Randomized phase III study 306: Adjunctive perampanel for refractory partial-onset seizures

A Phase 4, multicenter, prospective, non-interventional, observational study to investigate the effectiveness and safety/tolerability of perampanel when used as first adjunctive therapy in routine clinical practice in people with epilepsy: Study 512

Introduction

Study 512 aimed to assess the efficacy and safety of perampanel (PER) as the first add-on therapy.

Methods

In this 12-month, prospective, observational, multicenter study, people with epilepsy (PWE) aged ≥12 years with focal-onset seizures or generalized tonic-clonic seizures (GTCS) associated with idiopathic generalized epilepsy received PER as the first add-on therapy to antiseizure medication (ASM) monotherapy. The primary efficacy endpoint was the retention rate at 12 months. Other endpoints included change in seizure frequency from baseline; pragmatic seizure freedom rate (proportion of PWE in the full analysis set achieving freedom from all seizures); responder rate (≥50% seizure frequency reduction from baseline), changes from baseline in the 10-item Quality of Life in Epilepsy questionnaire (QOLIE-10) total score, the Epworth Sleepiness Scale (ESS), and the age-corrected EpiTrack and EpiTrack Junior total score; safety/tolerability (treatment-emergent adverse events [TEAEs]); and PER dose.

Results

Of 184 PWE (Safety Set, n = 182; Full Analysis Set, n = 174), 135 (73.4%) completed the 12-month study. The mean PER dose was 4.7 mg/day. Retention rate at 12 months was 74.2% in the overall population, 81.8% in the 12 to <18 years age group, 74.3% in the 18 to <65 years age group, and 66.7% in the ≥65 years age group. Retention rates were similar between PWE with focal-onset seizures (74.5%) and GTCS (75.0%). The median reduction in monthly seizure frequency per 28 days from baseline to 12 months was 78.6% in the overall population, 92.3% in the 12 to <18 age group, 75.0% in the 18 to <65 years age group, and 87.5% in the ≥65 years age group. In the overall population, pragmatic seizure freedom rates at 12 months were 36.2% (all seizures), 34.1% (all focal seizures), and 45.5% (GTCS); the responder rate at 12 months was 64.4% in the overall population. In total, 52.7% of PWE experienced TEAEs, and 12.1% discontinued due to TEAEs. No significant changes were identified from baseline to 12 months in QOLIE-10, ESS, and the age-corrected EpiTrack and EpiTrack Junior scores.

Conclusion

PER was efficacious for focal and generalized seizures across all age groups and was generally well-tolerated, as demonstrated by the high retention rates at 12 months.

Long-term safety and efficacy of adjunctive perampanel in pediatric patients (ages 4 to <12 years) with inadequately controlled focal-onset seizures or generalized tonic-clonic seizures

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.

Cognitive and behavioral effects of perampanel 4 mg daily dose

OBJECTIVE

The neuropsychological adverse effects of antiseizure medications (ASMs) influence the tolerability, and in turn effectiveness of these medications, which can occur in a dose-dependent fashion. In this study, we examine the neuropsychological effects of perampanel (PER) at 4 mg daily as this dose has not been previously assessed with objective cognitive tests.

METHODS

The study was originally designed to assess (1) effects of perampanel at 4 mg using different titration rates, and (2) habituation over time. Due to the COVID-19 pandemic, the study was halted, limiting the sample size needed to analyze titration and habituation effects. Therefore, we compared the neuropsychological effects of perampanel 4 mg daily from non-drug baseline to the end of drug titration and end of drug maintenance in this randomized double-blind study of healthy volunteers. Treatment period was 6 weeks total with 2 weeks of variable titration followed by 4-week maintenance. Composite Z-scores were calculated by combining Z-scores from both cognitive (computerized and non-computerized) and behavioral tests. Secondary analyses were conducted on the independent cognitive and behavioral domain Z-scores, and on the raw scores from 19 items in the full battery.

RESULTS

The overall composite Z-scores did not differ across baseline, the end of titration, and the end of maintenance. Similarly, individual cognitive and behavioral domain Z-scores did not differ across the three titration rates. Exploratory analyses of the raw scores were marginally significant on only two of the 19 neuropsychological measures.

CONCLUSIONS

Perampanel 4 mg daily was well tolerated with few neuropsychological effects in healthy volunteers.

Improving the tolerability of antiseizure medications: When and how to use cenobamate and other new antiseizure medications

Despite the introduction of newer antiseizure medications (ASMs) with improved safety profiles over the past several years, rates of treatment-related intolerable adverse events (AEs) for people with epilepsy have not changed substantially. Tolerability issues can potentially jeopardize optimal dosing and effectiveness, regimen adherence, and treatment retention with these newer medications. Long-term clinical studies, open-label extension studies, and postmarketing studies allow flexible dosing and adjustment of concomitant ASMs, which can help clinicians reduce treatment-related AEs and thus improve the retention and tolerability of these treatments. With newer effective treatments (e.g., lacosamide, eslicarbazepine, perampanel, brivaracetam, and most recently, cenobamate), the risk of AEs may be minimized by proactively adjusting concomitant ASMs that have known pharmacokinetic and/or pharmacodynamic drug interactions. Additional tolerability considerations should be made for specific populations, for example, more determined reductions in concomitant ASMs may be required to improve treatment tolerability in older people, and individuals with more refractory seizures may require higher doses. Strategies to improve the tolerability of effective ASMs further, including earlier add-on therapy and transition to, or initial, monotherapy should be investigated. Ongoing clinical studies in children and people with generalized tonic-clonic seizures of the most recent ASM addition, cenobamate, will further inform the safety profile of cenobamate and its potential utility as a broad-spectrum treatment option.

Epilepsy medication management: Addressing common treatment barriers to adopting cenobamate and other new antiseizure medications

Seizure freedom is an important therapeutic goal for people with epilepsy and is associated with improved quality of life and reduced morbidity and mortality. Yet despite the use of multiple antiseizure medications (ASMs; either as monotherapy or in combination), seizures persist in approximately one third of patients. Third-generation ASMs, such as lacosamide, eslicarbazepine, perampanel, and brivaracetam, have demonstrated good efficacy in terms of reductions in the frequency of focal seizures. The newest ASM, cenobamate, which is indicated for the treatment of focal seizures in adults, has demonstrated notable rates of seizure freedom for some patients with drug-resistant epilepsy. In long-term, open-label clinical studies of adjunctive cenobamate, between 18.4% and 36.3% of patients achieved seizure freedom for a consecutive ≥12-month duration, and 1-year retention rates ranged from 73% to 83%. This article reviews some of the potential treatment barriers encountered during the medication management of patients with epilepsy that may impede the use and optimization of newer ASMs like cenobamate. These include treatment complacency, inadequate trial of new adjunctive therapies ("last in, first out"), pitfalls of rational polytherapy, and restricting the use of newer drugs. Although treatment must always be tailored to the specific patient, clinicians should consider the potential benefits of newer therapies and continue to reassess and optimize ASM treatment to achieve the best outcomes for their patients.

Factors associated with placebo response rate in randomized controlled trials of antiseizure medications for focal epilepsy

OBJECTIVE

Randomized controlled trials (RCTs) are necessary to evaluate the efficacy of novel treatments for epilepsy. However, there have been concerning increases in the placebo responder rate over time. To understand these trends, we evaluated features associated with increased placebo responder rate.

METHODS

Using individual-level data from 20 focal-onset seizure trials provided by seven pharmaceutical companies, we evaluated associations with change in seizure frequency in participants randomized to placebo. We used multivariable logistic regression to evaluate participant and study factors associated with differing rates of 50% reduction in seizure frequency during blinded placebo treatment, as compared to pre-randomization baseline seizure frequency. In addition, we focused on the association of placebo responder rate with pre-randomization baseline seizure frequency and country of recruitment.

RESULTS

In the pooled analysis of 1674 participants randomized to placebo, a higher 50% responder rate (50RR) was associated with a shorter duration of epilepsy (p = .006), lower baseline seizure rate (p = .002), fewer concomitant antiseizure medications (p = .004), absence of adverse events (p < .001), more trial arms (p = .006), and geographic region (p < .001). Mixture modeling indicated a significantly higher 50RR in Bulgaria, Croatia, India, and Canada (42% in the higher group vs 22% in the lower group comprising all 40 other countries, p < 10-15). In addition, there was a significantly higher 50RR in participants with a baseline seizure frequency of six or fewer seizures per 28 days (29% vs 21%, p = .00018).

SIGNIFICANCE

These results can assist future RCTs in estimating the expected placebo responder rate, which may lead to more reliable power estimates. Higher placebo responder rate was associated with markers of less-refractory epilepsy. There were concerning significant differences in placebo responder rate by country and geographic region as well as an elevated placebo responder rate in participants with baseline seizure frequency close to the minimum eligibility criteria.

Efficacy and safety of perampanel in patients with seizures associated with Lennox-Gastaut syndrome: A randomized trial

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.

Pilot Trial of Perampanel on Peritumoral Hyperexcitability in Newly Diagnosed High-grade Glioma

PURPOSE

Glutamatergic neuron-glioma synaptogenesis and peritumoral hyperexcitability promote glioma growth in a positive feedback loop. The objective of this study was to evaluate the feasibility and estimated effect sizes of the targeted AMPA receptor antagonist perampanel on peritumoral hyperexcitability.

EXPERIMENTAL DESIGN

An open-label trial was performed comparing perampanel with standard of care (SOC) in patients undergoing resection of newly diagnosed radiologic high-grade glioma. Perampanel was administered as a preoperative loading dose followed by maintenance therapy until progressive disease or up to 12 months. SOC treatment involved levetiracetam for 7 days or as clinically indicated. The primary outcome of hyperexcitability was defined by intraoperative electrocorticography high-frequency oscillation (HFO) rates. Seizure freedom and overall survival were estimated by the Kaplan-Meier method. Tissue concentrations of perampanel, levetiracetam, and correlative biomarkers were measured by mass spectrometry.

RESULTS

HFO rates were similar between patients treated with perampanel and levetiracetam. The trial was terminated early after a planned interim analysis, and outcomes assessed in 11 patients (seven perampanel treated; four treated with SOC). Over a median 281 days of postenrollment follow-up, 27% of patients had seizures, including 14% maintained on perampanel and 50% treated with SOC. Overall survival in perampanel-treated patients was similar to that in a glioblastoma reference cohort. Glutamate concentrations in surface biopsies were positively correlated with HFO rates in adjacent electrode contacts and were not significantly associated with treatment assignment or drug concentrations.

CONCLUSIONS

Glioma peritumoral glutamate concentrations correlated with high-gamma oscillation rates. Targeting glutamatergic activity with perampanel achieved similar electrocorticographic hyperexcitability levels as in levetiracetam-treated patients.

Effects of the AMPAR Antagonist, Perampanel, on Cognitive Function in Rats Exposed to Neonatal Iron Overload

Iron accumulation has been associated with the pathogenesis of neurodegenerative diseases and memory decline. As previously described by our research group, iron overload in the neonatal period induces persistent memory deficits and increases oxidative stress and apoptotic markers. The neuronal insult caused by iron excess generates an energetic imbalance that can alter glutamate concentrations and thus trigger excitotoxicity. Drugs that block glutamatergic receptor eligibly mitigate neurotoxicity; among them is perampanel (PER), a reversible AMPA receptor (AMPAR) antagonist. In the present study, we sought to investigate the neuroprotective effects of PER in rats subjected to iron overload in the neonatal period. Recognition and aversive memory were evaluated, AMPAR subunit phosphorylation, as well as the relative expression of genes such as GRIA1, GRIA2, DLG4, and CAC, which code proteins involved in AMPAR anchoring. Male rats received vehicle or carbonyl iron (30 mg/kg) from the 12th to the 14th postnatal day and were treated with vehicle or PER (2 mg/kg) for 21 days in adulthood. The excess of iron caused recognition memory deficits and impaired emotional memory, and PER was able to improve the rodents' memory. Iron increased the phosphorylation of GLUA1 subunit, which was reversed by PER. Furthermore, iron overload increased the expression of the GRIA1 gene and decreased the expression of the DLG4 gene, demonstrating the influence of metal accumulation on the metabolism of AMPAR. These results suggest that iron can interfere with AMPAR functionality, through altered phosphorylation of its subunits, and the expression of genes that code for proteins critically involved in the assembly and anchoring of AMPAR. The blockade of AMPAR with PER is capable of partially reversing the cognitive deficits caused by iron overload.

Phenobarbital use in pediatric perampanel overdose with coma, respiratory compromise

Perampanel (Fycompa®) is a non-competitive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor antagonistic antiepileptic medication used to treat generalized seizure disorders. Very little is known about the management of patients following perampanel overdose, particularly in the pediatric population. We report a case of a pediatric patient, initially presenting with increased aggression and erratic behavior, who quickly developed severe respiratory failure and prolonged coma following an intentional ingestion of between 80 and 216 mg of perampanel (1.64-4.43 mg/kg of body weight). Phenobarbital was initiated to increase the metabolism of perampanel and for seizure prophylaxis. Perampanel toxicity has been associated with a range of symptoms including bradycardia, hypotension, hyponatremia, central nervous system depression, prolonged coma, hypercoagulable state, and erratic, aggressive "zombie-like" behavior. With a reported half-life of 105 hours, no known reversal agent, and limited evidence-based management, clinicians should be prepared for prompt resuscitation and prolonged management of patients with suspected perampanel intoxication.

Educational Objectives

1.Identify symptoms of perampanel overdose and consider early intubation and resuscitation for prolonged coma and respiratory failure.2.Describe alternative methods to increase metabolization of medications with prolonged half-life.

Perampanel for the treatment of Asian people with epilepsy: Real-world evidence from the PERMIT extension study

This post-hoc analysis of the PERMIT Extension study compared the effectiveness and safety/tolerability of perampanel (PER) between Asian and non-Asian participants. Retention rates, adverse events (AEs), seizure frequency, responder rate (≥50% seizure frequency reduction), and seizure freedom rate (no seizures since at least the prior visit) were assessed. Retention was assessed after 3, 6 and 12 months. Effectiveness assessments were evaluated at 3, 6 and 12 months and the last visit by seizure type (total, focal and generalised). PERMIT Extension included 730 Asian and 1662 non-Asian individuals. Significant differences in demographic/baseline characteristics were reported for the Asian versus non-Asian subgroups including higher median age at epilepsy onset, longer median duration of epilepsy, higher mean number of previous and concomitant ASMs and lower mean monthly seizure frequency (total, focal and generalised). Retention rates were similar between the two subgroups at 3 and 12 months, but significantly lower in the Asian versus non-Asian subgroup at 6 months (65.6% vs. 71.8%; p = 0.004). At last visit, seizure freedom rate was significantly higher in the Asian versus non-Asian for total (35.9% vs. 25.4%; p = 0.001) and focal seizures (32.4% vs. 18.9%; p = 0.001) as was responder rate for both total (63.9% vs. 52.3%; p = 0.001) and focal seizures (62.2% vs. 44.7%; p < 0.001). Seizure freedom and responder rates for generalised seizures were similar between the two subgroups at the last visit. Rates of AEs were similar between the two subgroups (Asian, 47.6%; non-Asian, 45.4%). PER was effective and generally well-tolerated in Asian and non-Asian individuals.

Efficacy and safety of add-on antiseizure medications for focal epilepsy: A network meta-analysis

OBJECTIVE

Several antiseizure medications (ASMs) have been approved for the treatment of focal epilepsy. However, there is a paucity of evidence on direct comparison of ASMs. We evaluated the comparative efficacy and safety of all approved add-on ASMs for the treatment of focal epilepsy using network meta-analysis.

METHODS

Data through extensive literature search was retrieved from PubMed, Embase, Cochrane, and ClinicalTrial.gov databases using predefined search terms from inception through March 2023. PRISMA reporting guidelines (CRD42023403450) were followed in this study. Efficacy outcomes assessed were ≥50%, ≥75%, and 100% responder rates. Patient retention rate and safety outcomes such as overall treatment-emergent adverse events (TEAEs) and individual TEAEs were assessed. "Gemtc" 4.0.4 package was used to perform Bayesian analysis. Outcomes are reported as relative risks (RRs) and 95% confidence interval (CI).

RESULTS

Literature search retrieved 5807 studies of which, 75 studies were included in the analysis. All ASMs showed significantly higher ≥50% responder rate compared with placebo. Except the ≥75% seizure frequency reduction for zonisamide (2.23; 95% CI: 1.00-5.70) and 100% for rufinamide (2.03; 95% CI: 0.54-11.00), all other interventions showed significantly higher ≥75% and 100% responder rates compared with placebo. Among treatments, significantly higher 100% responder rate was observed with cenobamate compared to eslicarbazepine (10.71; 95% CI: 1.56-323.9) and zonisamide (10.63; 95% CI: 1.37-261.2). All ASMs showed a lower patient retention rate compared to placebo, with the least significant value observed for oxcarbazepine (0.77; 95% CI: 0.7-0.84). Levetiracetam showed a lower risk of incidence (1.0; 95%CI: 0.94-1.1; SUCRA: 0.885067) for overall TEAE compared with other medications.

SIGNIFICANCE

All approved ASMs were effective as add-on treatment for focal epilepsy. Of the ASMs included, cenobamate had the greatest likelihood of allowing patients to attain seizure freedom.

PLAIN LANGUAGE SUMMARY

This article compares the efficacy and safety of antiseizure medications (ASMs) currently available to neurologists in the treatment of epileptic patients. Several newer generation ASMs that have been developed may be as effective or better than the older medications. We included 75 studies in the analysis. In comparison, all drugs improved ≥50%, ≥75% and 100% responder rates compared to control, except for Zonisamide and Rufinamide in the ≥75% and 100% responder rate categories. Retention of patients undergoing treatment was lower in drugs than placebo. All drugs were tolerated, the levetiracetam showed the best tolerability. Cenobamate more likely help completely to reduce seizures.

Efficacy and safety of adjunctive perampanel treatment in pediatric patients with epilepsy aged 4-12 years: a real-world study

OBJECTIVE

To determine the efficacy and safety of perampanel (PER) as an adjunctive therapy in children aged 4-12 years with epilepsy.

METHODS

We performed a non-randomized, open-label, placebo-uncontrolled, real-world self-controlled study that included 216 young children (aged 4-12 years) with epilepsy who received PER as adjunctive therapy at the children's hospital affiliated with Chongqing Medical University from July 4, 2020, to September 20, 2023.

RESULTS

(1) The efficacy rates of adjunctive PER therapy at 3, 6, 9, and 12 months were 62.8%, 67.8%, 65.3%, and 61.2%, respectively. PER showed efficacy in alleviating focal seizures, generalized tonic-clonic seizures, myoclonic seizures, and absence seizures. The efficacy rates for variants of self-limited epilepsy with centrotemporal spikes (SeLECTS) and Lennox-Gastaut syndrome (LGS) were 89.5% and 66.7%, respectively. (2) Focal non-motor onset seizures with or without impaired awareness, focal to bilateral tonic-clonic seizures (FBTCS), LGS, variants of SeLECTS, the number of concomitant antiseizure medications (ASMs), a family history of epilepsy, and focal lesions on cranial magnetic resonance imaging were independent factors affecting efficacy. The order of PER addition did not affect efficacy. The retention rates at 3, 6, 9, and 12 months were 90.7%, 84.7%, 74.7%, 64.9%, respectively. (3) Adverse reactions occurred in 45 patients (45/216, 20.8%), with irritability/aggressive behavior (18/216, 8.3%) and somnolence (14/216, 6.5%) being the most common. Twelve patients (12/216, 5.6%) withdrew from the study because of adverse reactions.

CONCLUSION

In young Chinese children with epilepsy, PER is effective, safe, and well-tolerated as an adjunctive therapy, making it a viable option for use with broad-spectrum ASMs.

Perampanel as monotherapy or first adjunctive therapy in pediatric and adult patients with epilepsy: the first United States-based phase IV open-label ELEVATE study

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.

Perampanel for Treatment of People with a Range of Epilepsy Aetiologies in Clinical Practice: Evidence from the PERMIT Extension Study

INTRODUCTION

It is important to assess the effectiveness of an antiseizure medication in treating different epilepsy aetiologies to optimise individualised therapeutic approaches. Data from the PERaMpanel pooled analysIs of effecTiveness and tolerability (PERMIT) Extension study were used to assess the effectiveness and safety/tolerability of perampanel (PER) when used to treat individuals with a range of epilepsy aetiologies in clinical practice.

METHODS

A post hoc analysis was conducted of PERMIT Extension data from individuals with a known aetiology. Retention was assessed after 3, 6 and 12 months. Effectiveness was assessed after 3, 6 and 12 months and at the last visit (last observation carried forward). Effectiveness assessments included responder rate (≥ 50% seizure frequency reduction) and seizure freedom rate (no seizures since at least the prior visit). Safety/tolerability was assessed by evaluating adverse events (AEs) and AEs leading to discontinuation.

RESULTS

PERMIT Extension included 1945 individuals with structural aetiology, 1012 with genetic aetiology, 93 with an infectious aetiology, and 26 with an immune aetiology. Retention rates at 12 months were 61.1% (structural), 65.9% (genetic), 56.8% (infectious) and 56.5% (immune). At the last visit, responder rates (total seizures) were 43.3% (structural), 68.3% (genetic), 37.0% (infectious) and 20.0% (immune), and corresponding seizure freedom rates were 15.8%, 46.5%, 11.1% and 5.0%, respectively. AE incidence rates were 58.0% (structural), 46.5% (genetic), 51.1% (infectious) and 65.0% (immune), and corresponding rates of discontinuation due to AEs over 12 months were 18.9%, 16.4%, 18.5% and 21.7%, respectively. The types of AEs reported were generally consistent across aetiology subgroups, with no idiosyncratic AEs emerging.

CONCLUSION

Although PER was effective and generally well tolerated when used to treat individuals with a range of epilepsy aetiologies in clinical practice, variability in its effectiveness and tolerability across the subgroups indicates that PER may be particularly useful for individuals with specific epilepsy aetiologies.

Efficacy and Safety of adjunctive Perampanel in a prospective, real-world, Phase IV study in Indian patients aged ≥12 years for Treatment of focal-onset Epilepsy: Study 508

OBJECTIVE

ESPRITE (Study 508; NCT03836924) evaluated the real-world safety, tolerability, and efficacy of adjunctive perampanel in patients aged ≥12 years with focal-onset seizures (FOS), with or without focal to bilateral tonic-clonic seizures (FBTCS), in India.

METHODS

ESPRITE was a prospective, multicenter, single-arm, observational, Phase IV study with a 6-month Treatment Period. Patients were aged ≥12 years and had been prescribed perampanel for adjunctive treatment of FOS, with or without FBTCS. Assessments included incidence of treatment-emergent adverse events (TEAEs; primary endpoint), median percent reduction in seizure frequency per 28 days from baseline, 50% responder rates, and seizure-freedom rates.

RESULTS

Overall, 200 patients were enrolled (199 patients in the Safety Analysis Set and 174 patients who completed all visits in the main efficacy analyses). TEAEs (all mild or moderate in severity) were reported in 18.1% (n = 36/199) of patients (the most common were dizziness [3.0%] and irritability [2.0%]). TEAEs leading to discontinuation of perampanel were reported in 2.0% of patients; no deaths or serious TEAEs occurred. At 6 months, median percent reduction in seizure frequency was 100.0%, 50% responder rate was 83.3%, and seizure-freedom rate was 49.4%.

SIGNIFICANCE

Adjunctive perampanel (at a mean daily dose of 4 mg/day) was shown to be well tolerated and effective in patients aged ≥12 years with FOS, with or without FBTCS, from India.

PLAIN LANGUAGE SUMMARY

Many patients do not receive adequate treatment for epilepsy and need effective seizure control medications. In this 6-month clinical study, 199 patients from India, aged 12 years or older, added perampanel to the anti-seizure medications they were already taking. At 6 months, 49% of patients experienced no seizures since starting perampanel and seizure frequency was reduced by half in 83% of patients. Side effects occurred in 18% of patients (most commonly dizziness and irritability) and caused 2% to stop perampanel; no deaths were reported. Perampanel was an effective and generally safe added medication for patients with epilepsy from India.

Phase IV PROVE study: Perampanel in real-world clinical care of pediatric patients with epilepsy

INTRODUCTION

The non-interventional Phase IV PROVE study (NCT03208660) assessed retention, efficacy, safety and tolerability, and perampanel dosing in patients with epilepsy during routine clinical care. This analysis evaluated final data from patients aged <4 years and 4-<12 years.

METHODS

Data were obtained retrospectively from medical/pharmacy records of patients in the United States initiating perampanel after January 1, 2014, according to treating clinician recommendations. Retention rate was the primary endpoint. Secondary assessments included median percent changes in seizure frequency, seizure-freedom rates, investigator impression of seizure effect, and safety and tolerability.

RESULTS

The Safety Analysis Set (SAS) included 41 patients (<4 years; mean maximum dose, 3.5 mg/day) and 203 patients (4-<12 years; mean maximum dose, 5.3 mg/day); 24-month retention rates were 35.7% (n = 5/14) and 42.0% (n = 47/112), respectively. In the Full Analysis Set, during Months 1-3, median percent reductions in seizure frequency were 33.3% (n = 8 [<4 years]) and 26.0% (n = 32 [4-<12 years]), and seizure-freedom rates were 12.5% in both groups (n = 1/8 and n = 4/32); patient numbers were low at later time points. Most patients showed improvements in seizure control (45.9% [<4 years] versus 52.4% [4-<12 years]) or no change (45.9% versus 34.5%) (SAS). Treatment-emergent adverse events (TEAEs) were reported in 12 (<4 years: 29.3%; most common, irritability [7.3%]) and 64 patients (4-<12 years: 31.5%; most common, aggression [6.9%]).

CONCLUSIONS

Perampanel was generally well tolerated with <21% of TEAEs leading to withdrawal at 24 months, had favorable retention rates (≥50% and >35% at 12 and 24 months, respectively), and sustained efficacy in pediatric patients during routine clinical care.

A comparison of cenobamate with other newer antiseizure medications for adjunctive treatment of focal-onset seizures: A systematic review and network meta-analysis

PURPOSE

To compare the efficacy, safety, and tolerability of cenobamate with other newer anti-seizure medications (ASMs) including brivaracetam, eslicarbazepine, lacosamide, perampanel, and zonisamide, approved for adjunctive treatment of drug-resistant focal-onset seizures (FOS) in adults with epilepsy.

METHODS

A systematic literature review (SLR) was conducted to obtain relevant efficacy, safety, and tolerability data for ASMs for the treatment of drug-resistant FOS. All studies were thoroughly assessed for potential sources of heterogeneity and analysed via Bayesian network meta-analyses (NMAs). Efficacy outcomes were ≥50 % responder rate and seizure freedom during the maintenance period, which were modelled simultaneously using a multinomial Bayesian NMA. Safety and tolerability outcomes were the proportion of patients who experienced at least one treatment-emergent adverse event (TEAE) and the proportion who experienced at least one TEAE leading to discontinuation.

RESULTS

The SLR identified 76 studies, of which 23 were included in the Bayesian NMAs. Cenobamate was associated with statistically significant higher rates for the ≥50 % responder rate and seizure freedom outcomes compared with all ASMs analysed. The point estimates indicated that cenobamate was associated with higher rates of experiencing at least one TEAE and at least one TEAE leading to discontinuation compared with brivaracetam, lacosamide, and zonisamide; however, no results were statistically significant.

CONCLUSION

Cenobamate was associated with increased efficacy compared with all ASMs analysed. There were no statistically significant differences in the safety and tolerability outcomes. The results presented corroborate the conclusions drawn from previous published NMAs, which also highlight the notable efficacy of cenobamate in comparison with other ASMs.

Perampanel for the treatment of epilepsy with genetic aetiology: Real-world evidence from the PERMIT Extension study

Genetic factors contribute to the aetiology of epilepsy in >50% of cases, and information on the use of antiseizure medications in people with specific aetiologies will help guide treatment decisions. The PERMIT Extension study pooled data from two real-world studies (PERMIT and PROVE) to investigate the effectiveness and safety/tolerability of perampanel (PER) when used to treat people with focal and generalised epilepsy in everyday clinical practice. This post-hoc analysis of PERMIT Extension explored the use of PER when used to treat individuals presumed to have epilepsy with a genetic aetiology. Assessments included retention rate (evaluated at 3, 6 and 12 months), effectiveness (responder and seizure freedom rates; evaluated at 3, 6, 12 months and the last visit [last observation carried forward) and tolerability (adverse events [AEs]). Of the 6822 people with epilepsy included in PERMIT Extension, 1012 were presumed to have a genetic aetiology. The most common genetic aetiologies were idiopathic generalised epilepsy (IGE; 58.2%), tuberous sclerosis (1.1%), Dravet syndrome (0.8%) and genetic epilepsy with febrile seizures plus (GEFS+; 0.5%). Retention rates at 3, 6 and 12 months in the total genetic aetiology population were 89.3%, 79.7% and 65.9%, respectively. In the total genetic aetiology population, responder rates at 12 months and the last visit were 74.8% and 68.3%, respectively, and corresponding seizure freedom rates were 48.9% and 46.5%, respectively. For the specific aetiology subgroups, responder rates at 12 months and the last visit were, respectively: 90.4% and 84.4% (IGE), 100% and 57.1% (tuberous sclerosis), 100% and 71.4% (Dravet syndrome), and 33.3% and 20.0% (GEFS+). Corresponding seizure freedom rates were, respectively: 73.1% and 64.6% (IGE), 33.3% and 22.2% (tuberous sclerosis), 20.0% and 28.6% (Dravet syndrome), and 0% and 0% (GEFS+). The incidence of AEs was 46.5% for the total genetic aetiology population, 48.8% for IGE, 27.3% for tuberous sclerosis, 62.5% for Dravet syndrome, and 20% for GEFS+. Tolerability findings were consistent with PER's known safety profile. PER was effective and generally well tolerated when used in individuals with a presumed genetic epilepsy aetiology in clinical practice. PER was effective across a wide range of genetic aetiologies.

Pilot trial of perampanel on peritumoral hyperexcitability and clinical outcomes in newly diagnosed high-grade glioma

Background

Glutamatergic neuron-glioma synaptogenesis and peritumoral hyperexcitability promote glioma growth in a positive feedback loop. The objective of this study was to evaluate the feasibility and estimated effect sizes of the AMPA-R antagonist, perampanel, on intraoperative electrophysiologic hyperexcitability and clinical outcomes.

Methods

An open-label trial was performed comparing perampanel to standard of care (SOC) in patients undergoing resection of newly-diagnosed radiologic high-grade glioma. Perampanel was administered as a pre-operative loading dose followed by maintenance therapy until progressive disease or up to 12-months. SOC treatment involved levetiracetam for 7-days or as clinically indicated. The primary outcome of hyperexcitability was defined by intra-operative electrocorticography high frequency oscillation (HFO) rates. Seizure-freedom and overall survival (OS) were estimated by the Kaplan-Meier method. Tissue concentrations of perampanel, levetiracetam, and metabolites were measured by mass spectrometry.

Results

HFO rates were similar between perampanel-treated and SOC cohorts. The trial was terminated early after interim analysis for futility, and outcomes assessed in 11 patients (7 perampanel-treated, 4 SOC). Over a median 281 days of post-enrollment follow-up, 27% of patients had seizures, including 14% treated with perampanel and 50% treated with SOC. OS in perampanel-treated patients was similar to a glioblastoma reference cohort (p=0.81). Glutamate concentrations in surface biopsies were positively correlated with HFO rates in adjacent electrode contacts and were not significantly associated with treatment assignment or drug concentrations.

Conclusions

A peri-operative loading regimen of perampanel was safe and well-tolerated, with similar peritumoral hyperexcitability as in levetiracetam-treated patients. Maintenance anti-glutamatergic therapy was not observed to impact survival outcomes.

Efficacy, tolerability and safety of add-on third-generation antiseizure medications in treating focal seizures worldwide: a network meta-analysis of randomised, placebo-controlled trials

Background

Adjunctive newer antiseizure medications (ASMs) are being used in patients with treatment-resistant focal-onset seizures (FOS). An updated network meta-analysis (NMA) was necessary to compile evidence in this critical area.

Methods

We systematically searched PubMed, Embase, Cochrane Library, Web of Science, and Scopus from their inception until 17 January 2024, evaluating the efficacy, tolerability, and safety of rufinamide (RUF), brivaracetam (BRV), cenobamate (CNB), eslicarbazepine (ESL), lacosamide (LCM), retigabine (RTG), and perampanel (PER) as adjunctive treatments for FOS. Efficacy outcomes included seizure response and seizure freedom. Tolerability was assessed by discontinuation due to adverse events (AEs). Safety outcomes were evaluated based on the number of patients experiencing at least one AE and serious adverse events (SAEs). This review is registered with PROSPERO (CRD42023485130).

Findings

A total of 29 studies involving 11,750 participants were included. For seizure response, all ASMs were significantly superior to placebo, with RTG ranking highest, followed by CNB. Considering dosage, CNB 400 mg/d was top-ranked, followed by RTG 1200 mg/d. For seizure freedom, BRV was highest-ranked, followed by CNB, with BRV 100 mg/d leading, followed by CNB 400 mg/d. Regarding tolerability, LCM 600 mg/d had the lowest ranking, followed by CNB 400 mg/d. For the safety outcome of AEs, ESL 1200 mg/d was ranked lowest, followed by CNB 400 mg/d. Regarding SAEs, LCM 400 mg/d was ranked lowest, followed by RTG 1200 mg/d.

Interpretation

ASMs at different dosages have varying efficacy and tolerability profiles. We have provided hierarchical rankings of ASMs for efficacy and safety outcomes. Our findings offer the most comprehensive evidence available to inform patients, families, physicians, guideline developers, and policymakers about the choice of ASMs in patients with treatment-resistant FOS.

Funding

None.

Long-term efficacy and safety of perampanel as an add-on therapy in patients with epilepsy

BACKGROUND

Perampanel (PER) is a newly developed amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor antagonist that has been globally approved for the treatment of both focal and generalized seizures. The efficacy and safety of PER have only been reported over short periods of treatment so far. This study aims to clarify the long-term efficacy and safety of PER as an add-on therapy.

METHOD

This retrospective observational study investigated 176 epilepsy patients who received PER as add-on medical therapy in two Japanese epilepsy centers between June 2016 and July 2022. The adherence, seizure frequency, and plasma concentration of PER were evaluated at three time points: 6 months, 12 months, and 24 months or longer after the start of adjunctive PER treatment.

RESULTS

112 patients undergoing PER treatment were evaluated at 6 months, 86 were evaluated at 12 months, and 52 were evaluated at 24 months or longer. Overall, 42.9 % (48/112), 45.4 % (40/86), and 44.2 % (23/52) of the patients were seizure-free at 6, 12, and 24 months or longer, respectively. The rate of PER tolerance was 78.3 %, 69.9 %, and 54.7 % at 6, 12, and 24 months or longer, respectively. At the latest timepoint, the seizure-free group was taking a significantly lower dose of PER than the seizure-remnant group, and the number of anti-seizure medications (ASMs) was associated with seizure outcomes. In addition, the seizure-free rate was significantly higher in patients who received PER as a first add-on than in those who received it as a late add-on. No significant difference was found in the plasma concentration of PER between the seizure-free and seizure-remnant groups at 24 months or longer. Among the patients receiving PER at dose of 2 mg, however, the plasma concentrations were significantly higher in the seizure-free group than in the seizure-remnant group (282.7 ± 109.8 μg/ml vs 94.7 ± 54.9 μg/ml, p = 0.0024).

CONCLUSION

This long-term retrospective observational study provides evidence of the efficacy and safety of PER over 2 years treatment period in Japan. Notably, patients who started on PER as the first add-on showed a better seizure outcome than those who received it as a late add-on over the long term. Measured plasma concentrations may provide valuable guidance for the management of patients. Higher plasma concentration at low dose PER may suggest the better seizure control.

WRAPPER study: Real-world effectiveness and tolerability of adjunctive perampanel for people with drug-resistant epilepsy in Hong Kong

OBJECTIVE

The Prince of Wales Hospital (PWH) Real-world Analysis of People with Drug-Resistant Epilepsy (DRE) on PERampanel (WRAPPER) study assessed effectiveness and tolerability of adjunctive perampanel in people with DRE attending PWH.

METHODS

This was a prospective single-center real-world observational study involving 70 people with DRE between July 2016 and June 2021. A post hoc analysis after the initial study period of 16 weeks assessed outcomes for an extended period up to 52 weeks.

RESULTS

After 16 weeks, median dose of perampanel was 2 mg (IQR 24 mg). 50% responder rates were 40.0%, 41.5%, and 48.7% at 16, 26, and 52 weeks. Seizure freedom was 12.9%, 20.7%, and 25.6% at 16, 26, and 52 weeks. Monthly seizure frequency reduced from 3.0 (IQR 3.0-6.6) at baseline to 2.0 (IQR 2.0-6.0, p = 0.005) at 16 weeks; 2.0 (IQR 2.0-5.0, p = 0.01) at 26 weeks; and 2.0 (IQR 0.0-4.0, p = 0.018) at 52 weeks. Older age predicted 50% responders (OR 1.08, 95% CI 1.01-1.14, p = 0.048). At 16 weeks, 51.4% (36/70) had treatment-emergent adverse effects (TEAEs). Most common was seizure exacerbation at 35.7% (25/70) followed by fatigue at 15.7% (11/70). NPI-12 and ZBI scores indicated no increase in neuropsychiatric symptoms on perampanel.

SIGNIFICANCE

Low-dose 2-4 mg adjunctive perampanel for people with DRE conferred appreciable improvements in seizure reduction without significant neuropsychiatric adverse effects in the real-world setting at a tertiary center in Hong Kong and had better antiseizure effect with advancing age.

PLAIN LANGUAGE SUMMARY

This real-world study from Hong Kong found low-dose perampanel was effective and tolerable for people with drug-resistant epilepsy. Furthermore, perampanel was also potentially more effective with advancing age.

Therapeutic drug monitoring of perampanel: Clinical utility and impact of co-medication on pharmacokinetic variability

BACKGROUND

Perampanel (PER) is a newly developed antiseizure medication (ASM). This study aimed to determine the utilization of therapeutic drug monitoring (TDM) for PER in a real-world clinical setting and investigate the influence of concomitant use of ASMs on the plasma concentration profile of PER.

METHOD

We analyzed data from the Chang Gung Research Database, which is the largest multi-institutional electronic medical records database in Taiwan. The main outcomes were the comparisons of PER plasma concentration and the ratio of concentration to the weight-adjusted dose (C/D; [ng/mL]/[mg/kg/d]) among patients received TDM of different clinical indication and among different ASM co-medication subgroups.

RESULTS

Overall, 88 plasma samples were collected from 66 epilepsy patients treated with PER. The majority of patients (77.3 %) underwent PER TDM owing to poorly controlled seizures. There was a trend toward a higher plasma concentration and C/D ratio in those suspected of having PER toxicity owing to adverse events than of other indications. The PER concentration exhibited dose linearity. The mean PER plasma concentrations in patients co-medicated with enzyme-inducing ASMs were significantly lower than those in the patients who were not prescribed enzyme-inducing or enzyme-inhibiting ASMs, and co-medication with carbamazepine (CBZ) resulted in a significant reduction in the PER concentration.

CONCLUSION

PER concentration exhibited a linear regression relationship with PER dose, and the plasma concentration of the drug was highly susceptible to the drug's interactions with enzyme-inducing ASMs. TDM with clear indication could help determine the influence of ASMs used concomitantly on PER concentrations and guide clinical adjustments.

The Rogdi knockout mouse is a model for Kohlschütter-Tönz syndrome

Kohlschütter-Tönz syndrome (KTS) is a rare autosomal recessive disorder characterized by severe intellectual disability, early-onset epileptic seizures, and amelogenesis imperfecta. Here, we present a novel Rogdi mutant mouse deleting exons 6-11- a mutation found in KTS patients disabling ROGDI function. This Rogdi-/- mutant model recapitulates most KTS symptoms. Mutants displayed pentylenetetrazol-induced seizures, confirming epilepsy susceptibility. Spontaneous locomotion and circadian activity tests demonstrate Rogdi mutant hyperactivity mirroring patient spasticity. Object recognition impairment indicates memory deficits. Rogdi-/- mutant enamel was markedly less mature. Scanning electron microscopy confirmed its hypomineralized/hypomature crystallization, as well as its low mineral content. Transcriptomic RNA sequencing of postnatal day 5 lower incisors showed downregulated enamel matrix proteins Enam, Amelx, and Ambn. Enamel crystallization appears highly pH-dependent, cycling between an acidic and neutral pH during enamel maturation. Rogdi-/- teeth exhibit no signs of cyclic dental acidification. Additionally, expression changes in Wdr72, Slc9a3r2, and Atp6v0c were identified as potential contributors to these tooth acidification abnormalities. These proteins interact through the acidifying V-ATPase complex. Here, we present the Rogdi-/- mutant as a novel model to partially decipher KTS pathophysiology. Rogdi-/- mutant defects in acidification might explain the unusual combination of enamel and rare neurological disease symptoms.

Perampanel as only add-on epilepsy treatment in elderly: A subgroup analysis of real-world data from retrospective, multicenter, observational study

INTRODUCTION

Drug management of epilepsy in the elderly presents unique but data on this population are scarce. This study aimed to assess the effectiveness and tolerability of perampanel (PER) used as only add-on to a background anti-seizure medication (ASM) in the elderly in a real-world setting.

METHODS

We performed a subgroup analysis of patients aged ≥65 years included in a previous 12-month multicenter study on adults. Treatment discontinuation, seizure frequency, and adverse events were recorded at 3, 6 and 12 months after PER introduction. Sub-analyses by early (≤1 previous ASM) or late PER add-on were also conducted.

RESULTS

The sample included 65 subjects (mean age: 75.7 ± 7.2 years), with mainly focal (73.8%) epilepsy. The mean PER daily dose was ≈4 mg during all follow-up. Retention rates at 3, 6, and 12 months were 90.5%, 89.6%, and 79.4%ly. The baseline median normalized per 28-day seizure number significantly decreased at 3-, 6- and 12-month visits. One year after PER introduction, the responder rate (≥50% reduction in baseline seizure frequency) was 89.7%, with a seizure freedom rate of 72.4%. Adverse events occurred in 22 (34.9%) patients with dizziness and irritability being the most frequent. No major differences between early (41 patients, 63.1%), and late add-on groups were observed.

CONCLUSION

Adjunctive PER was effective and well-tolerated when used as only add-on treatment in elderly people with epilepsy in clinical practice, thus representing a suitable therapeutic option in this age category.

Intravenous perampanel as an alternative to the oral formulations in Japanese patients with epilepsy

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.

Increasing challenges to trial recruitment and conduct over time

OBJECTIVE

This study was undertaken to evaluate how the challenges in the recruitment and retention of participants in clinical trials for focal onset epilepsy have changed over time.

METHODS

In this systematic analysis of randomized clinical trials of adjunct antiseizure medications for medication-resistant focal onset epilepsy, we evaluated how the numbers of participants, sites, and countries have changed since the first such trial in 1990. We also evaluated the proportion of participants who completed each trial phase and their reasons for early trial exit. We analyzed these trends using mixed effects generalized linear models accounting for the influence of the number of trial sites and trial-specific variability.

RESULTS

The number of participants per site has steadily decreased over decades, with recent trials recruiting fewer than five participants per site (reduction by .16 participants/site/year, p < .0001). Fewer participants also progressed from recruitment to randomization over time (odds ratio = .94/year, p = .014). Concurrently, there has been an increase in the placebo response over time (increase in median percent reduction of .4%/year, p = .02; odds ratio of increase in 50% responder rate of 1.03/year, p = .02), which was not directly associated with the number of sites per trial (p > .20).

SIGNIFICANCE

This historical analysis highlights the increasing challenges with participant recruitment and retention, as well as increasing placebo response. It serves as a call to action to change clinical trial design to address these challenges.

Effectiveness, safety and tolerability of perampanel by age group when used to treat people with focal and generalized epilepsy in clinical practice: The PERMIT Extension study

OBJECTIVE

To assess the effectiveness and safety/tolerability of perampanel (PER) in people with epilepsy (PWE) treated in everyday clinical practice for focal and generalized seizures, both in the total cohort and by age group.

METHODS

The PERMIT Extension study was a pooled analysis of data from PWE included in two large previous clinical practice studies (PERMIT and PROVE). Retention was assessed over 12 months. Effectiveness was assessed based on total seizures and by seizure type (focal and generalized) after 3, 6, and 12 months of PER treatment and at final follow-up (last observation carried forward; "last visit"); assessments included responder rate (≥50% seizure frequency reduction from baseline) and seizure freedom rate (no seizures since at least the previous visit). Safety/tolerability was assessed throughout PER treatment by evaluating adverse events (AEs). All assessments were conducted for the total population and by age category (<12, ≥12 to <18, ≥18 to <65, and ≥65 years at baseline).

RESULTS

Full Analysis Set included 6,822 PWE (51.1% female; mean age, 36.9 years; mean duration of epilepsy 21.4 years) with 6,433, 4,648, and 6,233 PWE assessed for retention, effectiveness, and safety/tolerability, respectively. The majority of PWE (81.1%) were aged 18-64 at baseline, with 4.5% aged <12 years, 8.4% aged 12-17 years, and 5.9% aged ≥65 years. In the overall population, retention rates at 3, 6, and 12 months were 88.0%, 77.6%, and 61.4%, respectively; responder rates at 12 months were 58.5% for total seizures, 54.6% for focal seizures, and 77.7% for generalized seizures, and corresponding seizure freedom rates were 23.6%, 19.0%, and 51.3%, respectively. PER was effective regardless of age category, although effectiveness was greatest in PWE aged ≥65 years, for both focal and generalized seizures. In the overall population, the incidence of AEs was 49.2% and the most frequent AEs (≥5% of PWE) were dizziness/vertigo (13.4%), somnolence (8.8%), irritability (7.3%), and behavioral disorders (5.3%); AEs led to treatment discontinuation in 18.3% of PWE over 12 months. The incidence of AEs and the discontinuation rate due to AEs increased with increasing age (55.0% and 23.9%, respectively, in PWE aged ≥65 years).

CONCLUSION

In this study, the largest pooled analysis of PER clinical practice data conducted to date, PER was shown to be effective and generally well tolerated when used to treat people with focal or generalized epilepsy in everyday clinical practice, regardless of age category. No new or unexpected side effects emerged following long-term use in the real-world setting.

Perampanel and lacosamide monotherapy in pediatric patients with newly diagnosed focal epilepsy: A prospective study evaluating efficacy, tolerability, and behavior

PURPOSE

Perampanel (PER) and lacosamide (LCM) are the new third-generation anti-seizure medications (ASMs) that were approved for the monotherapy of focal epilepsy in children over four years of age in China, in 2021. Very few studies have analyzed the application of PER monotherapy among pediatric patients aged ≥four years, and no study compared the efficacy and tolerability of PER monotherapy with LCM monotherapy in pediatric patients with focal epilepsy. The present study aimed to investigate the efficacy, tolerability, and effect on behavior and emotion of PER and LCM as monotherapy in pediatric patients with newly diagnosed focal epilepsy, which is beneficial for clinicians to have more choices to treat pediatric patients with focal epilepsy.

METHODS

This was a prospective, single-center, observational study that involved pediatric patients (disease onset age ≥four years) with newly diagnosed focal epilepsy treated with PER or LCM as primary monotherapy. Outcomes included retention, being responders, and seizure-free rates after 3, 6, and 12 months. Adverse events (AEs) were noticed throughout the follow-up period. Behavioral outcomes were evaluated with Achenbach Child Behavior Checklist (CBCL/4-16) at baseline and after three and six months.

RESULTS

Using randomization, 60 patients receiving PER (31 females, 29 males, median age: 7.79 [5.34, 10.16] years, median dose: 3.0 [2.0, 4.0] mg/day) and 60 patients receiving LCM (25 females, 35 males, median age: 7.72 [5.91, 10.72] years, median dose: 150.0 [100.0, 200.0] mg/day) were enrolled in the study. At the 12-month follow-up, the retention rates in the PER and LCM groups, both were 90.4%, and the responder rates were 65.4% and 71.2%, while seizure-free rates were 57.7% and 67.3%, respectively. There were no significant differences in the retention, responder and seizure-free rates between the two groups (P > 0.05). There were no significant differences in the responder rates between patients with BECTS, abnormal brain magnetic resonance imaging (MRI), or types of seizure in the two groups (P > 0.05). In the PER group, 28.8% (15/52) of patients experienced AEs, of which the most frequently reported were irritability (n = 7; 13.5%), dizziness (n = 5; 9.6%), somnolence (n = 3; 5.8%), ataxia (n = 1; 1.9%), headache (n = 1; 1.9%), and rash (n = 1; 1.9%). In the LCM group, 15.4% (8/52) of the patients had AEs, including headache (n = 4; 7.5%), dizziness (n = 4; 7.5%), nausea (n = 2; 3.8%), somnolence (n = 2; 3.8%), irritability (n = 1; 1.9%), stomach ache (n = 1; 1.9%), and vomiting (n = 1; 1.9%). The incidence of irritability was significantly higher in the PER group than in the LCM group (13.5% vs. 1.9%, P = 0.031), which occurred mainly within eight weeks after drug administration. Patients with irritability were not dangerous to surrounding people by the assessment of parental observation in the life. And the symptoms were relieved spontaneously within a few months. The outcomes of total scores, internalizing scores, and externalizing scores of the CBCL did not show statistically significant differences in the PER and LCM groups between baseline and three and six months. Characteristics of behavior and emotion did not have substantial changes in patients treated with PER and LCM monotherapy.

CONCLUSIONS

The present study documented similar good effectiveness and good tolerance of PER and LCM as monotherapy in pediatric patients with newly diagnosed focal epilepsy and showed no behavioral or emotional impact, as assessed by the CBCL. Though the incidence of irritability with PER monotherapy may be higher than that with LCM monotherapy soon after medication initiation, this side effect appears to resolve spontaneously within a few months. At present, this study was the first research about PER and LCM monotherapy in pediatric patients with newly diagnosed focal epilepsy evaluating efficacy, tolerability, and behavior in China.

Perioperative perampanel administration for early seizure prophylaxis in brain tumor patients

Background

The efficacy of perioperative prophylactic antiepileptic drug therapy in "seizure-naïve" patients with brain tumor, including glioblastoma (GBM), remains controversial. This study investigated whether perampanel (PER) is effective and safe for preventing perioperative onset of epileptic seizures, so-called early seizure, in patients with brain tumors.

Methods

Forty-five patients underwent tumor resection through craniotomy for a primary supratentorial brain tumor at Ehime University Hospital between April 2021 and July 2022. PER was administered from the 1st to the 6th day after surgery for seizure prophylaxis. Occurrence of early seizure, hematological toxicities, and various side effects were recorded on postoperative days 7 and 14. In addition, the clinical course of these patients was compared with 42 brain tumor patients under the same treatment protocol who received levetiracetam (LEV) for seizure prophylaxis between April 2017 and October 2018.

Results

In 45 patients with brain tumor, including GBM, who received PER administration, no early seizures were identified within 7 days postoperatively. No adverse drug reactions such as hematological toxicity, liver or kidney dysfunction, or exanthematous drug eruption were observed in any cases. As side effects, somnolence was reported in 14 patients (31.1%), vertigo in 3 patients (6.7%), and headache in 3 patients (6.7%). Although somnolence and vertigo were difficult to assess in the case of intraparenchymal tumors, particularly GBM, these side effects were not identified in patients with extraparenchymal tumors such as meningiomas, epidermoid cysts, and pituitary adenomas. In addition, no significant differences were identified compared to patients who received LEV.

Conclusion

The efficacy and safety of PER in preventing early seizures among patients with brain tumors were retrospectively evaluated. Perioperative administration of PER to patients with brain tumors may reduce the risk of early seizures without incurring serious side effects, showing no significant differences compared to patients who received LEV.

The broad-spectrum activity of perampanel: state of the art and future perspective of AMPA antagonism beyond epilepsy

Glutamate is the brain's main excitatory neurotransmitter. Glutamatergic neurons primarily compose basic neuronal networks, especially in the cortex. An imbalance of excitatory and inhibitory activities may result in epilepsy or other neurological and psychiatric conditions. Among glutamate receptors, AMPA receptors are the predominant mediator of glutamate-induced excitatory neurotransmission and dictate synaptic efficiency and plasticity by their numbers and/or properties. Therefore, they appear to be a major drug target for modulating several brain functions. Perampanel (PER) is a highly selective, noncompetitive AMPA antagonist approved in several countries worldwide for treating different types of seizures in various epileptic conditions. However, recent data show that PER can potentially address many other conditions within epilepsy and beyond. From this perspective, this review aims to examine the new preclinical and clinical studies-especially those produced from 2017 onwards-on AMPA antagonism and PER in conditions such as mesial temporal lobe epilepsy, idiopathic and genetic generalized epilepsy, brain tumor-related epilepsy, status epilepticus, rare epileptic syndromes, stroke, sleep, epilepsy-related migraine, cognitive impairment, autism, dementia, and other neurodegenerative diseases, as well as provide suggestions on future research agenda aimed at probing the possibility of treating these conditions with PER and/or other AMPA receptor antagonists.

Five-Year Retention of Perampanel and Polytherapy Patterns: 328 Patients From a Single Center in South Korea

BACKGROUND AND PURPOSE

Perampanel (PER) is an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid antagonist used to treat focal and generalized epilepsy. Comprehensive data from real-world settings with long-term follow-ups are still scarce. This study aimed to determine the factors related to PER retention and the polytherapy pattern with PER.

METHODS

We reviewed all patients with epilepsy with a history of PER prescription during 2008-2017 and over a follow-up of >3 years. PER usage patterns and associated factors were analyzed.

RESULTS

Among the 2,655 patients in the cohort, 328 (150 females, 178 males) were enrolled. The ages at onset and diagnosis were 21.1±14.7 years and 25.6±16.1 years (mean±standard deviation), respectively. The age at the first visit to our center was 31.8±13.8 years. Seizure types were focal, generalized, and unknown onset in 83.8%, 15.9%, and 0.3% of patients, respectively. The most common etiology was structural (n=109, 33.2%). The maintenance duration of PER was 22.6±19.2 months (range=1-66 months). The initial number of concomitant antiseizure medications was 2.4±1.4 (range=0-9). The most common regimen was PER plus levetiracetam (n=41, 12.5%). The median number of 1-year seizures before PER usage was 8 (range=0-1,400). A seizure reduction of >50% was recorded in 34.7% of patients (52.0% and 29.2% in generalized and focal seizures, respectively). The 1-, 2-, 3-, 4-, and 5-year retention rates for PER were 65.3%, 50.4%, 40.4%, 35.3%, and 21.5%, respectively. A multivariate analysis indicated that lower age at onset was associated with longer retention (p=0.01).

CONCLUSIONS

PER was safely used in patients with diverse characteristics and was maintained for a long time in a real-world setting, especially in patients with a lower age at onset.

Time-to-event clinical trial designs: Existing evidence and remaining concerns

Well-designed placebo-controlled clinical trials are critical to the development of novel treatments for epilepsy, but their design has not changed for decades. Patients, clinicians, regulators, and innovators all have concerns that recruiting for trials is challenging, in part, due to the static design of maintaining participants for long periods on add-on placebo when there are an increasing number of options for therapy. A traditional trial maintains participants on blinded treatment for a static period (e.g., 12 weeks of maintenance), during which participants on placebo have an elevated risk of sudden unexpected death in epilepsy compared to patients on an active treatment. Time-to-event trials observe participants on blinded treatment until a key event occurs (e.g., post-randomization seizure count matches pre-randomization monthly seizure count). In this article, we review the evidence for these designs based on re-analysis of prior trials, one published trial that used a time-to-second seizure design, and experience from an ongoing blinded trial. We also discuss remaining concerns regarding time-to-event trials. We conclude that, despite potential limitations, time-to-event trials are a potential promising mechanism to make trials more patient friendly and reduce placebo exposure, which are urgent needs to improve safety and increase recruitment to trials.

Safety and effectiveness of perampanel monotherapy after adjunctive therapy through retention rate in subjects with focal-onset seizures with or without focal to bilateral tonic-clonic seizures: A multicenter retrospective study in Korea

OBJECTIVE

To assess the effectiveness and tolerability of perampanel monotherapy following conversion from adjunctive therapy.

METHODS

This was a multicenter, retrospective, non-interventional study of Korean patients aged ≥12 years with focal-onset seizures (FOS) with or without focal to bilateral tonic-clonic seizures. Data were extracted from electronic medical records of perampanel-treated patients from 1 February 2016 to 31 October 2020. Kaplan-Meier estimated retention rates, effectiveness, and safety were recorded.

RESULTS

Subjects (n = 66, mean age 46.2 years) were mostly male (68.2%) with focal to bilateral tonic-clonic seizure (71.2%). Mean duration of illness was 86.3 months. Retention rates after conversion to perampanel monotherapy at 3, 6, and 12 months (primary outcome) were 96.0%, 96.0%, and 75.6%, respectively. Overall retention rates in patients receiving perampanel as adjunctive or monotherapy at 3, 6, 12, 18, and 24 months after perampanel add-on were 100%, 98.3%, 95.9%, 92.6%, and 92.6%, respectively. Mean retention duration was 41.2 months (overall perampanel administration) and 21.4 months (monotherapy). Mean seizure frequency/28 days in the Full Analysis Set (n = 61) was comparable for adjunctive and monotherapy (0.2 ± 0.79 vs 0.2 ± 0.64; change between adjunctive and monotherapy periods: 0.0 ± 0.59; p = 0.498). Perampanel was well tolerated and no new safety signals were identified. Dizziness (4.6%), only reported during adjunctive therapy, was the most common treatment-emergent adverse event.

CONCLUSIONS

Conversion to perampanel monotherapy from adjunctive therapy showed promising results in subjects with FOS with/without focal to bilateral tonic-clonic seizures; further studies in a larger population are needed to confirm these encouraging data.

Efficacy and Safety of Perampanel in Children with Drug-Resistant Focal-Onset Seizures: A Retrospective Review

BACKGROUND

Epilepsy is one of the most common neurological disorders. Existing antiseizure medications (ASMs) are still unable to control seizures in one-third of these patients, making the discovery of antiseizure therapies with novel mechanisms of action a necessity.

AIM OF THE STUDY

This study aimed to determine the safety and efficacy of perampanel (PER) as an adjuvant treatment for children with drug-resistant focal-onset seizures with or without focal to bilateral tonic-clonic seizures.

PATIENTS AND METHODS

This is a single-center retrospective study of 38 epileptic pediatric patients, aged 2 to 14, at King Faisal Specialist Hospital and Research Center whose seizures were pharmaco-resistant to more than two antiseizure medications and followed for at least three months after PER adjuvant therapy initiation. Efficacy was assessed by the PER response rate at 3-, 6-, and 12-month follow-up evaluations, and side effects were also reported.

RESULTS

Multiple seizure types were reported. Myoclonic seizures were the predominant type of epilepsy in 17 children (44.7%). At 3 months, 6 months, and 12 months of follow-up, approximately 23.4%, 23.4%, and 18.4% of the patients were seizure-free at these time points, respectively. Adverse events were documented in 14 patients (35.7%) and led to the discontinuation of PER in 26.3%, 31.6%, and 36.8% of the studied group at the 3-, 6-, and 12-month follow-ups, respectively. The most common adverse events included dizziness or drowsiness, irritability, gait disturbance, and confusion; however, all were transient, and no serious adverse effects occurred.

CONCLUSION

Our findings confirm the therapeutic efficacy of adjunctive PER in the treatment of drug-resistant epilepsy in children. As an adjunctive treatment for epilepsy, perampanel demonstrated sufficient effectiveness and tolerability.

Open-label study to investigate the safety and efficacy of adjunctive perampanel in pediatric patients (aged 4 to <12 years) with inadequately controlled focal-onset seizures: Japanese subgroup analysis

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).

The Efficacy and Cognitive Impact of Perampanel Monotherapy in Patients with Self-Limited Epilepsy with Centrotemporal Spikes: A Retrospective Analysis

Objective

The third generation of antiepileptic medication (ASM) perampanel (PER), is mostly used as an add-on treatment for refractory epilepsy patients, and rarely used as a monotherapy. This study aims to observe the efficacy and assess the cognitive effects of PER monotherapy in patients with self-limited epilepsy with centrotemporal spikes (SeLECTS).

Patients and Methods

Through screening, 86 patients who were first diagnosed with SeLECTS and treated with PER monotherapy were included in this study. All patients were followed up at least 12 months, and Evaluated the efficacy and safety of PER by observing the seizures of patients. At the same time, we used the P300 event-related potential (ERP) component and Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) to evaluate the cognitive changes in children before and after treatment with PER.

Results

Ten percent of the children experienced adverse effects, such as dizziness, gait instability, and irritability. The drug retention rate at the last follow-up was 98.83%. Further more, the P300 ERP component and WISC-IV tests were performed no significant difference before and 12 months after PER monotherapy in SeLECTS children.

Conclusion

The third-generation of ASM PER monotherapy had a clear effect in children with SeLECTS. A small dose of PER can control seizures well and has no obvious effect on cognitive development.

Perampanel add-on for drug-resistant focal epilepsy

BACKGROUND

Epilepsy is one of the most common neurological disorders. Approximately 30% of people with epilepsy are considered to be drug-resistant, and usually need treatment with a combination of other antiepileptic drugs. Perampanel is a newer antiepileptic drug that has been investigated as add-on therapy for drug-resistant focal epilepsy.

OBJECTIVES

To evaluate the benefits and harms of perampanel as add-on therapy for people with drug-resistant focal epilepsy.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 20 October 2022.

SELECTION CRITERIA

We included randomised controlled trials comparing add-on perampanel with placebo.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcome was 1. 50% or greater reduction in seizure frequency. Our secondary outcomes were 2. seizure freedom, 3. treatment withdrawal due to any reason, 4. treatment withdrawal due to adverse effects, and 5.

ADVERSE EFFECTS

We used an intention-to-treat population for all primary analyses. We presented the results as risk ratios (RR) with 95% confidence intervals (CIs), except for individual adverse effects, which we reported with 99% CIs to compensate for multiple testing. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We included seven trials involving 2524 participants, all aged over 12 years. The trials were double-blind, randomised, placebo-controlled trials with treatment duration of 12 to 19 weeks. We assessed four trials at overall low risk of bias, and three trials at overall unclear risk of bias, due to risk of detection, reporting, and other biases. Compared with placebo, participants receiving perampanel were more likely to achieve a 50% or greater reduction in seizure frequency (RR 1.67, 95% CI 1.43 to 1.95; 7 trials, 2524 participants; high-certainty evidence). Compared to placebo, perampanel increased seizure freedom (RR 2.50, 95% CI 1.38 to 4.54; 5 trials, 2323 participants; low-certainty evidence) and treatment withdrawal (RR 1.30, 95% CI 1.03 to 1.63; 7 trials, 2524 participants; low-certainty evidence). Participants treated with perampanel were more likely to withdraw from treatment due to adverse effects compared to those receiving placebo (RR 2.36, 95% CI 1.59 to 3.51; 7 trials, 2524 participants; low-certainty evidence). A higher proportion of participants receiving perampanel reported one or more adverse effects when compared to participants who received placebo (RR 1.17, 95% CI 1.10 to 1.24; 7 trials, 2524 participants; high-certainty evidence). Compared with placebo, participants receiving perampanel were more likely to experience ataxia (RR 14.32, 99% CI 1.09 to 188.31; 2 trials, 1098 participants; low-certainty evidence), dizziness (RR 2.87, 99% CI 1.45 to 5.70; 7 trials, 2524 participants; low-certainty evidence), and somnolence (RR 1.76, 99% CI 1.02 to 3.04; 7 trials, 2524 participants). Subgroup analysis indicated that a larger proportion of participants who received perampanel at a dose of 4 mg/day (RR 1.38, 95% CI 1.05 to 1.83; 2 trials, 710 participants), 8 mg/day (RR 1.83, 95% CI 1.51 to 2.22; 4 trials, 1227 participants), or 12 mg/day (RR 2.38, 95% CI 1.86 to 3.04; 3 trials, 869 participants) achieved a 50% or greater reduction in seizure frequency compared to placebo; however, treatment with perampanel 12 mg/day also increased treatment withdrawal (RR 1.77, 95% CI 1.31 to 2.40; 3 trials, 869 participants).

AUTHORS' CONCLUSIONS

Add-on perampanel is effective at reducing seizure frequency and may be effective at maintaining seizure freedom for people with drug-resistant focal epilepsy. Although perampanel was well-tolerated, there was a higher proportion of treatment withdrawals with perampanel compared with placebo. Subgroup analysis suggested that 8 mg/day and 12 mg/day are the most efficacious perampanel doses; however, the use of 12 mg/day would likely increase the number of treatment withdrawals. Future research should focus on investigating the efficacy and tolerability of perampanel with longer-term follow-up, as well as exploring an optimal dose.

Dynamics of AMPA receptors regulate epileptogenesis in patients with epilepsy

The excitatory glutamate α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) contribute to epileptogenesis. Thirty patients with epilepsy and 31 healthy controls are scanned using positron emission tomography with our recently developed radiotracer for AMPARs, [¹¹C]K-2, which measures the density of cell-surface AMPARs. In patients with focal-onset seizures, an increase in AMPAR trafficking augments the amplitude of abnormal gamma activity detected by electroencephalography. In contrast, patients with generalized-onset seizures exhibit a decrease in AMPARs coupled with increased amplitude of abnormal gamma activity. Patients with epilepsy had reduced AMPAR levels compared with healthy controls, and AMPARs are reduced in larger areas of the cortex in patients with generalized-onset seizures compared with those with focal-onset seizures. Thus, epileptic brain function can be regulated by the enhanced trafficking of AMPAR due to Hebbian plasticity with increased simultaneous neuronal firing and compensational downregulation of cell-surface AMPARs by the synaptic scaling.

Perampanel outcomes at different stages of treatment in people with focal and generalized epilepsy treated in clinical practice: Evidence from the PERMIT study

Introduction

The PERMIT study is the largest pooled analysis of perampanel (PER) clinical practice data conducted to date.

Methods

This post-hoc analysis of PERMIT investigated the effectiveness, safety and tolerability of PER when used as early add-on therapy (after failure of one or two previous antiseizure medications) in comparison with late add-on therapy (after failure of three or more previous antiseizure medications). Retention and effectiveness were assessed after 3, 6, and 12 months, and at the last visit (last observation carried forward). Effectiveness was assessed by seizure type (total seizures, focal seizures, generalized tonic-clonic seizures [GTCS]) and assessments included seizure freedom rate and responder rate. Safety and tolerability were assessed by evaluating adverse events (AEs) and discontinuation due to AEs.

Results

The Full Analysis Set included 1184 and 2861 PWE treated with PER as early and late add-on therapy, respectively. Compared to the late add-on subgroup, the early add-on subgroup was characterized by later mean age at epilepsy onset, shorter mean duration of epilepsy, lower rates of intellectual disability and psychiatric comorbidity, and lower frequency of seizures per month, suggesting a less severe form of epilepsy in this subgroup. After 12 months, retention was significantly higher in the early versus late add-on subgroup (67.7% vs. 62.4%; p = 0.004). At the last visit, responder rates in the early versus late add-on subgroup were significantly higher for total seizures (68.2% vs. 39.3%; p &lt; 0.001), focal seizures (65.0% vs. 36.8%; p &lt; 0.001) and GTCS (83.7% vs. 67.2%; p &lt; 0.001), as were seizure freedom rates (total seizures, 35.9% vs. 11.9% [p &lt; 0.001]; focal seizures, 29.4% vs. 8.7% [p &lt; 0.001]; GTCS, 69.0% vs. 48.1% [p &lt; 0.001]). Incidence of AEs was significantly lower in the early versus late add-on subgroup (42.1% vs. 54.7%; p &lt; 0.001), as was the rate of discontinuation due to AEs over 12 months (15.0% vs. 18.1%; p = 0.031).

Discussion

This study demonstrated that PER was effective and generally well tolerated when initiated as early or late add-on therapy, but it was significantly more effective and better tolerated when initiated early. These findings support PER's use as a broad-spectrum, early add-on therapy for use in PWE with focal and generalized seizures.

Efficacy and tolerability of perampanel in patients with seizures in real-world clinical practice: A systematic review and meta-analysis

Objectives: The aim of this study was to systematically review the efficacy and tolerability of perampanel (PER) when used as add-on treatment or monotherapy in patients with epilepsy aged 12 years and older in routine clinical practice.

Methods: Electronic and clinical trials databases were searched for observational studies of PER published up to 1 March 2022. The outcomes of interest were responder rates, adverse effects (AEs), and withdrawal rates. Subgroup analyses were performed to explore the potential factors that might affect the efficacy and safety of PER usage.

Results: A total of 56 studies, which included 10,688 patients, were enrolled. The results showed that after 3, 6, and 12 months of PER treatment, the pooled 50% responder rates in patients with epilepsy were 50.0% (95% CI: 0.41–0.60), 44.0% (95% CI: 0.38–0.50), and 39.0% (95% CI: 0.31–0.48), respectively, and the pooled seizure-free rates were 24.0% (95% CI: 0.17–0.32), 21.0% (95% CI: 0.17–0.25), and 20.0% (95% CI: 0.16–0.24), respectively. Subgroup analyses revealed that the efficacy of PER could be affected by the way in which PER is administrated. Patients in the groups where PER was used as the first add-on, primary monotherapy, or combined with non–enzyme-inducing AEDs (non-EIAEDs) displayed a high 50% responder rate and seizure-free rate when compared with those in the late add-on, conversion therapy, or combined with the EIAEDs groups, respectively. Furthermore, the incidences of AEs at 3, 6, and 12 months of PER treatment were 46% (95% CI: 0.38–0.55), 52.0% (95% CI: 0.43–0.60), and 46.0% (95% CI: 0.40–0.52), respectively. The withdrawal rates due to AEs were 8.0% (95% CI: 0.06–0.11), 16.0% (95% CI: 0.13–0.20), and 16% (95% CI: 0.11–0.21) at 3, 6, and 12 months of PER treatment, respectively. Subgroup analyses showed a higher withdrawal rate in the rapid (30%, 95% CI: 0.22–0.38) than in the slow (12%, 95% CI: 0.06–0.18) titration group.

Conclusion: Altogether, PER was effective and could be fairly tolerated in both short-term and long-term usage in patients with epilepsy in routine clinical practice. Furthermore, PER appeared to be more effective when PER was used as the first add-on, monotherapy, or concomitant with non-EIAEDs.

Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022384532.

Effect of Serum Perampanel Concentration on Sporadic Amyotrophic Lateral Sclerosis Progression

BACKGROUND AND PURPOSE

To clarify the effect of perampanel (PER) on sporadic amyotrophic lateral sclerosis (sALS) progression, the relationship between the changes in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) scores and serum PER concentrations was investigated.

METHODS

12 patients with sALS from our hospital who agreed to participate and completed the PER for sALS randomized phase 2 study were included. After completing the study, we retrospectively obtained serum PER concentration data from the patients. Based on their mean PER concentrations, we divided the patients who had been taking PER into two groups: four patients with a mean PER concentration of ≥400 ng/mL were assigned to the H group, and three with a mean PER concentration of <400 ng/mL were assigned to the L group. The control group consisted of five patients who had been taking a placebo. We obtained the ALSFRS-R scores of each patient at 36 and 48 weeks after randomization. The differences in ALSFRS-R scores at baseline (0 weeks) and each subsequent week were used in the analysis.

RESULTS

At 48 weeks, there were no differences in the degree of deterioration of the bulbar, upper and lower limb, and respiratory ALSFRS-R subscores and total ALSFRS-R score. However, at 36 weeks, the bulbar subscore was significantly lower in the H group than in the control group (p=0.032).

CONCLUSIONS

Because high PER concentrations may exacerbate bulbar symptoms in patients with sALS, serum PER measurements may be beneficial when patients with sALS are taking PER.

Reasons for ineligibility for clinical trials of patients with medication-resistant epilepsy

Selection criteria for clinical trials for medication-resistant epilepsy are used to limit variability and to ensure safety. However, it has become more challenging to recruit subjects for trials. This study investigated the impact of each inclusion and exclusion criterion on medication-resistant epilepsy clinical trial recruitment at a large academic epilepsy center. We retrospectively identified all patients with medication-resistant focal or generalized onset epilepsy who attended an outpatient clinic over a consecutive 3-month period. We assessed each patient's eligibility for trials with commonly required inclusion and exclusion criteria to evaluate the proportion of eligible patients and the most common reasons for exclusion. Among 212 patients with medication-resistant epilepsy, 144 and 28 patients met the criteria for focal or generalized onset epilepsy, respectively. Overall, 9.4% (n = 20) patients were eligible for trials (19 focal onset and one generalized onset). Most patients were excluded from the study due to insufficient seizure frequency (58% of focal onset, 55% of generalized onset). A small proportion of patients with medication-resistant epilepsy were eligible for trials based on common selection criteria. These eligible patients may not be representative of the general population of patients with medication-resistant epilepsy. Insufficient seizure frequency was the most common reason for exclusion.

The Role of Glutamate Receptors in Epilepsy

Glutamate is an essential excitatory neurotransmitter in the central nervous system, playing an indispensable role in neuronal development and memory formation. The dysregulation of glutamate receptors and the glutamatergic system is involved in numerous neurological and psychiatric disorders, especially epilepsy. There are two main classes of glutamate receptor, namely ionotropic and metabotropic (mGluRs) receptors. The former stimulate fast excitatory neurotransmission, are N-methyl-d-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and kainate; while the latter are G-protein-coupled receptors that mediate glutamatergic activity via intracellular messenger systems. Glutamate, glutamate receptors, and regulation of astrocytes are significantly involved in the pathogenesis of acute seizure and chronic epilepsy. Some glutamate receptor antagonists have been shown to be effective for the treatment of epilepsy, and research and clinical trials are ongoing.

A Single- and Multiple-Dose Pharmacokinetic Study of Oral Perampanel in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVE

Perampanel is a once-daily oral anti-seizure medication indicated for focal-onset seizures and generalized tonic-clonic seizures. This study investigated the single- and multiple-dose pharmacokinetics of perampanel in healthy Chinese adults.

METHODS

Study 052 (NCT03424564) was a phase I, single-center, open-label, parallel-group study. In the single-dose part of the study, subjects received a single oral dose of perampanel 2, 4, or 8 mg. In the multiple-dose part, subjects received once-daily oral perampanel 2 mg on Days 1-7 and 4 mg on Days 8-21. Pharmacokinetic parameters were determined from perampanel plasma concentrations using non-compartmental analysis. Dose proportionality after single doses of perampanel was assessed. Safety and tolerability were evaluated.

RESULTS

In the single-dose part (N = 30), median time to reach maximum concentration (t_max) was 0.75-1.0 h, mean terminal elimination phase half-life (t_½) was 85.6-122 h, mean maximum observed concentration (C_max) was 77.9-276 ng/mL, and mean area under the concentration-time curve from time zero to time of the last quantifiable concentration (AUC_(0-t)) was 4070-15100 ng·h/mL. Single-dose pharmacokinetics were linear for perampanel 2-8 mg. In the multiple-dose part (N = 12), Day 21 steady-state (4 mg/day) parameters were median time at which the highest drug concentration occurs at steady state (t_ss,max), 1.25 h; mean t_½, 109 h; mean maximum observed concentration at steady state (C_ss,max), 453 ng/mL; and mean area under the concentration-time curve over the dosing interval on multiple dosing (AUC_{(0- τ)}), 7540 ng·h/mL. For single- and multiple-dose perampanel, the most common treatment-emergent adverse events were dizziness and somnolence.

CONCLUSIONS

Single- and multiple-dose pharmacokinetics of perampanel in healthy Chinese adults revealed rapid perampanel absorption, slow elimination, and a linear relationship with single perampanel doses of 2-8 mg. Findings were consistent with previous studies of perampanel pharmacokinetics in other ethnic/racial populations of healthy subjects. Single and multiple doses of perampanel were generally safe and well tolerated.

CLINICAL TRIAL REGISTRATION

NCT03424564; registered February 2018.

Efficacy and Tolerability of Perampanel in Brain Tumor-Related Epilepsy: A Systematic Review

(1) Background: Epilepsy is a frequent comorbidity in patients with brain tumors, in whom seizures are often drug-resistant. Current evidence suggests that excess of glutamatergic activity in the tumor microenvironment may favor epileptogenesis, but also tumor growth and invasiveness. The selective non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist perampanel (PER) was demonstrated to be efficacious and well-tolerated in patients with focal seizures. Moreover, preclinical in vitro studies suggested a potential anti-tumor activity of this drug. In this systematic review, the clinical evidence on the efficacy and tolerability of PER in brain tumor-related epilepsy (BTRE) is summarized. (2) Methods: Five databases and two clinical trial registries were searched from inception to December 2022. (3) Results: Seven studies and six clinical trials were included. Sample size ranged from 8 to 36 patients, who received add-on PER (mean dosage from 4 to 7 mg/day) for BTRE. After a 6–12 month follow-up, the responder rate (% of patients achieving seizure freedom or reduction ≥ 50% of seizure frequency) ranged from 75% to 95%, with a seizure freedom rate of up to 94%. Regarding tolerability, 11–52% of patients experienced non-severe adverse effects (most frequent: dizziness, vertigo, anxiety, irritability). The retention rate ranged from 56% to 83%. However, only up to 12.5% of patients discontinued the drug because of the adverse events. (4) Conclusions: PER seems to be efficacious, safe, and well-tolerated in patients with BTRE. Further randomized studies should be conducted in more homogeneous and larger populations, also evaluating the effect of PER on tumor progression, overall survival, and progression-free survival.

Perampanel Monotherapy for Focal and Generalized Epilepsy in Clinical Practice

Objectives. To investigate the effectiveness, safety, and tolerability of perampanel (PER) when used as monotherapy to treat focal or generalized epilepsy in everyday clinical practice, using data from the PERMIT study. Methods. PERMIT was a pooled analysis of 44 real-world studies from 17 countries, in which people with focal and generalized epilepsy were treated with PER. This post hoc analysis included people with epilepsy (PWE) from PERMIT who were treated with PER monotherapy at baseline. Retention and effectiveness were assessed after 3, 6, and 12 months. Effectiveness assessments included ≥50% responder rate and seizure freedom rate (no seizures since at least the prior visit). Safety and tolerability were assessed by evaluating adverse events (AEs) and discontinuation due to AEs. Results. Overall, 268 PWE were treated with PER monotherapy at baseline. Retention was assessed for 168 PWE, effectiveness for 183 PWE, and safety and tolerability for 197 PWE. Retention rates were 91.1%, 87.3%, and 73.3% at 3, 6, and 12 months, respectively. At 12 months, responder rates were 84.2% overall, 82.9% in PWE with only focal-onset seizures at baseline, and 88.0% in those with only generalized-onset seizures at baseline; corresponding freedom rates were 62.9%, 57.7%, and 80.0%, respectively. AEs were reported for 45.2% of PWE. The most frequently reported AEs (≥5% of PWE) were dizziness/vertigo (16.8%), irritability (11.2%), somnolence (9.1%), and depression (6.6%). Over 12 months, 13.7% discontinued due to AEs. Conclusions. PER was effective when used as monotherapy in clinical practice, particularly in those with generalized-onset seizures, and was generally well tolerated.