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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).)

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.)