Clinical experience with perampanel: focus on psychiatric adverse effects

An analysis of suicidal and self-injurious behavior reports with antiseizure medications in the FDA adverse event database

BACKGROUND

Pharmacovigilance systems such as the FDA Adverse Event Reporting System (FAERS), are established models for adverse event surveillance that may have been missed during clinical trials. We aimed to analyze twenty-five anti-seizure medications (ASMs) in FAERS to assess for increased reporting of suicidal and self-injurious behavior.

METHODS

Twenty-five ASMs were analyzed: brivaracetam, cannabidiol, carbamazepine, clobazam, clonazepam, diazepam, eslicarbazepine, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, perampanel, phenobarbital, phenytoin, pregabalin, primidone, rufinamide, stiripentol, tiagabine, topiramate, valproate, vigabatrin, zonisamide. Reports of "suicidal and self-injurious behavior" were collected from January 1, 2004, to December 31, 2020, using OpenVigil 2.1 tool with indication as "Epilepsy". Relative reporting ratio, proportional reporting ratio, and reporting odds ratio were calculated utilizing all other drug reports for epilepsy patients as a control.

RESULTS

Significant relative operating ratio, ROR (greater than 1, p<0.05) were observed for diazepam (2.909), pregabalin (2.739), brivaracetam (2.462), gabapentin (2.185), clonazepam (1.649), zonisamide (1.462), lacosamide (1.333), and levetiracetam (1.286).

CONCLUSIONS

Of the 25 ASMs that were analyzed in this study, 4 (16%) were identified to have been linked with a likely true adverse event. These drugs included diazepam, brivaracetam, gabapenetin, and pregabalin. Although several limitations are present with the FAERS database, it is imperative to closely monitor patient comorbidities for increased risk of suicidality with the use of several ASMs.

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.

Structural basis of AMPA receptor inhibition by trans-4-butylcyclohexane carboxylic acid

BACKGROUND AND PURPOSE

AMPA receptors, which shape excitatory postsynaptic currents and are directly involved in overactivation of synaptic function during seizures, represent a well-accepted target for anti-epileptic drugs. Trans-4-butylcyclohexane carboxylic acid (4-BCCA) has emerged as a new promising anti-epileptic drug in several in vitro and in vivo seizure models, but the mechanism of its action remained unknown. The purpose of this study is to characterize structure and dynamics of 4-BCCA interaction with AMPA receptors.

EXPERIMENTAL APPROACH

We studied the molecular mechanism of AMPA receptor inhibition by 4-BCCA using a combination of X-ray crystallography, mutagenesis, electrophysiological assays, and molecular dynamics simulations.

KEY RESULTS

We identified 4-BCCA binding sites in the transmembrane domain (TMD) of AMPA receptor, at the lateral portals formed by transmembrane segments M1-M4. At this binding site, 4-BCCA is very dynamic, assumes multiple poses, and can enter the ion channel pore.

CONCLUSION AND IMPLICATIONS

4-BCCA represents a low-affinity inhibitor of AMPA receptors that acts at the TMD sites distinct from non-competitive inhibitors, such as the anti-epileptic drug perampanel and the ion channel blockers. Further studies might examine the possibsility of synergistic use of these inhibitors in treatment of epilepsy and a wide range of neurological disorders and gliomas.

LINKED ARTICLES

This article is part of a themed issue on Structure Guided Pharmacology of Membrane Proteins (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.14/issuetoc.

PERMIT study: a global pooled analysis study of the effectiveness and tolerability of perampanel in routine clinical practice

The PERaMpanel pooled analysIs of effecTiveness and tolerability (PERMIT) study was a pooled analysis of data from 44 real-world studies from 17 countries, in which people with epilepsy (PWE; focal and generalized) were treated with perampanel (PER). Retention and effectiveness were assessed after 3, 6, and 12 months, and at the last visit (last observation carried forward). Effectiveness assessments included 50% responder rate (≥ 50% reduction in seizure frequency from baseline) and seizure freedom rate (no seizures since at least the prior visit); in PWE with status epilepticus, response was defined as seizures under control. Safety and tolerability were assessed by evaluating adverse events (AEs) and discontinuation due to AEs. The Full Analysis Set included 5193 PWE. Retention, effectiveness and safety/tolerability were assessed in 4721, 4392 and 4617, respectively. Retention on PER treatment at 3, 6, and 12 months was 90.5%, 79.8%, and 64.2%, respectively. Mean retention time on PER treatment was 10.8 months. The 50% responder rate was 58.3% at 12 months and 50.0% at the last visit, and the corresponding seizure freedom rates were 23.2% and 20.5%, respectively; 52.7% of PWE with status epilepticus responded to PER treatment. Overall, 49.9% of PWE reported AEs and the most frequently reported AEs (≥ 5% of PWE) were dizziness/vertigo (15.2%), somnolence (10.6%), irritability (8.4%), and behavioral disorders (5.4%). At 12 months, 17.6% of PWEs had discontinued due to AEs. PERMIT demonstrated that PER is effective and generally well tolerated when used to treat people with focal and/or generalized epilepsy in everyday clinical practice.

Perampanel effectiveness and tolerability in patients with epilepsy at long-term follow-up

INTRODUCTION

The main of the present study was to assess the effectiveness and tolerability of perampanel (PER) in association with 1 or 2 concomitant antiseizure medications (ASMs) in patients with epilepsy throughout a follow-up period of 24 months or longer in a real-world setting.

METHODS

This retrospective, observational, multi-center study collected data from both underage (<18 years old) and adult patients who had started PER in association with 1 or 2 ASMs. Only patients who had started PER and were followed up for at least 24 months were included. Response to treatment was analyzed at the 24-, 36-, and 48-month visits by considering the last visit undergone by patients. Subgroup analyses were performed according to age, gender, and epilepsy type and patients were categorized following PER treatment in concomitance with 1 or 2 ASMs to evaluate the factors affecting the achievement of seizure freedom (SF) at the 24-month FU.

RESULTS

Ninety-four patients were included (mean age 36.89 years; 51.1% female). At the 24-month follow-up visit, 90 (95.74%) patients were still receiving PER concomitantly with 1 or 2 ASMs. The mean PER dose was 6.02 mg/day and SF was achieved by 33 (35.1%) patients. A significantly higher SF rate was found in patients who had started PER with only 1 ASM when compared to those who had started PER with 2 concomitant ASMs. Effectiveness was maintained also in the subgroups of patients with a 36- or 48-month follow-up visit. Adult patients had a higher final daily dosage of PER than underage patients. Logistic regression found that the lowest number of previously failed ASMs was associated with a higher SF rate (p = 0.036).

CONCLUSION

Perampanel demonstrated a good effectiveness in association with 1 or 2 ASMs in both pediatric and adult patients, without having to use a high dose of the drug. The possibility to present SF was higher when PER was added early. Finally, the maintenance of effectiveness was observed also in the subgroups of patients with a follow-up of 36 and 48 months.

Efficacy and tolerability of adjuvant perampanel: an Australian multicenter real-world observational study in refractory focal and generalized epilepsy syndromes

PURPOSE

To explore the efficacy and tolerability of adjuvant perampanel (PER) and their associated risk factors in late add-on drug-resistant epilepsy.

METHOD

Retrospective multicenter 'real-world' observational study. Consecutively identified patients commenced on PER, with mixed epilepsy syndromes, from nine Australian epilepsy centers. Primary efficacy endpoints were at least 50% reduction in seizure frequency (responders), seizure freedom, and retention at 6 and 12 months, following a 3-month titration period. Tolerability endpoints were cessation of PER for any reason, cessation of PER due to treatment-emergent adverse events (TEAE), or cessation due to inefficacy. Outcomes were assessed for a-priori risk factors associated with efficacy and tolerability.

RESULTS

Three-hundred and eighty seven adults were identified and followed up for a median of 12.1 months (IQR 7.0-25.2). Focal epilepsy accounted for 79.6% (FE), idiopathic generalized epilepsy (IGE), 10.3% and developmental epileptic encephalopathy (DEE) 10.1%, of the cohort. All patients had drug-resistant epilepsy, 71.6% had never experienced six months of seizure freedom, and the mean number of antiepileptic medications (AEDs) prior to starting PER was six. At 12 months, with missing cases classified as treatment failure, retention was 40.0%, responder 21.7%, and seizure freedom 9.0%, whereas, using last outcome carried forward (LOCF), responder and seizure freedom rates were 41.3% and 14.7%, respectively. Older age of epilepsy onset was associated with a marginal increase in the likelihood of seizure freedom at 12-month maintenance (OR 1.04, 95% CI 1.02, 1.06). Male sex (adjusted OR [aOR] 2.06 95% CI 1.33, 3.19), lower number of prior AEDs (aOR 0.84, 95% CI 0.74, 0.96) and no previous seizure-free period of at least 6-month duration (aOR 2.04 95% CI 1.21, 3.47) were associated with retention. Perampanel combined with a GABA receptor AED was associated with a lower responder rate at 12 months but reduced cessation of PER. The most common TEAEs were neuropsychiatric (18.86%), followed by dizziness (13.70%), and sleepiness (5.68%).

CONCLUSIONS

Adjuvant PER treatment, even in late-add on drug-resistant epilepsy is an effective and well-tolerated treatment for drug-resistant epilepsy.

Behavioral adverse events with brivaracetam, levetiracetam, perampanel, and topiramate: A systematic review

PURPOSE

To understand the currently available post-marketing real-world evidence of the incidences of and discontinuations due to the BAEs of irritability, anger, and aggression in people with epilepsy (PWE) treated with the anti-seizure medications (ASMs) brivaracetam (BRV), levetiracetam (LEV), perampanel (PER), and topiramate (TPM), as well as behavioral adverse events (BAEs) in PWE switching from LEV to BRV.

METHODS

A systematic review of published literature using the Cochrane Library, PubMed/MEDLINE, and Embase was performed to identify retrospective and prospective observational studies reporting the incidence of irritability, anger, or aggression with BRV, LEV, PER, or TPM in PWE. The incidences of these BAEs and the rates of discontinuation due to each were categorized by ASM, and where possible, weighted means were calculated but not statistically assessed. Behavioral and psychiatric adverse events in PWE switching from LEV to BRV were summarized descriptively.

RESULTS

A total of 1500 records were identified in the searches. Of these, 44 published articles reporting 42 studies met the study criteria and were included in the data synthesis, 7 studies were identified in the clinical trial database, and 5 studies included PWE switching from LEV to BRV. Studies included a variety of methods, study populations, and definitions of BAEs. While a wide range of results was reported across studies, weighted mean incidences were 5.6% for BRV, 9.9% for LEV, 12.3% for PER, and 3.1% for TPM for irritability; 3.3%* for BRV, 2.5% for LEV, 2.0% for PER, and 0.2%* for TPM for anger; and 2.5% for BRV, 2.6% for LEV, 4.4% for PER, and 0.5%* for TPM for aggression. Weighted mean discontinuation rates were 0.8%* for BRV, 3.4% for LEV, 3.0% for PER, and 2.2% for TPM for irritability and 0.8%* for BRV, 2.4% for LEV, 9.2% for PER, and 1.2%* for TPM for aggression. There were no discontinuations for anger. Switching from LEV to BRV led to improvement in BAEs in 33.3% to 83.0% of patients (weighted mean, 66.6%). *Denotes only 1 study.

CONCLUSIONS

This systematic review characterizes the incidences of irritability, anger, and aggression with BRV, LEV, PER, and TPM, and it provides robust real-world evidence demonstrating that switching from LEV to BRV may improve BAEs. While additional data remain valuable due to differences in methodology (which make comparisons difficult), these results improve understanding of the real-world incidences of discontinuations due to these BAEs in clinical practice and can aid in discussions and treatment decision-making with PWE.

Efficacy of perampanel in epilepsy patients with autism spectrum disorder

AIM

The aim of this study was to assess the usefulness of perampanel (PER), and to identify the relationship between behavioral impairments and electroencephalogram (EEG) findings in epilepsy patients with autism spectrum disorder (ASD).

METHODS

Participants were ASD patients with epilepsy recruited between June 1, 2016 and June 30, 2018. Inclusion criteria were: seizures refractory to two appropriate antiseizure medications (ASMs); presence of neuropsychological impairments; and ≥12 months of monitoring. PER was administered once daily, starting at a dose of 2 mg/day, increased to 12 mg/day. Seizure/EEG responders were identified as participants showing a >50 % reduction in seizure/interictal epileptiform discharge (IED) frequency (indicated as complete disappearance and response). Behavioral responders were identified as participants with a ≥50 % reduction in scores of the Japanese manuals for the Aberrant Behavior Checklist (ABC-J).

RESULTS

Eleven (64.7 %) of 17 patients were considered to be both seizure and EEG responders. Five (45.5 %) of these 11 patients with seizure/EEG response were considered as behavioral responders. Mean ABC-J scores were significantly decreased at 12 months after PER administration (p = 0.0002). A correlation between decreased IED frequency and ABC-J score was evident in frontal IEDs, but not in non-frontal IEDs. Participants presenting with frontal IEDs showed a significantly higher correlation between seizures/EEG and behavioral improvements (p = 0.023). Moreover, 2 of 6 patients without seizure/EEG improvement were considered as behavioral responders. No patients discontinued PER.

CONCLUSIONS

The results from this study suggest the utility of PER treatment in reducing clinical seizures and IEDs for ASD patients with intractable epilepsy, at least in some patients. Moreover, the present results also indicate the usefulness of PER in improving neuropsychiatric impairments, including behavioral disturbances in ASD related to improvement of clinical seizures/frontal IEDs, but also unrelated to seizure/EEG improvement in at least some ASD patients.

European perspective of perampanel response in people with Intellectual Disability

BACKGROUND

Epilepsy prevalence is over 20% for those with ID. It is difficult to diagnose and treat and more likely to be treatment resistant. The evidence informing prescribing is sparse, particularly for new drugs such as perampanel (PMP).

AIMS OF THE STUDY

This study seeks to strengthen the research evidence regarding PMP for people with ID by pooling information from two isolated and separately conducted studies: the UK-based Epilepsy Database Register (Ep-ID) and the data from the Kempenhaeghe clinic in the Netherlands.

METHODS

A single data set of comparable data was created and analysed under agreement and supervision of a UK statistician.

RESULTS

Seizure reduction within twelve months was evident in 62% of Dutch and 47% of UK patients. Retention rates were higher for those in the UK (P = .01) and for patients with moderate to profound ID, whilst side effects were more prominent in the Dutch cohort.

CONCLUSIONS

Comparable rates of seizure reduction are in line with estimates for non-ID patients, adding to the evidence suggesting that PMP has a similar impact on those with ID. Taking a European perspective and sharing data across centres can help strengthen the evidence for prescribing antiepileptic drugs in the ID population.

HLAs associated with perampanel-induced psychiatric adverse effects in a Korean population

Perampanel (PER) is a new-generation antiepileptic drug that has an occasional but significant shortcoming, psychiatric adverse effects (PAEs). Recently, antiepileptic drug-related adverse reactions, such as skin rash and even PAEs, have been discovered to be correlated with certain human leukocyte antigen (HLA) types. Thus, we aimed to analyze specific HLA alleles as risk factors for PER-PAEs. We prospectively enrolled 17 patients with epilepsy who were prescribed PER between May 2016 and Jul 2018 at Seoul National University Hospital and developed PAEs while taking PER. Their HLA types were analyzed compared to those of 19 patients in the PAE-tolerant group and the general Korean population. In silico docking was performed with two different computational programs, AutoDock Vina and SwissDock, to theoretically evaluate the binding affinity of PER in the grooves of the specific HLA alleles. The HLA-DQB1*06:01, DRB1*08:03, and B*54:01 alleles were significantly associated with the patients who developed PER-PAEs compared with the general Korean population (odds ratio [OR] 3.94, p = 0.008, OR 9.24, p = 0.037, and OR 3.25, p = 0.041, respectively). As a haplotype, the combination of the three alleles was significantly more frequent in the PER-PAE group than in both the PER-tolerant group and the general Korean population. DQB1*06:01 and B*54:01 also demonstrated higher docking scores with PER than other alleles. This is the first study to analyze the association of PER-PAEs with specific HLA genotypes. Our results suggest that an HLA-associated genetic predisposition and a possible immunological mechanism are involved in the occurrence of PER-PAEs.

Perampanel in brain tumor-related epilepsy: Observational pilot study

OBJECTIVE

Possible loss of efficacy and potential interactions between antiepileptic drugs (AEDs) and chemotherapy could complicate the management of patients with brain tumor-related epilepsy (BTRE) that may expose patients to an increased risk of adverse events. Perampanel (PER) is a highly selective, noncompetitive, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptor antagonist. This study evaluates the effectiveness, QoL, cognition, and mood of PER in add-on therapy in BTRE patients.

MATERIAL AND METHODS

Observational pilot study on the effectiveness of PER as add-on therapy in BTRE patients with uncontrolled seizures with a 6-month follow-up.

RESULTS

We recruited 26 BTRE patients. During the follow-up, 16 underwent chemotherapy and 11 radiotherapy; 11 had disease progression. Five patients dropped out. Mean daily PER dosage was 6.6 mg in the 21 patients who completed the follow-up and 6.4 mg in the ITT population. The mean number of seizures/month decreased from 10.8 ± 15.03 at baseline to 1.7 ± 4.34 in the 21 patients who reached the final follow-up. Responder rate was 88.4%: Eight patients were seizure-free, 15 had ≥50% seizure reduction, and 3 remained stable. Four patients (15.4%) reported AEs: 2 required PER dose reduction, and 2 dropped out. Neuropsychological, mood, and QoL questionnaires were not statistically different compared to baseline. There were no significant differences in seizure control in patients with/without IDH1 mutation and with/without MGMT methylation.

CONCLUSIONS

Perampanel proved to be effective on seizure control in BRTE patients and to be well tolerated without negative effects on cognition and QoL. Perampanel could be a valid therapeutic option in BTRE.

Improved irritability, mood, and quality of life following introduction of perampanel as late adjunctive treatment for epilepsy

OBJECTIVE

The objective of this study was to evaluate the efficacy and tolerability of perampanel (PER) in late adjunctive treatment of focal epilepsy. We assessed outcomes 1) according to patients' clinical profiles and the broad mechanism of action (MoA) of concomitant antiepileptic drugs (AEDs) and 2) the effects of PER on adverse events, irritability, mood, and quality of life (QOL).

METHODS

Consecutive patients commenced on PER at two epilepsy centers in Melbourne, Australia were identified. A nested cohort underwent detailed prospective assessment, while the remainder were retrospectively analyzed. Six- and 12-month efficacy endpoints were at least a 50% reduction in seizure frequency (responders) and complete seizure freedom. The prospective cohort underwent standardized validated questionnaires at 0, 1, 3, 6, and 12 months using the modified semi-structured seizure interview (SSI), Liverpool Adverse Events Profile (LAEP), Quality of Life in Epilepsy-Patient-Weighted (QOLIE-10-P), Neurological Disorders Depression Inventory Epilepsy (NDDI-E), and an Irritability Questionnaire.

RESULTS

One hundred sixty patients were followed for a median of 6 months: the mean number of prior AEDs was 6, 99% had drug-resistant epilepsy, and 72% had never experienced a prior seizure-free period of at least 6 months (=continuously refractory epilepsy). Perampanel was associated with responder and seizure freedom rates of 30.6% and 9.4% at 6 months and 19.4% and 4.4% (5.6% adjusted for the titration period) at 12 months. Having "continuously refractory epilepsy" was associated with a reduced likelihood of seizure freedom at 6 months (5% vs. 30%; p = 0.001) and 12 months (3% vs. 13%; p = 0.058). Quality of Life in Epilepsy-Patient-Weighted, irritability, and NDDI-E showed mean improvement at 6 months from baseline.

SIGNIFICANCE

Even when used as late add-on adjunctive therapy in patients with highly refractory focal epilepsy, PER can result in 12-month seizure freedom of 5.6%. The likelihood of seizure freedom was associated with prior "continuous medication refractoriness". Six months after introduction of PER patients reported improved mood, QOL, and decreased irritability.

Perampanel tolerability in children and adolescents with focal epilepsy: Effects on behavior and executive functions

OBJECTIVES

Perampanel (PER) is a noncompetitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor antagonist recently approved for focal and generalized epilepsies as an add-on therapy. It is well tolerated and effective as treatment of various pediatric epilepsy syndromes; PER does not seem to negatively affect the cognitive profile of children and adolescents, but its influence on executive functions is still to be assessed.

METHODS

Our sample included 37 children aged 12-18 years, with focal pharmacoresistant epilepsy already in therapy with 2 or 3 antiepileptic drug (AED); PER was added with 1 mg/week increments up to a dose of 2-4 mg/day. Changes in executive functions were assessed by the EpiTrack Junior test. Emotional and behavioral aspects were evaluated through the interview for parents Child Behavior Checklist (CBCL). Both tests were performed before taking PER and after 6 and 12 months of treatment.

RESULTS

After 12 months of PER in 22/30 patients, global score of the EpiTrack Junior test remained almost unchanged; in 7/30 patients, this score improved. The CBCL did not show significant changes in emotional or behavioral problems.

CONCLUSIONS

Adjunctive treatment with PER did not negatively affect executive functions that could also be improved. No emotional/behavioral negative effects have been reported, and this suggests a good tolerability in the middle/long term.

Real-Life Effectiveness and Tolerability of Perampanel in Pediatric Patients Aged 4 Years or Older with Epilepsy: A Korean National Multicenter Study

Background and Purpose

The US Food and Drug Administration approval for perampanel has only recently been expanded to patients as young as 4 years, and so there have been few real-life studies of the effects of perampanel in pediatric patients. The aim of this study was to determine the long-term efficacy, factors affecting treatment response, and tolerability of perampanel as an add-on therapy in pediatric patients aged 4 years or older with epilepsy.

Methods

This multicenter retrospective observational study collected data from pediatric epilepsy centers of four Korean national universities. Changes in the seizure frequency from baseline, adverse events, and retention rates were obtained at 3, 6, and 12 months. Adverse events and discontinuation profiles were obtained to assess tolerability.

Results

This study included 220 children and adolescents (117 males and 103 females) aged 4 to 20 years. The overall response rate was 43.6%, and the seizure-freedom rate was 17.7%. Factors affecting a good treatment response were the absence of intellectual disability, small number of concomitant antiepileptic drugs, and low baseline seizure frequency. Eighty-eight patients (40%) experienced adverse events, but they mostly were of mild severity and resolved after the dose reduction or discontinuation of perampanel. The retention rates at 3, 6, and 12 months were 85.0%, 71.8%, and 50.5%, respectively.

Conclusions

Adjunctive treatment with perampanel was efficacious and tolerated in pediatric patients aged 4 years or older with epilepsy. Early perampanel treatment may help to reduce the burden of their seizures and improve their quality of life.

Structure based virtual screening of novel noncompetitive antagonist of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor

The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) subtype ionotropic glutamate receptors are attractive antiepileptic targets responsible for mediating the majority of excitatory neurotransmission and plasticity. The noncompetitive antagonists obtain more and more attention as drug candidates for treatment of the neurological diseases involving excessive activity of AMPARs, due to they regulate AMPA receptors (AMPARs) activity independently of endogenous glutamate levels unlike the competitive antagonists. Development of novel AMPAR noncompetitive antagonists, which are safer and more efficacious than competitive antagonists, is highly under demand. Here, we present the discovery of novel antagonists against AMPAR through Structure-Based Virtual Screening (SBVS). Three compounds were successfully distinguished by several different filtering strategies, namely STOCK6S-10902, STOCK1N-49134 and STOCK5S-68665. The interaction mode of these compounds was further explored through molecular dynamics simulation, binding free energy calculation and the binding free energy decomposition. It is demonstrated that some residues within the binding pocket, which have been proved their importance in antagonist binding and gating, form strong hydrogen bond interactions with these three molecules. In particular, H-bond interactions with high occupancies between Ser516, Ser788 and STOCK6S-10902 and Ser516, Asn791 and STOCK1N-49134 were observed. The three hit compounds with new scaffolds and the detailed binding modes could potentially serve as a starting point for further optimization and development.

Preliminary evidence about irritability in patients with epilepsy treated by perampanel as first add-on therapy compared to levetiracetam and valproic acid

Aims

Irritability has been described as a frequent adverse event in patients affected by epilepsy and treated with perampanel (PER), levetiracetam (LEV), and less frequently with valproic acid (VPA). Since the questionnaire for irritability (I‐EPI) is a validated instrument to measure this psychiatric manifestation in patients affected by epilepsy, in this study we aimed at investigating the effect of PER as first add‐on therapy on I‐EPI. Moreover, we compared the effectiveness and I‐EPI scores obtained at 12‐month follow‐up visits in patients treated by PER, LEV, or VPA in order to measure irritability as a consequence of these treatments.

Methods

We collected data from 17 patients treated by PER, 16 patients treated by LEV, and 16 patients under VPA treatment followed for 12 months.

Results

We did not document significant changes of I‐EPI questionnaire between baseline and follow‐up in the PER group. As concerning the comparison of I‐EPI among PER, LEV, and VPA groups, we documented lower global scores in PER than both LEV (P < 0.05) and VPA (P < 0.05) groups. Moreover, patients under PER treatment showed lower scores than LEV and VPA (P < 0.05) in I‐EPI items measuring the gentle personality, anxiety of having epileptic seizures in front of others, and irritability in thinking that they can have an epileptic seizure.

Conclusions

This retrospective study described a stable and possibly lower degree of irritability in patients starting PER than LEV and VPA treatments, although we documented the comparable effectiveness of PER, LEV, and VPA as first add‐on treatments in patients affected by uncontrolled epileptic seizures. However, the small sample of patients included in this study and the absence of I‐EPI scores obtained at baseline visits in LEV and VPA groups require further investigations to confirm this preliminary evidence.

Usefulness of perampanel with concomitant levetiracetam for patients with drug-resistant epilepsy

PURPOSE

The purpose was to evaluate the efficacy of treatment and the occurrence of aggression-related adverse events among children receiving perampanel (PER) with concomitant levetiracetam (LEV).

METHODS

Patients were selected according to the following criteria: 1) between 12 and 18 years old; 2) seizures refractory to at least 2 first-line drugs; 3) at least 4 seizures a month before PER administration; and 4) at least 12 months of follow-up. Patients were subdivided into groups with and without LEV as concomitant treatment. PER was administered at a dose of 2 mg/day, increasing by 2 mg/day every 2 weeks up to 12 mg/day if seizures appeared. In comparison with the baseline seizure frequency, response to PER treatment was classified as follows: complete cessation (100% seizure control); response (≥50% reduction in seizures); and exacerbation (≥50% increase in seizures). Responders were identified as patients showing complete cessation or response.

RESULTS

The study group comprised 39 outpatients with a mean age of 13.7 years at enrollment. Responder status was seen in 13 of the 19 patients with LEV and 4 of the 20 patients without LEV. PER appeared significantly more effective in patients with LEV than in those without LEV (p = 0.0076). Seizure-free status was significantly more frequent among patients with LEV (47.4%) than among those without LEV (15.0% (p = 0.0407)). Aggression was present in 2 patients without LEV, but none with LEV.

CONCLUSION

The present study suggests the utility of PER with concomitant LEV for children with drug-resistant epilepsy.

Prolonged Stupor in Perampanel Overdose and Pharmacokinetic Considerations

Perampanel is a new antiepileptic drug with a long half-life, but there are currently no data on the effects of acute perampanel overdose in epilepsy patients. We report a patient who had such an overdose. A 39-year-old woman was admitted for altered consciousness after taking 10 times the daily dose of perampanel. Her blood level of the drug was predicted, by pharmacokinetic calculation, to decrease to a steady-state level after 7 days, followed by a full recovery 8 days after the overdose. During her hospital stay, the patient experienced pulmonary embolism, which may be associated with the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) antagonistic mechanism of perampanel. The present findings show that perampanel overdose can produce prolonged stupor and that caution should be exercised during transient hypercoagulable states.

Mechanisms Underlying Aggressive Behavior Induced by Antiepileptic Drugs: Focus on Topiramate, Levetiracetam, and Perampanel

Antiepileptic drugs (AEDs) are effective against seizures, but their use is often limited by adverse effects, among them psychiatric and behavioral ones including aggressive behavior (AB). Knowledge of the incidence, risk factors, and the underlying mechanisms of AB induced by AEDs may help to facilitate management and reduce the risk of such side effects. The exact incidence of AB as an adverse effect of AEDs is difficult to estimate, but frequencies up to 16% have been reported. Primarily, levetiracetam (LEV), perampanel (PER), and topiramate (TPM), which have diverse mechanisms of action, have been associated with AB. Currently, there is no evidence for a specific pharmacological mechanism solely explaining the increased incidence of AB with LEV, PER, and TPM. Serotonin (5-HT) and GABA, and particularly glutamate (via the AMPA receptor), seem to play key roles. Other mechanisms involve hormones, epigenetics, and “alternative psychosis” and related phenomena. Increased individual susceptibility due to an underlying neurological and/or a mental health disorder may further explain why people with epilepsy are at an increased risk of AB when using AEDs. Remarkably, AB may occur with a delay of weeks or months after start of treatment. Information to patients, relatives, and caregivers, as well as sufficient clinical follow-up, is crucial, and there is a need for further research to understand the complex relationship between AED mechanisms of action and the induction/worsening of AB.

Perampanel in routine clinical use in idiopathic generalized epilepsy: The 12-month GENERAL study

OBJECTIVE

To analyze the effectiveness and tolerability of perampanel across different seizure types in routine clinical care of patients with idiopathic generalized epilepsy (IGE).

METHODS

This multicenter, retrospective, 1-year observational study collected data from patient records at 21 specialist epilepsy units in Spain. All patients who were aged ≥12 years, prescribed perampanel before December 2016, and had a confirmed diagnosis of IGE were included.

RESULTS

The population comprised 149 patients with IGE (60 with juvenile myoclonic epilepsy, 51 generalized tonic-clonic seizures [GTCS] only, 21 juvenile absence epilepsy, 10 childhood absence epilepsy, 6 adulthood absence epilepsy, and one Jeavons syndrome). Mean age was 36 years. The retention rate at 12 months was 83% (124/149), and 4 mg was the most common dose. At 12 months, the seizure-free rate was 59% for all seizures (88/149); 63% for GTCS (72/115), 65% for myoclonic seizures (31/48), and 51% for absence seizures (24/47). Seizure frequency was reduced significantly at 12 months relative to baseline for GTCS (78%), myoclonic (65%), and absence seizures (48%). Increase from baseline seizure frequency was seen in 5.2% of patients with GTCS seizures, 6.3% with myoclonic, and 4.3% with absence seizures. Perampanel was effective regardless of epilepsy syndrome, concomitant antiepileptic drugs (AEDs), and prior AEDs, but retention and seizure freedom were significantly higher when used as early add-on (after ≤2 prior AEDs) than late (≥3 prior AEDs). Adverse events were reported in 50% of patients over 12 months, mostly mild or moderate, and irritability (23%), somnolence (15%), and dizziness (14%) were most frequent.

SIGNIFICANCE

In routine clinical care of patients with IGE, perampanel improved seizure outcomes for GTCS, myoclonic seizures, and absence seizures, with few discontinuations due to adverse events. This is the first real-world evidence with perampanel across different seizure types in IGE.

Evaluating the longer-term cognitive effects of adjunctive perampanel compared to lacosamide in a naturalistic outpatient setting

PURPOSE

This retrospective longitudinal study aims to compare the longer-term cognitive and behavioral side effects of adjunctive antiepileptic treatment with perampanel (PER) and lacosamide (LCM), two third generation antiepileptic drugs with suggested favorable cognitive profiles. The two drugs were monitored according to a previously established routine diagnostic protocol (Helmstaedter et al. E&B 2013;26:182-7) which facilitates the retrospective comparison of antiepileptic drug tolerability in a naturalistic outpatient setting.

METHODS

Records from 94 patients were evaluated who underwent neuropsychological assessment before and under adjunctive treatment with either PER (n = 57) or LCM (n = 37). Cognition was assessed using the EpiTrack screening for executive functions and a VLMT short form for verbal memory. Subjective assessments included a German QOLIE-10 adaptation (quality of life) and an extended Adverse Events Profile (AEP). The median follow-up interval was 36 weeks.

RESULTS

Multivariate repeated measures statistics revealed a non-significant trend towards an interaction effect "time - treatment arm" on both executive function and memory. When analyzed separately executive functions and memory scores significantly improved under LCM (t = -2.76 p < 0.01 and t = -2.44 p < 0.05 respectively). Subjectively, PER was associated with improvements in 2/18 physiological domains and in the LCM group 1/9 cognitive domains deteriorated. Seizure freedom was achieved for five patients treated with LCM (14%) and 15 treated with PER (26%, χ² = 2.2, n.s.).

CONCLUSION

In a naturalistic outpatient setting, chronic adjunctive treatment with PER and LCM did not negatively affect cognition and LCM may even improve cognition. Neither drug increased self-reported irritability or aggression. This suggests favorable longer-term tolerability.

Efficacy and tolerability of perampanel and levetiracetam as first add-on therapy in patients with epilepsy: A retrospective single center study

Perampanel (PER) is a third generation antiepileptic drug (AED), recently approved as add-on therapy in both focal and generalized seizures. Levetiracetam (LEV) is a second generation AED, widely used in patients with epilepsy because of its favorable safety and efficacy profiles. Perampanel and LEV treatments have been associated with the occurrence of similar adverse events (AEs) (sleepiness, irritability, depression, anxiety, aggressiveness). The aim of the present retrospective single center study was to verify the efficacy and tolerability of PER and LEV used as first add-on therapy in patients with epilepsy affected by secondarily generalized seizures. We collected data from 15 patients treated with PER and 26 patients treated with LEV and followed at our site with follow-up visits at 3, 6, and 12months. This retrospective study documented the comparable efficacy of PER and LEV as first add-on treatments in patients affected by uncontrolled secondarily generalized seizures. However, more patients withdrawn LEV because of AEs compared with PER at the 3- and 12-month follow-up visits. The better tolerability of PER observed in this study could be related to the low therapeutic dose of PER prescribed when it is used as first adjunctive treatment for better controlling secondarily generalized seizures.

Preliminary Asian experience of using perampanel in clinical practice

Background

To analyze the efficacy and safety of perampanel over a 3-month period in a sample of Asian people with epilepsy.

Methods

The efficacy and safety of perampanel as an adjunctive therapy for patients with epilepsy were retrospectively reviewed and analyzed. Patients were categorized according to seizure type, concomitant antiepileptic drug usage, and perampanel dosage.

Results

A total of 210 patients were included in the study and 131 patients completed 3 months of perampanel treatment. The average dosage of perampanel was 5.31 mg/day, and the 50% responder rate (≥50% seizure frequency reduction) in all patients was 45.8%, with a 27.5% seizure-free rate. For focal seizures, focal to bilateral tonic-clonic seizures, and primary generalized seizures, the 50% responder rates were respectively 29.4%, 49.5%, and 36.4%. In total, 39.5% of patients experienced adverse events within 3 months of observation period, and the rate of drug withdrawal due to adverse events was 8.6%. Dizziness, ataxia, irritability/aggression were the most common adverse events.

Conclusions

The efficacy and safety of perampanel in a real-world setting with Asian patients is comparable to that in clinical trials that have included fewer Asian patients.

The Pharmacology and Toxicology of Third-Generation Anticonvulsant Drugs

Epilepsy is a neurologic disorder affecting approximately 50 million people worldwide, or about 0.7% of the population [1]. Thus, the use of anticonvulsant drugs in the treatment of epilepsy is common and widespread. There are three generations of anticonvulsant drugs, categorized by the year in which they were developed and released. The aim of this review is to discuss the pharmacokinetics, drug-drug interactions, and adverse events of the third generation of anticonvulsant drugs. Where available, overdose data will be included. The pharmacokinetic properties of third-generation anticonvulsant drugs include relatively fewer drug-drug interactions, as well as several unique and life-threatening adverse events. Overdose data are limited, so thorough review of adverse events and knowledge of drug mechanism will guide expectant management of future overdose cases. Reporting of these cases as they occur will be necessary to further clarify toxicity of these drugs.

Clinical Experience With Perampanel for Refractory Pediatric Epilepsy in One Canadian Center

Perampanel (PER) is a new antiseizure medication that inhibits the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) class of glutamate receptors. It is important for physicians to be aware of the efficacy and tolerability of new drugs in the postmarketing phase. We performed a retrospective review of our experience with perampanel at BC Children's Hospital. Twenty-four pediatric patients prescribed perampanel from 2014 to 2016 were identified. Fifteen (63%) discontinued perampanel, and 10 (42%) had greater than 50% reduction in seizures. Twelve (50%) had behavioral and 8 (33%) had nonbehavioral adverse events. One-third experienced serious adverse events. One patient experienced oculogyric crisis, which is not previously reported with perampanel. Adverse events were not dose related and were reversible. Possible risk factors for behavioral adverse events include a history of behavioral problems with other antiseizure medications and preexisting behavioral comorbidities. It is important to counsel patients about the potential for serious adverse events, particularly behavioral, when prescribing perampanel.

Retention of perampanel in adults with pharmacoresistant epilepsy at a single tertiary care center

RATIONALE

Observational data on antiepileptic drugs (AEDs) inform about their use in clinical practice. We describe our clinical experience with perampanel (PER) in a large UK tertiary epilepsy center.

METHODS

Adults initiated on PER between October 2012 and March 2015 were followed until they discontinued PER or 10 September 2016. Data on epilepsy syndrome, duration, seizure types, concomitant and previous AED use, PER dosing, efficacy and side effects were recorded. Efficacy was categorized as temporary or ongoing (at last follow-up) seizure freedom, ≥50% seizure reduction, or other benefit (e.g. No convulsions or daytime seizures). These categories were mutually exclusive except for people with temporary seizure freedom.

RESULTS

391 received a PER prescription, five of whom never took it. No follow-up data were available for ten. 83% had focal epilepsy. People were prescribed PER in addition to 1-7 (Interquartile range [IQR] 2, 2, 3) AEDs and had previously used up to 18 (IQR 5, 7, 10) AEDs. Total exposure was 639patient/years. Retention rates were 60.4% at one year, 48.3% at two years, and 42.7% at three years. 19 (5%) people reported seizure free periods lasting at least six months. A ≥50% reduction in seizures lasting at least six months was reported by 76 people (20%), and marked improvement for ≥6months was seen in 52 (14%). Five (1%) were taken off other AEDs and continued on PER monotherapy for 4-27months. Seizures were aggravated in 57 (15%). Somatic side effects were reported by 197 (52%), mostly CNS. Mood changes, irritability or challenging behavior were reported by 137 (36%). PER was discontinued by 211 (56%) due to adverse effects (39%), inefficacy (26%), or both (35%). No idiosyncratic adverse events were seen.

CONCLUSION

PER resulted in some benefit in 40% of those exposed. Adverse effects on mental health and on balance were common and should be discussed with people before initiating PER.

Cognitive and behavioral effects of new antiepileptic drugs in pediatric epilepsy

BACKGROUND

In pediatric epilepsy, neurodevelopmental comorbidities could be sometimes even more disabling than seizures themselves, therefore it is crucial for the clinicians to understand how to benefit these children, and to choose the proper antiepileptic drug for the treatment of epilepsy associated to a specific neurodevelopmental disorder. Aim of this paper is to discuss the potential impact on cognition and behavior of new and newest AEDs and to guide the choice of the clinicians for a targeted use in epilepsy associated with specific neurodevelopmental disorders.

METHODS

Information in this review is mainly based on peer-reviewed medical publications from 2002 until October 2016 (PubMed). We choose to include in our review only the AEDs of second and third generation approved for pediatric population.

RESULTS

Vigabatrin, lamotrigine, topiramate, levetiracetam, oxcarbazepine, zonisamide, rufinamide, lacosamide, eslicarbazepine, and perampanel have been included in this review. The most tolerated AEDs from a cognitive and behavioral point of view are lamotrigine and rufinamide, thus representing optimal drugs for children with cognitive and/or attention problems.

DISCUSSION

Most of the new AEDs are initially licensed for adult patients. Data on children are usually very limited, both in terms of efficacy and safety, and the use standardized cognitive and behavioral outcome measures are very limited in pediatric clinical trials.

CONCLUSION

Several factors including polytherapy, administration of AEDs with the same mechanism of action and the dose and titration of the drug, should be considered as important in the development of cognitive and behavioral side effects.

Epilepsy, Antiepileptic Drugs, and Aggression: An Evidence-Based Review

Antiepileptic drugs (AEDs) have many benefits but also many side effects, including aggression, agitation, and irritability, in some patients with epilepsy. This article offers a comprehensive summary of current understanding of aggressive behaviors in patients with epilepsy, including an evidence-based review of aggression during AED treatment. Aggression is seen in a minority of people with epilepsy. It is rarely seizure related but is interictal, sometimes occurring as part of complex psychiatric and behavioral comorbidities, and it is sometimes associated with AED treatment. We review the common neurotransmitter systems and brain regions implicated in both epilepsy and aggression, including the GABA, glutamate, serotonin, dopamine, and noradrenaline systems and the hippocampus, amygdala, prefrontal cortex, anterior cingulate cortex, and temporal lobes. Few controlled clinical studies have used behavioral measures to specifically examine aggression with AEDs, and most evidence comes from adverse event reporting from clinical and observational studies. A systematic approach was used to identify relevant publications, and we present a comprehensive, evidence-based summary of available data surrounding aggression-related behaviors with each of the currently available AEDs in both adults and in children/adolescents with epilepsy. A psychiatric history and history of a propensity toward aggression/anger should routinely be sought from patients, family members, and carers; its presence does not preclude the use of any specific AEDs, but those most likely to be implicated in these behaviors should be used with caution in such cases.

AMPA GluA1-flip targeted oligonucleotide therapy reduces neonatal seizures and hyperexcitability

Glutamate-activated α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPA-Rs) mediate the majority of excitatory neurotransmission in brain and thus are major drug targets for diseases associated with hyperexcitability or neurotoxicity. Due to the critical nature of AMPA-Rs in normal brain function, typical AMPA-R antagonists have deleterious effects on cognition and motor function, highlighting the need for more precise modulators. A dramatic increase in the flip isoform of alternatively spliced AMPA-R GluA1 subunits occurs post-seizure in humans and animal models. GluA1-flip produces higher gain AMPA channels than GluA1-flop, increasing network excitability and seizure susceptibility. Splice modulating oligonucleotides (SMOs) bind to pre-mRNA to influence alternative splicing, a strategy that can be exploited to develop more selective drugs across therapeutic areas. We developed a novel SMO, GR1, which potently and specifically decreased GluA1-flip expression throughout the brain of neonatal mice lasting at least 60 days after single intracerebroventricular injection. GR1 treatment reduced AMPA-R mediated excitatory postsynaptic currents at hippocampal CA1 synapses, without affecting long-term potentiation or long-term depression, cellular models of memory, or impairing GluA1-dependent cognition or motor function in mice. Importantly, GR1 demonstrated anti-seizure properties and reduced post-seizure hyperexcitability in neonatal mice, highlighting its drug candidate potential for treating epilepsies and other neurological diseases involving network hyperexcitability.

A two-year retrospective evaluation of perampanel in patients with highly drug-resistant epilepsy and cognitive impairment

PURPOSE

The objective of this work was to review systematically the efficacy and tolerability of perampanel (PER) in residential patients of an epilepsy center.

METHOD

We adopted an industry-independent noninterventional retrospective evaluation on the basis of the paper and electronic records complemented by personal information on the part of the treating neurologists. All patients (N=26, 15 females, mean age: 30, range 21-55years) started on PER from its introduction to the market in September 2012 until December 15th 2013 were included. Evaluation was carried out after 6, 12, and 24months of PER treatment. Changes in seizure frequency were calculated as the number of seizures during three months on PER compared to a three-month baseline period. The Clinical Global Impression Scale served as an instrument to record changes in seizure intensity beyond numerical values. Adverse effects were documented by means of the Liverpool Adverse Events Profile.

RESULTS

Most patients had structural or metabolic epilepsy, 2 patients suffered from Lennox-Gastaut syndrome, 2 from other symptomatic generalized epilepsy. All patients had grade III drug-resistant epilepsy. All patients had additional cognitive deficits of different degree. The retention rates were 61.5% after 6months, 46.2% after 12months, and 42.3% after 24months. The responder rates were 11.5% after 6months, 23.1% after 12months, and 7.7% after 24months. Partial responders (positive CGI and/or seizure reduction <50%) included, the respective values were 26.9%, 38.5%, and 23.1%. Only 1 patient was seizure free at 12months (but not at 24months). A loss of efficacy in the second year of treatment was suspected but the decrease of the responder rate could also be ascribed to a number of different circumstances. Adverse effects in the psychiatric field like irritability, aggression, increased sensitivity, and suicidal ideation/behavior occurred in 50% of the patients. They were the main reason to discontinue PER.

CONCLUSIONS

After one year of treatment PER showed reasonable efficacy in a particularly difficult-to-treat population. Psychiatric adverse effects forced discontinuation in many cases.

Evaluation of perampanel in patients with intellectual disability and epilepsy

INTRODUCTION

Initial registration studies of perampanel (PMP), an AMPA receptor antagonist, have now been followed up by 'clinical' studies that confirmed its efficacy and safety in patients with refractory epilepsy. Publications on the use of PMP among patients with intellectual disability (ID) are still limited. This study extends our knowledge with respect to the relevance of PMP for patients with both ID and epilepsy, and furthermore specifies the behavioral side effects of PMP in this specific population.

METHODS

Retrospective evaluation of medical records at 3, 6 and 12months of follow-up after the initial start of PMP.

RESULTS

62 patients were included. 21 patients (33.9%) were female. All patients had complete data of 6months follow-up and we were able to review 42 patients with a 1-year follow-up. Level of ID varied from borderline to profound, and mild ID was most common (43.5%). The mean maximum daily dosage of PMP was 5.6mg (range 1-12mg). Retention rates for PMP were 87.1% and 67.7% after three and six months. A trend indicated a longer mean retention time in patients with a more severe ID (borderline-mild-moderate ID: 205days, severe-profound ID: 275days). Seizure reduction was achieved in 53.2%. 36 patients (58.1%) experienced adverse effects, 80.6% of those within 3months. 45.2% of the patients experienced somatic adverse effects. Most common were fatigue & sleep problems, motor problems & unsteadiness, and gastrointestinal problems. Behavioral adverse effects were present in 40.3%. Most common were aggression, agitated behavior, disruptive behavior, and mood symptoms. Reasons for discontinuation of PMP were lack of efficacy in 14.8%, intolerable adverse effects in 44.4%, and a combination of both in 40.7%. Altogether, 24.2% (15/62) of the patients achieved seizure reduction without experiencing adverse effects, though none reached seizure freedom.

CONCLUSIONS

The use of PMP might lead to an effective seizure reduction without adverse effects in a minority of patients with both epilepsy and ID. Pre-existing behavioral problems or polypharmacy do not predict the occurrence of additional behavioral adverse effects, implying that these patients need not be excluded from the introduction of PMP when clinically indicated. Patients should, ideally, be monitored at a multidisciplinary clinic.

Perampanel as add-on treatment in refractory focal epilepsy. The Dianalund experience

BACKGROUND

Perampanel (PER) is an antagonist of AMPA receptors that has been approved for adjunctive treatment of partial-onset seizures.

AIMS

To evaluate effectiveness and safety of PER as add-on treatment in patients with severely refractory focal epilepsy.

METHODS

PER was introduced as add-on treatment in 22 consecutive patients with drug-resistant focal epilepsy. PER was started with 2 mg/day at bedtime and was up-titrated by 2 mg/day every 2-4 weeks.

RESULTS

All patients suffered from severely refractory focal epilepsy (86% took 2 or more AEDs prior PER initiation; 40% had been submitted to surgery or were surgery candidates; 7 had VNS). After 12 months since PER initiation, the retention rate was 54.5% and the responder rate was 27.2%, including 9.1% seizure-free patients. Mean PER dose in the responders was 8 mg/day (range 4-10). Most common side effects were tiredness, behavioral changes (primarily aggressivity), dizziness and were reported in 59.1% of patients, leading to PER discontinuation in 31.8% of subjects.

CONCLUSIONS

PER as add-on treatment can achieve clinically meaningful improvement in patients suffering from severely refractory focal epilepses. Further studies are warranted to explore the tolerability profile, with particular focus on psychiatric adverse events.

Structural Bases of Noncompetitive Inhibition of AMPA-Subtype Ionotropic Glutamate Receptors by Antiepileptic Drugs

Excitatory neurotransmission plays a key role in epileptogenesis. Correspondingly, AMPA-subtype ionotropic glutamate receptors, which mediate the majority of excitatory neurotransmission and contribute to seizure generation and spread, have emerged as promising targets for epilepsy therapy. The most potent and well-tolerated AMPA receptor inhibitors act via a noncompetitive mechanism, but many of them produce adverse side effects. The design of better drugs is hampered by the lack of a structural understanding of noncompetitive inhibition. Here, we report crystal structures of the rat AMPA-subtype GluA2 receptor in complex with three noncompetitive inhibitors. The inhibitors bind to a novel binding site, completely conserved between rat and human, at the interface between the ion channel and linkers connecting it to the ligand-binding domains. We propose that the inhibitors stabilize the AMPA receptor closed state by acting as wedges between the transmembrane segments, thereby preventing gating rearrangements that are necessary for ion channel opening.

[Perampanel as a therapy option in patients with epilepsy]

BACKGROUND

This article describes a monocentric retrospective analysis of clinical experience with the latest antiepileptic drug perampanel with non-competitive modulation of postsynaptic AMPA receptors.

MATERIAL AND METHODS

Evaluation of electronic medical charts of patients newly treated with perampanel between 2012 and 2014 at the epilepsy center of the University Hospital Freiburg regarding effectiveness and tolerability.

RESULTS

A total of 85 patients (45 male, mean age 37.4 years, range 14-80 years) with therapy resistance to an average of 6 antiepileptic medications were newly treated with add-on perampanel. Of the patients 35 % experienced a relevant reduction in seizures. The most commonly reported side effects were tiredness (32.5 %), dizziness (24.5 %) and irritability (10.5 %). The dosages resulting in a significant reduction in seizures which varied between patients from 4 to 12 mg/day. Even multidrug-resistant patients who had not benefited from vagus nerve and deep brain stimulation, profited from add-on treatment with perampanel.

CONCLUSION

In this cohort, even epilepsy patients who did not respond to multiple previous antiepileptic treatment profited from add-on therapy with the new mode of action of perampanel.

Prospective audit with adjunctive perampanel: Preliminary observations in focal epilepsy

PURPOSE

Perampanel (PER) was first licensed in the United Kingdom in 2012 for the adjunctive treatment of focal seizures with or without secondary generalization in adults and children over 12years of age. It has recently also been approved for use as add-on therapy for patients with primary generalized tonic-clonic seizures. This prospective audit reports preliminary outcomes with adjunctive PER in patients with focal-onset seizures in everyday clinical practice using a standard design.

METHODS

To date, 54 patients (38 males, 16 females; 21-65years, median: 48years) have completed the study. The median monthly seizure frequency was 4 (range: 1-60). At baseline, patients were taking a median of 2 other antiepileptic drugs (range: 1-4 drugs), with their seizures having previously failed to improve on a median of 3 schedules (range: 1-15 schedules). After 12weeks of stable dosing, PER was added, aiming at a target range of 6-12mg/daily. Review took place every 6-8weeks until one of 4 endpoints was reached: seizure freedom for ≥6months on a given PER dose, ≥50% (responder) or <50% (marginal effect) seizure reduction over 6months, compared with the prospective baseline, on the highest tolerated PER dose, or withdrawal of PER due to a lack of efficacy or side effects.

RESULTS

Three (5.6%) patients have remained seizure-free, with 8 (14.8%) demonstrating a ≥50% response and a further 17 (31.5%) reporting a marginal effect. Of the 26 (48.1%) dropping out of PER treatment, 21 (38.9%) did so because of side effects. The commonest problems were nausea, vomiting, ataxia, dizziness, and sedation. Overall, 6 (11%) patients developed neuropsychiatric problems, with 3 reporting irritability and/or aggression. Two patients had substantial weight gain, and another patient suffered recurrent falls. Treatment with enzyme-inducing AEDs had no effect on PER dosing in patients responding to PER or withdrawing due to side effects.

SIGNIFICANCE

These data support the value of adjunctive PER in some patients with pharmacoresistant epilepsy in everyday clinical practice.

Clinical efficacy of perampanel for partial-onset and primary generalized tonic-clonic seizures

BACKGROUND AND PURPOSE

Perampanel, a selective noncompetitive antagonist at the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, is highly effective in a wide range of experimental models. Although initially licensed as adjunctive therapy for partial seizures with or without secondary generalization in patients aged 12 years or older, the US Food and Drug Administration has recently approved its use in the treatment of primary generalized tonic-clonic seizures (PGTCS). This paper reviews the pharmacokinetics, efficacy, and tolerability of perampanel as an antiepileptic drug.

RESULTS

After oral ingestion, perampanel is rapidly absorbed (T max, 0.5-2.5 hours), has a bioavailability of ~100%, and is highly protein bound (~95%) in plasma. It undergoes extensive (>90%) hepatic metabolism, primarily via cytochrome P450 3A4 (CYP3A4), with a half-life of 48 hours. Carbamazepine and other antiepileptic drugs can enhance its metabolism via induction of CYP3A4. Efficacy of perampanel in focal seizures has been extensively evaluated in Phase II and randomized, placebo-controlled Phase III trials. The efficacy in PGTCS has been reported in one class I study. In the treatment of focal seizures, perampanel showed significant dose-dependent median seizure reductions: 4 mg/d, 23%; 8 mg/d, 26%-31%; 12 mg/d, 18%-35%; and placebo, 10%-21%. The 50% responder rates were 15%-26%, 29%, 33%-38%, and 34%-36% for placebo, 4 mg/d, 8 mg/d, and 12 mg/d perampanel, respectively. Freedom from seizures was recorded in 0%-1.7% of the placebo group, 1.9% of the 2 mg group, 2.6%-4.4% of the 8 mg group, and 2.6%-6.5% of the 12 mg group. For PGTCS, the median seizure reduction was 76.5% for perampanel and 38.4% for placebo. The 50% responder rate was 64.2% for perampanel and 39.5% for placebo. Seizure freedom during maintenance phase was 30.9% for perampanel and 12.3% for placebo. Adverse effects included dose-dependent increases in the frequency of dizziness, somnolence, fatigue, irritability, falls, and probably nausea.

CONCLUSION

Perampanel is effective in treating both partial-onset seizures and PGTCS.

Practical Use of Newer Antiepileptic Drugs as Adjunctive Therapy in Focal Epilepsy

This article lays the background for, and discusses the practical issues surrounding, the adjunctive use of the last four antiepileptic drugs (AEDs) to be licensed for the treatment of pharmacoresistant focal seizures in the UK and elsewhere. More than 30% of adolescent and adult patients will not be fully controlled on the currently available therapeutic armamentarium. After not responding to their first three AED schedules, only a handful of patients attained seizure freedom on subsequent regimens. To optimise the response to any new AED in this setting, it is often necessary to reduce the existing drug burden. The pharmacology, tolerability and safety, and everyday use of lacosamide, eslicarbazepine acetate, retigabine (ezogabine) and perampanel will be reviewed and discussed. This will be accompanied by data from prospective audits with each drug undertaken at the Western Infirmary in Glasgow, Scotland, and a report of their successful introduction in an illustrative case. Overall, there is a large variation in the course of refractory epilepsy and the effect of AED therapy on this process seems minimal. Nevertheless, a number of patients will benefit from the introduction of each new AED, with some becoming seizure-free.

The AMPA receptor antagonist perampanel in the adjunctive treatment of partial-onset seizures: clinical trial evidence and experience

More than 20 antiepileptic drugs (AEDs) are currently available for the medical treatment of epilepsies. However, still about 30% of all epilepsies have a drug-resistant course. Even worse, in the case of some epilepsy syndromes, freedom from seizures is almost never achieved. Therefore, new treatment options are still necessary, especially if theoretical concepts such as a new mode of action offer new horizons. Perampanel is the first-in-class orally active, selective, noncompetitive antagonist of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. The pharmacokinetic profile offers once-daily dosing in the evening as the best route of administration. According to the results of three pivotal placebo-controlled, double-blind phase III trials that investigated perampanel as an adjunctive AED in adult and adolescent patients from age 12 years who had ongoing focal epileptic seizures despite receiving one to three AEDs, perampanel has been widely licensed and introduced. Phase III trials showed superiority of adjunctive perampanel over placebo consistently in the range between 4 and 12 mg. Dizziness and somnolence were by far the leading adverse events. This review covers the clinical trial evidence but also clinical experience with perampanel after launch according to observational studies.

Perampanel in the management of partial-onset seizures: a review of safety, efficacy, and patient acceptability

Perampanel (PER) is a novel antiepileptic drug recently introduced for the adjunctive treatment in epilepsy patients aged 12 years or older with partial-onset seizures with or without secondary generalization in the US and Europe. Its antiepileptic action is based on noncompetitive inhibition of postsynaptic AMPA receptors, decreasing excitatory synaptic transmission. Evaluation of efficacy in three placebo-controlled randomized Phase III studies showed that add-on therapy of PER decreased seizure frequencies significantly compared to placebo at daily doses between 4 mg/day and 12 mg/day. PER's long half-life of 105 hours allows for once-daily dosing that is favorable for patient compliance with intake. Long-term extension studies showed a 62.5%-69.6% adherence of patients after 1 year of treatment, comparing favorably with other second-generation antiepileptic drugs. Whereas these trials demonstrated an overall favorable tolerability profile of PER, nonspecific central nervous system adverse effects like somnolence, dizziness, headache, and fatigue may occur. In addition, neuropsychiatric disturbances ranging from irritability to suicidality were reported in several case reports; both placebo-controlled and prospective long-term extension trials showed a low incidence of such behavioral and psychiatric complaints. For early recognition of neuropsychiatric symptoms like depression, anxiety, and aggression, slow titration and close monitoring during drug introduction are mandatory. This allows on the one hand to recognize patients particularly susceptible to adverse effects of the drug, and on the other hand to render the drug's full potential of seizure control available for the vast majority of patient groups tolerating the drug well.