Brivaracetam in Unverricht-Lundborg disease (EPM1): Results from two randomized, double-blind, placebo-controlled studies

Development of SV2A Ligands for Epilepsy Treatment: A Review of Levetiracetam, Brivaracetam, and Padsevonil

Epilepsy is a common neurological disorder that is primarily treated with antiseizure medications (ASMs). Although dozens of ASMs are available in the clinic, approximately 30% of epileptic patients have medically refractory seizures; other limitations in most traditional ASMs include poor tolerability and drug-drug interactions. Therefore, there is an urgent need to develop alternative ASMs. Levetiracetam (LEV) is a first-line ASM that is well tolerated, has promising efficacy, and has little drug-drug interaction. Although it is widely accepted that LEV acts through a unique therapeutic target synaptic vesicle protein (SV) 2A, the molecular basis of its action remains unknown. Even so, the next-generation SV2A ligands against epilepsy based on the structure of LEV have achieved clinical success. This review highlights the research and development (R&D) process of LEV and its analogs, brivaracetam and padsevonil, to provide ideas and experience for the R&D of novel ASMs.

Progressive Myoclonus Epilepsy: A Scoping Review of Diagnostic, Phenotypic and Therapeutic Advances

The progressive myoclonus epilepsies (PME) are a diverse group of disorders that feature both myoclonus and seizures that worsen gradually over a variable timeframe. While each of the disorders is individually rare, they collectively make up a non-trivial portion of the complex epilepsy and myoclonus cases that are seen in tertiary care centers. The last decade has seen substantial progress in our understanding of the pathophysiology, diagnosis, prognosis, and, in select disorders, therapies of these diseases. In this scoping review, we examine English language publications from the past decade that address diagnostic, phenotypic, and therapeutic advances in all PMEs. We then highlight the major lessons that have been learned and point out avenues for future investigation that seem promising.

Efficacy and Safety of Brivaracetam in Persons With Epilepsy in a Real-World Setting: A Prospective, Non-Interventional Study

BACKGROUND AND AIM

Epilepsy stands out as one of the most prevalent neurological conditions. Brivaracetam (BRV) is a noteworthy antiseizure medication (ASM) distinguished by its pronounced and selective interaction with the synaptic vesicle protein 2A (SV2A) within the brain. Prior investigations, including regulatory trials, post-marketing assessments, and comparative meta-analyses, have consistently underscored BRV's equivalency in efficacy and superior tolerability when pitted against other antiseizure drugs. This study aimed to evaluate the effectiveness, safety, and acceptability of BRV in treating epileptic patients in the Pakistani population.

METHODS

This prospective observational study, conducted in Pakistan from February to December 2022, employed a non-probability consecutive sampling technique. This study included 368 adult patients diagnosed with epilepsy, with a focus on those aged 18 and above experiencing focal seizures. Demographic data, clinical history, seizure types, and epilepsy profiles were recorded. Patients were administered BRV (Brivera; manufactured by Helix Pharma Pvt Ltd., Sindh, Pakistan) monotherapy therapy under physician guidance and followed up for three months. The study assessed changes in seizure frequency, side effects, and drug resistance at baseline, 14th day, and 90th day. Safety aspects were monitored, including documenting any adverse effects associated with BRV therapy.

RESULTS

A total of 368 epileptic patients were included in this study, of which 287 (61.3%) were males and 181 (38.7%) were females. The mean age was 32.91±17.11 years. The mean number of seizures at the baseline visit was 5.74±6.21, at 14 days was 2.89±3.84 and at 90 days was 1.73±5.01 (p<0.001). Overall, a more than 50% reduction in seizure episodes was achieved in 178 (56.3%) patients at day 90, and less than 50% reduction in seizure episodes was achieved by 95 (26.8%) patients on Day 14, with a highly significant association between them (p<0.001). Among 316 patients, only 41 (4.4%) of all BRV-treated patients experienced adverse events; Of these 41 patients, 17 (41.7%) reported dizziness and 14(34.2%) reported behavioral issues.

CONCLUSIONS

Epileptic patients receiving BRV demonstrated a substantial reduction of greater than 50% seizure episodes at the end of follow-up visits. Moreover, BRV exhibited fewer adverse effects in individuals with epilepsy.

The bee venom active compound melittin protects against bicuculline-induced seizures and hippocampal astrocyte activation in rats

Epilepsy is a chronic neuropathology characterized by an abnormal hyperactivity of neurons that generate recurrent, spontaneous, paradoxical and synchronized nerve impulses, leading or not to seizures. This neurological disorder affects around 70 million individuals worldwide. Pharmacoresistance is observed in about 30% of the patients and long-term use of antiepileptics may induce serious side effects. Thus, there is an interest in the study of the therapeutic potential of bioactive substances isolated from natural products in the treatment of epilepsy. Arthropod venoms contain neurotoxins that have high affinity for molecular structures in the neural tissue such as receptors, transporters and ion channels both in glial and neuronal membranes. This study evaluated the potential neuroprotective effect of melittin (MEL), an active compound of bee venom, in the bicuculline-induced seizure model (BIC) in rats. Male Wistar rats (3 months, 250-300 g) were submitted to surgery for the implantation of a unilateral cannula in the lateral ventricle. After the recovery period, rats received a microinjection of saline solution or MEL (0.1 mg per animal). Firstly, rats were evaluated in the open field (20 min) and in the elevated plus maze (5 min) tests after received microinjection of saline or MEL. After, 30 min later animals received BIC (100 mg/ml) or saline, and their behaviors were analyzed for 20 min in the open field according to a seizure scale. At the end, rats were euthanized, brains collected and processed to glial fibrillary acidic protein (GFAP) immunohistochemistry evaluation. No changes were observed in MEL-treated rats in the open field and elevated plus maze. However, 90% of MEL-treated animals were protected against seizures induced by BIC. There was an increase in the latency for the onset of seizures, accompanied by a reduction of GFAP-immunoreactivity cells in the dentate gyrus and CA1. Thus, our study suggests that MEL has an anticonvulsant potential, and further studies are needed to elucidate the mechanisms involved in this action.

Wearable monitoring of positive and negative myoclonus in progressive myoclonic epilepsy type 1

OBJECTIVE

To develop and test wearable monitoring of surface electromyography and motion for detection and quantification of positive and negative myoclonus in patients with progressive myoclonic epilepsy type 1 (EPM1).

METHODS

Surface electromyography and three-dimensional acceleration were measured from 23 EPM1 patients from the biceps brachii (BB) of the dominant and the extensor digitorum communis (EDC) of the non-dominant arm for 48 hours. The patients self-reported the degree of myoclonus in a diary once an hour. Severity of myoclonus with action was evaluated by using video-recorded Unified Myoclonus Rating Scale (UMRS). Correlations of monitored parameters were quantified with the UMRS scores and the self-reported degrees of myoclonus.

RESULTS

The monitoring-based myoclonus index correlated significantly (p < 0.001) with the UMRS scores (ρ = 0.883 for BB and ρ = 0.823 for EDC) and with the self-reported myoclonus degrees (ρ = 0.483 for BB and ρ = 0.443 for EDC). Ten patients were assessed as probably having negative myoclonus in UMRS, while our algorithm detected that in twelve patients.

CONCLUSIONS

Wearable monitoring was able to detect both positive and negative myoclonus in EPM1 patients.

SIGNIFICANCE

Our method is suitable for quantifying objective, real-life treatment effects at home and progression of myoclonus.

Myoclonus- A Review

Myoclonus is a hyperkinetic movement disorder characterized by a sudden, brief, involuntary jerk. Positive myoclonus is caused by abrupt muscle contractions, while negative myoclonus by sudden cessation of ongoing muscular contractions. Myoclonus can be classified in various ways according to body distribution, relation to activity, neurophysiology, and etiology. The neurophysiological classification of myoclonus by means of electrophysiological tests is helpful in guiding the best therapeutic strategy. Given the diverse etiologies of myoclonus, a thorough history and detailed physical examination are key to the evaluation of myoclonus. These along with basic laboratory testing and neurophysiological studies help in narrowing down the clinical possibilities. Though symptomatic treatment is required in the majority of cases, treatment of the underlying etiology should be the primary aim whenever possible. Symptomatic treatment is often not satisfactory, and a combination of different drugs is often required to control the myoclonus. This review addresses the etiology, classification, clinical approach, and management of myoclonus.

Adjunctive brivaracetam - A prospective audit of outcomes from an epilepsy clinic

OBJECTIVE

Brivaracetam (BRV), is licensed in Europe as adjunctive treatment, and in the United States of America as adjunctive and monotherapy for focal seizures with or without secondary generalization in adults, adolescents, and children ≥4 years. As BRV becomes available globally, this prospective audit was undertaken to gain an understanding of how best to use the anti-seizure medication (ASM) in the everyday clinical setting.

METHODS

Brivaracetam was started by patients ≥16 years with difficult-to-control epilepsy at Glasgow epilepsy clinics following a 12-week baseline on stable ASM doses. Target dosing was 200 mg/day. Review occurred every 12-16 weeks until 1 of 4 end-points occurred: seizure freedom for ≥6 months on a given BRV dose; ≥50% (responder) or <50% (marginal benefit) seizure reduction over 6 months compared with baseline on the highest tolerated BRV dose; withdrawal of BRV due to lack of efficacy, adverse effects, or both.

RESULTS

An end-point has been reached by 108 patients (38 men, 70 women; median age 45 years), 88 with focal-onset seizures and 20 with genetic generalized epilepsies (GGEs). Of these, 71 (65.7%) have benefitted from BRV, including 23 (21.3%) who have been seizure free for ≥6 months on a median BRV dose of 100 mg/day (range 25-200 mg/day). A further 18 (16.7%) were classified as responders and 30 (27.8%) showed marginal benefit. Brivaracetam benefitted 16 (80.0%) patients with GGEs, 5 becoming seizure free. Generalized tonic-clonic seizures, absences, and myoclonic seizures were completely controlled in 4 (25%) patients with juvenile myoclonic epilepsy. Brivaracetam monotherapy was established in 12 patients, 3 of whom had GGEs. Levetiracetam (LEV) had previously been prescribed in 53 patients who had discontinued the ASM due to lack of efficacy, side effects, or both. Adjunctive BRV benefitted 34 (64.2%) of these patients. Brivaracetam was withdrawn in 37 (34.3%) patients, (23 side effects, 4 lack of efficacy, 10 both). Sedation was the commonest side effect leading to BRV withdrawal (n = 14; 13.0%). Psychiatric side effects resulted in BRV discontinuation in 9 (8.3%) patients.

SIGNIFICANCE

Brivaracetam has efficacy for a range of seizure types and syndromes in a wide range of doses. The ASM can produce positive outcomes in patients who have failed LEV. Post-marketing studies remain a useful tool to evaluate the efficacy and tolerability of novel ASMs in everyday clinical practice.

A novel lipase from Aspergillus oryzae WZ007 catalyzed synthesis of brivaracetam intermediate and its enzymatic characterization

Brivaracetam is a structural derivative of the chiral drug levetiracetam and has been approved for the adjuvant treatment of partial epilepsy. As a new antiepileptic drug, it is widely used in a variety of epilepsy models. In this study, a novel lipase M16 derived from Aspergillus oryzae WZ007 was cloned, expressed, and used for chiral resolution. Lipase M16 has a high enantioselectivity to the racemic substrate (R,S)-methyl 2-propylsuccinate 4-tert-butyl ester, and the intermediate (R)-2-propylsuccinic acid 4-tert-butyl ester of brivaracetam was obtained efficiently. Under optimal conditions, the enantiomeric excess of substrate was up to 99.26%, and the e.e.p was 96.23%. The conversion and apparent E value were 50.63% and 342.48, respectively. This study suggests a new biocatalytic resolution via lipase M16 for preparing the brivaracetam chiral intermediate and its potential application in the pharmaceutical industry.

Safety, tolerability, and efficacy of brivaracetam as adjunctive therapy in patients with focal seizures, generalized onset seizures, or Unverricht-Lundborg disease: An open-label, long-term follow-up trial

This long-term open-label extension (OLE) trial was conducted to evaluate the long-term safety and tolerability of brivaracetam (BRV) at individualized doses in patients with epilepsy and focal (partial-onset) or generalized onset seizures, or Unverricht-Lundborg disease (ULD). A secondary objective was to evaluate efficacy of BRV in the subgroups of patients with focal or generalized onset seizures. Patients with epilepsy were eligible to enroll in this OLE (N01125; NCT00175916) and were analyzed if they had completed a previous double-blind BRV trial (N01114 [NCT00175929], N01252 [NCT00490035], N01254 [NCT00504881], N01187 [NCT00357669], and N01236 [NCT00368251]), and were expected to obtain a reasonable benefit from long-term BRV treatment. Patients entered the OLE at the BRV dose recommended at the end of the previous trial, with dose adjustments of BRV and concomitant antiseizure medications permitted. Safety variables included treatment-emergent adverse events (TEAEs). Efficacy variables in patients with focal seizures were percent reduction in focal seizure frequency, 50 % responder rates, and 6- and 12-month seizure-freedom. Eight hundred and fifty-three patients (729 [85.5 %] with focal seizures, 30 [3.5 %] with generalized onset seizures, and 94 [11.0 %] with ULD) were enrolled and included in the Safety Set. Overall, 619 (72.6 %) patients discontinued the trial, mainly due to lack of efficacy (354 [41.5 %]), adverse events (100 [11.7 %]), and patient choice (98 [11.5 %]). During the OLE, 588 (68.9 %) patients received BRV for ≥12 months, 403 (47.2 %) for ≥36 months, and 223 (26.1 %) for ≥96 months. The most common modal dose of BRV was 150 mg/day (415 [48.7 %] patients). In the ULD subgroup, the most common modal BRV dose was 100 mg/day (44/94 [46.8 %] patients), and 37/94 (39.4 %) patients had ≥96 months of BRV exposure. Overall, 720/853 (84.4 %) patients reported TEAEs, 451 (52.9 %) had a drug-related TEAE, and 95 (11.1 %) discontinued BRV due to a TEAE. In the ULD subgroup, 87/94 (92.6 %) patients reported TEAEs, 60 (63.8 %) had a drug-related TEAE, and 16 (17.0 %) discontinued due to a TEAE. In patients with focal seizures, the median reduction in focal seizure frequency from Baseline was 43.1 % (n = 728), the 50 % responder rate was 43.6 % (n = 729), and 6- and 12-month seizure freedom rates were 22.2 % and 15.8 %, respectively (n = 595). Overall, BRV was well-tolerated as long-term adjunctive therapy in patients with focal seizures, generalized onset seizures, or Unverricht-Lundborg disease, with improvements in focal seizure frequency maintained over time.

Physiology-Based Treatment of Myoclonus

Myoclonus can cause significant disability for patients. Myoclonus has a strikingly diverse array of underlying etiologies, clinical presentations, and pathophysiological mechanisms. Treatment of myoclonus is vital to improving the quality of life of patients with these disorders. The optimal treatment strategy for myoclonus is best determined based upon careful evaluation and consideration of the underlying etiology and neurophysiological classification. Electrophysiological testing including EEG (electroencephalogram) and EMG (electromyogram) data is helpful in determining the neurophysiological classification of myoclonus. The neurophysiological subtypes of myoclonus include cortical, cortical-subcortical, subcortical-nonsegmental, segmental, and peripheral. Levetiracetam, valproic acid, and clonazepam are often used to treat cortical myoclonus. In cortical-subcortical myoclonus, treatment of myoclonic seizures is prioritized, valproic acid being the mainstay of therapy. Subcortical-nonsegmental myoclonus may be treated with clonazepam, though numerous agents have been used depending on the etiology. Segmental and peripheral myoclonus are often resistant to treatment, but anticonvulsants and botulinum toxin injections may be of utility depending upon the case. Pharmacological treatments are often hampered by scarce evidence-based knowledge, adverse effects, and variable efficacy of medications.

Brivaracetam for the treatment of focal-onset seizures: pharmacokinetic and pharmacodynamic evaluations

INTRODUCTION

The goal of pharmacologic therapy with antiseizure medications (ASMs) is to achieve a seizure-free state with minimal side effects. About one third of patients treated with available ASMs continue to experience uncontrolled seizures. There is still need for new ASMs with enhanced effectiveness and tolerability.

AREAS COVERED

The present manuscript is based on an extensive Internet and PubMed search from 1999 to 2020. It is focused on the clinical and pharmacological properties of brivaracetam (BRV) in the treatment of epilepsy.

EXPERT OPINION

BRV is approved as add-on or monotherapy (in US) for the treatment of focal-onset seizures with or without secondary generalization. BRV is a high affinity synaptic vesicle glycoprotein 2A ligand, with 15-30-fold higher affinity than levetiracetam. The selectivity of BRV may be associated with fewer clinical adverse effects. BRV shares many of the pharmacokinetic characteristics of an ideal ASMs. Additionally, BRV has a low potential for clinically relevant drug-drug interactions. Its pharmacokinetic profile makes BRV a promising agent for the treatment of status epilepticus (SE). Although BRV is not approved for the treatment of SE, it has demonstrated promising preliminary results. Further studies are needed to explore the efficacy and tolerability of BRV in SE.

Drug Treatment of Progressive Myoclonic Epilepsy

The progressive myoclonic epilepsies (PMEs) represent a rare but devastating group of syndromes characterized by epileptic myoclonus, typically action-induced seizures, neurological regression, medically refractory epilepsy, and a variety of other signs and symptoms depending on the specific syndrome. Most of the PMEs begin in children who are developing as expected, with the onset of the disorder heralded by myoclonic and other seizure types. The conditions are considerably heterogenous, but medical intractability to epilepsy, particularly myoclonic seizures, is a core feature. With the increasing use of molecular genetic techniques, mutations and their abnormal protein products are being delineated, providing a basis for disease-based therapy. However, genetic and enzyme replacement or substrate removal are in the nascent stage, and the primary therapy is through antiepileptic drugs. Epilepsy in children with progressive myoclonic seizures is notoriously difficult to treat. The disorder is rare, so few double-blinded, placebo-controlled trials have been conducted in PME, and drugs are chosen based on small open-label trials or extrapolation of data from drug trials of other syndromes with myoclonic seizures. This review discusses the major PME syndromes and their neurogenetic basis, pathophysiological underpinning, electroencephalographic features, and currently available treatments.

Automatic assessment of the myoclonus severity from videos recorded according to standardized Unified Myoclonus Rating Scale protocol and using human pose and body movement analysis

PURPOSE

Myoclonus in progressive myoclonus epilepsy type 1 (EPM1) patients shows marked variability, which presents a substantial challenge in devising treatment and conducting clinical trials. Consequently, fast and objective myoclonus quantification methods are needed.

METHODS

Ten video-recorded unified myoclonus rating scale (UMRS) myoclonus with action tests were performed on EPM1 patients who were selected for the development and testing of the automatic myoclonus quantification method. Human pose and body movement analyses of the videos were used to identify body keypoints and further analyze movement smoothness and speed. The automatic myoclonus rating scale (ARMS) was developed. It included the jerk count during movement score and the log dimensionless jerk (LDLJ) score to evaluate changes in the smoothness of movement.

RESULTS

The scores obtained with the automatic analyses showed moderate to strong significant correlation with the UMRS myoclonus with action scores. The jerk count of the primary keypoints and the LDLJ scores were effective in the evaluation of the myoclonic jerks during hand movements. They also correlated moderately to strongly with the total UMRS test panel scores (r2 = 0,77, P = 0,009 for the jerk count score and r2 = 0,88, P = 0,001 for the LDLJ score). The automatic analyses was weaker in quantification of the neck, trunk, and leg myoclonus.

CONCLUSION

Automatic quantification of myoclonic jerks using human pose and body movement analysis of patients' videos is feasible and was found to be quite consistent with the accepted clinical gold standard quantification method. Based on the results of this study, the automatic analytical method should be further developed and validated to improve myoclonus severity follow-up for EPM1 patients.

Myoclonus

PURPOSE OF REVIEW

This article offers clinicians a strategic approach for making sense of a symptom complex that contains myoclonus. The article presents an evaluation strategy that highly leverages the two major classification schemes of myoclonus. The goal of this article is to link evaluation strategy with diagnosis and treatment of myoclonus.

RECENT FINDINGS

The growth of medical literature has helped better define myoclonus etiologies. Physiologic study of myoclonus types and etiologies with electrophysiologic testing has provided greater clarity to the pathophysiology of the myoclonus in various diseases. Although studies have been limited, the role of newer treatment agents and methods has made progress.

SUMMARY

Myoclonus has hundreds of different etiologies. Classification is necessary to evaluate myoclonus efficiently and pragmatically. The classification of myoclonus etiology, which is grouped by different clinical presentations, helps determine the etiology and treatment of the myoclonus. The classification of myoclonus physiology using electrophysiologic test results helps determine the pathophysiology of the myoclonus and can be used to strategize symptomatic treatment approaches. Both basic ancillary testing (including EEG and imaging) and more comprehensive testing may be necessary. Treatment of the underlying etiology is the ideal approach. However, if such treatment is not possible or is delayed, symptomatic treatment guided by the myoclonus physiology should be considered. More controlled study of myoclonus treatment is needed. Further research on myoclonus generation mechanisms should shed light on future treatment possibilities.

Levetiracetam and brivaracetam: a review of evidence from clinical trials and clinical experience

Until the early 1990s, a limited number of antiepileptic drugs (AEDs) were available. Since then, a large variety of new AEDs have been developed and introduced, several of them offering new modes of action. One of these new AED families is described and reviewed in this article. Levetiracetam (LEV) and brivaracetam (BRV) are pyrrolidone derivate compounds binding at the presynaptic SV2A receptor site and are thus representative of AEDs with a unique mode of action. LEV was extensively investigated in randomized controlled trials and has a very promising efficacy both in focal and generalized epilepsies. Its pharmacokinetic profile is favorable and LEV does not undergo clinically relevant interactions. Adverse reactions comprise mainly asthenia, somnolence, and behavioral symptoms. It has now been established as a first-line antiepileptic drug. BRV has been recently introduced as an adjunct antiepileptic drug in focal epilepsy with a similarly promising pharmacokinetic profile and possibly increased tolerability concerning psychiatric adverse events. This review summarizes the essential preclinical and clinical data of LEV and BRV that is currently available and includes the experiences at a large tertiary referral epilepsy center.

An Italian multicentre study of perampanel in progressive myoclonus epilepsies

Perampanel (PER) is a novel anti-seizure medication useful in different types of epilepsy. We intended to assess the effectiveness of PER on cortical myoclonus and seizure frequency in patients with progressive myoclonus epilepsy (PME), using quantitative validated scales. Forty-nine patients aged 36.6 ± 15.6 years with PME of various aetiology (18 EPM1, 12 EPM2, five with sialidosis, one with Kufs disease, one with EPM7, and 12 undetermined) were enrolled between January 2017 and June 2018. PER at the dose of 2-12 mg (5.3 ± 2.5) was added to existing therapy. Myoclonus severity was assessed using a minimal myoclonus scale (MMS) in all the patients before and after 4-6 months of steady PER dose, and by means of the Unified Myoclonus Rating Scale (UMRS) in 20 patients. Logistic regression analysis was used to identify the factors potentially predicting treatment efficacy. Four patients dropped out in the first two months due to psychiatric side effects. In the remaining patients, PER reduced myoclonus severity as assessed using MMS (Wilcoxon test: p < 0.001) and UMRS (p < 0.001), with the 'Action myoclonus' section of the UMRS showing the greatest improvement. The patients with EPM1 or EPM1-like phenotype were more likely to improve with PER (p = 0.011). Convulsive seizures which have recurred at least monthly in 17 patients were reduced by >50%. Side effects occurred in 22/49 (44.8%) patients, the most common being irritability followed by drowsiness. PER is effective in treating myoclonus and seizures in PME patients. The frequency of psychiatric side effects suggests the need for careful patient monitoring.

Brivaracetam: a newly approved medication for epilepsy

Brivaracetam (BRV) in both the USA and EU was developed as a novel molecule for the adjunctive treatment of partial-onset (focal) seizures in patients ≥16 years of age and as of September 2017 was approved for use as monotherapy in the USA uniquely as an antiseizure medication that may be prescribed without a dose finding uptitration. This article reviews BRV's pharmacology, efficacy, safety and adverse event profiles, along with the relevant and noted regulatory hurdles in the USA and the EU. Available postmarketing data will also be summarized. Approximately 3000 patients were studied over about 9 years in the clinical trial program illustrating that BRV has efficacy at 50–200 mg/day with an acceptable adverse event profile.

Update on Pharmacological Treatment of Progressive Myoclonus Epilepsies

BACKGROUND

Progressive myoclonus epilepsies (PMEs) are a group of rare inherited diseases featuring a combination of myoclonus, seizures and variable degree of cognitive impairment. Despite extensive investigations, a large number of PMEs remain undiagnosed. In this review, we focus on the current pharmacological approach to PMEs.

METHODS

References were mainly identified through PubMed search until February 2017 and backtracking of references in pertinent studies.

RESULTS

The majority of available data on the efficacy of antiepileptic medications in PMEs are primarily anecdotal or observational, based on individual responses in small series. Valproic acid is the drug of choice, except for PMEs due to mitochondrial diseases. Levetiracetam and clonazepam should be considered as the first add-on treatment. Zonisamide and perampanel represent promising alternatives. Phenobarbital and primidone should be reserved to patients with resistant disabling myoclonus or seizures. Lamotrigine should be used with caution due to its unpredictable effect on myoclonus. Avoidance of drugs known to aggravate myoclonus and seizures, such as carbamazepine and phenytoin, is paramount. Psychiatric (in particular depression) and other comorbidities need to be adequately managed. Although a 3- to 4-drug regimen is often necessary to control seizures and myoclonus, particular care should be paid to avoid excessive pharmacological load and neurotoxic side effects. Target therapy is possible only for a minority of PMEs.

CONCLUSIONS

Overall, the treatment of PMEs remains symptomatic (i.e. pharmacological treatment of seizures and myoclonus). Further dissection of the genetic background of the different PMEs might hopefully help in the future with individualised treatment options.

Brivaracetam efficacy and safety in focal epilepsy

Introduction: Brivaracetam (BRV) is an analog of levetiracetam (LEV) with 15-30 times greater affinity to SV2A and greater brain permeability than LEV. These properties have stimulated interest in its clinical trial data and post-marketing experience. Areas covered: The authors provide a background on epilepsy and its treatment, discuss the racetam family of antiepileptic drugs to which BRV belongs, and then discuss BRV properties and its efficacy and tolerability in the treatment of epilepsy. Expert opinion: While preclinical data suggest a broad spectrum of efficacy, BRV is only approved for focal epilepsy. The recommended starting dose is 100 mg per day, but in the absence of urgency, it may be prudent to start at 50 mg per day, considered the lowest effective dose. There was no added benefit when BRV was used adjunctively with LEV in clinical trials. However, post-marketing data suggest that some patients may experience improved seizure control when switching from LEV. Behavioral adverse effects seemed less common than with LEV, and most patients switched to BRV after experiencing behavioral adverse effects on LEV reported improvement. Prior or anticipated intolerability to LEV is the strongest indication for BRV in clinical practice.

An Update on Myoclonus Management

INTRODUCTION

Myoclonus is a hyperkinetic movement disorder characterized by sudden, brief, lightning-like involuntary jerks. There are many possible causes of myoclonus and both the etiology and characteristics of the myoclonus are important in securing the diagnosis and treatment. Myoclonus may be challenging to treat, as it frequently requires multiple medications for acceptable results. Few randomized controlled trials investigating the optimal treatment for myoclonus are available, and expert experience and case series guide treatment. Areas Covered: In this article, the authors review the basics of myoclonus and its classification. The authors discuss the current management of myoclonus and then focus on recent updates in the literature, including both pharmacologic and surgical options. Expert opinion: Myoclonus remains a challenge to manage, and there is a paucity of rigorous clinical trials guiding treatment paradigms. Furthermore, due to the etiological heterogeneity of myoclonus, defining the appropriate scope for high-quality clinical trials is challenging. In order to advance the field, the myoclonus study group needs to be revived in the US and abroad so that interested investigators can collaborate on multicenter clinical trials for myoclonus treatments.

Brivaracetam in the treatment of epilepsy: a review of clinical trial data

Brivaracetam (BRV), an analog of levetiracetam (LEV), was discovered during a target-based rational drug discovery program that aimed to identify potent synaptic vesicle protein 2A (SV2A) ligands. Among the 12,000 compounds screened in vitro, BRV was found to have 15-30 times greater affinity for SV2A and faster brain permeability than LEV. Although preclinical and post-marketing studies suggest broad spectrum of efficacy, BRV is currently only approved as monotherapy and adjunctive therapy of focal-onset seizures in patients age 4 years and older. This review examines the use of BRV as add-on (5-200 mg/day) therapy for epilepsy with a particular emphasis on the six regulatory randomized clinical trialsinvolving 2399 participants. Participants receiving BRV add-on at doses of 50-200 mg/day were more likely to experience a 50% or greater reduction in seizure frequency (pooled risk ratio [RR]) 1.79 with 95% CI of 1.51-2.12) than those receiving placebo. Participants receiving BRV were also more likely to attain seizure freedom (57 [3.3%] vs 4 [0.5%]; RR 4.74, 95% CI 2.00-11.25) than those receiving placebo. In addition, BRV demonstrated a favorable safety profile similar to placebo across all BRV doses. Treatment emergent adverse events significantly associated with BRV were irritability, fatigue, somnolence, and dizziness. Post-hoc analysis of regulatory trials, post-marketing studies, and indirect comparison meta-analyses demonstrated equivalent efficacy and better tolerability of BRV when compared to other antiseizure drugs. Further, these studies appear to suggest that behavioral adverse events are likely to be less frequent and less severe with BRV than LEV. Therefore, switching to BRV may be considered for patients who have seizure control with LEV, but who cannot tolerate its behavioral adverse effects. In this setting, immediate switch from LEV to BRV at a 10:1-15:1 ratio without titration is feasible. Further research is needed to examine the long-term tolerability and efficacy of BRV as well as its role in the treatment of other types of epilepsies, particularly dementia-related epilepsy and brain tumor-related epilepsy.

Use of brivaracetam in genetic generalized epilepsies and for acute, intravenous treatment of absence status epilepticus

OBJECTIVE

The objective of this study was to evaluate effectiveness, retention, and tolerability of brivaracetam (BRV) in genetic generalized epilepsies (GGE) in clinical practice.

METHODS

A multicenter, retrospective cohort study recruiting all patients that started BRV in 2016 and 2017.

RESULTS

A total of 61 patients (mean age = 29.8, range = 9-90 years, 41 female [67%]) were treated with BRV. They were difficult to control, with 2.4 failed antiepileptic drugs (AEDs) in the past, taking 1.9 AEDs on average at baseline. The length of exposure to BRV ranged from 7 days to 24 months, with a mean retention time of 7.9 months, resulting in a total exposure time to BRV of 483 months. The retention rate was 82% at 3 months and 69% at 6 months. Efficacy at 3 months was 36% (50% responder rate), with 25% seizure-free for 3 months. Patients with juvenile myoclonic epilepsy showed a responder rate of 60%, with 40% being free of any seizures. Long-term 50% responder rate was present in 17 patients (28%; 11 seizure-free [18%]) for >6 months and in 14 patients (23%; 10 seizure-free [16%]) for >12 months. Treatment-emergent adverse events were observed in 26% of the patients, with the most common being somnolence, ataxia, and psychobehavioral adverse events. Use of intravenous BRV with bolus injection of 200-300 mg in two females with absence status epilepticus was well tolerated, but did not result in cessation of status epilepticus.

SIGNIFICANCE

Use of BRV in GGE is well tolerated, and 50% responder rates are similar to those observed in the regulatory trials for focal epilepsies. An immediate switch from levetiracetam (LEV) to BRV at a ratio of 15:1 is feasible. The occurrence of psychobehavioral adverse events seems less prominent than under LEV, and a switch to BRV can be considered in patients with LEV-induced adverse events.

Effect of repetitive transcranial magnetic stimulation on action myoclonus: A pilot study in patients with EPM1

OBJECTIVE

The objective of this study was to explore the short-term effects of repetitive transcranial magnetic stimulation (rTMS) on action myoclonus.

METHODS

Nine patients with Unverricht-Lundborg (EPM1) progressive myoclonus epilepsy type underwent two series of 500 stimuli at 0.3Hz through round coil twice a day for five consecutive days. Clinical and neurophysiological examinations were performed two hours before starting the first rTMS session and two hours after the end of the last rTMS session.

RESULTS

Eight patients completed the protocol; one discontinued because of a transient increase in spontaneous jerks. The unified myoclonus rating scale indicated a 25% reduction in posttreatment myoclonus with action score associated with an increase in the cortical motor threshold and lengthening of the cortical silent period (CSP). The decrease in the myoclonus with action scores correlated with the prolongation of CSP.

CONCLUSIONS

Repetitive transcranial magnetic stimulation can be safely used in patients with EPM1, improves action myoclonus, and partially restores deficient cortical inhibition.

A review of the pharmacology and clinical efficacy of brivaracetam

Brivaracetam (BRV; Briviact) is a new antiepileptic drug (AED) approved for adjunctive treatment of focal (partial-onset) seizures in adults. BRV is a selective, high-affinity ligand for synaptic vesicle 2A (SV2A) with 15- to 30-fold higher affinity than levetiracetam, the first AED acting on SV2A. It has high lipid solubility and rapid brain penetration, with engagement of the target molecule, SV2A, within minutes of administration. BRV has potent broad-spectrum antiepileptic activity in animal models. Phase I studies indicated BRV was well tolerated and showed a favorable pharmacokinetic profile over a wide dose range following single (10–1,000 mg) and multiple (200–800 mg/day) oral dosing. Three pivotal Phase III studies have demonstrated promising efficacy and a good safety and tolerability profile across doses of 50–200 mg/day in the adjunctive treatment of refractory focal seizures. Long-term data indicate that the response to BRV is sustained, with good tolerability and retention rate. BRV is highly effective in patients experiencing secondarily generalized tonic–clonic seizures. Safety data to date suggest a favorable psychiatric adverse effect profile in controlled studies, although limited postmarketing data are available. BRV is easy to use, with no titration and little drug–drug interaction. It can be initiated at target dose with no titration. Efficacy is seen on day 1 of oral use in a significant percentage of patients. Intravenous administration in a 2-minute bolus and 15-minute infusion is well tolerated. Here, we review the pharmacology, pharmacokinetics, and clinical data of BRV.

Brivaracetam: a novel antiepileptic drug for focal-onset seizures

Brivaracetam (BRV), the n-propyl analogue of levetiracetam (LEV), is the latest antiepileptic drug (AED) to be licensed in Europe and the USA for the adjunctive treatment of focal-onset seizures with or without secondary generalization in patients aged 16 years or older. Like LEV, BRV binds to synaptic vesicle protein 2A (SV2A), but BRV has more selective binding and a 15- to 30-fold higher binding affinity than LEV. BRV is more effective than LEV in slowing synaptic vesicle mobilization and the two AEDs may act at different binding sites or interact with different conformational states of the SV2A protein. In animal models, BRV provides protection against focal and secondary generalized seizures and has significant anticonvulsant effects in genetic models of epilepsy. The drug undergoes first-order pharmacokinetics with an elimination half-life of 7-8 h. Although BRV is metabolized extensively, the main circulating compound is unchanged BRV. Around 95% of metabolites undergo renal elimination. No dose reduction is required in renal impairment, but it is recommended that the daily dose is reduced by one-third in hepatic dysfunction that may prolong half-life. BRV has a low potential for drug interactions. The efficacy and tolerability of adjunctive BRV in adults with focal-onset seizures have been explored in six randomized, placebo-controlled studies. These showed significant efficacy outcomes for doses of 50-200 mg/day. The most common adverse events reported were headache, somnolence, dizziness, fatigue and nausea. Patients who develop psychiatric symptoms with LEV appear to be at risk of similar side effects with BRV, although preliminary data suggest that these issues are likely to be less frequent and perhaps less severe. As with all AEDs, a low starting dose and slow titration schedule help to minimize side effects and optimize seizure control and thereby quality of life.

The Pharmacology and Toxicology of Third-Generation Anticonvulsant Drugs

Epilepsy is a neurologic disorder affecting approximately 50 million people worldwide, or about 0.7% of the population [1]. Thus, the use of anticonvulsant drugs in the treatment of epilepsy is common and widespread. There are three generations of anticonvulsant drugs, categorized by the year in which they were developed and released. The aim of this review is to discuss the pharmacokinetics, drug-drug interactions, and adverse events of the third generation of anticonvulsant drugs. Where available, overdose data will be included. The pharmacokinetic properties of third-generation anticonvulsant drugs include relatively fewer drug-drug interactions, as well as several unique and life-threatening adverse events. Overdose data are limited, so thorough review of adverse events and knowledge of drug mechanism will guide expectant management of future overdose cases. Reporting of these cases as they occur will be necessary to further clarify toxicity of these drugs.

Evaluation of brivaracetam: a new drug to treat epilepsy

INTRODUCTION

High prevalence of therapy-resistant epilepsy demands development of anticonvulsants with new mechanisms of action. Brivaracetam is an analogue of levetiracetam which binds to the synaptic vesicle protein 2A (SV2A) and decreases release of excitatory neurotransmitters. Areas covered: Relevant published studies were searched for by predefined strategy in MEDLINE, EBSCO and SCINDEKS electronic databases. Brivaracetam is effective as adjunctive therapy for uncontrolled partial-onset seizures with or without secondary generalization in patients 16 years and older with epilepsy. It reduces baseline-adjusted focal seizure frequency per week from 7.3 to 12.8% over placebo. Adverse events rate in patients with brivaracetam is not higher than in patients with placebo. Expert opinion: Brivaracetam is an important step forward in the treatment of therapy-resistant partial-onset seizures with or without secondary generalization. Its development was systematic and targeted. Due to its efficacy and excellent safety profile, it is likely that brivaracetam will be often prescribed. In future, efficacy and safety of brivaracetam should be tested in monotherapy settings and also in the first-line therapy of partial-onset seizures.

Methodological issues associated with clinical trials in epilepsy

INTRODUCTION

despite methodological advances in epilepsy clinical trials, the proportion of patients reaching seizure-freedom has not substantially changed over the years. We review the main methodological limitations of current trials, the possible strategies to overcome these limits, and the issues that need to be addressed in next future. Area covered: references were identified by PubMed search until March 2017 and unpublished literature was searched on ClinicalTrials.gov. Add-on trials mainly involve refractory epilepsy subjects, reducing overall response to the investigational drug. The inclusion of subjects with earlier disease from less developed countries has partially allowed overcoming this limitation, but has introduced more random variability of results. Monotherapy trials rise methodological, economical, and ethical concerns with different regulatory requirements in European Union and in the United States of America. Newer trial designs, such as futility trials or 'time-to-event' design, have been implemented. Moreover, both add-on and monotherapy trials results might be affected by patient's ability to recognize and record seizures, and by randomness of seizures occurrence over time. Possible strategies to achieve more reliable outcomes are detailed. Expert commentary: clinical trial methodology needs to be optimized to better address regulatory agencies requirements and to encounter both patients' and clinicians' needs.

New developments in the management of partial-onset epilepsy: role of brivaracetam

Currently, a number of novel anticonvulsant drugs, the so-called third generation, are in various stages of development. Several of them are already available or in ongoing clinical trials. These new compounds should take advantage of new insights into the basic pathophysiology of epileptogenesis, drug metabolism and drug interactions. Many of them still need to be further evaluated mainly in real-world observational trials and registries. Among newer anticonvulsant drugs for partial-onset seizures (POSs), rufinamide, lacosamide, eslicarbazepine and perampanel are those new treatment options for which more substantial clinical evidence is currently available, both in adults and, to some extent, in children. Among the newest anticonvulsant drugs, brivaracetam, a high-affinity synaptic vesicle protein 2A ligand, reported to be 10- to 30-fold more potent than levetiracetam, is highly effective in a broad range of experimental models of focal and generalized seizures. Unlike levetiracetam, brivaracetam does not inhibit high-voltage Ca2+ channels and AMPA receptors and appears to inhibit neuronal voltage-gated sodium channels playing a role as a partial antagonist. Brivaracetam has a linear pharmacokinetic profile, is extensively metabolized and is excreted by urine (only 8%-11% unchanged). It does not seem to influence the pharmacokinetics of other antiepileptic drugs. It was approved in the European Union in January 2016 and in the US in February 2016 as an adjunctive therapy for the treatment of POS in patients older than 16 years of age. To date, its clinical efficacy as adjunctive antiepileptic treatment in adults with refractory POS at doses between 50 and 200 mg daily has been extensively assessed in two Phase IIb and four Phase III randomized controlled studies. Long-term extension studies show sustained efficacy of brivaracetam. Overall, the drug is generally well tolerated with only mild-to-moderate side effects. This is true also by intravenous route. Brivaracetam has not yet been evaluated as monotherapy or in comparison with other new anticonvulsant drugs.

Perampanel in 12 patients with Unverricht-Lundborg disease

OBJECTIVE

Perampanel (PER) was used in 12 patients with Unverricht-Lundborg disease (ULD) to evaluate its efficacy against myoclonus and seizures.

METHODS

We treated 11 patients with EPM1 mutations (6 F, 5 M, aged 13-62 years) and a 43-year-old man with de novo KCNC1 mutation. PER was introduced by 2 mg steps at 2-4 week intervals until 6 mg/day, with a possible dose reduction or dose increase.

RESULTS

Ten patients had a clear clinical response of myoclonus, and five were able to reduce concomitant therapy. Improvement was noted sometimes as soon as with 2 mg/day. Epileptic seizures stopped on PER in the six patients who still had experienced generalized tonic-clonic or myoclonic seizures (100%). Some abatement of efficacy on myoclonus was seen in two patients who still retained some benefit. Weight gain was reported in six patients (50%). Psychological and behavioral side-effects were observed in six patients (50%) and led to withdrawal of PER in three cases and dose reduction in three, with abatement of the problems.

SIGNIFICANCE

This study provides evidence that for ULD patients, PER may show marked efficacy even in severe cases, particularly against myoclonus, but also against seizures. PER should thus be tried in ULD patients whose seizures are not satisfactorily controlled. Its use is limited because of psychological and behavioral side effects, with higher doses of approximately 6 mg/day or greater likely risk factors.

Update on pharmacotherapy of myoclonic seizures

INTRODUCTION

Myoclonic seizures are brief, involuntary muscular jerks arising from the central nervous system that can occur in different epilepsy syndromes, including idiopathic generalized epilepsies or the most severe group of epileptic encephalopathies. Valproate is commonly the first choice alone or in combination with some benzodiazepines or levetiracetam. However, more treatment options exist today as there is emerging evidence to support the efficacy of some newer antiepileptic drugs. In addition, of major importance remains avoidance of medications (e.g., carbamazepine, phenytoin) that may aggravate myoclonic seizures. This is an updated review on the available therapeutic options for treatment of myoclonic seizures. Areas covered: Key efficacy, tolerability and efficacy data are showed for different antiepileptic drugs with antimyoclonic effect, alone and/or in combination. Expert opinion: Pharmacological treatment of myoclonic seizures is based on clinical experience with little evidence from randomized clinical trials. Valproate, levetiracetam, and some benzodiazepines, are widely used. There is still insufficient evidence for the use of other antiseizure drugs, such as topiramate or zonisamide as monotherapy. Better understanding of pathophysiologic mechanisms of myoclonic epilepsies could yield great improvement in the treatment and quality of life of patients.

Synaptic Vesicle Glycoprotein 2A Ligands in the Treatment of Epilepsy and Beyond

The synaptic vesicle glycoprotein SV2A belongs to the major facilitator superfamily (MFS) of transporters and is an integral constituent of synaptic vesicle membranes. SV2A has been demonstrated to be involved in vesicle trafficking and exocytosis, processes crucial for neurotransmission. The anti-seizure drug levetiracetam was the first ligand to target SV2A and displays a broad spectrum of anti-seizure activity in various preclinical models. Several lines of preclinical and clinical evidence, including genetics and protein expression changes, support an important role of SV2A in epilepsy pathophysiology. While the functional consequences of SV2A ligand binding are not fully elucidated, studies suggest that subsequent SV2A conformational changes may contribute to seizure protection. Conversely, the recently discovered negative SV2A modulators, such as UCB0255, counteract the anti-seizure effect of levetiracetam and display procognitive properties in preclinical models. More broadly, dysfunction of SV2A may also be involved in Alzheimer's disease and other types of cognitive impairment, suggesting potential novel therapies for levetiracetam and its congeners. Furthermore, emerging data indicate that there may be important roles for two other SV2 isoforms (SV2B and SV2C) in the pathogenesis of epilepsy, as well as other neurodegenerative diseases. Utilization of recently developed SV2A positron emission tomography ligands will strengthen and reinforce the pharmacological evidence that SV2A is a druggable target, and will provide a better understanding of its role in epilepsy and other neurological diseases, aiding in further defining the full therapeutic potential of SV2A modulation.

Brivaracetam as adjunctive therapy for the treatment of partial-onset seizures in patients with epilepsy: the current evidence base

Brivaracetam (BRV) is a novel antiepileptic drug recently licensed for the treatment of partial epilepsy in adults and adolescents over 16 years old. Like levetiracetam (LEV), it is a ligand of the synaptic vesicle protein SV2A. BRV has been shown in animal models and in studies using human brain slices to have a higher SV2A affinity and faster penetration into the brain. Its efficacy and safety have been shown in several randomized, controlled studies. The recommended initial dose is 50-100 mg, divided into two daily doses. Up-titration to a 200 mg daily dose is possible. Dizziness and somnolence are frequent side effects. There are some hints that BRV may be less frequently associated with behavioural adverse events than LEV. Long-term efficacy and safety and BRV use in special patient groups have to be assessed in the future.

Brivaracetam in the treatment of focal and idiopathic generalized epilepsies and of status epilepticus

Brivaracetam is the latest approved antiepileptic drug in focal epilepsy and exhibits high affinity as SV2A-ligand. More than two thousand patients have received brivaracetam within randomized placebo-controlled trials. Significant median seizure reduction rates of 30.5% to 53.1% for 50 mg/d, 32.5% to 37.2% for 100 mg/d and 35.6% for 200 mg/d were reported. Likewise, 50% responder rates were 32.7% to 55.8% for 50 mg/d, 36% to 38.9% for 100 mg/d and 37.8% for 200 mg/d. Overall, brivaracetam is well tolerated. The main adverse events are fatigue, dizziness, and somnolence. Immediate switch from levetiracetam to brivaracetam at a conversion ratio between 10:1 to 15:1 is feasible, and might alleviate the behavioral side effects associated with levetiracetam. Brivaracetam has the potential to perform as an important, possibly broad-spectrum AED, initially in patients with drug-refractory epilepsies. Its intravenous formulation may be a new and desirable alternative for status epilepticus, but there is so far no experience in these patients.