Development Of Novel Antiepileptic Drugs Research Articles

Synthesis, in silico screening, and biological evaluation of novel pyridine congeners as anti-epileptic agents targeting AMPA (α-amino-3-hydroxy-5-methylisoxazole) receptors.

The research involves the synthesis of a series of new pyridine analogs 5(i-x) and their evaluation for anti-epileptic potential using in silico and invivo models. Synthesis of the compounds was accomplished by using the Vilsmeier-Haack reaction principle. AutoDock 4.2 was used for their in silico screening against AMPA (-amino-3-hydroxy-5-methylisoxazole) receptor (PDB ID:3m3f). For invivo testing, the maximal electroshock seizure (MES) model was used. The physicochemical, pharmacokinetic, drug-like, and drug-score features of all synthesized compounds were assessed using the online Swiss ADME and Protein Plus software. The in silico results showed that all the synthesized compounds 5(i-x) had 1-3 interactions and affinities ranging from -6.5 to -8.0 kJ/mol with the targeted receptor compared to the binding affinities of the standard drug phenytoin and the original ligand of the target (P99), which were -7.6 and -6.8 kJ/mol, respectively. Invivo study results showed that the compound 5-Carbamoyl-2-formyl-1-[2-(4-nitrophenyl)-2-oxo-ethyl]-pyridinium gave 60% protection against epileptic seizures compared to 59% protection afforded by regular phenytoin. All of them met Lipinski's rule of five and had drug-likeness and drug score values of 0.55 and 0.8, respectively, making them chemically and functionally like phenytoin. According to the findings of the studies, the synthesized derivatives have the potential to be employed as a stepping stone in the development of novel anti-epileptic drugs.

Development of Antiepileptic Drugs throughout History: From Serendipity to Artificial Intelligence.

This article provides a comprehensive narrative review of the history of antiepileptic drugs (AEDs) and their development over time. Firstly, it explores the significant role of serendipity in the discovery of essential AEDs that continue to be used today, such as phenobarbital and valproic acid. Subsequently, it delves into the historical progression of crucial preclinical models employed in the development of novel AEDs, including the maximal electroshock stimulation test, pentylenetetrazol-induced test, kindling models, and other animal models. Moving forward, a concise overview of the clinical advancement of major AEDs is provided, highlighting the initial milestones and the subsequent refinement of this process in recent decades, in line with the emergence of evidence-based medicine and the implementation of increasingly rigorous controlled clinical trials. Lastly, the article explores the contributions of artificial intelligence, while also offering recommendations and discussing future perspectives for the development of new AEDs.

Analysis and Construction of a Molecular Diagnosis Model of Drug-Resistant Epilepsy Based on Bioinformatics.

Background: Epilepsy is a complex chronic disease of the nervous system which influences the health of approximately 70 million patients worldwide. In the past few decades, despite the development of novel antiepileptic drugs, around one-third of patients with epilepsy have developed drug-resistant epilepsy. We performed a bioinformatic analysis to explore the underlying diagnostic markers and mechanisms of drug-resistant epilepsy. Methods: Weighted correlation network analysis (WGCNA) was applied to genes in epilepsy samples downloaded from the Gene Expression Omnibus database to determine key modules. The least absolute shrinkage and selection operator (LASSO) regression and support vector machine-recursive feature elimination (SVM-RFE) algorithms were used to screen the genes resistant to carbamazepine, phenytoin, and valproate, and sensitivity of the three-class classification SVM model was verified through the receiver operator characteristic (ROC) curve. A protein–protein interaction (PPI) network was utilized to analyze the protein interaction relationship. Finally, ingenuity pathway analysis (IPA) was adopted to conduct disease and function pathway and network analysis. Results: Through WGCNA, 72 genes stood out from the key modules related to drug resistance and were identified as candidate resistance genes. Intersection analysis of the results of the LASSO and SVM-RFE algorithms selected 11, 4, and 5 drug-resistant genes for carbamazepine, phenytoin, and valproate, respectively. Subsequent union analysis obtained 17 hub resistance genes to construct a three-class classification SVM model. ROC showed that the model could accurately predict patient resistance. Expression of 17 hub resistance genes in healthy subjects and patients was significantly different. The PPI showed that there are six resistance genes (CD247, CTSW, IL2RB, MATK, NKG7, and PRF1) that may play a central role in the resistance of epilepsy patients. Finally, IPA revealed that resistance genes (PRKCH and S1PR5) were involved in “CREB signaling in Neurons.” Conclusion: We obtained a three-class SVM model that can accurately predict the drug resistance of patients with epilepsy, which provides a new theoretical basis for research and treatment in the field of drug-resistant epilepsy. Moreover, resistance genes PRKCH and S1PR5 may cooperate with other resistance genes to exhibit resistance effects by regulation of the cAMP-response element-binding protein (CREB) signaling pathway.

From the Molecular Mechanism to Pre-clinical Results: Anti-epileptic Effects of Fingolimod.

Epilepsy is a devastating neurological condition characterized by long-term tendency to generate unprovoked seizures, affecting around 1-2% of the population worldwide. Epilepsy is a serious health concern which often associates with other neurobehavioral comorbidities that further worsen disease conditions. Despite tremendous research, the mainstream anti-epileptic drugs (AEDs) exert only symptomatic relief leading to 30% of untreatable patients. This reflects the complexity of the disease pathogenesis and urges the precise understanding of underlying mechanisms in order to explore novel therapeutic strategies that might alter the disease progression as well as minimize the epilepsy-associated comorbidities. Unfortunately, the development of novel AEDs might be a difficult process engaging huge funds, tremendous scientific efforts and stringent regulatory compliance with a possible chance of end-stage drug failure. Hence, an alternate strategy is drug repurposing, where anti-epileptic effects are elicited from drugs that are already used to treat non-epileptic disorders.Herein, we provide evidence of the anti-epileptic effects of Fingolimod (FTY720), a modulator of sphingosine-1-phosphate (S1P) receptor, USFDA approved already for Relapsing-Remitting Multiple Sclerosis (RRMS). Emerging experimental findings suggest that Fingolimod treatment exerts disease-modifying anti-epileptic effects based on its anti-neuroinflammatory properties, potent neuroprotection, anti-gliotic effects, myelin protection, reduction of mTOR signaling pathway and activation of microglia and astrocytes. We further discuss the underlying molecular crosstalk associated with the anti-epileptic effects of Fingolimod and provide evidence for repurposing Fingolimod to overcome the limitations of current AEDs.

Eslicarbazepine in patients with brain tumor-related epilepsy: a single-center experience

Purpose Brain tumor-related epilepsy (BTRE) is frequent in patients affected with glioma. Most patients have refractory seizures and require polytherapy. Promising treatment options derive from the development of novel anti-epileptic drugs (AEDs), like Eslicarbazepine (ESL), whose role in BTRE has not yet been explored. Our aim was to report a retrospective cohort of patients affected by BTRE treated with ESL as an adjunctive therapy and to discuss the potential role of this third-generation AED in this clinical context. Methods We analyzed a single-center, retrospectively collected cohort of patients affected by glioma and BTRE, treated with ESL as an adjunctive therapy. Results Analysis included 5 males and 3 females with age ranging from 37 to 75 years (mean = 55.5). Mean baseline Karnofsky performance status was 87.5 (range 70–100). Patients were affected by diffuse astrocytoma (3), low grade oligodendroglioma (2), anaplastic glioma (2) and glioblastoma (1). Mean follow-up was 19 months (range 6–59). Mean dose at the last follow-up was 950 mg daily. Mean weekly seizures in the month before initiation of ESL numbered 17.6 (range 0.25–50). At the last follow-up, mean weekly seizures were 2.2 (range 0–10), i.e. significantly lower than baseline (p = 0.03). The mean reduction of seizures achieved after introduction of ESL was 65%, with 6/8 patients (75%) showing a reduction of more than 50%. Two patients (25%) were seizure free. Conclusions This single-center experience suggests that ESL may be a well-tolerated, efficacious option as an add-on drug in the treatment of BTRE.

Efficacy of cannabinoids in pharmacoresistant epilepsy: A narrative review of the literature

Epilepsy is a common neurological disorder that affects approximately 1% of the world’s pop7ulation. About one third of those patients suffer from treatment-resistant epilepsy (TRE8), defined as failure to stop seizures despite adequate trials of at least two medications at therapeutic dosages. There has been a growing interest in the development of novel antiepileptic drugs with different mechanisms of action. This narrative review, based on 42 references retrieved from Scopus and Medline, discusses the scientific data from human and animal studies regarding the efficacy of cannabis-based treatment for epilepsy. Benefits have been described in pre-clinical and clinical studies in children, but ongoing research will clarify the real role of cannabinoids in TRE.

Role of NKCC1 and KCC2 in Epilepsy: From Expression to Function.

As a main inhibitory neurotransmitter in the central nervous system, γ-aminobutyric acid (GABA) activates chloride-permeable GABAa receptors (GABAa Rs) and induces chloride ion (Cl−) flow, which relies on the intracellular chloride concentration ([Cl−]i) of the postsynaptic neuron. The Na-K-2Cl cotransporter isoform 1 (NKCC1) and the K-Cl cotransporter isoform 2 (KCC2) are two main cation-chloride cotransporters (CCCs) that have been implicated in human epilepsy. NKCC1 and KCC2 reset [Cl−]i by accumulating and extruding Cl−, respectively. Previous studies have shown that the profile of NKCC1 and KCC2 in neonatal neurons may reappear in mature neurons under some pathophysiological conditions, such as epilepsy. Although increasing studies focusing on the expression of NKCC1 and KCC2 have suggested that impaired chloride plasticity may be closely related to epilepsy, additional neuroelectrophysiological research aimed at studying the functions of NKCC1 and KCC2 are needed to understand the exact mechanism by which they induce epileptogenesis. In this review, we aim to briefly summarize the current researches surrounding the expression and function of NKCC1 and KCC2 in epileptogenesis and its implications on the treatment of epilepsy. We will also explore the potential for NKCC1 and KCC2 to be therapeutic targets for the development of novel antiepileptic drugs.

The treatment of epileptic seizures: the potential of Malaysian medicinal plants

Epileptic seizures result from excessive brain activity and may affect sensory, motor and autonomic function; as well as, emotional state, memory, cognition or behaviour. Effective anti-epileptic drugs (AEDs) are available but have tolerability issues due to their side effects. Medicinal plants are potential candidates for novel AEDs, as many are traditional epilepsy remedies. Malaysia is a megadiverse country, with many endemic plants serving as a large pool of potential candidates for the development of local herbal products. The large variety of flora make Malaysia a prime location for the discovery of medicinal plants with anti-convulsive potential. This review lists 23 Malaysian medicinal plants, of which four are used traditionally to treat epilepsy, without any scientific evidence. A further eight plants have no known traditional anti-epileptic use but have scientific evidence of its anti-epileptic activity. The remaining 11 plants possess both traditional use and scientific evidence. Thus, this review identified several potential candidates for the development of novel AEDs or enhancing current ones; as well as identified an imbalance between traditional use and scientific evidence. In addition, this review also identified several limitations in the reviewed studies and provided additional information to facilitate the design of future studies.

Rufinamide (inovelon) in the treatment of Lennox–gastaut syndrome (a review of literature)

Lennox–Gastaut syndrome (LGS) is a childhood epileptic encephalopathy characterized by frequent polymorphic seizures (including tonic axial seizures), pronounced cognitive impairment, typical changes in the electroencephalogram and drug resistance. Since the disease is quite common (accounts for 4–10 % of all childhood epilepsy) and is characterized by various seizures that are frequently resistant to multiple antiepileptic drugs, great hopes are currently centered on the development of novel antiepileptic drugs with principally different mechanisms of action aimed to treat this severe form of epilepsy. Rufinamide (inovelon) is a promising antiepileptic drug for LGS therapy. In 2008, it was approved by the FDA as an adjunctive treatment of seizures associated with LGS in adults and children over 4 years of age. Rufinamide demonstrated its efficacy against both drop seizures (tonic/atonic) and generalized seizures (tonic, atonic and tonic-clonic) in LGS. In January 2015, the drug was approved for use in the Russian Federation for seizures associated with LGS in patients over 4 years of age. Multiple studies have demonstrated high efficacy and good tolerability of rufinamide in children and adults with epilepsy. In this article, we provide a systematic review of the currently available data on the use of rufinamide in the treatment of seizures associated with LGS.

Novel venom-derived inhibitors of the human EAG channel, a putative antiepileptic drug target

Recently, we and other groups revealed that gain-of-function mutations in the human ether à go-go voltage-gated potassium channel hEAG1 (Kv10.1) lead to developmental disorders with associated infantile-onset epilepsy. However, the physiological role of hEAG1 in the central nervous system remains elusive. Potent and selective antagonists of hEAG1 are therefore much sought after, both as pharmacological tools for studying the (patho)physiological functions of this enigmatic channel and as potential leads for development of anti-epileptic drugs. Since animal venoms are a rich source of potent ion channel modifiers that have been finely tuned by millions of year of evolution, we screened 108 arachnid venoms for hEAG1 inhibitors using electrophysiology. Two hit peptides (Aa1a and Ap1a) were isolated, sequenced, and chemically synthesised for structure-function studies. Both of these hEAG1 inhibitors are C-terminally amidated peptides containing an inhibitor cystine knot motif, which provides them with exceptional stability in both plasma and cerebrospinal fluid. Aa1a and Ap1a are the most potent peptidic inhibitors of hEAG1 reported to date, and they present a novel mode of action by targeting both the activation and inactivation gating of the channel. These peptides should be useful pharmacological tools for probing hEAG1 function as well as informative leads for the development of novel anti-epileptic drugs.

Design, synthesis and evaluation of novel N-phenylbutanamide derivatives as KCNQ openers for the treatment of epilepsy

KCNQ (Kv7) has emerged as a validated target for the development of novel anti-epileptic drugs. In this paper, a series of novel N-phenylbutanamide derivatives were designed, synthesized and evaluated as KCNQ openers for the treatment of epilepsy. These compounds were evaluated for their KCNQ opening activity in vitro and in vivo. Several compounds were found to be potent KCNQ openers. Compound 1 with favorable in vitro activity was submitted to evaluation in vivo. Results showed that compound 1 owned significant anti-convulsant activity with no adverse effects. It was also found to posses favorable pharmacokinetic profiles in rat. This research may provide novel potent compounds for the discovery of KCNQ openers in treating epilepsy.

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 (2mg every 2-4weeks), and bedtime administration can mitigate somnolence and dizziness. Counseling about the potential for behavioral changes and close monitoring are recommended.

Basic Mechanisms of Action of the Antiepileptic Drugs

Abstract Available antiepileptic drugs interact with a variety of different molecular targets. The mechanism of action of most anticonvulsants is most often complex with a number of affected regions. The combination of mechanisms of action of drugs in particular proportions can possibly determine the showcase of its antiepileptic activity. The common factor between the different supposed mechanisms for a number of drugs includes the possibility for modulating the excitatory and inhibitory neurotransmission through effects upon the voltage-gated ion channels, synaptic plasticity, heterogeneous receptors, and metabolism of neurotransmitters. There are controversial data on the extent to which a specific action can be the reason for the wholesome anticonvulsive characteristics of various medications, as well as the relation with the presence of undesired drug effects. The complexity of the action of some antiepileptic drugs creates conditions for optimal choice during therapy. In many cases, the insufficient familiarity with individual genetic differences and the disease related receptor damages can hinder defining a particular drug action. Characterizing the mechanisms of action of the present antiepileptic medications would increase the understanding for the pathophysiological mechanisms of epileptic seizures, as well as the development of new therapeutic strategies. The development of novel antiepileptic drugs and the ongoing research regarding the mechanism of action of established antiepileptic drugs, are continuously increasing the level of complexity in the spectrum of molecular targets relevant for epilepsy therapy. The current state of knowledge as well as the limitations in our understanding should guide future research aiming for a more detailed elucidation of the impact of genetics and pathophysiological mechanisms on interindividual differences in expression and function of antiepileptic drug targets.

Neuritin Mediates Activity-Dependent Axonal Branch Formation in Part via FGF Signaling.

This study reveals the molecular mechanism underlying mossy fiber sprouting. Mossy fiber sprouting is the aberrant axonal branching of granule neurons in the hippocampus, which is observed in patients with epilepsy. Excess amounts of neuritin, a protein upregulated by neural activity, promoted axonal branching in granule neurons. A deficiency of neuritin suppressed mossy fiber sprouting and resulted in mitigation of seizure severity. Neuritin and fibroblast growth factor (FGF) cooperated in stimulating FGF signaling and enhancing axonal branching. Neuritin is necessary for FGF-mediated recruitment of FGF receptors to the cell surface. The recruitment of FGF receptors would promote axonal branching. The discovery of this new mechanism should contribute to the development of novel antiepileptic drugs to inhibit axonal branching via neuritin-FGF signaling.

Enhanced in vitro CA1 network activity in a sodium channel β1(C121W) subunit model of genetic epilepsy

A NaV β1(C121W) mouse model of human genetic epilepsy has enhanced neuronal excitability and temperature sensitivity attributed to a decreased threshold for action potential firing in the axon initial segment. To investigate the network consequences of this neuronal dysfunction and to establish a genetic disease state model we developed an in vitro assay to investigate CA1 network properties and antiepileptic drug sensitivity. CA1 network oscillations were induced by tetanic stimulation and average number of spikes, interspike interval (ISI), duration, and latency were measured in slices from control and NaV β1(C121W) heterozygous mice in the presence and absence of retigabine or carbamazepine. Retigabine was also tested in a thermogenic seizure model. Oscillations were reliably induced by tetanic stimulation and were maintained after severing connections between CA3 and CA1, suggesting a local recurrent circuit. Blocking α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), γ-aminobutyric acid receptor A (GABAA ), Ih , and T-type Ca(2+) channels/receptors reduced the number of spikes. Slices from NaV β1(C121W) heterozygous mice displayed several hallmarks of increased network excitability including increases in duration of the oscillation, the number and frequency of spikes and a decrease in their onset latency. The effect of genotype on network excitability was temperature sensitive, as it was seen only at elevated temperatures. Carbamazepine and retigabine were more effective in reducing network excitability in slices from NaV β1(C121W) heterozygous mice. Retigabine appeared to be more effective in suppressing time to thermogenic seizures in NaV β1(C121W) heterozygous mice compared to wild-type (WT) controls. Hippocampal networks of the NaV β1(C121W) heterozygous mouse model of genetic epilepsy show enhanced excitability consistent with earlier single neuron studies bridging important scales of brain complexity relevant to seizure genesis. Altered pharmacosensitivity further suggests that genetic epilepsy models may be useful in the development of novel antiepileptic drugs that target disease state pathology. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.

What new modeling approaches will help us identify promising drug treatments?

Despite the development of numerous novel antiepileptic drugs (AEDs) in recent years, several unmet clinical needs remain, including resistance to AEDs in about 30 % of patients with epilepsy, adverse effects of AEDs that can reduce quality of life, and the lack of treatments that can prevent development of epilepsy in patients at risk. Animal models of seizures and epilepsy have been instrumental in the discovery and preclinical development of novel AEDs, but obviously the previously used models have failed to identify drugs that address unmet medical needs. Thus, we urgently need fresh ideas for improving preclinical AED development. In this review, a number of promising models will be described, including the use of simple vertebrates such as zebrafish (Danio rerio), large animal models such as the dog and newly characterized rodent models of pharmacoresistant epilepsy. While these strategies, like any animal model approach also have their limitations, they offer hope that new more effective AEDs will be identified in the coming years.

The Class 4 Semaphorin Sema4D Promotes the Rapid Assembly of GABAergic Synapses in Rodent Hippocampus

Proper circuit function in the mammalian nervous system depends on the precise assembly and development of excitatory and inhibitory synaptic connections between neurons. Through a loss-of-function genetic screen in cultured hippocampal neurons, we previously identified the class 4 Semaphorin Sema4D as being required for proper GABAergic synapse development. Here we demonstrate that Sema4D is sufficient to promote GABAergic synapse formation in rodent hippocampus and investigate the kinetics of this activity. We find that Sema4D treatment of rat hippocampal neurons increases the density of GABAergic synapses as detected by immunocytochemistry within 30 min, much more rapidly than has been previously described for a prosynaptogenic molecule, and show that this effect is dependent on the Sema4D receptor PlexinB1 using PlxnB1(-/-) mice. Live imaging studies reveal that Sema4D elicits a rapid enhancement (within 10 min) in the rate of addition of synaptic proteins. Therefore, we demonstrate that Sema4D, via PlexinB1, acts to initiate synapse formation by recruiting molecules to both the presynaptic and the postsynaptic terminals; these nascent synapses subsequently become fully functional by 2 h after Sema4D treatment. In addition, acute treatment of an organotypic hippocampal slice epilepsy model with Sema4D reveals that Sema4D rapidly and dramatically alters epileptiform activity, which is consistent with a Sema4D-mediated shift in the balance of excitation and inhibition within the circuit. These data demonstrate an ability to quickly assemble GABAergic synapses in response to an appropriate signal and suggest a potential area of exploration for the development of novel antiepileptic drugs.

Introduction

Based on a 2010 systematic review and meta-analysis, Beyenburg et al. 1 recently concluded that modern antiepileptic drugs (AEDs) have little impact on patients with refractory epilepsy, lamenting the lack of progress in the development of novel AEDs. Such articles have highlighted the importance of the continued quest for effective, novel therapies to help patients with this condition. This supplement provides an overview of the development of perampanel, the first non-competitive AMPA-type glutamate receptor antagonist to be developed as an adjunctive treatment for refractory partial-onset seizures. After years of development, this AED has now been approved by the European Medicines Agency (EMA) and the Food and Drug Administration (FDA). Perampanel has completed clinical evaluation in three pivotal, randomized, double-blind, placebo-controlled Phase III registration studies in patients experiencing partial-onset seizures despite treatment with up to three AEDs 2-4. In these studies, adjunctive perampanel provided significant improvements in seizure reduction. In addition, perampanel was associated with a favorable adverse event profile, with few cognitive or psychiatric side effects: a vital attribute in this vulnerable population. Previously, most AEDs have been discovered through serendipity, screening large numbers of compounds, or the further development of existing AEDs. Perampanel, however, is one of the few to be developed based upon a specific hypothesis of seizure inhibition. This development program will be reviewed by Andrew Satlin and colleagues in the first article in this supplement 5. In the second article, Michael Rogawski 6 provides an in-depth account of the role of AMPA receptors in seizures and epileptogenesis, while in the third article, Michael Rogawski and Takahisa Hanada 7 will go on to review the exciting possibilities of AMPA receptor antagonism and how perampanel utilizes this mechanism to inhibit seizure occurrence. As perampanel is now approved for use in Europe and the USA, it is important that clinicians have an understanding of how this drug can be used to treat patients in a real-life clinical setting. With this in mind, the fourth article in this supplement, by Frank Kerling and Burkhard Kasper 8, will provide an overview of efficacy data from the published Phase II and Phase III clinical trials. Alongside this, Jose Serratosa, Vicente Villanueva, Frank Kerling and Burkhard Kasper 9 will provide an overview of Phase II and Phase III safety data in the fifth article. Severe seizures are particularly difficult to control, and the more AEDs a patient has tried previously, the less likely they are to respond to the next AED 10. Therefore, in the sixth and final article in this supplement, David Ko and Eugene Ramsay 11 will discuss the efficacy of perampanel for the treatment of severe seizures in refractory patients already receiving one or more concomitant AEDs. As perampanel is now approved for use in Europe and the USA, we hope that the information covered in this supplement will support the reader in treating eligible and appropriate patients with this third-generation AED. However, it is important to recognize that the full potential of perampanel is not yet known and many challenges still remain. For example, ‘How effective will perampanel be in monotherapy?’ and ‘Will patients with generalized seizure types also benefit from treatment (as indicated in animal models) 12?’ Only further rigorous studies will be able to answer the question of whether perampanel is a broad spectrum AED for patients with varied seizure types and syndromes or not. The future is indeed exciting. David Squillacote, MD, of Eisai Inc. assisted in the preparation of the article by providing up-to-date data access and editorial support. Editorial support was provided by Hannah FitzGibbon, PhD, of Complete Medical Communications and was funded by Eisai Inc. E. Ben-Menachem is currently an investigator for Eisai and UCB Pharma and is a consultant for Biocontrol, Eisai, Janssen-Cilag, Lundbeck, and UCB Pharma. She has received a research grant from Västra Götelands Region and is chief editor of Acta Neurologica Scandinavica.

Pharmacological treatment strategies: Mechanisms of antiepileptic drugs

Both, the development of novel antiepileptic drugs as well as ongoing research regarding the mechanism of action of established antiepileptic drugs, are continuously increasing the level of complexity in the spectrum of molecular targets relevant for epilepsy therapy. Although we are far from a reliable prediction of the optimal choice for polytherapy in individual patients, evidence exists that the mechanisms of action of the combination partners can matter regarding tolerability and efficacy. Moreover, the current state of knowledge as well as the limitations in our understanding should guide future research aiming for a more detailed elucidation of the exact mechanisms of target modulation as well as a more comprehensive investigation of the impact of genetics and pathophysiological mechanisms on interindividual differences in expression and function of antiepileptic drug targets.Therefore, this review gives a short overview of the mechanism of action of currently marketed antiepileptic drugs.

Validation criteria for genetic animal models of epilepsy

In the past decades, several mutant genes that encode ion channel subunit proteins or their functionally-related proteins have been identified in pedigrees of idiopathic epilepsy. To explore the pathogenesis and pathophysiology of epilepsy syndrome, the functional abnormalities of transmission in genetic animal models bearing the mutant genes identified in pedigrees of idiopathic epilepsy should be analyzed. In spite of these efforts, it is important to identify the most suitable genetic animal models for exploration of epileptogenesis and ictogenesis, as well as the development of novel antiepileptic drugs. In the literature on genetic epileptic animal models, there is no systematic discussion on how to assess the validation criteria for such models. In this review, we describe the validation criteria for genetic animal models of epilepsy.