Perampanel: A therapeutic alternative in refractory status epilepticus associated with MELAS syndrome

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.

Mitochondrial Epilepsy, a Challenge for Neurologists

Primary mitochondrial diseases are relatively common inborn errors of energy metabolism, with a combined prevalence of 1 in 4300. These disorders typically affect tissues with high energy requirements, including the brain. Epilepsy affects >1% of the worldwide population, making it one of the most common neurological illnesses; it may be the presenting feature of a mitochondrial disease, but is often part of a multisystem clinical presentation. The major genetic causes of mitochondrial epilepsy are mutations in mitochondrial DNA and in the nuclear-encoded gene POLG. Treatment of mitochondrial epilepsy may be challenging, often representing a poor prognostic feature. This narrative review will cover the most recent advances in the field of mitochondrial epilepsy, from pathophysiology and genetic etiologies to phenotype and treatment options.

Delay in diagnosing a patient with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome who presented with status epilepticus and lactic acidosis: a case report

Background

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episode syndrome is a rare mitochondrial genetic disorder that can present with a variety of clinical manifestations, including stroke, hearing loss, seizures, and lactic acidosis. The most common genetic mutation associated with this syndrome is M.3243A>G. The main underlying mechanism of the disease relates to protein synthesis, energy depletion, and nitric oxide deficiency. Controlling disease complications and improving patient quality of life are the primary aims of treatment options.

Case presentation

A 28-year-old Arabic female visited Al-Amiri Hospital in Kuwait. The patient was newly diagnosed with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episode syndrome following her admission as a case of status epilepticus requiring further investigation. The patient’s seizures were controlled, and she was evaluated to rule out the most serious complications by carrying out appropriate clinical, laboratory, and radiological imaging. The patient was discharged from the hospital after 2 weeks with a follow-up plan.

Conclusion

This case report emphasizes the importance of considering mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episode syndrome as a potential cause of status epilepticus with lactic acidosis in a young female patient with a past history of stroke-like episodes. It also stresses the most important workup to rule out every possible life-threatening complication to improve patients’ lives.

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.

The effect of Perampanel on EEG spectral power and connectivity in patients with focal epilepsy

OBJECTIVE

Quantitative Encephalography (qEEG) depicts synthetically the features of EEG signal and represents a promising tool in the assessment of neurophysiological changes brought about by Anti-Seizure Medications (ASMs). In this study we characterized qEEG alterations related to add-on therapy with Perampanel (PER). PER is the only ASM presenting a direct glutamatergic antagonism, hence the characterization of PER induced EEG changes could help to better understand its large spectrum of efficacy.

METHODS

We analysed standard-19 channel-EEG from 25 People with Epilepsy (PwE) both before (T0) and after (T1) the introduction of PER as add-on treatment. Normal values were obtained in 30 healthy controls (HC) matched for sex and age. EEGs were analysed using Matlab™ and the EEGlab and Brainstorm toolkits. We extracted spectral power and connectivity (Phase locking Value) of EEG signal and then compared these features between T0 and T1 and across groups (PwE, HC), we also evaluated the correlations with clinical features.

RESULTS

PwE showed increased theta power (p = 0.036) after the introduction of PER but no significant change of EEG connectivity. We also found that PwE have reduced beta power (p = 0.012) and increased connectivity in delta (p = 0.013) and theta (p = 0.007) range as compared to HC, but no significant change was observed between T0 and T1 in PwE. Finally, we found that PwE classified as drug responders to PER have greater alpha power both at T0 and at T1 (p = 0.024) suggesting that this parameter may predict response to treatment.

CONCLUSIONS

PER causes slight increase of theta activity and does not alter connectivity as assessed by standard EEG. Moreover, greater alpha power could be a good marker of response to PER therapy, and potentially ASM therapy in general.

SIGNIFICANCE

Our results corroborate the hypothesis that pharmaco-EEG is a viable tool to study neurophysiological changes induced by ASM. Additionally, our work highlights the role of alpha power as a marker of ASM therapeutic response.

Epilepsy in Mitochondrial Diseases-Current State of Knowledge on Aetiology and Treatment

Mitochondrial diseases are a heterogeneous group of diseases resulting from energy deficit and reduced adenosine triphosphate (ATP) production due to impaired oxidative phosphorylation. The manifestation of mitochondrial disease is usually multi-organ. Epilepsy is one of the most common manifestations of diseases resulting from mitochondrial dysfunction, especially in children. The onset of epilepsy is associated with poor prognosis, while its treatment is very challenging, which further adversely affects the course of these disorders. Fortunately, our knowledge of mitochondrial diseases is still growing, which gives hope for patients to improve their condition in the future. The paper presents the pathophysiology, clinical picture and treatment options for epilepsy in patients with mitochondrial disease.

Effects of the noncompetitive AMPA receptor antagonist perampanel on thalamo-cortical excitability: A study of high-frequency oscillations in somatosensory evoked potentials

OBJECTIVE

Wedesignedalongitudinalcohortstudyon People with Epilepsy (PwE) with the aimofassessingthe effect of Perampanel (PER) oncortico-subcortical networks, as measured by high-frequency oscillations of somatosensory evoked potentials (SEP-HFOs). SEP-HFOs measure the excitability of both thalamo-corticalprojections(early HFOs) and intracortical GABAergic synapses (late HFOs), thus they could be used to study the anti-glutamatergic action of PER, a selective antagonist of the AMPA receptor.

METHODS

15 PwE eligible for PER add-on therapy, were enrolled prospectively. Subjects underwent SEPs recording from the dominant hand at two times: PwE_T0 (baseline, before PER titration) and PwE_T1 (therapeutic dose of 4 mg). HFOs were obtained by filtering N20 scalp response in the 400-800 Hz range. Patients were compared with a normative population of 15 healthy controls (HC) matched for age and sex.

RESULTS

We found a significant reduction ofTotal HFOs and mostly early HFOs area between PwE_T0 and PwE_T1 (p = 0.05 and p = 0.045 respectively) and between HC and PwE_T1 (p = 0.01). Furthermore, we found a significant reduction of P24/N24 Amplitude between PwE_T0 and HC and between PwE_T0 and PwE_T1 (p = 0.006 and p = 0.032, respectively).

CONCLUSIONS

Introduction of PER as add-on therapy reduced the area of total HFOs, acting mainly on the early burst, related to thalamo-cortical pathways. Furthermore P24/N24 amplitude, which seems to reflect a form of cortico-subcortical integration, resulted increased in PwE at T0 and normalized at T1.

SIGNIFICANCE

Our findings suggest that PER acts on cortico-subcortical excitability. This could explain the broad spectrum of PER and its success in forms of epilepsy characterized by thalamo-cortical hyperexcitability.

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.

Ionotropic Glutamate Receptors in Epilepsy: A Review Focusing on AMPA and NMDA Receptors

It is widely accepted that glutamate-mediated neuronal hyperexcitation plays a causative role in eliciting seizures. Among glutamate receptors, the roles of N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors in physiological and pathological conditions represent major clinical research targets. It is well known that agonists of NMDA or AMPA receptors can elicit seizures in animal or human subjects, while antagonists have been shown to inhibit seizures in animal models, suggesting a potential role for NMDA and AMPA receptor antagonists in anti-seizure drug development. Several such drugs have been evaluated in clinical studies; however, the majority, mainly NMDA-receptor antagonists, failed to demonstrate adequate efficacy and safety for therapeutic use, and only an AMPA-receptor antagonist, perampanel, has been approved for the treatment of some forms of epilepsy. These results suggest that a misunderstanding of the role of each glutamate receptor in the ictogenic process may underlie the failure of these drugs to demonstrate clinical efficacy and safety. Accumulating knowledge of both NMDA and AMPA receptors, including pathological gene mutations, roles in autoimmune epilepsy, and evidence from drug-discovery research and pharmacological studies, may provide valuable information enabling the roles of both receptors in ictogenesis to be reconsidered. This review aimed to integrate information from several studies in order to further elucidate the specific roles of NMDA and AMPA receptors in epilepsy.

Metabolic stroke or stroke-like lesion: Peculiarities of a phenomenon

OBJECTIVES

One of the most frequent cerebral lesions in mitochondrial disorders(MIDs) on imaging is the stroke-like lesion(SLL) clinically manifesting as stroke-like episode (SLE, metabolic stroke). This review aims at discussing recent advances concerning the presentation, diagnosis, and treatment of SLLs.

METHODS

Systematic literature review using appropriate search terms.

RESULTS

SLLs are the hallmark of MELAS but occasionally occur in other MIDs. SLLs are best identified on multimodal, cerebral MRI. SLLs may present as uni-/multilocular, symmetric/asymmetric, cortical/subcortical, supra-/infratentorial condition, initially resembling a cytotoxic edema and later a vasogenic edema, or a variable mix between them. SLLs run through an acute and a chronic stage. The acute stage is characterised by a progressively expanding lesion over days, weeks, or months, showing up as increasing hyperintensity on T2/FLAIR, DWI, and PWI and by hyperperfusion, that does not conform to a vascular territory. ADC maps are initially hypointens to become hyperintens during the course. More rarely, a variable mixture of hyper- and hypointensities may be found. The chronic stage is characterised by hypoperfusion, gadolinium enhancement, and regression of hyperintensities to various endpoints. SLLs originate from an initial cortical lesion due to focal metabolic breakdown, which either remains stable or expands within the cortex or to subcortical areas. Some SLLs show spontaneous reversibility (fleeing cortical lesions) suggesting that neuronal/glial damage does not reach the threshold of irreversible cell death.

CONCLUSIONS

SLLs are a unique feature of various MIDs in particular MELAS. SLLs are dynamic and change their appearance over time. SLLs are accessible to treatment.

Advances in the treatment of mitochondrial epilepsies

Epilepsy is frequently a severe and sinister symptom in primary mitochondrial diseases, a group of more than 350 different genetic disorders characterized by mitochondrial dysfunction and extreme clinical and biochemical heterogeneity. Mitochondrial epilepsy is notoriously difficult to manage, principally because the vast majority of primary mitochondrial diseases currently lack effective therapies. Treating the underlying mitochondrial disorder is likely to be a more effective strategy than using traditional antiepileptic drugs. This review, initially presented at the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures at the Francis Crick Institute in London, summarizes the currently available and emerging therapies for mitochondrial epilepsy. Potentially treatable mitochondrial diseases include disorders of coenzyme Q₁₀ biosynthesis and a group of mitochondrial respiratory chain complex I subunit and assembly factor defects that respond to riboflavin (vitamin B2). Approaches that have been adopted in actively recruiting clinical trials include redox modulation, harnessing mitochondrial biogenesis, using rapamycin to target mitophagy, nucleoside supplementation, and gene and cell therapies. Most of the clinical trials are at an early stage (Phase 1 or 2) and none of the currently active trials is specifically targeting mitochondrial epilepsy. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".

Mitochondrial disorders and drugs: what every physician should know

Mitochondrial disorders are a group of metabolic conditions caused by impairment of the oxidative phosphorylation system. There is currently no clear evidence supporting any pharmacological interventions for most mitochondrial disorders, except for coenzyme Q10 deficiencies, Leber hereditary optic neuropathy, and mitochondrial neurogastrointestinal encephalomyopathy. Furthermore, some drugs may potentially have detrimental effects on mitochondrial dysfunction. Drugs known to be toxic for mitochondrial functions should be avoided whenever possible. Mitochondrial patients needing one of these treatments should be carefully monitored, clinically and by laboratory exams, including creatine kinase and lactate. In the era of molecular and ‘personalized’ medicine, many different physicians (not only neurologists) should be aware of the basic principles of mitochondrial medicine and its therapeutic implications. Multicenter collaboration is essential for the advancement of therapy for mitochondrial disorders. Whenever possible, randomized clinical trials are necessary to establish efficacy and safety of drugs. In this review we discuss in an accessible way the therapeutic approaches and perspectives in mitochondrial disorders. We will also provide an overview of the drugs that should be used with caution in these patients.