1 PK assessment of perampanel during the Maintenance Period (Core Phase) with a documented dosing history. Here, "overall number of participants analyzed" signifies participants who were evaluable for this Outcome Measure (OM).

Outcome measures

Outcome measures
Measure	Core Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel n=4 Participants Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 2, Age >6 to <=12 Months: Perampanel n=3 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 3, Age >12 to <24 Months: Perampanel n=4 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 4, Age >=24 to <48 Months: Perampanel n=1 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Extension Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from \>6 to \<=12 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to \<24 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Dose Normalized Area Under the Concentration-Time Curve for Dosing Interval at Steady State (AUCtau,ss) of Perampanel During the Maintenance Period of the Core Phase for Non-EIAED Participants	3840 nanogramhour per milliliter (ngh/mL) Standard Deviation 2280	6110 nanogramhour per milliliter (ngh/mL) Standard Deviation 1490	6030 nanogramhour per milliliter (ngh/mL) Standard Deviation 1940	5810 nanogramhour per milliliter (ngh/mL) Standard Deviation NA Standard Deviation could not be calculated as only one participant was available for analysis.	—	—	—	—

PRIMARY outcome

Timeframe: Maintenance Period of the Core Phase- Days 99 and 113: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 99 and 113: Pre-dose, 1-5 hours post-dose (Cohort 4)

Dose normalized Cmax,ss was calculated as Cmax,ss/maintenance dose, where Cmax,ss is the maximum (peak) steady-state concentration calculated using population PK model. PK sparse sampling was performed. One sample was collected at anytime between 1 to 5 hours post-dose on Days 99 and 113 (Cohort 1, Cohort 2, Cohort 3) and two samples were collected, one at pre-dose and other at anytime between 1 to 5 hours post-dose on Days 99 and 113 (Cohort 4). Plasma concentrations of perampanel were measured and concentration data were summarized. Plasma concentrations of perampanel were quantified using a validated LC MS/MS analytical method.

Outcome measures

Outcome measures
Measure	Core Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel n=4 Participants Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 2, Age >6 to <=12 Months: Perampanel n=3 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 3, Age >12 to <24 Months: Perampanel n=4 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 4, Age >=24 to <48 Months: Perampanel n=1 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Extension Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from \>6 to \<=12 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to \<24 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Dose Normalized Maximum (Peak) Steady-state Concentration (Cmax,ss) of Perampanel During the Maintenance Period of the Core Phase for Non-EIAED Participants	305 nanogram per milliliter (ng/mL) Standard Deviation 73.1	388 nanogram per milliliter (ng/mL) Standard Deviation 68.4	386 nanogram per milliliter (ng/mL) Standard Deviation 103	341 nanogram per milliliter (ng/mL) Standard Deviation NA Standard Deviation could not be calculated as only one participant was available for analysis.	—	—	—	—

PRIMARY outcome

Timeframe: Maintenance Period of the Core Phase- Days 99 and 113: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 99 and 113: Pre-dose, 1-5 hours post-dose (Cohort 4)

Dose normalized Css,Av was calculated as Css,Av/maintenance dose. Css,Av of perampanel was calculated as the ratio of area under the curve (AUC)/tau, (tau = 24 hours for perampanel) using population PK model. PK sparse sampling was performed. One sample was collected at anytime between 1 to 5 hours post-dose on Days 99 and 113 (Cohort 1, Cohort 2, Cohort 3) and two samples were collected, one at pre-dose and other at anytime between 1 to 5 hours post-dose on Days 99 and 113 (Cohort 4). Plasma concentrations of perampanel were measured and concentration data were summarized. Plasma concentrations of perampanel were quantified using a validated LC MS/MS analytical method.

Outcome measures

Outcome measures
Measure	Core Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel n=4 Participants Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 2, Age >6 to <=12 Months: Perampanel n=3 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 3, Age >12 to <24 Months: Perampanel n=4 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 4, Age >=24 to <48 Months: Perampanel n=1 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Extension Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from \>6 to \<=12 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to \<24 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Dose Normalized Average Steady-state Drug Concentration (Css,Av) of Perampanel During the Maintenance Period of the Core Phase for Non-EIAED Participants	160 ng/mL Standard Deviation 95	255 ng/mL Standard Deviation 62.2	251 ng/mL Standard Deviation 80.8	242 ng/mL Standard Deviation NA Standard Deviation could not be calculated as only one participant was available for analysis.	—	—	—	—

PRIMARY outcome

Timeframe: Maintenance Period of the Core Phase- Days 99 and 113: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 99 and 113: Pre-dose, 1-5 hours post-dose (Cohort 4)

Dose normalized Cmin,ss was calculated as Cmin,ss/maintenance dose, where Cmin,ss is the minimum observed steady state plasma concentration calculated using population PK model. PK sparse sampling was performed. One sample was collected at anytime between 1 to 5 hours post-dose on Days 99 and 113 (Cohort 1, Cohort 2, Cohort 3) and two samples were collected, one at pre-dose and other at anytime between 1 to 5 hours post-dose on Days 99 and 113 (Cohort 4). Plasma concentrations of perampanel were measured and concentration data were summarized. Plasma concentrations of perampanel were quantified using a validated LC MS/MS analytical method.

Outcome measures

Outcome measures
Measure	Core Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel n=4 Participants Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 2, Age >6 to <=12 Months: Perampanel n=3 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 3, Age >12 to <24 Months: Perampanel n=4 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 4, Age >=24 to <48 Months: Perampanel n=1 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Extension Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from \>6 to \<=12 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to \<24 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Dose Normalized Minimum Observed Steady State Plasma Concentration (Cmin,ss) of Perampanel During the Maintenance Period of the Core Phase for Non-EIAED Participants	114 ng/mL Standard Deviation 96.4	203 ng/mL Standard Deviation 58.2	199 ng/mL Standard Deviation 71	203 ng/mL Standard Deviation NA Standard Deviation could not be calculated as only one participant was available for analysis.	—	—	—	—

PRIMARY outcome

Timeframe: Maintenance Period of the Core Phase- Days 127 and 141: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 127 and 141: Pre-dose, 1-5 hours post-dose (Cohort 4)

Dose normalized AUCtau,ss was calculated as AUCtau,ss/maintenance dose, where AUCtau,ss is the area under the curve during a dosing interval (tau, 24 hours) at steady state calculated using population PK model. PK sparse sampling was performed. One sample was collected at anytime between 1 to 5 hours post-dose on Days 127 and 141 (Cohort 1, Cohort 2, Cohort 3) and two samples were collected, one at pre-dose and other at anytime between 1 to 5 hours post-dose on Days 127 and 141 (Cohort 4). Plasma concentrations of perampanel were measured and concentration data were summarized. Plasma concentrations of perampanel were quantified using a validated LC MS/MS analytical method.

Outcome measures

Outcome measures
Measure	Core Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 2, Age >6 to <=12 Months: Perampanel n=2 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 3, Age >12 to <24 Months: Perampanel n=3 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 4, Age >=24 to <48 Months: Perampanel n=1 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Extension Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from \>6 to \<=12 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to \<24 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Dose Normalized AUCtau,ss of Perampanel During the Maintenance Period of the Core Phase for EIAED Participants	—	5220 ng*h/mL Standard Deviation 3600	3300 ng*h/mL Standard Deviation 1530	2510 ng*h/mL Standard Deviation NA Standard Deviation could not be calculated as only one participant was available for analysis.	—	—	—	—

PRIMARY outcome

Timeframe: Maintenance Period of the Core Phase- Days 127 and 141: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 127 and 141: Pre-dose, 1-5 hours post-dose (Cohort 4)

Dose normalized Cmax,ss was calculated as Cmax,ss/maintenance dose, where Cmax,ss is the maximum (peak) steady-state concentration calculated using population PK model. PK sparse sampling was performed. One sample was collected at anytime between 1 to 5 hours post-dose on Days 127 and 141 (Cohort 1, Cohort 2, Cohort 3) and two samples were collected, one at pre-dose and other at anytime between 1 to 5 hours post-dose on Days 127 and 141 (Cohort 4). Plasma concentrations of perampanel were measured and concentration data were summarized. Plasma concentrations of perampanel were quantified using a validated LC MS/MS analytical method.

Outcome measures

Outcome measures
Measure	Core Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 2, Age >6 to <=12 Months: Perampanel n=2 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 3, Age >12 to <24 Months: Perampanel n=3 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 4, Age >=24 to <48 Months: Perampanel n=1 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Extension Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from \>6 to \<=12 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to \<24 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Dose Normalized Cmax,ss of Perampanel During the Maintenance Period of the Core Phase for EIAED Participants	—	341 ng/mL Standard Deviation 151	276 ng/mL Standard Deviation 81.8	201 ng/mL Standard Deviation NA Standard Deviation could not be calculated as only one participant was available for analysis.	—	—	—	—

PRIMARY outcome

Timeframe: Maintenance Period of the Core Phase- Days 127 and 141: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 127 and 141: Pre-dose, 1-5 hours post-dose (Cohort 4)

Dose normalized Css,Av was calculated as Css,Av/maintenance dose. Css,Av of perampanel was calculated as the ratio of area under the curve (AUC)/tau, (tau = 24 hours for perampanel) using population PK model. PK sparse sampling was performed. One sample was collected at anytime between 1 to 5 hours post-dose on Days 127 and 141 (Cohort 1, Cohort 2, Cohort 3) and two samples were collected, one at pre-dose and other at anytime between 1 to 5 hours post-dose on Days 127 and 141 (Cohort 4). Plasma concentrations of perampanel were measured and concentration data were summarized. Plasma concentrations of perampanel were quantified using a validated LC MS/MS analytical method.

Outcome measures

Outcome measures
Measure	Core Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 2, Age >6 to <=12 Months: Perampanel n=2 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 3, Age >12 to <24 Months: Perampanel n=3 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 4, Age >=24 to <48 Months: Perampanel n=1 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Extension Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from \>6 to \<=12 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to \<24 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Dose Normalized Css,Av of Perampanel During the Maintenance Period of the Core Phase for EIAED Participants	—	217 ng/mL Standard Deviation 150	137 ng/mL Standard Deviation 63.8	105 ng/mL Standard Deviation NA Standard Deviation could not be calculated as only one participant was available for analysis.	—	—	—	—

PRIMARY outcome

Timeframe: Maintenance Period of the Core Phase- Days 127 and 141: 1-5 hours post-dose (Cohort 1, Cohort 2, Cohort 3); Days 127 and 141: Pre-dose, 1-5 hours post-dose (Cohort 4)

Dose normalized Cmin,ss was calculated as Cmin,ss/maintenance dose, where Cmin,ss is the minimum observed steady state plasma concentration calculated using population PK model. PK sparse sampling was performed. One sample was collected at anytime between 1 to 5 hours post-dose on Days 127 and 141 (Cohort 1, Cohort 2, Cohort 3) and two samples were collected, one at pre-dose and other at anytime between 1 to 5 hours post-dose on Days 127 and 141 (Cohort 4). Plasma concentrations of perampanel were measured and concentration data were summarized. Plasma concentrations of perampanel were quantified using a validated LC MS/MS analytical method.

Outcome measures

Outcome measures
Measure	Core Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 2, Age >6 to <=12 Months: Perampanel n=2 Participants Participants of age range from \>6 to \<=12 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 3, Age >12 to <24 Months: Perampanel n=3 Participants Participants of age range from \>12 to \<24 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Core Phase, Cohort 4, Age >=24 to <48 Months: Perampanel n=1 Participants Participants of age range from \>=24 to \<48 months received perampanel 0.5 mg, oral suspension, before bedtime during Week 0 and then dose up titrated to a maximum of 12 mg/day (for participants who are not taking any EIAED), or titrated up to a maximum of 16 mg/day (for participants who are taking any EIAED). Dose titration was up to Week 12 for Non-EIAED participants and up to Week 16 for EIAED participants to identify each participant's optimum dose during Core Phase. Participants then continued to take perampanel at optimal dose up to 12 mg/day (for non-EIAED participants) or 16 mg/day (for EIAED participants) as a maintenance dose for up to 4 weeks during Core Phase. The total treatment duration of Core Phase was up to 16 weeks for non-EIAED participants or up to 20 weeks for EIAED participants.	Extension Phase, Cohort 1, Age >=1 to <=6 Months: Perampanel Participants of age range from \>=1 month to \<=6 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 2, Age >6 to <=12 Months: Perampanel Participants of age range from \>6 to \<=12 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 3, Age >12 to <24 Months: Perampanel Participants of age range from \>12 to \<24 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.	Extension Phase, Cohort 4, Age >=24 to <48 Months: Perampanel Participants of age range from \>=24 to \<48 months who completed the Core Phase continued their optimal perampanel oral suspension, at the dose level achieved at the end of the Core Phase. The maximum total daily allowed dose for a non-EIAED participants was 12 mg and 16 mg for EIAED participants. The total treatment duration of Extension Phase was up to 36 weeks for non-EIAED participants and 32 weeks for EIAED participants.
Dose Normalized Cmin,ss of Perampanel During the Maintenance Period of the Core Phase for EIAED Participants	—	172 ng/mL Standard Deviation 145	90.5 ng/mL Standard Deviation 53.4	69.2 ng/mL Standard Deviation NA Standard Deviation could not be calculated as only one participant was available for analysis.	—	—	—	—

SECONDARY outcome

Timeframe: Core Phase: From the first dose of study drug up to 4 weeks of follow up after the last dose in Core Phase (up to Week 24); Extension Phase: From end of Core Phase treatment up to 4 weeks of follow up after the last dose in Extension Phase (up to Week 56)

Population: The SAS was the group of participants who received at least 1 dose of study drug and had at least 1 post-dose safety assessment.

TEAE was an adverse event (AE) that emerged during treatment, having been absent at pretreatment (Baseline); or re-emerged during treatment, having been present at pretreatment (Baseline) but stopped before treatment; or worsened in severity during treatment relative to the pretreatment state, when AE was continuous. SAE was any untoward medical occurrence that at any dose: Resulted in death; was life-threatening (meaning participant was at an immediate risk of death from AE as it occurred; this did not include an event that, had it occurred in a more severe form or was allowed to continue, might have caused death); Required inpatient hospitalization or prolongation of existing hospitalization; Resulted in persistent or significant disability/incapacity; Was a congenital anomaly/birth defect (in child of a participant who was exposed to the study drug).