Perampanel for epilepsy with partial-onset seizures: a pharmacokinetic and pharmacodynamic evaluation

Efficacy and safety of perampanel as the first add-on therapy for children with epilepsy: A real-world multicenter prospective observational study

OBJECTIVE

Perampanel (PER) is a new anti-seizure medication (ASM) with a novel mechanism of action. This study aimed to determine the efficacy and safety of PER when added to monotherapy in children and adolescents (age, 4-18 years) with epilepsy.

METHOD

A multicenter prospective observational study was performed on children and adolescents (age, 4-18 years) with epilepsy who did not respond to ASM monotherapy between July 2021 and October 2022. PER was used as the first add-on therapy for the enrolled patients. Seizure-free rate, response rate, inefficacy rate, and drug retention rate were the main observation indicators during the 6 months of treatment. The patients were grouped based on treatment efficacy, and factors affecting efficacy were statistically analyzed. Adverse reactions were also recorded.

RESULTS

In this study, 93 patients with epilepsy were enrolled; among them, 9 patients were lost to follow-up (attrition rate, 9.7 %), and 84 were included in the analysis. Five patients with unknown efficacy discontinued taking PER early due to intolerable adverse reactions, and 79 patients (48 males, 31 females; mean age, 11.0 ± 3.9 years) finally remained. Genetic epilepsy and structural epilepsy were found in 22 patients and 36 patients, respectively. The mean duration of epilepsy history at the time of PER initiation was 4.0 ± 3.8 years, and the mean maintenance dosage of add-on PER was 4.5 ± 1.8 mg/day (equivalent to 0.14 ± 0.07 mg/kg/day). Among the 79 patients, 28 patients were diagnosed with epilepsy syndrome, including 13 patients having self-limited epilepsy with centrotemporal spikes, among whom 9 patients were seizure-free after adding PER during the 6-month follow-up (seizure-free rate, 69.2 %). For these 79 patients, the seizure-free, response, and retention rates at the end of follow-up were 45.6 %, 74.7 %, and 82.1 %, respectively. Among the 84 patients included in the analyses, adverse reactions occurred in 20 patients, mainly dizziness (8 patients), somnolence (6 patients), and irritability (4 patients), and 4 patients developed two adverse reactions simultaneously. Univariate analyses revealed statistically significant differences in efficacy between groups with structural and non-structural epilepsy and between groups with different baseline concomitant ASMs, suggesting that these factors affected the efficacy of PER as the first add-on therapy.

CONCLUSION

The overall response rate of PER as the first add-on therapy for children and adolescents with epilepsy who were followed up for 6 months was 74.7 %, indicating a relatively favorable safety and tolerability profile. The group of the baseline concomitant ASM administered and the etiological classification of epilepsy as either structural or non-structural were the factors influencing the efficacy of PER as the first add-on therapy.

Efficacy and safety of Perampanel in the treatment of post stroke epilepsy: A multicenter, real-world study

Background

Since 2019, Perampanel (PER) has been endorsed in China as an adjunctive treatment for focal seizures, both with and without impaired awareness, and for the transition from focal to bilateral tonic-clonic seizures. Limited research exists regarding the efficacy of PER in treating post-stroke epilepsy (PSE) in China. Empirical studies are essential to guide treatment protocols. We conducted a retrospective study to assess the efficacy and tolerability of PER in 58 PSE patients treated between October 2019 and July 2023.

Method

This study encompassed 58 patients with PSE, treated with PER either as monotherapy or as part of adjunctive therapy, and underwent follow-up for a minimum duration of 6 months. The study assessed changes in seizure frequency, adverse events (AEs), drug retention rate, maintenance dose, and adverse reactions following PER treatment.

Results

The study included 58 PSE patients, with 60.3% males and 39.7% females, ranging in age from 18 to 89, mostly within the 61-70 age group. Ischemic strokes constituted 58.6% of cases, while hemorrhagic strokes accounted for 41.4%. Focal seizures, either with or without impaired awareness, were noted in 62.1% of patients, and a transition from focal to bilateral tonic-clonic seizures was seen in 32.8%. The retention rates for PER at 3 and 6 months stood at 94.8% and 84.5% respectively, and the most commonly administered maintenance dose was 4 mg/day (41.28%). In the adjunctive therapy group, efficacy rates were 66.7% at 3 months and 78.6% at 6 months, compared to 80.0% at 3 months and 85.7% at 6 months in the monotherapy group. In the efficacy analysis, with a criterion of ≥50% reduction in seizure frequency, the overall efficacy rates at 3 and 6 months were 69.1% and 79.6%, respectively. Adverse reactions occurred in 46.6% of patients, primarily involving irritability and somnolence (both 27.6%), with no marked difference in incidence between the adjunctive and monotherapy groups (P > 0.05).

Conclusion

PER exhibits favorable efficacy and tolerability in Chinese PSE patients, possibly at lower doses.

Role of Perampanel in the Management of Pediatric Epilepsies in Asia: Expert Opinion

Management of pediatric epilepsies poses unique challenges around diagnosis, treatment options, comorbidities, and the potential for these factors to interact with processes in the developing brain. In pediatric patients, broad-spectrum antiseizure medications (ASMs) with minimal potential for adverse events (AEs) and limited impact on cognition and behavior are preferred. Perampanel is a first-in-class ASM with broad-spectrum efficacy, a tolerable safety profile, minimal negative impact on cognitive function, and other features that make it a viable treatment option in this patient population. However, evidence and experience of its use in pediatric patients are less extensive than in adult patients. Experts in pediatric epilepsy across the region convened at a series of meetings to discuss the use of perampanel in pediatric patients, including dose optimization, AE prevention and management, and considerations in particular groups. This article summarizes key evidence for perampanel in the pediatric population and consolidates the experts' recommendations for using the ASM in managing pediatric epilepsies.

Intrinsic brain activity differences in perampanel-responsive and non-responsive drug-resistant epilepsy patients: an EEG microstate analysis

Background

Drug-resistant epilepsy (DRE) patients exhibit aberrant large-scale brain networks. Perampanel may be a therapeutic option for controlling seizures in these patients.

Objective

We aim to explore the differences of resting-state electroencephalogram (EEG) microstate in perampanel-responsive and non-responsive DRE patients.

Design

Retrospective study.

Methods

Clinical data were collected from DRE patients who received perampanel treatment at the Fujian Medical University Union Hospital from June 2020 to September 2021, with a minimum follow-up of 6 months. Patients were classified into three groups based on the extent of reduction in seizure frequency: non-responsive (seizure reduction <50%), responsive (seizure reduction >50% but not seizure-free), and seizure-free. Resting-state EEG data sets of all participants were subjected to EEG microstate analysis. The study comprehensively compared the mean duration, frequency per second, and temporal coverage of each microstate among the three groups.

Results

A total of 76 perampanel-treated DRE patients were categorized into three groups based on their response to treatment: non-responsive (n = 20), responsive (n = 36), and seizure-free (n = 20), according to the degree of seizure frequency reduction. The results of EEG microstate analysis revealed no statistically significant distinctions in frequency, duration, and coverage of microstate D in these DRE patients. However, the seizure-free group showed significantly increased duration and coverage of microstate A, frequency and coverage of microstate B, and significantly decreased duration, frequency, and coverage of microstate C when compared with the other groups.

Conclusion

Microstate A, B, and D is associated with the sensorimotor network, visual network, salience network, and attention network, respectively. This study demonstrates statistically significant differences in the sensorimotor, visual, and salience networks, but not in the attention network, between perampanel-responsive and non-responsive DRE patients.

Optimal Use of Perampanel in Elderly Asian Patients with Epilepsy: Expert Opinion

Managing epilepsy in the elderly remains complicated largely due to factors related to aging. In this population, management practices are increasingly shifting towards the use of newer-generation anti-seizure medications (ASMs) as they are generally associated with better tolerability and safety profiles than older ones. Perampanel is a new ASM with broad-spectrum efficacy and a favorable safety profile. However, because of the lack of information and experience in its use, the prescription of perampanel has not been optimized in the elderly in the real-world setting in Asia. A group of epilepsy experts across the region convened at a series of virtual meetings to share their experience and discuss recommendations on perampanel use in elderly patients, including dose optimization, considerations with treatment initiation, and strategies to manage adverse events and maximize tolerability. This article summarizes key clinical and real-world evidence for perampanel in the elderly and consolidates the experts’ opinions on optimizing perampanel use in elderly Asian patients with epilepsy, providing practical guidance for clinicians to address challenges related to treatment initiation and tolerance.

Intravenous Perampanel as an Interchangeable Alternative to Oral Perampanel: A Randomized, Crossover, Phase I Pharmacokinetic and Safety Study

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

Study of the metabolic stability profiles of perampanel, rufinamide and stiripentol and prediction of drug interactions using HepaRG cells as an in vitro human model

New-generation antiepileptic drugs as perampanel, rufinamide and stiripentol emerged as alternatives in chronic epilepsy polytherapy. Hence, their metabolic stability and potential involvement in relevant drug-drug interactions (DDI) are of great clinical interest, being HepaRG cells herein used as an in vitro human model. To characterize their metabolic stability profiles, HepaRG cells were incubated with perampanel (1 μM), rufinamide (100 μM) or stiripentol (5 μM) for 12-h. HepaRG cells, pretreated with known CYP450 isoenzymes inducers (rifampicin, phenytoin, phenobarbital, omeprazole and carbamazepine), were also incubated with perampanel, rufinamide or stiripentol to assess possible DDI mediated by CYP induction. Results suggest a considerable decrease in perampanel and stiripentol concentrations over 12-h; contrary, rufinamide concentrations did not variated. Cells pretreatment with all inducers significantly decreased stiripentol concentrations (between 20.3% and 31.9%), suggesting a considerable potential for DDI. Rufinamide concentrations only decreased when preincubated with rifampicin and with the highest tested concentrations of the remaining inducers. Perampanel levels decreased with rifampicin, carbamazepine and phenobarbital, supporting the involvement of CYP3A4-mediated metabolism. Besides relevant information concerning the metabolic stability profile and potential DDIs of the new antiepileptics here studied, it was also reinforced the HepaRG cells suitability as a reliable in vitro model to foresee in vivo metabolism in humans.

Pharmacokinetic considerations for anti-epileptic drugs in children

INTRODUCTION

Epilepsy is a chronic and debilitating neurological disease, with a peak of incidence in the first years of life. Today, the vast armamentarium of antiepileptic drugs (AEDs) available make even more challenging to select the most appropriate AED and establish the most effective dosing regimen. In fact, AEDs pharmacokinetics is under the influence of important age-related factors which cannot be ignored. Areas covered: Physiological changes occurring during development age (different body composition, immature metabolic patterns, reduced renal activity) can significantly modify the pharmacokinetic profile of AEDs (adsorption, volume of distribution, half-life, clearance), leading to an altered treatment response. We reviewed the main pharmacokinetic characteristics of AEDs used in children, focusing on age-related factors which are of relevance when treating this patient population. Expert opinion: To deal with this pharmacokinetic variability, physicians have at their disposal two tools: 1) therapeutic drug concentration monitoring, which may help to set the optimal therapeutic regimen for each patient and to monitor eventual fluctuation, and 2) the use of extended-release drug formulations, when available. In the next future, the development of 'ad-hoc' electronic dashboard systems will represent relevant decision-support tools making the AED therapy even more individualized and precise, especially in children.

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.

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.

[Perampanel in the treatment of patients with epilepsy]

Development of new antiepileptic drugs (AED) does not stop due to the fact that the number of patients with pharmacoresistant epilepsy remains at about 30%. One of the newest AEDs is perampanel (PER), a selective, non-competitive AMPA receptor antagonist to target post-synaptic glutamate transmission. PER is approved in the Russian Federation as adjunctive treatment for focal seizures with or without secondarily generalized seizures and for primary generalized tonic-clonic (PGTC) seizures in idiopathic generalized epilepsy (IGE) in patients with epilepsy aged ≥12 years. The drug is effective and well-tolerated in the dose of 4-8 mg/day, and most side effects are dose-dependent. The high efficacy of PER combined with the good tolerability, absence of life-threatening adverse reactions and convenient intake allow us to recommend PER as the first choice additional drug in treatment of patients with epilepsy.

[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.

The Use of Antiepileptics in Migraine Prophylaxis

BACKGROUND

Migraine is a chronic debilitating disorder. Selected antiepileptic drugs (AEDs) are proposed as preventives for migraine. Clinical efficacy and side effects of these AEDs are discussed.

SUMMARY OF REVIEW

The American Academy of Neurology and the American Society of Headache classify topiramate (TPM) and divalproex sodium (DVPX) as Level-A medications and recommend offering them to patients for migraine prophylaxis. Their mechanism(s) of actions remains not entirely known. Their recognized action as sodium channel blockers may affect the neural component of migraine pain. TPM or DVPX can be considered an obvious choice for those patients with a concomitant seizure disorder. Care must be taken to plan their treatment with their psychiatrist if a mood disorder is present. DVPX tends not to be prescribed as first/second choice due to its potential for weight gain and hepatotoxicity. TPM is generally first choice, but bears severe contraindications. Both medications require education on teratogenesis in childbearing women. Consideration of gabapentin, acetazolamide, leviteracetam, zonisamide, and carbamazipine may be given later as empiric options and in selected patients. Patients must be made aware that there is insufficient scientific support for their use in migraine.

CONCLUSIONS

Available AEDs to prophylactically treat migraine are few but of robust clinical efficacy. Special care needs to be exerted with respect to their side effects. Future research is needed for a better understanding of their mechanisms of action in migraine. Such research has the potential of providing some insight into the pathophysiology of migraine.

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.