Efficacy of perampanel in refractory nonconvulsive status epilepticus and simple partial status epilepticus

Use of perampanel oral suspension for the treatment of refractory and super-refractory status epilepticus

INTRODUCTION

Status epilepticus (SE) is a medical emergency associated with a significant risk of disability and death. The treatment of SE follows a step-wise approach, with limited data on ideal antiseizure medications (ASMs) for refractory and super refractory SE (RSE/SRSE). Perampanel (PER), an AMPA receptor antagonist, has shown promise in animal models but still has limited data in humans. This study tried to evaluate optimal dosage and safety of PER in RSE and SRSE patients.

MATERIALS AND METHODS

We retrospectively analysed 17 adult patients with RSE (1) or SRSE (16) treated with PER. Demographic and clinical data, including EEG patterns, ASMs administered, PER dosages, and PER plasma concentrations, were collected. For patients receiving a 24 mg PER loading dose (full dose group), the following treatment regimen was applied: 24 mg per day for 48 h following by 16 mg per day. The response to PER was assessed based on electroencephalographic (EEG) improvement from high to low epileptiform activity or from low to the absence of epileptiform activities. Safety was evaluated monitoring hepatic and renal function.

RESULTS

A response rate of 58.82 % was observed, with significantly higher responses in the full dose group (81.82 %) compared to those receiving PER doses below 24 mg (low dose group) (16.67 %) (p-value = 0.004; OR 0.044, 95 % CI 0.003 to 0.621, p = 0.021). No other clinical factors significantly influenced treatment response. Hepatic enzymes become elevated in most patients (70.59 %) but spontaneously decreased.

DISCUSSION

Our findings suggest that a 24 mg PER dose administered for 48 h may be more effective in managing RSE and SRSE compared to doses below 24 mg, potentially due to pharmacokinetic factors.

CONCLUSION

More robust data on PER in RSE and SRSE, including standardized dosing procedures and plasma level monitoring are needed. PER's potential benefits should be explored further, particularly in patients with RSE and SRSE.

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.

Efficacy of Perampanel in Refractory and Super-Refractory Status Epilepticus with Suspected Inflammatory Etiology: A Case Series

(1) Background: Increasing evidence supports the anti-inflammatory and neuroprotective role of perampanel (PER), mediated by decreased expression of pro-inflammatory cytokines and by interference with apoptosis processes. Therefore, the use of PER to treat status epilepticus (SE) with suspected inflammatory etiology is appealing and deserves further investigation. (2) Methods: We retrospectively analyzed seven patients (five F, two M; median age: 62 years) with refractory and super-refractory SE due to a probable or defined inflammatory etiology and treated with PER. (3) Results: PER was administered as the third (4/7) or fourth drug (3/7), with a median loading dose of 32 mg/day (range: 16-36 mg/day) and a median maintenance dose of 10 mg/day (range: 4-12 mg/day). In five cases, SE was focal, while in two patients, it was generalized. SE was caused by systemic inflammation in three patients, while in the other four subjects, it was recognized to have an autoimmune etiology. SE resolution was observed after PER administration in all cases, particularly within 24 h in the majority of patients (4/7, 57.1%). (4) Conclusions: Our data support the efficacy of PER in treating SE when first- and second-line ASMs have failed and suggest a possible earlier use in SE cases that are due to inflammatory/autoimmune etiology.

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

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

Perampanel in achieving status epilepticus cessation: A systematic review

BACKGROUND

Status epilepticus (SE) is a neurological emergency necessitating rapid seizure control to prevent long-term consequences. Perampanel (PER) is a novel selective, noncompetitive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) receptor antagonist that demonstrated efficacy and safety in lithium-pilocarpine models of SE; however, data in humans are limited. This systematic review was performed to assess the efficacy and safety of PER in patients with SE, RSE, and SRSE.

METHODS

We searched MEDLINE (accessed through PubMed), Embase, Scopus, Cochrane Library, and ClinicalTrials.gov from inception until May 30, 2021 to identify all human studies on PER for the treatment of SE of any type and etiology. An additional search was performed on DANS Easy Archive, in which OpenGrey data were stored, from inception until January 10, 2022 and conference proceedings by the International League Against Epilepsy from 2011 onward. The GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach was used to assess the overall certainty of the body of evidence.

RESULTS

Twenty-one studies (7 case reports, 9 case series, and 5 retrospective cohort studies) were included with a total of 369 cases of SE in 368 patients aged 11 months to 99 years, of which 56.2% were female. Seizures of the majority were refractory (n = 220), super refractory SE (n = 70), or either (n = 81) with prominent motor symptoms (n = 284) and are associated with a structural etiology (n = 218). The number of antiseizure medications and/or anesthetics used prior to PER ranged from 1 to 13. PER was administered in 324 cases and was initiated at a dose of 2-36 mg between 30 min to 59 days from SE onset. SE cessation ranged from 1 h to 4 weeks from PER initiation. A total of 119 cases (36.6%) were considered PER responders. According to the GRADE approach, there is very low certainty of evidence for all outcomes.

CONCLUSIONS

The real-world data of PER as a possible therapeutic option in SE of any type are increasing. However, there is very low certainty of evidence for its use and this requires further clinical studies to establish the appropriate timing, dosing, and titration that are efficacious and safe for SE cessation.

[Pharmacotherapy and intensive care aspects of status epilepticus: update 2020/2021]

Die gezielte Therapie epileptischer Ereignisse und im Speziellen des Status epilepticus (SE) setzt das sichere Erkennen der Krankheitsbilder voraus, wofür gerade bei Formen mit vorwiegend nichtmotorischen Symptomen klinische und elektroenzephalographische Expertise notwendig ist. Die im Jahr 2020 erfolgte Fortschreibung der deutschen Leitlinie zur Behandlung des SE hält an der streng stufengerechten Therapie fest, die eskalierend die Anwendung von Benzodiazepinen, spezifischen Antiepileptika und Anästhetika vorsieht. Bisher ist die Eingrenzung eines in den allermeisten Fällen wirksamen sowie zugleich sicheren und interaktionsfreien Antiepileptikums nicht gelungen. Individuelle Vorerkrankungen und aktuelle Begleitumstände gehen daher genauso wie Erfahrungen des Behandlerteams in die differenzierte Behandlung des SE ein. Insbesondere bei therapierefraktären Formen des SE erweist sich die Therapie als durchaus kompliziert und hat regelhaft intensivmedizinische Implikationen. Mithin ergeben sich im Zuge der modernen SE-Behandlung zahlreiche interdisziplinäre Schnittstellen. Zukünftige wissenschaftliche Fragstellungen werden sich u. a. mit der optimalen Therapie des nonkonvulsiven SE und hier v. a. dem Ausmaß und dem Zeitpunkt von adäquaten Therapieschritten sowie mit assoziierten ethischen Fragen einer Therapieeskalation beschäftigen.

Efficacy and safety of perampanel in refractory and super-refractory status epilepticus: cohort study of 81 patients and literature review

BACKGROUND

The effective dose of perampanel in status epilepticus (SE), refractory SE (RSE), and super-refractory SE (SRSE) in humans is unknown, and the potential of perampanel in treating SE has not been evaluated in a large cohort.

METHODS

Data of intensive care patients with RSE and SRSE treated with perampanel were retrospectively reviewed and analyzed.

RESULTS

Eighty-one patients received perampanel, including 39 females with median age 64 [17-91] years, perampanel responders (n = 27), and non-responders (n = 54). The initial perampanel dose was positively associated with treatment response in patients with RSE or SRSE (OR = 1.27, 95% CI 1.03-1.57, p = 0.025), while the maximum dose was negatively associated with treatment response (OR = 0.74, 95% CI 0.58-0.96, p = 0.022). Hypoxia caused seizures in six patients; five died in hospital and one had severe disability. A statistically non-significant tendency toward better response was found in patients with unique SE type and cause, particularly in nonconvulsive status epilepticus (NCSE) without coma (NCSE without coma vs. generalized tonic-clonic seizure: OR = 4.14, 95% CI 0.98-17.47, p = 0.053). In the high-dose (≥ 16 mg/day) groups, although distributions of modified Rankin Scale (mRS) scores were similar between perampanel responders and non-responders at discharge, a greater proportion of perampanel responders had less change in mRS scores from baseline than did perampanel non-responders (median mRS: 0 vs 4, p = 0.064). No cardiorespiratory adverse events or laboratory abnormalities were noted with perampanel treatment.

CONCLUSIONS

Perampanel is effective and has a satisfactory safety profile in the emergency treatment of established RSE and SRSE.

Principles of Pharmacotherapy of Seizures and Status Epilepticus

Status epilepticus is a neurological emergency with an outcome that is highly associated with the initial pharmacotherapy management that must be administered in a timely fashion. Beyond first-line therapy of status epilepticus, treatment is not guided by robust evidence. Optimal pharmacotherapy selection for individual patients is essential in the management of seizures and status epilepticus with careful evaluation of pharmacokinetic and pharmacodynamic factors. With the addition of newer antiseizure agents to the market, understanding their role in the management of status epilepticus is critical. Etiology-guided therapy should be considered in certain patients with drug-induced seizures, alcohol withdrawal, or autoimmune encephalitis. Some patient populations warrant special consideration, such as pediatric, pregnant, elderly, and the critically ill. Seizure prophylaxis is indicated in select patients with acute neurological injury and should be limited to the acute postinjury period.

Outcomes of status epilepticus and their predictors in the elderly-A systematic review

Status epilepticus (SE) is associated with high mortality and morbidity. Although SE is frequently seen in elderly patients, there is a lack of a cohesive report of outcome measures and associated factors within this population. Our aim was to systematically review studies reporting outcomes of SE among elderly patients and factors influencing these outcomes. A literature search was conducted in PubMed/MEDLINE, EMBASE, CINAHL Complete, and Cochrane Library from database conception to April 22, 2018. A total of 85 studies were included in this systematic review. The included studies show that mortality is higher in elderly patients than in adult patients. Lesional etiologies, higher number of comorbidities, NCSE, RSE, longer hospital and intensive care unit stays, and infection during hospitalization are associated with poor outcome. Future studies should consider measuring functional outcomes, comparative studies between elderly and adults and AED clinical trials specific for elderly with SE.

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.

Therapeutic Options for Patients with Refractory Status Epilepticus in Palliative Settings or with a Limitation of Life-Sustaining Therapies: A Systematic Review

BACKGROUND

Refractory status epilepticus (RSE) represents a serious medical condition requiring early and targeted therapy. Given the increasing number of elderly or multimorbid patients with a limitation of life-sustaining therapy (LOT) or within a palliative care setting (PCS), guidelines-oriented therapy escalation options for RSE have to be omitted frequently.

OBJECTIVES

This systematic review sought to summarize the evidence for fourth-line antiseizure drugs (ASDs) and other minimally or non-invasive therapeutic options beyond guideline recommendations in patients with RSE to elaborate on possible treatment options for patients undergoing LOT or in a PCS.

METHODS

A systematic review of the literature in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, focusing on fourth-line ASDs or other minimally or non-invasive therapeutic options was performed in February and June 2020 using the MEDLINE, EMBASE and Cochrane databases. The search terminology was constructed using the name of the specific ASD or therapy option and the term 'status epilepticus' with the use of Boolean operators, e.g. "(brivaracetam) AND (status epilepticus)". The respective Medical Subject Headings (MeSH) and Emtree terms were used, if available.

RESULTS

There is currently no level 1, grade A evidence for the use of ASDs in RSE. The best evidence was found for the use of lacosamide and topiramate (level 3, grade C), followed by brivaracetam, perampanel (each level 4, grade D) and stiripentol, oxcarbazepine and zonisamide (each level 5, grade D). Regarding non-medicinal options, there is little evidence for the use of the ketogenic diet (level 4, grade D) and magnesium sulfate (level 5, grade D) in RSE. The broad use of immunomodulatory or immunosuppressive treatment options in the absence of a presumed autoimmune etiology cannot be recommended; however, if an autoimmune etiology is assumed, steroid pulse, intravenous immunoglobulins and plasma exchange/plasmapheresis should be considered (level 4, grade D). Even if several studies suggested that the use of neurosteroids (level 5, grade D) is beneficial in RSE, the current data situation indicates that there is formal evidence against it.

CONCLUSIONS

RSE in patients undergoing LOT or in a PCS represents a challenge for modern clinicians and epileptologists. The evidence for the use of ASDs in RSE beyond that in current guidelines is low, but several effective and well-tolerated options are available that should be considered in this patient population. More so than in any other population, advance care planning, advance directives, and medical ethical aspects have to be considered carefully before and during therapy.

Recommandations Formalisées d’Experts SRLF/SFMU : Prise en charge des états de mal épileptiques en préhospitalier, en structure d’urgence et en réanimation dans les 48 premières heures (A l’exclusion du nouveau-né et du nourrisson)

La Société de réanimation de langue française et la Société française de médecine d’urgence ont décidé d’élaborer de nouvelles recommandations sur la prise en charge de l’état mal épileptique (EME) avec l’ambition de répondre le plus possible aux nombreuses questions pratiques que soulèvent les EME : diagnostic, enquête étiologique, traitement non spécifique et spécifique. Vingt-cinq experts ont analysé la littérature scientifique et formulé des recommandations selon la méthodologie GRADE. Les experts se sont accordés sur 96 recommandations. Les recommandations avec le niveau de preuve le plus fort ne concernent que l’EME tonico-clonique généralisé (EMTCG) : l’usage des benzodiazépines en première ligne (clonazépam en intraveineux direct ou midazolam en intramusculaire) est recommandé, répété 5 min après la première injection (à l’exception du midazolam) en cas de persistance clinique. En cas de persistance 5 min après cette seconde injection, il est proposé d’administrer la seconde ligne thérapeutique : valproate de sodium, (fos-)phénytoïne, phénobarbital ou lévétiracétam. La persistance avérée de convulsions 30 min après le début de l’administration du traitement de deuxième ligne signe l’EMETCG réfractaire. Il est alors proposé de recourir à un coma thérapeutique au moyen d’un agent anesthésique intraveineux de type midazolam ou propofol. Des recommandations spécifiques à l’enfant et aux autres EME sont aussi énoncées.

Molecular insights into the role of AMPA receptors in the synaptic plasticity, pathogenesis and treatment of epilepsy: therapeutic potentials of perampanel and antisense oligonucleotide (ASO) technology

Glutamate is considered as the predominant excitatory neurotransmitter in the mammalian central nervous systems (CNS). Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are the main glutamate-gated ionotropic channels that mediate the majority of fast synaptic excitation in the brain. AMPARs are highly dynamic that constitutively move into and out of the postsynaptic membrane. Changes in the postsynaptic number of AMPARs play a key role in controlling synaptic plasticity and also brain functions such as memory formation and forgetting development. Impairments in the regulation of AMPAR function, trafficking, and signaling pathway may also contribute to neuronal hyperexcitability and epileptogenesis process, which offers AMPAR as a potential target for epilepsy therapy. Over the last decade, various types of AMPAR antagonists such as perampanel and talampanel have been developed to treat epilepsy, but they usually show limited efficacy at low doses and produce unwanted cognitive and motor side effects when administered at higher doses. In the present article, the latest findings in the field of molecular mechanisms controlling AMPAR biology, as well as the role of these mechanism dysfunctions in generating epilepsy will be reviewed. Also, a comprehensive summary of recent findings from clinical trials with perampanel, in treating epilepsy, glioma-associated epilepsy and Parkinson's disease is provided. Finally, antisense oligonucleotide therapy as an alternative strategy for the efficient treatment of epilepsy is discussed.

Perampanel Treatment for Refractory Status Epilepticus in a Neurological Intensive Care Unit

BACKGROUND/OBJECTIVE

Perampanel is a novel anti-epileptic drug (AED) which acts as a non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist to reduce glutamate-mediated postsynaptic excitation. Previous animal studies and a few case reports/series have suggested that it may be effective to treat refractory status epilepticus (RSE).

METHODS

We retrospectively reviewed 67 consecutive patients with RSE, of whom 22 received perampanel. The clinical features, epidemiology-based mortality score in status epilepticus, status epilepticus severity score, seizure control, functional outcome, RSE etiology, and electroencephalogram findings were collected. Responder to perampanel was defined as seizure resolution within 4 days of therapy with perampanel being the last AED used plus no recurrence during hospitalization.

RESULTS

Eight of the 22 (36.4%) RSE patients fulfilled the definition of responder to perampanel. An additional 1 patient responded to perampanel after 4 days of treatment. In total, perampanel was the last AED in 9 (40.1%) patients. Among the 8 responders to perampanel, 5 had convulsive SE, 1 had non-convulsive SE, and 2 had focal motor SE. The responders accounted for both of the patients with focal motor SE (100%), 5 (33.3%) of the 15 patients with convulsive SE, and 1 (20%) of the 5 patients with non-convulsive SE. The ictal and inter-ictal activities also decreased after perampanel therapy, and three patients (13.6%) had preferable outcomes at last follow-up.

CONCLUSIONS

Perampanel may be an effective add-on treatment for RSE even in patients who failed multiple AEDs. Our study suggests that perampanel may be more effective for focal motor SE and convulsive SE than non-convulsive SE. As most previous studies have focused on non-convulsive SE, further studies are warranted to clarify the effectiveness of perampanel for different subtypes of SE.

Antiseizure medications in critical care: an update

PURPOSE OF REVIEW

Seizures and status epilepticus are very common diagnoses in the critically ill patient and are associated with significant morbidity and mortality. There is an abundance of research on the utility of antiseizure medications in this setting, but limited randomized-controlled trials to guide the selection of medications in these patients. This review examines the current guidelines and treatment strategies for status epilepticus and provides an update on newer antiseizure medications in the critical care settings.

RECENT FINDINGS

Time is brain applies to status epilepticus, with delays in treatment corresponding with worsened outcomes. Establishing standardized treatment protocols within a health system, including prehospital treatment, may lead to improved outcomes. Once refractory status epilepticus is established, continuous deep sedation with intravenous anesthetic agents should be effective. In cases, which prove highly refractory, novel approaches should be considered, with recent data suggesting multiple recently approved antiseizure medications, appropriate therapeutic options, as well as novel approaches to upregulate extrasynaptic γ-aminobutyric acid channels with brexanolone.

SUMMARY

Although there are many new treatments to consider for seizures and status epilepticus in the critically ill patient, the most important predictor of outcome may be rapid diagnosis and treatment. There are multiple new and established medications that can be considered in the treatment of these patients once status epilepticus has become refractory, and a multidrug regimen will often be necessary.

Focal status epilepticus: a review of pharmacological treatment

INTRODUCTION

Status epilepticus (SE) is a neurological emergency associated with high morbidity and mortality. One prognostic factor is the type of SE. The purpose of this review is to analyse the most recent recommendations of different scientific societies and expert groups on the treatment of SE, and the latest studies, to assess the literature on the management of focal SE.

METHODS

We searched PubMed for studies published between 1 August 2008 and 1 August 2018 on the pharmacological treatment of focal SE and its different types in adults.

RESULTS

We identified 29 publications among reviews, treatment guidelines, meta-analyses, clinical trials, and case series on the treatment of SE. Only 3 of them accounted for whether SE was focal or generalised; 4 focused exclusively on focal SE, and 7 differentiated between convulsive and non-convulsive SE and also record the presence of focal seizures. Treatment recommendations for focal SE do not differ from those of generalised SE in stages I and II: initially intravenous lorazepam or diazepam, if the intravenous route is available, and otherwise intramuscular midazolam, followed by intravenous phenytoin, valproate, levetiracetam, or lacosamide if seizures persist. Use of anaesthetic drugs should be delayed for as long as possible in patients with refractory focal SE.

CONCLUSIONS

The available scientific evidence is insufficient to claim that pharmacological treatment of focal SE should be different from treatment for generalised SE. More studies with a greater number of patients are needed.

Pharmacotherapy for Refractory and Super-Refractory Status Epilepticus in Adults

Patients with prolonged seizures that do not respond to intravenous benzodiazepines and a second-line anticonvulsant suffer from refractory status epilepticus and those with seizures that do not respond to continuous intravenous anesthetic anticonvulsants suffer from super-refractory status epilepticus. Both conditions are associated with significant morbidity and mortality. A strict pharmacological treatment regimen is urgently required, but the level of evidence for the available drugs is very low. Refractory complex focal status epilepticus generally does not require anesthetics, but all intravenous non-anesthetizing anticonvulsants may be used. Most descriptive data are available for levetiracetam, phenytoin and valproate. Refractory generalized convulsive status epilepticus is a life-threatening emergency, and long-term clinical consequences are eminent. Administration of intravenous anesthetics is mandatory, and drugs acting at the inhibitory gamma-aminobutyric acid (GABA)_A receptor such as midazolam, propofol and thiopental/pentobarbital are recommended without preference for one of those. One in five patients with anesthetic treatment does not respond and has super-refractory status epilepticus. With sustained seizure activity, excitatory N-methyl-d-aspartate (NMDA) receptors are increasingly expressed post-synaptically. Ketamine is an antagonist at this receptor and may prove efficient in some patients at later stages. Neurosteroids such as allopregnanolone increase sensitivity at GABA_A receptors; a Phase 1/2 trial demonstrated safety and tolerability, but randomized controlled data failed to demonstrate efficacy. Adjunct ketogenic diet may contribute to termination of difficult-to-treat status epilepticus. Randomized controlled trials are needed to increase evidence for treatment of refractory and super-refractory status epilepticus, but there are multiple obstacles for realization. Hitherto, prospective multicenter registries for pharmacological treatment may help to improve our knowledge.

Perampanel for treatment of status epilepticus in Austria, Finland, Germany, and Spain

OBJECTIVE

Novel treatments are needed to control treatment-resistant status epilepticus (SE). We report a summary of clinical cases where perampanel was used in established SE, refractory SE (RSE), or super-refractory SE (SRSE).

METHODS

Medical records were retrospectively reviewed for perampanel administration in SE at five European hospitals between 2011 and 2015.

RESULTS

Of 1319 patients identified as experiencing SE, 52 (3.9%) received perampanel. Median latency from SE onset to perampanel initiation was 10 days. Patients with SE had previously failed benzodiazepines (when received) and a median of five other antiepileptic drugs (AEDs). Median initial perampanel dose was 6 mg/d, up-titrated to a median maximum dose of 10 mg/d. Perampanel was the last drug added in 32/52 (61.5%) patients, with response attributed to perampanel in 19/52 (36.5%) patients. A greater proportion of perampanel non-responders had SRSE (51.5%; 17/33) vs perampanel responders (31.6%; 6/19), and had failed a higher mean number of AEDs before initiating perampanel (5.9 vs 5.1, respectively). Most commonly reported adverse effects during perampanel treatment were dizziness (n = 1 [1.9%]) and somnolence (n = 1 [1.9%]). No serious adverse effects were documented, and none led to discontinuation of perampanel.

CONCLUSIONS

Perampanel was administered to patients with established SE, RSE, or SRSE at greater initial doses than those administered in clinical practice to patients with epilepsy. The SE cases reported here represent a refractory and heterogeneous population, and rate of seizure cessation attributed to perampanel treatment (36.5%) represents a notable response. These data should be confirmed in a larger patient population.

Use of Newer Anticonvulsants for the Treatment of Status Epilepticus

Status epilepticus (SE) has a high mortality rate and is one of the most common neurologic emergencies. Fast progression of this neurologic emergency and lack of response to traditional antiepileptic drugs (AEDs) in most cases has challenged clinicians to use new agents. This article evaluates the efficacy and safety of AEDs released to the market after 2000 for SE, refractory status epilepticus (RSE), and super-refractory status epilepticus (SRSE). The PubMed database was searched for clinical trials published between January 2000 and July 2018 using the search terms status epilepticus, refractory status epilepticus, super refractory status epilepticus, brivaracetam, clobazam, cannabidiol, eslicarbazepine, lacosamide, perampanel, rufinamide, stiripentol, and zonisamide. Trials that evaluated these agents in adults with SE, RSE, and SRSE were included. Brivaracetam use was identified in two retrospective reviews with success rates of 27% and 57%. One unsuccessful case report of cannabidiol use in SE was found. Four clobazam studies were identified in SE and RSE with success rates ranging from 25-100%. No evidence for the use of eslicarbazepine and zonisamide was found. Using the search terms for lacosamide identified 38 articles: 1 systematic review, 5 prospective studies, 15 retrospective reviews, and 17 case reports. Success rates and dosing varied, but studies that included focal or partial types of SE showed higher success rates. Five articles were identified regarding perampanel use in this setting. Three were retrospective reviews with success rates ranging from 17-60%, and two were case reports. Only one case report regarding the use of rufinamide was found; rufinamide titrated up to 4.4 mg/day allowed discontinuation of barbiturate and clobazam. One case report and two case series of stiripentol were found with reported efficacy between 60% and 100% in SRSE. Evidence is currently insufficient to support the use of these agents in this setting.

Perampanel in the treatment of status epilepticus: A systematic review of the literature

OBJECTIVE

Perampanel (PER) is a noncompetitive β-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propionic acid (AMPA) receptor antagonist with demonstrated efficacy in animal models of status epilepticus (SE). We performed a systematic review of the literature to assess the efficacy and tolerability of PER in the treatment of refractory and super-refractory SE.

METHODS

We searched Medline, Embase, and CENTRAL (accessed from inception to April 30, 2018) to identify studies evaluating oral PER as treatment of SE of any type. We also searched the OpenGrey repository and conference proceedings of international congresses by the International League Against Epilepsy and by the American Epilepsy Society from 2012 onwards.

RESULTS

Ten articles were included, with a total of 69 episodes of SE occurring in 68 patients (aged 18 to 91 years). The type and etiology of SE varied remarkably across studies. The number of drugs used prior to PER ranged from 1 to 9. The time from SE onset to PER administration ranged from 9.25 h to 35 days. The initial PER dose ranged from 2 to 32 mg. The proportion of patients achieving clinical SE cessation varied from 17% to 100%. The time from PER administration to SE cessation ranged from 1 h to 4 weeks.

CONCLUSIONS

The currently available evidence supporting the use of PER in SE is weak and hampered by several confounding factors. Further studies should be performed in more clinically homogeneous and larger cohorts to evaluate the efficacy and safety of PER administered in earlier stages of SE, at higher dosages, and at intervals shorter than 24 h.

Novel drugs and early polypharmacotherapy in status epilepticus

PURPOSE

Rescue medications for status epilepticus (SE) have a relatively high rate of failure. The purpose of this review is to summarize the evidence for the efficacy of novel drugs and early polypharmacotherapy for SE.

METHOD

Literature review.

RESULTS

New drugs and treatment strategies aim to target the pathophysiology of SE in order to improve seizure control and outcomes. Changes at the synapse level during SE include a progressive decrease in synaptic GABA_A receptors and increase in synaptic NMDA receptors. These changes tend to promote self-sustaining seizures. Current SE guidelines recommend a rapid stepwise treatment using benzodiazepines in monotherapy as the first-line treatment, targeting GABA_A synaptic receptors. Novel treatment approaches target GABA_A synaptic and extrasynaptic receptors with allopregnanolone, and NMDA receptors with ketamine. Novel rescue treatments used for SE include topiramate, brivaracetam, and perampanel, which are already marketed in epilepsy. Some available drugs not marketed for use in epilepsy have been used in the treatment of SE, and other agents are being studied for this purpose. Early polytherapy, most frequently combining a benzodiazepine with a second-line drug or an NMDA receptor antagonist, might potentially increase seizure control with relatively minor increase in side effects. Although many preclinical studies support novel drugs and early polytherapy in SE, human studies are scarce and inconclusive. Currently, evidence is lacking to recommend specific combinations of these new agents.

CONCLUSIONS

Novel drugs and strategies target the underlying pathophysiology of SE with the intent to improve seizure control and outcomes.

Perampanel in patients with refractory and super-refractory status epilepticus in a neurological intensive care unit: A single-center audit of 30 patients

In refractory status epilepticus (SE), γ-aminobutyric acidergic drugs become less effective and glutamate plays a major role in seizure perpetuation. Data on the efficacy of perampanel (PER) in treatment of refractory SE in humans are limited. Here, we present a single-center case series of patients with refractory SE who received PER orally in an intensive care unit. We retrospectively analyzed treatment response, outcome, and adverse effects of all patients with refractory SE in our Neurological Intensive Care Unit who received add-on PER between September 2012 and February 2018. Thirty patients with refractory SE (median = 72 years, range = 18-91, 77% women) were included. In 14 patients (47%), a high-dose approach was used, with a median initial dose of 24 mg (range = 16-32). In five patients (17%), SE could be terminated after PER administration (median dose = 6 mg, range = 6-20 mg, 2/5 patients in high-dose group). Clinical response was observed after a median of 24 hours (range = 8-48 hours), whereas electroencephalogram resolved after a median of 60 hours (range = 12-72 hours). Time to treatment response tended to be shorter in patients receiving high-dose PER (median clinical response = 16 hours vs 18 hours; electroencephalographic response = 24 hours vs 72 hours), but groups were too small for statistical analysis. Continuous cardiorespiratory monitoring showed no changes in cardiorespiratory function after "standard" and "high-dose" treatment. Elevated liver enzymes without clinical symptoms were observed after a median of 6 days in seven of 30 patients (23%; 57% high dose vs 43% standard dose), of whom six also received treatment with phenytoin (PHT). Outcome was unfavorable (death, persistent vegetative state) in 13 patients (43%; 39% high dose vs 61% standard dose), and good recovery (no significant disability, moderate disability) was achieved in nine patients (56% high dose vs 44% standard dose). Oral PER in loading doses up to 32 mg were well tolerated but could terminate SE only in a few patients (5/30; 17%). Long duration of SE, route of administration, and severe underlying brain dysfunction might be responsible for the modest result. An intravenous formulation is highly desired to explore the full clinical utility in the treatment of refractory SE.

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.

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.

Newer Antiepileptic Drugs for Status Epilepticus in Adults: What's the Evidence?

Status epilepticus (SE) is one of the most frequent neurological emergencies. Despite this, understanding of its pathophysiology and evidence regarding its management is limited. Rapid, effective, and well-tolerated treatment to achieve seizure cessation is advocated to prevent brain damage or potentially lethal outcomes. The last two decades have witnessed an exponential increase in the number of available antiepileptic drugs (AEDs). These compounds, especially lacosamide and levetiracetam, in view of their intravenous formulation, have been increasingly prescribed in SE. These and other newer AEDs present a promising profile in terms of tolerability, with few centrally depressive effects, favorable pharmacokinetic properties, and fewer drug interactions than classical AEDs; conversely, they are more expensive. There is still no clear evidence to suggest a specific beneficial impact of newer AEDs on SE outcome, preventing any strong recommendation regarding their prescription in SE. Further comparative studies are urgently required to clarify their place and optimal use in the armamentarium of SE treatment.

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.

Enhanced AMPA receptor-mediated neurotransmission on CA1 pyramidal neurons during status epilepticus

Status epilepticus (SE) is a common neurological emergency that results from the failure of the mechanisms responsible for seizure termination or the initiation of mechanisms that lead to abnormally prolonged seizures. Although the failure of inhibitory mechanisms during SE is well understood, the seizure-initiating mechanisms are poorly understood. We tested whether hippocampal α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated transmission was enhanced during SE and assessed the underlying molecular mechanism. In animals in self-sustaining limbic SE the amplitudes of the miniature, spontaneous, and AMPA-evoked excitatory currents recorded from the CA1 pyramidal neurons were larger than those recorded in the controls. The evoked EPSCs rectified inwardly. In these animals, the surface expression of GluA1 subunit-containing AMPARs was increased in the CA1 pyramidal neurons. The phosphorylation of the GluA1 subunit on S831 and S845 residues was reduced in animals in SE. In contrast, the GluA1 subunit surface expression and AMPAR-mediated neurotransmission of dentate granule cells (DGCs) was not altered. Treating animals in SE with the NMDAR antagonist MK-801 or with diazaepam blocked the increased surface expression of the GluA1 subunits. NMDAR blockade also prevented the dephosphorylation of the S845 residue but not that of S831. Targeting NMDARs and AMPARs may provide novel strategies to treat benzodiazepine-refractory SE.

The efficacy of different kinds of intravenously applied antiepileptic drugs in the treatment of status epilepticus. How can it be determined?

We explored the influence of four different efficacy criteria on the results of observational studies concerning the treatment of status epilepticus (SE) and its subtypes. We compared and contrasted the results of four different efficacy criteria for the effectiveness of phenytoin, valproate, levetiracetam, and lacosamide. Criterion 1=the last antiepileptic drug (AED) administered before SE termination. Criterion 2=the last drug introduced into the antiepileptic therapy within 72h before the cessation of SE and without changes in dosage or number of the co-medication. Criterion 3=the last drug introduced into the antiepileptic therapy or increased in dose within 24h before termination of the SE without changes in the co-medication. Criterion 4=the last drug introduced into the antiepileptic therapy within 72h before the cessation of SE even allowing changes in the co-medication. We used two-tailed χ²-tests with the Yates adjustment for small samples to evaluate statistical differences between efficacy rates of different AEDs in the entire group and in subgroups of SE according to the second level of subdivisions in axis 1 and according to axis 2 of the new ILAE classification. A total of 145 treatment episodes in 124 patients (47 male, 77 female) were evaluated. There were 23 significant differences in efficacy according to the different criteria. Only criteria 1 and 3 led to significant results in our analysis. When incorporating theoretical considerations and the results of this study, criterion 3 seems to be the most appropriate measure for the evaluation of efficacy of an AED in the treatment of SE, because it seems to be more reasonable than criterion 1.

25 years of advances in the definition, classification and treatment of status epilepticus

PURPOSE

Status epilepticus (SE) requires not only urgent symptomatic treatment with antiepileptic drugs but also rapid identification and treatment of its cause. This narrative review summarizes the most important advances in classification and treatment of SE.

METHOD

Data sources included MEDLINE, EMBASE, ClinicalTrials.gov, and back tracking of references in pertinent studies, reviews, and books.

RESULTS

SE is now defined as "a condition resulting either from the failure of the mechanisms responsible for seizure termination or from the initiation of mechanisms, which lead to abnormally, prolonged seizures (after time point t1). It is a condition, which can have long-term consequences (after time point t2), including neuronal death, neuronal injury, and alteration of neuronal networks, depending on the type and duration of seizures." A new diagnostic classification system of SE introduces four axes: semiology, aetiology, EEG correlates, and age. For the acute treatment intravenous benzodiazepines (lorazepam, diazepam, clonazepam) and intramuscular midazolam appear as most effective treatments for early SE. In children, buccal or intranasal midazolam are useful alternatives. In established SE intravenous antiepileptic drugs (phenytoin, valproate, levetiracetam, phenobarbital, and lacosamide) are in use. Treatment options in refractory SE are intravenous anaesthetics; ketamine, magnesium, steroids and other drugs have been used in super-refractory SE with variable outcomes.

CONCLUSION

Over the past 25 years major advances in definition, classification and understanding of its mechanisms have been achieved. Despite this up to 40% of patients in early status cannot be controlled with first line drugs. The treatment of super-refractory status is still an almost evidence free zone.

[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.

Treatment of Convulsive Status Epilepticus

OPINION STATEMENT

Convulsive status epilepticus (CSE) is a medical emergency with an associated high mortality and morbidity. It is defined as a convulsive seizure lasting more than 5 min or consecutive seizures without recovery of consciousness. Successful management of CSE depends on rapid administration of adequate doses of anti-epileptic drugs (AEDs). The exact choice of AED is less important than rapid treatment and early consideration of reversible etiologies. Current guidelines recommend the use of benzodiazepines (BNZ) as first-line treatment in CSE. Midazolam is effective and safe in the pre-hospital or home setting when administered intramuscularly (best evidence), buccally, or nasally (the latter two possibly faster acting than intramuscular (IM) but with lower levels of evidence). Regular use of home rescue medications such as nasal/buccal midazolam by patients and caregivers for prolonged seizures and seizure clusters may prevent SE, prevent emergency room visits, improve quality of life, and lower health care costs. Traditionally, phenytoin is the preferred second-line agent in treating CSE, but it is limited by hypotension, potential arrhythmias, allergies, drug interactions, and problems from extravasation. Intravenous valproate is an effective and safe alternative to phenytoin. Valproate is loaded intravenously rapidly and more safely than phenytoin, has broad-spectrum efficacy, and fewer acute side effects. Levetiracetam and lacosamide are well tolerated intravenous (IV) AEDs with fewer interactions, allergies, and contraindications, making them potentially attractive as second- or third-line agents in treating CSE. However, data are limited on their efficacy in CSE. Ketamine is probably effective in treating refractory CSE (RCSE), and may warrant earlier use; this requires further study. CSE should be treated aggressively and quickly, with confirmation of treatment success with epileptiform electroencephalographic (EEG), as a transition to non-convulsive status epilepticus is common. If the patient is not fully awake, EEG should be continued for at least 24 h. How aggressively to treat refractory non-convulsive SE (NCSE) or intermittent non-convulsive seizures is less clear and requires additional study. Refractory SE (RSE) usually requires anesthetic doses of anti-seizure medications. If an auto-immune or paraneoplastic etiology is suspected or no etiology can be identified (as with cryptogenic new onset refractory status epilepticus, known as NORSE), early treatment with immuno-modulatory agents is now recommended by many experts.