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Objective: Study 311 (NCT02849626) Extension A assessed long-term outcomes of adjunctive perampanel treatment in children (ages 4 to <12 years) with uncontrolled focal-onset seizures (FOS), with/without focal to bilateral tonic-clonic seizures (FBTCS), or generalized tonic-clonic seizures (GTCS)., Methods: Patients completing the 23-week Core Study could enter Extension A (29-week Maintenance and 4-week Follow-up Periods) to receive perampanel at the dose achieved during the Core Study. Dose adjustments were permitted per the investigator's discretion during Extension A. The maximum dose was 12 mg/day for patients enrolled in Japan and without enzyme-inducing anti-seizure medications (EIASMs), or 16 mg/day with EIASM(s). Safety and tolerability were monitored throughout Extension A. Efficacy assessments included median percent change in seizure frequency per 28 days from baseline and 50% responder rates. Outcomes were analyzed by seizure type, age (4 to <7 vs 7 to <12 years), and EIASM use., Results: Of 180 patients enrolling in the Core Study, 136 entered (FOS, n = 116 [including 43 with FBTCS]; GTCS, n = 20) and 122 completed Extension A. Treatment-emergent adverse events (TEAEs) were the most common reason for discontinuation (4%). The mean (standard deviation) dose during Extension A was 8.3 (3.2) mg/day. Incidences of TEAEs in Extension A were 69% overall and 62%-89% across subgroups; TEAEs led to dose adjustment in 10% of patients. No changes of clinical concern in cognition, growth, development, or quality of life were identified over 52 weeks. At Weeks 40-52, median percent reductions in seizure frequency per 28 days from baseline were 69% (FOS, n = 108), 74% (FBTCS, n = 41), and 100% (GTCS, n = 13); 50% responder rates were 62% (FOS and GTCS) and 81% (FBTCS). Efficacy outcomes were comparable across age and EIASM groups., Significance: These findings support long-term (≤52 weeks) use of adjunctive perampanel in children with epilepsy, irrespective of seizure type, age, or EIASM use., (© 2025 International League Against Epilepsy.)

Objectives: The Phase 3 Study 338 (NCT02834793) assessed long-term clinical outcomes of adjunctive perampanel in patients ≥2 years of age with uncontrolled seizures associated with Lennox-Gastaut syndrome (LGS)., Methods: Eligible patients were diagnosed with LGS and receiving one to four concomitant antiseizure medications with an average of two or more drop seizures/week during baseline. The study comprised an 18-week double-blind, randomized, placebo-controlled Core Study and ≥52-week open-label Extension. The primary endpoint was median percent change in drop seizure frequency per 28 days during the Core Study. Key secondary endpoints included responder rates, seizure-freedom rates, and safety outcomes. Post hoc analyses were performed encompassing a broader range of drop seizures or all countable motor seizures., Results: Seventy patients were randomized into the Core Study (perampanel, n = 34; placebo, n = 36), and 58 entered the Extension. In the Core Study, numerically greater median percent reductions in drop seizure frequency were observed with perampanel (23.1%) vs placebo (4.5%) using prespecified assessments (p = .107), whereas significantly greater reductions were detected using the broader definition (48.6% vs -.7%, respectively, p = .001) or all countable motor seizures (44.0% vs -.6%, respectively, p = .017). The 50% responder rate for drop seizures was higher with perampanel vs placebo using modern definitions. Reductions in seizure frequency with perampanel were maintained over 52 weeks. Treatment-emergent adverse events occurred in 85.3% of perampanel-treated patients (somnolence [23.5%] was the most frequent) and 72.2% of placebo-treated patients., Significance: This study had a reduced sample size and was underpowered. Although the difference in reductions in drop seizure frequency between treatments was not statistically significant by prespecified assessments, adjunctive perampanel demonstrated sustained efficacy in reducing drop seizures associated with LGS for ≤71 weeks using modern definitions. No new safety signals emerged. These observations suggest the long-term efficacy and safety of perampanel in the LGS population., (© 2024 The Author(s). Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Objective: Static assignment of participants in randomized clinical trials to placebo or ineffective treatment confers risk from continued seizures. An alternative trial design of time to exceed prerandomization monthly seizure count (T-PSC) has replicated the efficacy conclusions of traditionally designed trials, with shorter exposure to placebo and ineffective treatment. Trials aim to evaluate efficacy as well as safety and tolerability; therefore, we evaluated whether this T-PSC design also could replicate the trial's safety and tolerability conclusions., Methods: We retrospectively applied the T-PSC design to analyze treatment-emergent adverse events (TEAEs) from a blinded, placebo-controlled trial of perampanel for primary generalized tonic-clonic seizures (NCT01393743). The safety analysis set consisted of 81 and 82 participants randomized to perampanel and placebo arms, respectively. We evaluated the incidences of TEAEs, treatment-related TEAEs, serious TEAEs, and TEAEs of special interest that occurred before T-PSC relative to those observed during the full-length trial., Results: Of the 67 and 59 participants who experienced TEAEs in the perampanel and placebo arms during full-length trial, 66 (99%) and 54 (92%) participants experienced TEAEs with onset occurring before T-PSC, respectively. When limited to treatment-related TEAEs, 55 of 56 (98%) and 32 of 37 (86%) participants reported treatment-related TEAEs that occurred before T-PSC in the perampanel and placebo arms, respectively. There were more TEAEs after T-PSC with placebo as compared to perampanel (Fisher exact odds ratio = 8.6, p = .035), which resulted in overestimation of the difference in TEAE rate. There was a numerical reduction in serious TEAEs (3/13 occurred after T-PSC, one in placebo and two in perampanel)., Significance: Almost all TEAEs occurred before T-PSC. More treatment-related TEAEs occurred after T-PSC for participants randomized to placebo than perampanel, which may be due to either a shorter T-PSC or delayed time to TEAE for placebo., (© 2024 The Author(s). Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

ELEVATE (Study 410; NCT03288129) is the first prospective, multicenter, open-label, Phase IV study of perampanel as monotherapy or first adjunctive therapy in patients aged ≥ 4 years with focal-onset seizures or generalized tonic-clonic seizures in the United States. The study included Screening, Titration (≤ 13 weeks), Maintenance (39 weeks), and Follow-up (4 weeks) Periods. During Titration, perampanel was initiated at 2 mg/day and up-titrated to 4 mg/day at Week 3. Depending on response and tolerability, optional up-titrations to a maximum of 12 mg/day occurred. The primary endpoint was retention rate; additional endpoints included seizure-freedom rate, 50% responder rate, and incidence of treatment-emergent adverse events (TEAEs). At baseline, 10 (18.5%) patients were assigned to the monotherapy group and 44 (81.5%) patients to the first adjunctive therapy group. However, due to the addition of an anti-seizure medication along with perampanel on the first day of treatment, one patient was excluded from the monotherapy subgroup analyses. The mean perampanel exposure duration was 39.8 weeks and 32 (59.3%) patients completed the study. Retention rate at 12 months (or study completion) was 63.0% (monotherapy, 77.8%; first adjunctive therapy, 59.1%). Seizure-freedom rate during the Maintenance Period was 32.7% (monotherapy, 44.4%; first adjunctive therapy, 29.5%) and the 50% responder rate was 78.7% (monotherapy, 85.7%; first adjunctive therapy, 76.9%). TEAEs and serious TEAEs were reported by 88.9% (n = 48/54) and 7.4% (n = 4/54) of patients, respectively. Overall, the efficacy and safety of perampanel as monotherapy or first adjunctive therapy support the use of perampanel as early-line treatment for epilepsy., (© 2024. The Author(s).)

Objective: Perampanel is an oral anti-seizure medication, which is approved in Japan for focal-onset seizures, with/without focal to bilateral tonic-clonic seizures, as monotherapy/adjunctive therapy in patients aged 4 years and older. Treatment for generalized tonic-clonic seizures as adjunctive therapy in patients aged 12 years and older is approved as well. We evaluated the feasibility of intravenous (IV) administration of perampanel as an alternative to oral administration., Methods: Study 240 (NCT03754582) was an uncontrolled, open-label study of IV perampanel, conducted in 21 Japanese patients with epilepsy who received a stable dose of 8-12 mg/day of oral perampanel. Patients received 30-minute IV infusions at equivalent daily doses of oral perampanel for 4 days, then were switched back to oral perampanel. Safety, tolerability, plasma concentration, and maintenance of efficacy throughout the transition between IV and oral dosing of perampanel were assessed. As supportive data, a subgroup analysis was also conducted using data from healthy Japanese subjects (n = 18) who were enrolled in Study 050 (NCT03376997) investigating the pharmacokinetics and safety of IV perampanel in healthy subjects who received an IV infusion (30-, 60-, or 90-minute) of perampanel 12 mg and a single oral administration of perampanel 12-mg tablet., Results: In Study 240, the transition between 30-minute IV and oral perampanel dosing was associated with a ≤1.4-fold increase in the mean change in maximum observed concentration of perampanel. Seizure outcomes demonstrated no considerable changes in efficacy before, during, or after 30-minute IV dosing of perampanel. The safety profiles were similar between IV and oral formulations. In Study 050, the pharmacokinetics of 30- or 60-minute IV infusion of perampanel further support the interchangeability between oral and IV formulations in the Japanese subjects., Significance: These results support that 30-minute IV perampanel may be a potential short-term alternative to oral formulations for patients with epilepsy., (© 2023 The Authors. Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Purpose: To evaluate the safety and tolerability of adjunctive perampanel in a Japanese subpopulation of Study 311 (NCT02849626), which was a global, multicenter, open-label, single-arm study of children (aged 4 to <12 years) with inadequately controlled focal-onset seizures (FOS), with or without focal to bilateral tonic-clonic seizures (FBTCS) or generalized tonic-clonic seizures (GTCS)., Methods: Study 311 comprised a Core Study, Extension A, and Extension B; this report focuses on the Japanese patient subgroup in the Core Study only. In the Core Study, Japanese patients (FOS only) received adjunctive perampanel ≤12 mg/day in a 23-week Treatment Phase. Endpoints included safety/tolerability (primary) and median percent change in seizure frequency per 28 days from baseline. Patients were stratified by age and concomitant enzyme-inducing anti-seizure medication (EIASM) use., Results: Of 65 enrolled Japanese patients, 56 completed the Core Study and nine withdrew. The most common reason for discontinuation was adverse events (AEs) (n = 4 [6.2%]). The mean (standard deviation) daily dose of perampanel in Japanese FOS patients was 5.8 (2.2) mg/day. During the Core Study, treatment-emergent AEs (TEAEs) were reported by 89% of Japanese patients, most commonly nasopharyngitis (28%) and somnolence (28%). The median percent reduction in seizure frequency per 28 days from baseline was 37% and the lower limit of the 95% CI was greater than 10.5%, satisfying the pre-defined efficacy criteria. Perampanel was effective regardless of age or concomitant EIASM use., Conclusion: Perampanel as adjunctive therapy is generally safe, well-tolerated, and efficacious in Japanese children aged 4 to <12 years with FOS (with/without FBTCS)., Competing Interests: Declaration of Competing Interest Hirowo Omatsu, Toshihide Watanabe have no potential conflicts of interest to disclose. Ryutaro Kira has received payments for lectures, including service on speakers bureaus from Eisai, Otsuka Pharmaceutical, and UCB Japan. Kaeko Ishiba and Takao Takase are employees of Eisai Co., Ltd. Anna Patten is an employee of Eisai Ltd. Leock Y Ngo is an employee of Eisai Inc., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To evaluate the exploratory time to exceed pre-randomization seizure count (T-PSC) in the determination of efficacy of adjunctive perampanel in participants with primary generalized tonic-clonic (PGTC) seizures in generalized-onset epilepsy., Methods: In this multicenter, double-blind study (ClinicalTrials.gov identifier: NCT01393743), participants ≥12 years of age with treatment-resistant idiopathic generalized epilepsy were randomized to receive placebo or adjunctive perampanel (≤8 mg/day) across a 17-week double-blind treatment phase (4-week titration; 13-week maintenance). We evaluated the pre-planned exploratory end point of the T-PSC using a Kaplan-Meier analysis. We also re-evaluated the correspondence of the primary end points of median percent seizure frequency change (MPC) and 50% responder rate (50RR) calculated at T-PSC and at the end of the trial., Results: The exploratory end point of median T-PSC on placebo was 43 days and >120 days on perampanel (log-rank p < .001). The primary end points calculated at T-PSC did not differ significantly from the end points at the end of the trial (MPC -31% vs -42% at T-PSC; 50RR 32% vs 51% at T-PSC). After T-PSC was reached, participants had a median (interquartile range) of 5 (3-13) additional seizures on placebo and 5 (2-10) on perampanel., Significance: The exploratory end point of T-PSC demonstrated the effectiveness of perampanel despite a shorter duration of monitoring. The seizures that occurred after T-PSC did not influence the conclusions of the trial; therefore, T-PSC may be a viable alternative to traditional trial end points that reduces the risk to participants., (© 2022 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Intravenous (IV) drug administration enables treatment of epilepsy when oral administration is temporarily not feasible. Perampanel is a once-daily antiseizure medication currently available as oral formulations. Study 050 (NCT03376997) was an open-label, randomized, single-dose, crossover study to evaluate the interchangeability of oral and IV perampanel in healthy subjects (N = 48). Bioequivalence of single 12-mg doses of IV (30-, 60-, or 90-minute infusion) and oral perampanel, ≥6 weeks apart, was assessed. Analyses indicated bioequivalence of area under the plasma concentration-time curve extrapolated to infinity for 30- and 60-minute IV infusions and oral perampanel doses (geometric mean ratio [90% confidence interval], 0.93 [0.84-1.02] and 1.03 [0.97-1.09], respectively); however, IV maximum observed drug concentration (C max ) values were 1.35- to 1.61-fold higher than C max . Simulated plasma concentration-time profiles using pooled pharmacokinetic data further supported oral and IV perampanel interchangeability in two scenarios: 12-mg per day IV dosing during a temporary 7-day switch from oral steady-state maintenance therapy, and treatment initiation with 2-mg perampanel. Thirty-four (70.8%) subjects experienced treatment-related adverse events. The IV perampanel safety profile was similar to that of oral perampanel without new safety concerns. Perampanel IV infusions may be a suitable temporary alternative to oral perampanel for treatment maintenance and/or initiation., (© 2022 Eisai Inc. Clinical Pharmacology in Drug Development published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Objective: This post hoc analysis evaluated whether continued treatment with perampanel monotherapy beyond initial titration may be appropriate for patients with focal-onset seizures (FOS) with currently untreated epilepsy to achieve seizure freedom with an effective dose., Methods: Study 342 (NCT03201900; FREEDOM) is a single-arm, open-label, Phase III study of perampanel monotherapy. Patients aged ≥12 years with untreated FOS received perampanel 4 mg/d in a 32-week Treatment Phase (6-week Titration and 26-week Maintenance Periods); in case of seizure(s) during Maintenance Period, patients could enter a 30-week Treatment Phase (4-week Titration and 26-week Maintenance Periods) to be up-titrated to perampanel 8 mg/d. The primary endpoint was seizure-freedom rate during Maintenance Period in the modified Intent-to-Treat (mITT) Analysis Set (patients who had ≥1 post-dose efficacy measurement during Maintenance Period); safety was monitored. This analysis of 4-mg/d efficacy data assessed the proportion of patients achieving seizure freedom during the Maintenance Period (responders) relative to patients with an early/later response (depending on seizure status during the Titration Period)., Results: In the mITT population (n = 73), 46 patients were 4-mg/d responders; of whom, 37 (80.4%) were early responders and nine (19.6%) were later responders. The mean (standard deviation) percent reductions in FOS frequency from baseline at the end of the 4-mg/d Titration Period were 100.0% (0.0%; early responders) and 46.3% (97.3%; later responders). Among the 27 4-mg/d nonresponders, nine (33.3%) patients who had an early response experienced seizure(s) during the subsequent 4-mg/d Maintenance Period. Safety outcomes were similar, regardless of responder status, without new safety concerns., Significance: Some patients with untreated FOS may benefit from continued treatment beyond initial titration of perampanel monotherapy to achieve seizure freedom, suggesting that it may not be appropriate to make treatment decisions to discontinue or switch from perampanel monotherapy solely based on seizure response before an effective dose has been reached., (© 2021 The Authors. Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Objective: Since increased mortality rates have been associated with convulsive seizures, it is important to achieve seizure control in these patients. Here, we report post hoc analyses to assess long-term seizure-freedom rates with adjunctive perampanel in patients (aged ≥ 12 years) with refractory focal to bilateral tonic-clonic seizures (FBTCS) or generalized tonic-clonic seizures (GTCS) who participated in open-label extension (OLEx) studies., Methods: Patients with focal-onset seizures, with/without FBTCS, who completed double-blind, Phase III Studies 304, 305, or 306 could enter OLEx Study 307 (16-week blinded Conversion; 256-week Maintenance). Patients with GTCS who completed the double-blind phase of Study 332 could enter the OLEx Phase (6-week blinded Conversion; 136-week Maintenance). Maximum perampanel dose: 12 mg/day. Seizure-freedom rates for up to 24 months were assessed in perampanel-treated patients who achieved seizure freedom during the double-blind studies to determine if their seizure-free status was maintained during the OLEx. In addition, to ensure any patients who only achieved seizure freedom during the OLEx were captured, seizure-freedom rates were also assessed in all patients who achieved and maintained a seizure-free status for a period of at least six consecutive months at any time during the double-blind and/or OLEx studies; some of these patients may have received placebo during the double-blind study but only their time on perampanel is included in the seizure-free analysis. Univariate and multivariate analyses were used to identify predictive factors for achieving seizure freedom for at least 6 months. Treatment-emergent adverse events (TEAEs) were assessed., Results: Overall, 53.8% (n = 42/78) of patients who received perampanel and were FBTCS free during the double-blind studies remained seizure free for up to 24 months during Study 307, and 31.6% (n = 6/19) of patients who were GTCS free during the double-blind phase of Study 332 remained seizure free for up to 24 months during the OLEx Phase. Over 40% (FBTCS, 41.5% [n = 197/475]; GTCS, 52.9% [n = 73/138]) of patients were seizure free for a period of at least six consecutive months. Multivariate analysis showed that the best predictors of achieving seizure freedom from FBTCS for at least 6 months were lower baseline seizure frequency (p = 0.0014) and absence of enzyme-inducing anti-seizure medications at baseline (p = 0.0056); multivariate analysis was not conducted for GTCS since only one variable was identified as a significant predictor of seizure freedom in the univariate analysis (lower baseline seizure frequency). Perampanel was generally well tolerated with no new safety signals identified. The most common TEAE was dizziness. For both seizure types, 10% or fewer seizure-free patients discontinued perampanel due to TEAEs., Conclusions: These results suggest that adjunctive perampanel may be a suitable long-term treatment option for patients (aged ≥ 12 years) with convulsive seizures to achieve and maintain seizure freedom., Competing Interests: Declaration of Competing Interest Trevor Resnick has served as a consultant and on the speakers bureau for Aquestive, Eisai, Lundbeck, Mallinkrodt, SK Life Science, Sunovion, Supernus, UCB Pharma, and Zogenix. Anna Patten is an employee of Eisai Europe Ltd. Leock Y Ngo and Manoj Malhotra are employees of Eisai Inc., (Copyright © 2021. Published by Elsevier Inc.)