Effectiveness and tolerability of perampanel in children and adolescents with refractory epilepsies-An Italian observational multicenter study

Efficacy and tolerability of perampanel as add-on therapy in Dravet syndrome: A prospective real-world study

OBJECTIVE

To investigate the efficacy and tolerability of perampanel (PER) on Dravet syndrome in China by a prospective real-world study.

METHODS

We prospectively enrolled children with Dravet syndrome from the neurology clinic of Shenzhen Children's Hospital from September 2020 to October 2021. The average monthly seizure frequency within 2 months before enrollment was recorded as the baseline. PER was administered after enrollment. The response rate (the rate of seizure reduction ≥50% compared to the baseline) was regarded as the major index. The adverse events and retention rates were regarded as the minor index. All indexes were calculated after 3 and 6 months' follow-up, respectively. The outcome-predictive value of various clinical factors was analyzed.

RESULTS

A total of 21 children were enrolled, including 15 boys and 6 girls, with a median age of 4 years and 8 months (1 year and 3 months to 15 years and 6 months). Averagely, 2.57 ASMs had been administrated and failed to control seizures before enrollment. The response rates were 52.4% (11/21) and 47.6% (10/21) after 3 and 6 months of PER administration, respectively. Adverse events were observed in 8 patients (38.1%), including irritability (3/8, 37.5%), fatigue (3/8, 37.5%), unstable walking (2/8, 25%), somnolence (2/8, 25%), and sluggish response (2/8, 25%); most of them were mild and temporary. The retention rate was 90.5% (19/21) at 6 months' follow-up. Two patients discontinued PER due to failure of seizure control, and no patients discontinued due to adverse events.

SIGNIFICANCE

This study provides a comprehensive analysis of PER's effectiveness and tolerability in treating DS, highlighting its importance as an additional treatment option. It broadens the range of anti-seizure medications (ASMs) that may be effective for patients with DS.

PLAIN LANGUAGE SUMMARY

In the neurology clinic of Shenzhen Children's Hospital, 21 children with Dravet syndrome were administered perampanel. Perampanel, as a novel anti-seizure medication approved for focal and generalized epilepsies as add-on therapy, showed sufficient efficacy and a satisfactory safety and tolerability profile in this study.

Usefulness of perampanel as initial monotherapy in children with non-lesional focal epilepsy

This study aimed to compare carbamazepine (CBZ) and perampanel (PER) in terms of the efficacy against clinical seizures and electroencephalographic abnormalities such as interictal epileptiform discharges (IEDs) and safety as initial monotherapy in children with non-lesional focal epilepsies. This retrospective review included participants recruited from among epilepsy outpatients treated at the authors' hospital between January 01, 2000, and December 31, 2019 in the CBZ group and between January 01, 2020, and December 31, 2022 in the PER group. The inclusion criterion in both groups was ≥12 months of follow-up. Responders were identified as participants demonstrating complete disappearance (100 % reduction in seizures or IEDs) or response (>50 % reduction in seizure frequency or IEDs). Safety primary outcome was defined as appearance rate of AEs. The study group comprised 247 participants treated with CBZ and 46 participants treated with PER. Total efficacy rate for clinical seizures was significantly higher with PER than with CBZ (p = 0.0148). Moreover, the rate of complete disappearance was significantly higher with PER than with CBZ (p = 0.0133). Total efficacy rate for IED was again significantly higher with PER than with CBZ (p < 0.0001). The appearance of adverse events was significantly lower with PER than with CBZ (p = 0.023). PER may be useful as initial monotherapy in children with non-lesional focal epilepsies.

The latest advances in the pharmacological management of focal epilepsies in children: a narrative review

INTRODUCTION

Focal epilepsy constitutes the most common epilepsy in children, and medical treatment represents the first-line therapy in this condition. The main goal of medical treatment for children and adolescents with epilepsy is the achievement of seizure freedom or, in drug-resistant epilepsies, a significant seizure reduction, both minimizing antiseizure medications (ASM)-related adverse events, thus improving the patient's quality of life. However, up to 20-40% of pediatric epilepsies are refractory to drug treatments. New ASMs came to light in the pediatric landscape, improving the drug profile compared to that of the preexisting ones. Clinicians should consider several factors during the drug choice process, including patient and medication-specific characteristics.

AREAS COVERED

This narrative review aims to summarize the latest evidence on the effectiveness and tolerability of the newest ASMs administered as monotherapy or adjunctive therapy in pediatric epilepsies with focal onset seizures, providing a practical appraisal based on the existing evidence.

EXPERT OPINION

The latest ASMs have the potential to be effective in the pharmacological management of focal onset seizures in children, and treatment choice should consider several drug- and epilepsy-related factors. Future treatments should be increasingly personalized and targeted on patient-specific pathways. Future research should focus on discovering new chemical compounds and repurposing medications used for other indications.

Efficacy and safety of perampanel monotherapy in Chinese patients with focal-onset seizures: A single-center, prospective, real-world observational study

OBJECTIVE

Efficacy and safety of perampanel monotherapy for treating focal-onset seizures (FOS) has been barely studied in China. This observational study aimed to evaluate the efficacy and safety of perampanel monotherapy in treating Chinese patients with FOS.

METHODS

This single-center, prospective, real-world observational study enrolled patients aged ≥4 years with FOS who visited the Epilepsy Out-Patient Clinic of Nanjing Brain Hospital affiliated to Nanjing Medical University from January 2020 to December 2021. All patients were treated with perampanel monotherapy. Seizure-freedom rates after 6 and 12 months of treatment were calculated. Adverse events (AEs) were recorded.

RESULTS

Seventy patients with FOS were enrolled. The mean maintenance perampanel dose was 4.64 ± 1.55 mg/day. The 6- and 12-month retention rates of perampanel monotherapy were 78.6% (55/70) and 70.0% (49/70), respectively. The 6- and 12-month seizure-freedom rates were 69.84% (44/63) and 65.08% (41/63), respectively. Patients with focal to bilateral tonic-clonic seizures had significantly higher 6-month and numerically higher 12-month seizure freedom rates than patients with focal impaired awareness seizures (P = 0.046 and P = 0.204, respectively). Twenty-six (37.1%) patients experienced treatment-emergent AEs, and the most common AE was dizziness. Four (5.7%) patients withdrew from the study due to AEs. No new safety concern was observed.

SIGNIFICANCE

This is the first prospective study on the efficacy and safety of perampanel monotherapy in treating Chinese patients with FOS, and perampanel monotherapy was effective and safe in treating Chinese patients aged ≥4 years with FOS up to 12 months. More multicenter, real-world studies with large sample sizes and longer follow-ups are needed to further evaluate the long-term efficacy and safety of perampanel monotherapy.

Efficacy and safety of perampanel for the treatment of epilepsy in adolescents: a meta-analysis

BACKGROUND

In the present meta-analysis, the efficacy and safety of perampanel (PER) for the treatment of adolescents with epilepsy were assessed.

METHODS

Keyword searches were performed in Embase, PubMed, Cochrane Library, Web of Science, EBSCO and CNKI from 1 January 2020 to 10 October 2020. The randomized controlled trials (RCTs) and case-control studies in which PER was compared with other Anti-seizure drugs (ASDs) and/or placebo in children with epilepsy, were considered eligible studies. Odds ratio (OR) with 95% confidence interval (95% CI) for the dichotomous outcome statistic was calculated using a fixed-effects or random-effects model.

RESULTS

Three RCTs with a total of 372 adolescents' patients were included in this meta-analysis. Placebo was used as a control in these studies. Compared with placebo, PER showed better efficacy in median seizure frequency reduction from baseline per 28 days (OR = 2.49, 95% CI: 1.25-4.96, p = 0.009) and in responder rate (OR = 1.87, 95% CI: 1.15-3.05, p = 0.01); both were considered statistically increased in PER group. Regarding adverse effects (AEs), significant differences between PER and placebo (OR = 1.47, 95% CI: 0.92-2.41, p = 0.11) were not found, and the most common AEs of PER were dizziness (24.0%), somnolence (15.9%), headache (11.2%), nasopharyngitis (9.7%), upper respiratory tract infection (7.0%) and aggression (7.0%).

CONCLUSION

Based on the results in this study, PER showed better efficacy than placebo therapy in children with epilepsy and the AEs were similar in PER group and placebo group. PER showed good efficacy and a low risk of AEs, and might be a promising medication for the treatment of pediatric epilepsy. In the future, well-designed and large-scale RCTs are necessary to validate the present findings.

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.

Efficacy, tolerability and safety of perampanel in children and adolescents with epilepsy: Systematic review and meta-analysis

OBJECTIVE

Perampanel (PER) is a novel antiepileptic drug. The efficacy, tolerability and safety of PER in children and adolescents with epilepsy are still unclear. We aimed to study the efficacy and safety of PER in children and adolescents with epilepsy.

METHODS

We searched PubMed, Embase and Cochrane Library for relevant literature up to November 2022. Then we extracted the relevant data from eligible literature for systematic review and meta-analysis.

RESULT

Twenty-one studies involving 1968 children and adolescent patients were included. A reduction in seizure frequency of at least 50 percent occurred in 51.5% (95% confidence interval [CI] [47.1%, 55.9%]) of patients. Complete seizure cessation occurred in 20.6% (95%CI [16.7%, 25.4%]). The incidence of adverse events was 40.8% (95%CI [33.8%, 48.2%]). The most common adverse events were drowsiness 15.3% (95% CI [13.7%, 16.9%]), irritability 9.3% (95%CI [8.0%, 10.6%]), dizziness 8.4% (95% CI [7.2%, 9.7%]). The incidence of drug discontinuation due to adverse events was 9.2% (95% CI [7.0%, 11.5%]).

CONCLUSION

PER is generally well tolerated and effective in the treatment of epilepsy in children and adolescents. Larger studies are still needed to explore the application of PER in children and adolescents.

RISK OF BIAS AND LIMITATION

The funnel plot suggests that there may be publication bias in our meta-analysis, and most of the included studies were Asian, so there may be some racial differences.

Bioinformatics and network pharmacology analysis of drug targets and mechanisms related to the comorbidity of epilepsy and migraine

OBJECTIVE

The present study aimed to explore the mechanisms underlying the comorbidity of epilepsy and migraine, identify potential common targets for drug intervention, and provide insight into new avenues for disease prevention and treatment using an integrated bioinformatic and network pharmacology approach.

METHODS

Disease targets in epilepsy and migraine were screened using the DisGeNET database to identify intersecting gene targets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEEG) enrichment analyses were then performed using the WebGestalt database. Furthermore, the STRING database was used to construct a protein-protein interaction (PPI) network, and Cytoscape software was used to analyze the protein molecular signals at the intersection of epilepsy and migraine. The Drugbank database was used to identify common targets for antiepileptic drugs in epilepsy and migraine to further analyze the disease-gene-target-drug interaction network. Finally, molecular docking simulations were performed to verify the hypothesis that migraine and epilepsy share common diseases and drug targets.

RESULTS

A total of 178 common targets for epilepsy and migraine were identified using the DisGeNET database, and the 24 genes most related to the diseases were screened using the Score_gda gene scoring system. GO enrichment analysis indicated that common targets were mainly enriched in biological processes and molecular functions, including membrane potential regulation, inorganic ion transmembrane transport, axonal signaling, and ion channel activity. KEGG pathway enrichment analysis indicated that the mechanism of action might be related to neuroactive ligand receptors, AGE-RAGE, cAMP, and VEGF signaling pathways. The PPI network construction and analysis results showed that the PPI grid had 23 central nodes and 24 connected edges, with an average node degree of 2.09 and an average clustering coefficient of 0.384. The 10 genes with potentially important roles in epilepsy and migraine were CACNA1A, KCNQ2, KCNA1, SCN1A, PRRT2, SCN8A, KCNQ3, SCN2A, GRIN2A, and GABRG2. Drugbank database results indicated that antiepileptic drugs, including lamotrigine, topiramate, valproic acid, carbamazepine, gabapentin, and perampanel, also had common targets with migraine. The three most important targets exhibited strong binding affinity with drugs in the molecular docking simulations.

CONCLUSION

Our systematic and comprehensive analyses of disease-gene-target-drug interaction networks identified several biological processes and molecular functions common to migraine and epilepsy, most of which were related to neuroactive ligand-receptor interactions. These data provide a new theoretical basis and reference for the clinical treatment of comorbid epilepsy and migraine and may aid in the development of novel pharmacological strategies.

Effectiveness and tolerability of adjunctive perampanel in pediatric patients (aged 4-12 years) with refractory epilepsy: An observational study

Information on the effects of perampanel in Chinese children ≤12 years of age with refractory epilepsy is limited; thus, we conducted an observational study to assess the effectiveness, safety, and tolerability of adjunctive perampanel in this pediatric population. In this study, we reviewed the medical records of pediatric patients aged 4 to 12 years with refractory epilepsy who were admitted to Children's Hospital of Soochow University and prescribed perampanel between January 2020 and January 2021. Effectiveness of perampanel was measured by 50% responder rates, seizure-freedom rates, and retention rates for up to 48 weeks. Adverse events were monitored and recorded throughout the study. A total of 34 patients (male, n = 15) who exhibited refractory epilepsy were included in this study, and 64.71% of patients had focal-onset seizures combined with generalized epilepsy. The mean (± standard deviation) age of patients was 7.21 (± 2.12) years, with a mean (± standard deviation) age at seizure onset of 4.57 (± 2.59) years. After the addition of perampanel, the 50% responder rates at 4, 8, 12, 24, 36, and 48 weeks were 37.50% (12/32), 43.75% (14/32), 53.13% (17/32), 59.38% (19/32), 59.38% (19/32), and 62.07% (18/29). Two patients withdrew from perampanel treatment due to adverse events in the first 2 weeks. Adverse events were reported by 44.12% (15/34) of patients, and the retention rates at 36 and 48 weeks were 94.12% (32/34) and 85.29% (29/34), respectively. Overall, perampanel exhibited good effectiveness, safety, and tolerability in the treatment of pediatric patients (aged 4-12 years) with refractory epilepsy. These findings suggest that personalized treatment and better baseline seizure control may increase the responder rate and retention rate of perampanel.

Psychobehavioural and Cognitive Adverse Events of Anti-Seizure Medications for the Treatment of Developmental and Epileptic Encephalopathies

The developmental and epileptic encephalopathies encompass a group of rare syndromes characterised by severe drug-resistant epilepsy with onset in childhood and significant neurodevelopmental comorbidities. The latter include intellectual disability, developmental delay, behavioural problems including attention-deficit hyperactivity disorder and autism spectrum disorder, psychiatric problems including anxiety and depression, speech impairment and sleep problems. Classical examples of developmental and epileptic encephalopathies include Dravet syndrome, Lennox-Gastaut syndrome and tuberous sclerosis complex. The mainstay of treatment is with multiple anti-seizure medications (ASMs); however, the ASMs themselves can be associated with psychobehavioural adverse events, and effects (negative or positive) on cognition and sleep. We have performed a targeted literature review of ASMs commonly used in the treatment of developmental and epileptic encephalopathies to discuss the latest evidence on their effects on behaviour, mood, cognition, sedation and sleep. The ASMs include valproate (VPA), clobazam, topiramate (TPM), cannabidiol (CBD), fenfluramine (FFA), levetiracetam (LEV), brivaracetam (BRV), zonisamide (ZNS), perampanel (PER), ethosuximide, stiripentol, lamotrigine (LTG), rufinamide, vigabatrin, lacosamide (LCM) and everolimus. Bromide, felbamate and other sodium channel ASMs are discussed briefly. Overall, the current evidence suggest that LEV, PER and to a lesser extent BRV are associated with psychobehavioural adverse events including aggressiveness and irritability; TPM and to a lesser extent ZNS are associated with language impairment and cognitive dulling/memory problems. Patients with a history of behavioural and psychiatric comorbidities may be more at risk of developing psychobehavioural adverse events. Topiramate and ZNS may be associated with negative effects in some aspects of cognition; CBD, FFA, LEV, BRV and LTG may have some positive effects, while the remaining ASMs do not appear to have a detrimental effect. All the ASMs are associated with sedation to a certain extent, which is pronounced during uptitration. Cannabidiol, PER and pregabalin may be associated with improvements in sleep, LTG is associated with insomnia, while VPA, TPM, LEV, ZNS and LCM do not appear to have detrimental effects. There was variability in the extent of evidence for each ASM: for many first-generation and some second-generation ASMs, there is scant documented evidence; however, their extensive use suggests favourable tolerability and safety (e.g. VPA); second-generation and some third-generation ASMs tend to have the most robust evidence documented over several years of use (TPM, LEV, PER, ZNS, BRV), while evidence is still being generated for newer ASMs such as CBD and FFA. Finally, we discuss how a variety of factors can affect mood, behaviour and cognition, and untangling the associations between the effects of the underlying syndrome and those of the ASMs can be challenging. In particular, there is enormous heterogeneity in cognitive, behavioural and developmental impairments that is complex and can change naturally over time; there is a lack of standardised instruments for evaluating these outcomes in developmental and epileptic encephalopathies, with a reliance on subjective evaluations by proxy (caregivers); and treatment regimes are complex involving multiple ASMs as well as other drugs.

Adjunctive perampanel therapy for patients with epileptic spasms

BACKGROUND

Perampanel is an antiepileptic drug. Some studies have documented the efficacy of perampanel in epileptic spasms. We aimed to evaluate the efficacy and safety of adjunctive perampanel therapy (PT) in patients with epileptic spasms.

METHODS

We retrospectively surveyed the efficacy and safety of adjunctive PT in 14 patients with epileptic spasms at the Saitama Children's Medical Center between June 2016 and September 2021. Seizure outcomes and safety were evaluated 12 months after commencing PT. Response to perampanel was defined as complete remission of epileptic spasms for more than 3 months.

RESULTS

The median age at onset of epileptic spasms was 0.4 years (range, 0.1-1.3 years). The etiology was structural in 11 patients, genetic in two, and unknown in one. The median age at the commencement of PT was 3.2 years (1.5-10.3 years). The initial and maintenance doses of perampanel were administered at 0.04 (range, 0.02-0.05) mg/kg/day and 0.12 (range, 0.03-0.24) mg/kg/day, respectively. Five of the 14 patients (35.7%) showed remission of epileptic spasms for more than 3 months at 12 months after PT; these patients had a structural etiology. The median duration between commencement of perampanel and spasm remission was 2 months (range, 1-6 months). No serious adverse effects occurred.

CONCLUSIONS

This is the first case series evaluating adjunctive PT for epileptic spasms. PT is worth investigating to treat epileptic spasms in patients with structural etiologies. As our study population primarily comprised children aged 2 years and older, PT may be useful for epileptic spasms beyond infancy.

Successful use of perampanel in GABRA1-related myoclonic epilepsy with photosensitivity

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Generalized epilepsies with variants in GABRA1 may be a treatment challenge when myoclonus remains drug-resistant.

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Photosensitivity may be particularly disabling and is without feature-specific treatments.

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We describe an adolescent with GABRA1 mutation and photosensitivity who improved with PER.

Pathogenic variants in gamma-aminobutyric acid type A receptor subunit alpha1 (GABRA1) is a protein coding gene that has been associated with a broad phenotypic spectrum of epilepsies. These have ranged from mild generalized forms to early-onset severe epileptic encephalopathies. Both in mild and in severe forms, tonic-clonic and myoclonic seizures with generalized spike and wave discharges and photoparoxysmal responses are common clinical manifestations. We present the case of a 14-year-old girl referred to our clinic with uncontrolled epilepsy. She was found to carry a heterozygous variant (c.335G > A) in GABRA1, already described in the literature and classified as “pathogenic” according to ACMG guidelines. The patient showed severe drug resistance with seizures often triggered by photic stimulation. The introduction of perampanel therapy led to overall reduction of the focal and generalized myoclonic seizures and complete clinical control of the light-triggered seizures.

To our knowledge this is the first report of perampanel efficacy in photosensitive epilepsy, and in particular in the presence of a GABRA1 variant. New evidence is needed to confirm our findings in this case.

Clinical spectrum of pediatric drug refractory epilepsy secondary to parieto-occipital gliosis

BACKGROUND

Parieto-occipital (PO) gliosis secondary to perinatal insult, is often associated with neurologic sequelae such as epilepsy, which can be drug resistant.

OBJECTIVE

To evaluate the spectrum of epilepsy among patients presenting with seizures in association with PO gliosis and to determine factors that influence the development of epileptic encephalopathy (EE) in these patients.

METHODS

We retrospectively evaluated patients aged < 16 years with drug refractory epilepsy and PO gliosis who underwent video electroencephalography (Video EEG). We evaluated the clinical, electrophysiological and radiological profile including treatment responsiveness of subjects with EE.

RESULTS

One hundred one patients (M: F=3:1) with mean age of onset of epilepsy at 28.9 ± 33.1 months were recruited into the study. Based on video EEG findings, Based on video EEG findings, the commonest type of focal onset ictus was tonic seizures with impaired awareness (n = 26, 29.9%). Myoclonic jerks (n = 20, 23%) were the commonest type of generalised onset seizures. Ictal onset from parieto occipital region were observed in 28 patients. Ictal onset from frontal, temporal and fronto temporal region were observed in 6 (6.8%), 7(7.9%) and 9 (8.9%) patients, respectively. Comparison of the seizure types and ictal onset among subgroups of patients with occipital gliosis, parieto-occipital gliosis and parieto-occipital with frontal gliosis revealed that the extent of gliosis did not significantly affect seizure semiology or ictal onset. EE was significantly associated with presence of neonatal seizures (p = 0.04), hypoglycaemia (p = 0.005), longer duration of ICU stay (Z score = -3.55, p < 0.001) and younger age of onset of seizures (Z score = - 2.97, p = 0.03). Eleven out of eighteen (64.7%) subjects with EE showed greater than 50% improvement in seizure frequency following three months of pulse intravenous methylprednisolone therapy.

CONCLUSIONS

Among subjects with PO gliosis on MRI, the seizure semiology is unaffected by laterality, radiologic extension beyond the occipital cortex or presence of ulegyria. Patients with PO gliosis can have florid interictal epileptiform discharges anteriorly and can have seizures with ictal onset from frontal and temporal region. Development of EE is strongly related to the age of onset of seizures, neonatal seizures, prolonged NICU admission, rather than the radiological findings. Subjects with EE and PO gliosis show good response to intravenous pulse methylprednisolone.

Utility and Safety of Perampanel in Pediatric FIRES and Other Drug-Resistant Epilepsies

Perampanel is a novel antiepileptic drug, which antagonises AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) glutamate receptor. We describe perampanel as an adjunctive treatment for FIRES (febrile infection-related epilepsy syndrome) and other drug-resistant epilepsies. A single-centre, observational, retrospective study involving 20 pediatric patients was conducted. Perampanel was started for three patients with FIRES, achieving seizure cessation in two patients within a day and on days 19 and 32 of illness. Doses used ranged from 4 to 12 mg/day, without any adverse effects reported or discontinuation of therapy. Responder-rate for other drug-resistant epilepsies is 25%. Median time to achieve ≥50% seizure reduction was 80 days (range: 26-326 days). Adverse effect reported in 47% of the patients includes central nervous system-related, and thrombocytopenia. Eight patients discontinued perampanel, because of ineffectiveness or adverse effects. The median time on perampanel before discontinuation was 179 days (range: 94-345 days). Perampanel may be of benefit in pediatrics FIRES and is of utility in other drug-resistant epilepsies.

Long-term Efficacy of Perampanel in a Child with Dravet Syndrome

Dravet syndrome is a genetic developmental and epileptic encephalopathy (DEE) mostly due to mutations in SCN1A gene. Perampanel is a selective and non-competitive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist. There is increasing experience in the use of perampanel in this syndrome; however, there is still a lack of evidence of sustained benefit years after the beginning of the treatment.

We report a twelve-year-old girl who was diagnosed with Dravet Syndrome when she was 2 years old and has been on perampanel since she was 7. Her genetic test showed a de novo previously described heterozygous SCN1A mutation in the 24th exon (c.4547C>A, p.Ser1516*). She received previous antiseizure drug combinations with little benefit. When perampanel was started, there was a complete resolution of her spontaneous seizures that has continued five years later. More studies are needed to investigate if there is an association between this excellent response and the genotype of our patient.

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.

Efficacy of oral perampanel in status epilepticus and acute repetitive seizures in children at a tertiary care hospital in Thailand

Status epilepticus (SE) and acute repetitive seizure (ARS) are emergency conditions associated with significant morbidity and mortality in children. Anti-seizure medications (ASMs) need to terminate seizures to prevent brain damage and death. Common challenges that delay the management of SE and ARS in children at Phramongkutklao hospital are difficulty in accessing intravenous route for drug administration and inadequate number of intensive care units (which will be required in case of the use of adverse events to anesthetic ASMs). Oral, non-sedating ASMs could be a potential option to terminate seizures effectively in SE and ARS in children and further studies in this aspect are needed. We performed a prospective, descriptive study in children with SE or ARS < 18 years of age who had contraindication to or their seizures were refractory to the second-line ASMs after benzodiazepine and received oral perampanel. Demographic data, efficacy, and adverse effects of treatment were recorded. Fifteen patients with SE (13.3%) and acute repetitive seizure (86.6%) were enrolled. All patients received an oral perampanel loading dose and the maintenance dose depended on their body weight. The average loading and maintenance dose were 0.24 mg/kg/dose and 0.12 mg/kg/day, respectively. At 48 h after administration of loading dose of perampanel, eight of fifteen patients (53.3%) became seizure free, one patient had seizure reduction of >75% from baseline, and three patients had seizure reduction of 25-50% from baseline. No serious side effects were observed. These results indicate that oral perampanel may be potential treatment option for SE and ARS in children.

Efficacy and tolerability of perampanel as a first add-on therapy with different anti-seizure drugs

PURPOSE

To investigate the efficacy and tolerability of perampanel (PER) when administered as a first add-on therapy to patients with focal epilepsy or idiopathic generalized epilepsy (IGE) taking one other antiseizure drug (ASD).

METHODS

This multicentre, retrospective, one-year observational study collected data from patients (≥12 years) who initiated treatment with PER as first add-on therapy. Patients had to be experiencing inadequate seizure control on ASD monotherapy and tried ≤3 ASD monotherapies before initiating PER. Multivariate logistic regression analyses were performed, adjusted for the number and type of previous seizures, duration and aetiology of epilepsy.

RESULTS

Of the 149 patients included in the study (mean age 41 years; 54.4 % male), 118 (79.2 %) were still receiving PER as first add-on treatment after 12 months. Mean PER dose was 6.2 mg/day. At 12 months, 45.6 % were seizure-free and 84.6 % responders. A significant difference in seizure freedom rate was found between patients with IGE and patients with focal epilepsy, but not in responders. Reduced seizure control was observed when PER was administered with strong enzyme-inducing ASDs; conversely, increased seizure control was seen when the same dose of PER was combined with enzyme-inhibiting ASDs. The most frequent adverse events were dizziness (15.4 %), irritability (14.1 %) and drowsiness (14.1 %); no differences in tolerance were observed among different combinations.

CONCLUSION

PER demonstrated a good efficacy and safety profile when used as a first add-on therapy in patients who did not respond to monotherapy. PER dose adjustments may optimize seizure control when combined with strong enzyme-inducing or enzyme-inhibiting ASDs.

Perampanel reduces paroxysmal depolarizing shift and inhibitory synaptic input in excitatory neurons to inhibit epileptic network oscillations

BACKGROUND AND PURPOSE

Perampanel is a newly approved anticonvulsant uniquely targeting AMPA receptors, which mediate the most abundant form of excitatory synaptic transmission in the brain. However, the network mechanism underlying the anti-epileptic effect of the AMPAergic inhibition remains to be explored.

EXPERIMENTAL APPROACH

The mechanism of perampanel action was studied with the basolateral amygdala network containing pyramidal-inhibitory neuronal resonators in seizure models of 4-aminopyridine (4-AP) and electrical kindling.

KEY RESULTS

Application of either 4-AP or electrical kindling to the basolateral amygdala readily induces AMPAergic transmission-dependent reverberating activities between pyramidal-inhibitory neuronal resonators, which are chiefly characterized by burst discharges in inhibitory neurons and corresponding recurrent inhibitory postsynaptic potentials in pyramidal neurons. Perampanel reduces post-kindling "paroxysmal depolarizing shift" especially in pyramidal neurons and, counterintuitively, eliminates burst activities in inhibitory neurons and inhibitory synaptic inputs onto excitatory pyramidal neurons to result in prevention of epileptiform discharges and seizure behaviours. Intriguingly, similar effects can be obtained with not only the AMPA receptor antagonist CNQX but also the GABA_A receptor antagonist bicuculline, which is usually considered as a proconvulsant.

CONCLUSION AND IMPLICATIONS

Ictogenesis depends on the AMPA receptor-dependent recruitment of pyramidal-inhibitory neuronal network oscillations tuned by dynamic glutamatergic and GABAergic transmission. The anticonvulsant effect of perampanel then stems from disruption of the coordinated network activities rather than simply decreased neuronal excitability or excitatory transmission. Positive or negative modulation of epileptic network reverberations may be pro-ictogenic or anti-ictogenic, respectively, constituting a more applicable rationale for the therapy against seizures.

The efficacy of perampanel as adjunctive therapy in drug-resistant focal epilepsy in a "real world" context: focus on temporal lobe epilepsy

BACKGROUND

Perampanel (PER) is a novel antiepileptic drug approved as an add-on therapy for focal onset seizures with or without generalization and primary generalized tonic-clonic seizures. Aim of this study was to evaluate PER efficacy and tolerability as add-on therapy in patients with drug-resistant focal onset seizures and especially temporal lobe epilepsy (TLE).

METHODS

An observational, prospective, multicentre study on adult with drug-resistant focal epilepsy consecutively recruited from six Italian tertiary epilepsy centres. All patients received add-on PER according to indication and clinical judgement. Seizure frequency and adverse events (AEs) were recorded at 6 and 12 months after PER introduction.

RESULTS

Study sample comprised 246 patients, 77 of which with TLE. Seventy-five (35.9%) out of 209 and 66 (38.8%) out of 170 patients still taking PER resulted to be responders (i.e. ≥50% of seizure frequency or seizure free) after six and 12 months, respectively. In the TLE group, 39 (57.3%) out of 68 subjects on PER after 6 months and 32 (60.4%) out of 53 subjects taking PER after 12 months were responders. Overall reported incidence of AEs was 26.1%. In 28 cases (11.3%) AEs lead/contributed to PER discontinuation. The most frequently reported AE were dizziness (14/84) and somnolence (14/84). Regarding TLE patients, 25.9% of them experienced at least one AE and discontinuation for AEs occurred in eight (10.4%).

CONCLUSIONS

This study confirmed the good efficacy and safety of PER for drug-resistant focal epilepsy in real-life conditions and, above all, for the first time provide its effectiveness in patients with TLE.

Assessment of the long-term efficacy and safety of adjunctive perampanel in tonic-clonic seizures: Analysis of four open-label extension studies

OBJECTIVE

This post hoc analysis evaluated long-term efficacy and safety in patients with focal to bilateral tonic-clonic seizures (FBTCS) or generalized tonic-clonic seizures (GTCS) who entered open-label extension (OLEx) studies to receive long-term adjunctive perampanel.

METHODS

Patients aged 12 years and older who completed phase II or III randomized, double-blind, placebo-controlled studies could enter an OLEx study, each comprising a blinded conversion period followed by an open-label maintenance period (32-424 weeks; maximum perampanel dose = 12 mg/d). Exposure, seizure outcomes, and treatment-emergent adverse events (TEAEs) were analyzed.

RESULTS

Baseline characteristics were generally balanced between patients with FBTCS (n = 720) and GTCS (n = 138). Mean (standard deviation) cumulative duration of perampanel exposure was 102.3 (70.3) weeks (FBTCS) and 83.9 (38.4) weeks (GTCS). Retention rates were 50.0% for up to 4 years (FBTCS) and 49.2% for up to 2 years (GTCS). Across OLEx treatment durations, median reductions in seizure frequency per 28 days were 66.7% (FBTCS) and 80.6% (GTCS). Fifty percent and 75% responder and seizure-freedom rates were 59.5%, 45.3%, and 18.4%, respectively (FBTCS), and 72.5%, 51.5%, and 16.7%, respectively (GTCS). Efficacy was sustained for up to 4 years (FBTCS) and up to 3 years (GTCS), even when accounting for early dropouts. TEAE incidence was highest during Year 1 (FBTCS, 85.3%; GTCS, 86.2%); most common were dizziness and somnolence. During Year 1, serious TEAEs were reported in 81 (11.3%; FBTCS) and 10 (7.2%; GTCS) patients. TEAEs were consistent with the known safety profile of perampanel; no new safety signals were identified with long-term treatment.

SIGNIFICANCE

This post hoc analysis suggests long-term (up to 4 years) adjunctive perampanel (up to 12 mg/d) is efficacious and well tolerated in patients (aged 12 years and older) with FBTCS or GTCS.

Neural Networks in Generalized Epilepsy and Novel Antiepileptic Drugs

BACKGROUND

In previous works, alterations of neurotransmitters and neuropeptides in the brain areas involved in generalized epilepsy have been reported.

OBJECTIVE

We reviewed the alterations of these neurotransmitters and neuropeptides in the following brain areas involved in generalized epilepsy: hippocampus, hypothalamus, thalamus and cerebral cortex. In these brain areas, the neural networks are also actualized. The mechanisms of action of newer antiepileptic drugs in the treatment of generalized epilepsy are also discussed.

RESULTS

Up-dating the neurotransmitter and neuropeptide alterations, we found that hippocampal GABAergic neurons presynaptically inhibit epileptogenic neurons via GABAB receptors. Epilepsy modulating neuropeptides (galanin, neuropeptide Y, dynorphin) are also involved. GABA deficiency, serotonin hyperactivity, dopamine hyperactivity and glutamate excitotoxicity can enhance ictogenesis: neurons containing these neurotransmitters form the main neural circuit. An increased excitability occurs when the alteration of these neurotransmitters is permanent.

CONCLUSION

In preclinical studies, the GABAB receptor agonist GS 39,783 exerted a good antiepileptic effect. Perampanel, an AMPA receptor antagonist, showed good clinical effects in the treatment of partial-onset seizures and primary generalized tonic-clonic seizures. In this treatment, perampanel can be combined with other antiepileptic drugs. Brivaracetam, which shows a high affinity for the synaptic vesicle 2A, exerted a good efficacy in the treatment of adult focal seizures and secondarily generalized tonic-clonic seizures.

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.

Successful treatment of intractable life-threatening seizures with perampanel in the first case of early myoclonic encephalopathy with a novel de novo SCN1A mutation

PURPOSE

Early myoclonic encephalopathy (EME) is a form of developmental and epileptic encephalopathy with myoclonic seizures and a suppression burst on electroencephalogram, which occurs during the neonatal or early infantile period and is characterized by highly intractable seizures and severe development impairment. Although multiple genetic aetiologies of EME have been identified, no SCN1A mutation has been reported.

METHODS

We described a female patient with EME due to an SCN1A mutation.

RESULTS

She developed frequent myoclonic and apnoeic seizures during the neonatal period. As her seizures were refractory to many antiepileptic drugs, she underwent a tracheotomy and has since been treated with continuous mechanical ventilation. Eventually, perampanel was added, which resulted in the cessation of the apnoeic seizures. Genetic analysis revealed a heterozygous de novo missense mutation in the SCN1A gene (c.2588 T > C:p.Leu863Ser).

CONCLUSION

This is the first patient with EME due to anSCN1A mutation to be successfully treated with perampanel. Recently, perampanel was reported to be effective in treating Dravet syndrome, including cases with an SCN1A mutation. Perampanel may contribute to seizure reduction in patients with intractable epilepsy carrying the SCN1A mutation.

Clinical profiles associated with serum perampanel concentrations in children with refractory epilepsy

BACKGROUND

Perampanel (PER) is a new antiepileptic drug (AED) with a novel mechanism of action. Investigations of the efficacy and safety of PER in pediatric and adult patients have increased recently. Although the clinical usefulness and pharmacokinetics of PER have been investigated in adolescent and adult populations, similar studies have not been performed in children.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of patients treated with PER for more than 6 months in the Department of Pediatrics, Hiroshima University Hospital, between September 2016 and November 2018. We obtained demographic and clinical data including age, sex, epilepsy type, seizure type, seizure frequency before and after treatment initiation, adverse events, reasons for discontinuing PER treatment, doses at evaluation points, serum concentrations, concomitant AEDs, intellectual status, and epilepsy etiology. Seizure types and epilepsy syndromes were classified according to the criteria of the International League Against Epilepsy.

RESULTS

The study included 44 patients (22 males) between the ages of 6 months and 16 years. Of those, 10 patients discontinued PER therapy. The 50% response rate was 52.3% in patients treated with PER, and four patients achieved complete seizure control. Perampanel was highly effective in patients with generalized and focal epilepsy (50% responder rates, 52.9% and 50.0%, respectively). Favorable response rates were observed for tonic-clonic, focal nonmotor, and absence seizures with 50% response rates of 54.5%, 50.0%, and 66.7%, respectively. The 50% responder rate was 31.3 for epileptic spasms (ES). Treatment-emergent adverse events (TEAEs) included somnolence (n = 8), irritability (n = 2), ataxia (n = 2), and one case each of dizziness, compulsiveness, and enuresis. Serum concentrations of PER were compared in patients taking concomitant enzyme-inducing antiepileptic drugs (EIAEDs; carbamazepine, phenytoin, and phenobarbital) and those taking concomitant non-EIAEDs. Serum PER concentrations were correlated with dose per body weight in both groups (EIAED: r = 0.765, p = 0.00000212; non-EIAED: r = 0.71, p = 0.0000158). The mean concentration-to-dose (CD) ratio was 2398.4 ng mL^-1 mg^-1 kg^-1 (range: 800-4524.7) in the non-EIAED group and 693.7 ng mL^-1 mg^-1 kg^-1 (range: 344-1309.7) in the EIAED group. Serum PER levels were lower in the EIAED group than in the non-EIAED group. All patients with serum PER concentrations above 400 ng/mL experienced somnolence.

CONCLUSIONS

Perampanel is effective against various types of seizures, including ES, in pediatric patients with refractory epilepsy. Furthermore, PER has good tolerability when the dose is adjusted based on serum concentrations. The PER CD ratio was lower in pediatric patients than in adolescents and adults; therefore, clinicians must consider the CD ratio when treating children with PER.

Efficacy and tolerability of perampanel in pediatric patients with Dravet syndrome

PURPOSE

In the present study, we aimed to investigate the efficacy and tolerability of perampanel in patients with Dravet syndrome.

METHODS

We retrospectively reviewed data regarding seizure frequency and adverse effects in 10 patients (four boys, six girls) with Dravet syndrome following treatment with perampanel. Perampanel treatment was considered effective when seizure frequency had been reduced by more than 50%.

RESULTS

The mean age of patients at perampanel introduction was 11.5 ± 2.2 years. Seizure types were as follows: generalized tonic-clonic seizure (n = 8), unilateral clonic seizure (n = 6), myoclonic seizure (n = 3), atypical absence seizure (n = 3), and focal impaired awareness seizure (n = 1). The average number of concomitant anti-epileptic drugs (AEDs) was 3 ± 0.9. The mean duration of perampanel use was 11.1 ± 3.8 months. Seizure frequency was reduced by more than 50% in five patients (50%). The efficacy of perampanel for each seizure type was as follows: generalized tonic-clonic seizure: 50% (4/8), unilateral clonic seizure: 50% (3/6), myoclonic seizure: 33% (1/3), atypical absence seizure: 33% (1/3), and focal impaired awareness seizure: 100% (1/1). The effects of perampanel in each patient occurred between 3 and 6 months following the initiation of treatment. Seizure reduction was observed beginning at perampanel doses of 0.1 ± 0.07 mg/kg/day. Adverse events were observed in seven of 10 patients. Although somnolence was noted in 50% of patients, most events were mild.

CONCLUSIONS

The results of this retrospective observational study indicate that perampanel treatment may be promising in some patients with Dravet syndrome. Additional studies are necessary to verify the actual efficacy of perampanel for Dravet syndrome.

An Evidence-Based Review On The Use Of Perampanel For The Treatment Of Focal-Onset Seizures In Pediatric Patients

Perampanel, a non-competitive AMPA receptor antagonist, is a once-daily oral antiepileptic drug approved for the treatment of focal seizures and primary generalized tonic-clonic seizures in children 12 years of age and over. We conducted a systematic review of the data on perampanel in children and adolescents with focal-onset seizures. We found 21 published papers on the pediatric use of perampanel for focal-onset seizures, including 9 papers on clinical trials and ancillary studies of these trials, of which 2 focused on pharmacokinetics, 1 was a meta-analysis, and 9 were real-life studies (1 was prospective). Perampanel, as an adjunctive treatment for uncontrolled focal-onset seizures, results in an improvement of seizure control with a generally good safety profile. Evidence-based data are currently available for children 12 years of age and over. Higher amounts of perampanel might be required in patients taking enzyme-inducing antiepileptic drugs. The most common adverse events are somnolence, dizziness and behavioral adverse events. The latter seems more frequent in adolescents than in adults and in adolescents with preexisting behavioral comorbidities. Current studies did not identify any short-term impact of perampanel on cognitive functions. Its long half-life allows once-daily administration. Real-life studies further established that a decrease of the dose frequently resolves adverse events, as demonstrated in pivotal studies. Pharmacokinetic and safety studies are still ongoing in the younger population, down to 4 years of age, in order to apply for approval in this age group.

Clinical Experience with Perampanel in Intractable Focal Epilepsy Over 12 Months of Follow-Up

Background and Purpose

There are only limited studies on perampanel (PER), one of the latest antiepileptic drug. This study aimed to evaluate the long-term efficacy and tolerability of perampanel as an add-on therapy in patients with intractable focal epilepsy.

Methods

The medical records of 97 patients (age, 12-30 years) were retrospectively reviewed and analyzed. The patients had been diagnosed with focal epilepsy, treated with PER, and regularly followed up over 12 months.

Results

All patients had uncontrolled seizures despite treatment with two or more antiepileptic drugs. The mean age of seizure onset was 5.2 years (range, 0-17.0). PER was first prescribed at an average age of 15.7 years (range, 12.0-25.3), and mean follow-up duration after PER initiation was 15.9 months (range, 12-20). The responder rate was 41.7%, with over 75% seizure reduction obtained in 11 cases (15.3%), including three seizure-free cases (4.2%). The retention rates at 3, 6, 12, and 18 months of follow-up were 82.5% (80/97), 72.1% (70/97), 60.8% (59/97), and 37.5% (6/16), respectively. Forty-four patients (44/97, 45.4%) discontinued PER, because of treatment-related adverse events in 20 (20.6%) and no efficacy in 24 (24.7%). Treatment-related adverse events were reported by 52 patients (53.6%). The most common adverse event was somnolence or lethargy, reported by 17 patients (17/97, 23%), followed by dizziness (15/97, 20%) and psychological problems such as aggressiveness or irritability (15/97, 20%). Thirty-three patients (33/52, 63.4%) showed their first adverse symptom for 2 or 4 mg/day of PER.

Conclusions

PER would be an effective therapeutic option for patients with intractable focal epilepsy. However, careful monitoring of adverse events is essential from treatment initiation, with particular attention to psychological problems in adolescents and young adults.

Efficacy and tolerability of adjunctive perampanel treatment in children under 12 years of age with refractory epilepsy

Purpose

There is limited data on the use of perampanel in children under 12 years of age. We evaluated the efficacy and tolerability of adjunctive perampanel treatment in children under 12 years of age with refractory epilepsy.

Methods

This retrospective observational study was performed in Kyungpook National University Hospital from July 2016 to March 2018. A responder was defined as a patient with ≥50% reduction in monthly seizure frequency compared with the baseline. Adverse events and discontinuation data were obtained to evaluate tolerability.

Results

Twenty-two patients (8 males, 14 females) aged 3.1–11.4 years (mean, 8.0±2.5 years) were included in this study. After an average of 9.2 months (range, 0.5–19 months) of follow-up, 15 patients (68%) showed a reduction in seizure frequency, including 5 patients (23%) with seizure freedom. The age at epilepsy onset was significantly lower (P=0.048), and the duration of epilepsy was significantly longer (P=0.019) in responders than in nonresponders. Nine patients (41%) experienced adverse events, including somnolence (23%), respiratory depression (9%), violence (4.5%), and seizure aggravation (4.5%). The most serious adverse event was respiratory depression, which required mechanical ventilation in 2 patients (9%). Eight patients (36%) discontinued perampanel due to lack of efficacy or adverse events. Three out of 4 patients (75%) who discontinued perampanel due to adverse events had an underlying medical condition.

Conclusion

Perampanel offers a treatment option for refractory epilepsy in children. Adjunctive treatment with perampanel requires special consideration in those with underlying medical conditions to prevent serious adverse events.

Pharmacokinetic and pharmacodynamic considerations for the clinical efficacy of perampanel in focal onset seizures

INTRODUCTION

Medical therapy is the mainstay of management of epilepsy. Despite the increasing number of available antiepileptic drugs (AEDs), approximately one-third of epileptic patients do not have adequate control of seizures. There is still a need for the development of new AEDs with enhanced effectiveness and tolerability. Areas covered: The present manuscript is based on an Internet and PubMed search (January 2005 to August 2018). It is focused on pharmacokinetic and clinical data of perampanel (PER) for the treatment of epilepsy. Expert opinion: PER has a novel mechanism of action, which opens up new options for a rational combination therapy. Phase III trials have demonstrated the efficacy and safety of PER as adjunctive therapy for the treatment of partial-onset seizures (POS) and primary generalized tonic-clonic seizures in patients aged ≥12 years. PER is also approved by FDA as monotherapy for the treatment of POS. A clinical trial is ongoing to verify the efficacy and safety of PER monotherapy in untreated patients with POS. In the future, head-to-head comparisons are needed to determine the exact position of PER relative to other AEDs. Moreover, further studies are needed to evaluate the efficacy and safety of PER in patients aged <12 years.

ABBREVIATIONS

4βOHC: 4β-hydroxycholesterol; AUC: area under the curve; CBZ: Carbamazepine; CLCr: creatinine clearance; Cmax: maximum plasma concentration; CYP: cytochrome P; EIAED: enzyme-inducing antiepileptic drug; EMA: European Medicines Agency; FDA: Food and Drug Administration; GI: gastrointestinal; OXC: oxcarbazepine; PER: perampanel; PGTC: primary generalized tonic-clonic; PHT: phenytoin; POS: partial-onset seizures; QD: once-daily; TEAE: treatment-emergent adverse event; Tmax: median time to reach peak concentration; UGT: uridine diphosphoglucose-glucuronosyltransferase; VPA: valproic acid.

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.

Pharmacokinetics and Drug Interaction of Antiepileptic Drugs in Children and Adolescents

Selecting the most appropriate antiepileptic drug (AED) or combination of drugs for each patient and identifying the most suitable therapeutic regimen for their needs is increasingly challenging, especially among pediatric populations. In fact, the pharmacokinetics of several drugs vary widely in children with epilepsy because of age-related factors, which can influence the absorption, distribution, metabolism, and elimination of the pharmacological agent. In addition, individual factors, such as seizure type, associated comorbidities, individual pharmacokinetics, and potential drug interactions, may contribute to large fluctuations in serum drug concentrations and, therefore, clinical response. Therapeutic drug concentration monitoring (TDM) is an essential tool to deal with this complexity, enabling the definition of individual therapeutic concentrations and adaptive control of dosing to minimize drug interactions and prevent loss of efficacy or toxicity. Moreover, pharmacokinetic/pharmacodynamic modelling integrated with dashboard systems have recently been tested in antiepileptic therapy, although more clinical trials are required to support their use in clinical practice. We review the mechanism of action, pharmacokinetics, drug-drug interactions, and safety/tolerability profiles of the main AEDs currently used in children and adolescents, paying particular regard to issues of relevance when treating this patient population. Indications for TDM are provided for each AED as useful support to the clinical management of pediatric patients with epilepsy by optimizing pharmacological therapy.

Safety and tolerability profile of new antiepileptic drug treatment in children with epilepsy

INTRODUCTION

Treatment of pediatric epilepsy requires a careful evaluation of the safety and tolerability profile of antiepileptic drugs (AEDs) to avoid or minimize as much as possible adverse events (AEs) on various organs, hematological parameters, and growth, pubertal, motor, cognitive and behavioral development.

AREAS COVERED

Treatment-emergent AEs (TEAEs) reported in the literature 2000-2018 regarding second- and third-generation AEDs used in the pediatric age, with exclusion of the neonatal period that exhibits specific peculiarities, have been described on the basis of their frequency, severity/tolerability, and particular association with a given AED.

EXPERT OPINION

Somnolence/sedation and behavioral changes, like irritability and nervousness, are among the most commonly observed TEAEs associated with almost all AEDs. Lamotrigine, Gabapentin, Oxcarbazepine, and Levetiracetam appear to be the best-tolerated AEDs with a ≤2% withdrawal rate, while Tiagabine and Everolimus are discontinued in up to >20% of the patients because of intolerable TEAEs. For some AEDs, literature data are scanty to draw a high-level evidence on their safety and tolerability profile. The reasons are: insufficient population size, short duration of treatments, or lack of controlled trials. A future goal is that of identifying clearer, easier, and more homogeneous methodological strategies to facilitate AED testing in pediatric populations.

Efficacy and tolerability of perampanel in children and adolescents with pharmacoresistant epilepsy: The first real-world evaluation in Asian pediatric neurology clinics

AIM

This study investigated the efficacy and safety of perampanel (PER) adjunctive therapy in pediatric patients with epilepsy whose seizures are pharmacoresistant to existing antiepileptic drugs.

METHODS

A clinical retrospective study was conducted from 2016 to 2017 in the pediatric neurology clinic at a tertiary children's hospital. We reviewed the data obtained from 66 children whose seizures were pharmacoresistant to more than two antiepileptic drugs, and could be followed up for a minimum of 3 months after PER adjunctive therapy initiation. The efficacy was estimated by the PER response rate at 3-, 6-, and 12-month follow-up evaluations, and adverse events were also recorded.

RESULTS

The rate of seizure reduction of >50% was 30.3%, 37.5%, and 34.7% for all seizure types at 3, 6, and 12 months, in which 7.6%, 8.9%, and 14.3% of the patients became seizure-free at these time points, respectively. No significant differences were found between enzyme-inducing and nonenzyme-inducing antiepileptic drugs in combination with PER with regard to the responder rate. Five patients with Dravet syndrome were included in the study. Four of them (80%) exhibited 50% seizure reduction at the last visit, at which point, two patients (40.0%) were seizure-free. The retention rate was 51% at 12 months. Adverse events were documented in 25 patients (35.7%) and led to PER discontinuation in eight patients (12.1%). The most common adverse events comprised irritability, skin rash, dizziness, and somnolence; however, all were transient and successfully managed after PER dose reduction or discontinuation.

CONCLUSION

The current data support the value of adjunctive PER in child and adolescent patients with pharmacoresistant epilepsy in daily clinical practice. Perampanel was efficacious and generally well-tolerated as an add-on treatment for epilepsy.

Perampanel: Does it have broad-spectrum potential?

This article reviews the profile of perampanel, a novel noncompetitive α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptor antagonist, and its role as a potential broad-spectrum antiepileptic drug in the treatment of epilepsy. For this narrative review, data were collected using specified search criteria. Articles reporting the evidence for perampanel's efficacy from preclinical models, phase 3 clinical studies, observational studies, and descriptive evidence were included. AMPA receptors play a key role in mediating the action of glutamate at the excitatory synapse. Preclinical research showed the AMPA receptor blockade to constitute a promising target for antiepileptic drug therapy. In animal models, perampanel proved to be protective against seizures and reduce seizure severity and duration. Four phase-3 randomized controlled trials (3 in patients with focal seizures and one in primary generalized tonic-clonic seizures in idiopathic generalized epilepsy) have been completed. In focal (partial) onset seizures, perampanel (4, 8, and 12 mg) significantly reduced seizure frequency per 28 days (23.3%-28.8% vs 12.8%; P < .01) and responder rates (≥50% reduction in seizures) (28.5%-35.3% vs 19.3%; P < .05) compared with placebo. In primary generalized tonic-clonic seizures, perampanel 8 mg resulted in greater reduction in seizure frequency per 28 days (-76.5% vs -38.4%; P < .0001) and responder rate (64.2% vs 39.5%; P = .0019) than placebo. The efficacy, safety, and tolerability of perampanel have been reproduced in real-world clinical practice, and the agent has been shown to be effective in other epilepsy syndromes. Perampanel is a potentially broad-spectrum antiepileptic drug with a novel mechanism of action that may be a useful addition for patients with epilepsy with various seizure types. The availability of novel antiepileptic drugs for epilepsy treatment enables more individualized treatment for these patients.

The Challenge of Pharmacotherapy in Children and Adolescents with Epilepsy-ADHD Comorbidity

Epilepsy is common in children and adolescents where its prevalence is 3.2-5.5/1000. About one-third of patients also have attention deficit hyperactivity/impulsivity disorder (ADHD). The possible relationship between epilepsy and ADHD is still unclear, and ADHD symptoms (such as inattention, hyperactivity, behavioral disturbances) are frequently considered as adverse effects of antiepileptic drugs (AEDs). The literature was searched for data on the behavioral effects of AEDs. Phenobarbital is the most frequently reported medication to induce symptoms of ADHD, followed by topiramate and valproic acid. Phenytoin seems to exert modest effects, while for levetiracetam there are contrasting data. Lacosamide induces some beneficial effects on behavior; carbamazepine and lamotrigine exert favorable effects on attention and behavior. Gabapentin and vigabatrin have limited adverse effects on cognition. Oxcarbazepine, rufinamide, and eslicarbazepine do not seem to aggravate or induce ADHD symptoms, whereas perampanel can lead to a high incidence of hostile/aggressive behavior, which increases with higher dosages. Information about the behavioral effects of ethosuximide, zonisamide, tiagabine, pregabalin, stiripentol, and retigabine is still limited. Because ADHD significantly affects the quality of life of epilepsy patients, the clinical management of this neuropsychiatric disorder should be a priority. Methylphenidate is effective most children and adolescents with ADHD symptoms and comorbid epilepsy, without a significant increase of seizure risk, although data are still limited with few controlled trials.

Benign and severe early-life seizures: a round in the first year of life

BACKGROUND

At the onset, differentiation between abnormal non-epileptic movements, and epileptic seizures presenting in early life is difficult as is clinical diagnosis and prognostic evaluation of the various seizure disorders presenting at this age. Seizures starting in the first year of life including the neonatal period might have a favorable course, such as in infants presenting with benign familial neonatal epilepsy, febrile seizures simplex or acute symptomatic seizures. However, in some cases, the onset of seizures at birth or in the first months of life have a dramatic evolution with severe cerebral impairment. Seizure disorders starting in early life include the "epileptic encephalopathies", a group of conditions characterized by drug resistant seizures, delayed developmental skills, and intellective disability. This group of disorders includes early infantile epileptic encephalopathy also known as Ohtahara syndrome, early myoclonic encephalopathy, epilepsy of infancy with migrating focal seizures, infantile spasms syndrome (also known as West syndrome), severe myoclonic epilepsy in infancy (also known as Dravet syndrome) and, myoclonic encephalopathies in non-progressive disorder. Here we report on seizures manifesting in the first year of life including the neonatal period. Conditions with a benign course, and those with severe evolution are presented. At this early age, clinical identification of seizures, distinction of each of these disorders, type of treatment and prognosis is particularly challenging. The aim of this report is to present the clinical manifestations of each of these disorders and provide an updated review of the conditions associated with seizures in the first year of life.

Perampanel, an AMPA receptor antagonist: From clinical research to practice in clinical settings

Epileptic seizures are refractory to treatment in approximately one-third of patients despite the recent introduction of many newer antiepileptic drugs (AEDs). Development of novel AEDs therefore remains a high priority. Perampanel is a first-in-class non-competitive selective AMPA receptor antagonist with a unique mechanism of action. Clinical efficacy and safety of perampanel as adjunctive treatment for focal seizures with/without secondary generalization (±SG) and primary generalized tonic-clonic (PGTC) seizures have been established in five phase 3 randomized controlled trials (RCTs), and a long-term extension study, and perampanel is approved as monotherapy for focal seizures ±SG in the USA. In patients with focal seizures ±SG, add-on perampanel resulted in median percent reduction in seizure frequency 23.3%-34.5% and ≥50% responder rate 28.5%-37.6%; in PGTC seizures, these results were 76.5% and 64.2%, respectively. Efficacy among adolescents (reduction in seizure frequency 34.8%-35.6%; ≥50% responder rate 40.9%-45.0%) and elderly people (reduction in seizure frequency 12.5%-16.9%; ≥50% responder rate 22.2%-42.9%) is similar to those in adults, and results remain comparable between Asian (reduction in seizure frequency 17.3%-38.0%) and global populations. Perampanel has been extensively studied in real-world clinical practice, with similar efficacy and safety results to the RCTs (≥50% responder rate 12.8%-75.0%; adverse events of somnolence/sedation, dizziness, ataxia, and behavioral changes). Real-world observational studies suggest that perampanel tolerability can be improved by slow titration (2 mg every 2-4 weeks), and bedtime administration can mitigate somnolence and dizziness. Counseling about the potential for behavioral changes and close monitoring are recommended.

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 effectiveness and safety of lacosamide in children with epilepsy in a clinical practice setting

BACKGROUND

Seizures in up to 30% of children with epilepsy become refractory to treatment, decreasing their quality of life. Studies suggest that lacosamide may be effective in pediatric patients with refractory epilepsy.

AIMS

To assess the effectiveness and safety of lacosamide in a population of children with mostly focal refractory epilepsy.

METHODS

Retrospective analysis of children aged <18years presenting to a single hospital in Spain. Data from baseline, and 3, 6, and 12months after lacosamide initiation were collected and analyzed. Response to lacosamide was categorized by seizure frequency (seizure freedom or ≥75%, ≥50%, and <50% reduction in seizures).

RESULTS

One hundred ninety-one pediatric patients (~55% male) with focal epilepsy treated with lacosamide were included. The mean age at lacosamide initiation was 9.4years, and the mean duration of epilepsy was 5.4years. Seizure-free rates at 3, 6, and 12months were 9.7%, 11.8%, and 16.0%. At 12months, 44.4% of the population had a ≥50% reduction in seizure frequency. When analyzing response according to the number of previous/concomitant AEDs, those patients who received ≤2 previous AEDs/fewer concomitant AEDs had significantly greater response rates than those who received greater numbers of previous/concomitant AEDs; however, no predictive factors for response were identified. The most common adverse events were seizure number increased (14.7%), diplopia (5.2%), dizziness (3.7%), ataxia (2.1%), and drowsiness (2.1%).

CONCLUSIONS

Lacosamide use in children with refractory focal epilepsy can result in a reduction in seizure rate that improves progressively over time with few adverse effects, making lacosamide a promising option in these patients.

Adverse Events During Perampanel Adjunctive Therapy in Intractable Epilepsy

Background and Purpose

Perampanel is the first α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)-receptor antagonist developed to treat epilepsy. The effects of either rapid or slow dose titration on adverse events remain to be elucidated.

Methods

Eighty-five patients received perampanel between March 2016 and August 2016. Patients were divided into two groups according to their dosing schedule: rapid dose titration (2-mg increments at intervals of 1 to 2 weeks) and slow dose titration (2-mg increments at intervals of at least 3 weeks). Seizure frequency and adverse events were analyzed over 3 months.

Results

Adverse events were reported by 47 (58%) of the 81 patients analyzed, with 12 (15%) patients discontinuing perampanel due to adverse events. Common adverse events included dizziness (n=30, 37%), aggressive mood and behavior (n=19, 24%), gait disturbance (n=16, 20%), and sleep problems (n=10, 12.4%). The overall adverse events were similar in the slow-titration group (38 of 61 patients) and the rapid-titration group (8 of 20 patients, p=0.081). However, none of the 20 patients in the slow-titration group experienced gait disturbance, compared with 16 of the 61 patients in the rapid-titration group (p=0.009), while appetite change was experienced by 4 patients in the slow-titration group but only 1 in the rapid-titration group (p=0.003). No relationship was noted between adverse events and the maximum dose of perampanel (p=0.116). Sex differences were observed, with the response to perampanel being better and the rate of adverse events being higher in females (p=0.015 and p=0.046, respectively).

Conclusions

Slow titration of perampanel may reduce perampanel-related adverse events.

Simple and rapid validated HPLC-fluorescence determination of perampanel in the plasma of patients with epilepsy

We present a simple and fast high-performance liquid chromatography method with fluorescence detection for the determination of the antiepileptic drug perampanel in human plasma. The chromatographic separation was performed on a Kinetex PFP (100 × 2.6 mm, 4.6 µm) column, using a mobile phase of sodium acetate 0.03 M pH 3.7 and acetonitrile (40/60, v/v), at a flow rate of 0.8 mL/min. Total chromatography time for each run was 5 min. Sample preparation (250 µL) involved only one simple precipitation step by acetonitrile spiked with mirtazapine as internal standard. The method was validated over a concentration range of 20-1000 ng/mL and successfully applied to measure perampanel concentrations in plasma samples obtained from patients with epilepsy. This assay combines the high specificity of fluorescence detection with a very simple and fast sample pretreatment and can offer real advantages over existing methods in terms of simplicity and transferability to a therapeutic drug monitoring setting.

Cognitive and Behavioral Comorbidities: An Unwanted Effect of Antiepileptic Drugs in Children

Epilepsy is one of the most common neurological disorders and, despite optimally chosen and dosed antiepileptic drugs (AEDs), approximately 20%-30% of patients will continue to have seizures. Behavior and cognition are negatively impacted by seizures, but AEDs are also a major contributor to behavioral and cognitive deficits. However, the cognitive and behavioral effect of AEDs in children is insufficiently emphasized in the literature. This review summarizes the cognitive and behavioral effects of AEDs in the pediatric population with the objective of helping pediatricians and pediatric neurologists to select the AEDs with the best profile for their individual patient's needs.

AMPA receptors and perampanel behind selected epilepsies: current evidence and future perspectives

INTRODUCTION

The alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors are the major mediators of glutamate-mediated excitatory neurotransmission, and are critical for synchronization and spread of epileptic activity. Areas covered: AMPA receptor antagonists have been also developed as antiepileptic drugs and perampanel (PER) is the first highly selective, non-competitive AMPA-type glutamate receptor antagonist that is available on the market. It is approved as adjunctive therapy for the treatment of partial-onset seizures with or without secondary generalization, and for primary generalized tonic-clonic seizures in idiopathic generalized epilepsy, in patients aged ≥ 12 years. This article reviews the role of AMPA receptors in the neuronal hyperexcitability underlying epilepsy, the mechanism of action and clinical experience on the anti-seizure activity of PER. Moreover, the rationale for targeting AMPA receptor in specific epileptic disorders, including brain tumor-related epilepsy, mesial temporal lobe epilepsy with/without hippocampal sclerosis, and status epilepticus is evaluated. Finally, the pharmacological rationale for the development of AMPA receptor antagonists in other neurological disorders beyond epilepsy is considered. Expert opinion: Further research aimed at better understanding the pharmacology and blocking mechanism of PER and other AMPA receptor antagonists will drive future development of therapeutic agents that target epilepsy and other neurological diseases.