Evaluation of brivaracetam: a new drug to treat epilepsy

Physiologically based pharmacokinetic modeling of brivaracetam and its interactions with rifampin based on CYP2C19 phenotypes

Brivaracetam (BRV), a third-generation antiepileptic drug (AED), is primarily metabolized through amidase hydrolysis and CYP2C19-mediated hydroxylation in vivo. This study utilized physiologically based pharmacokinetic (PBPK) modeling to explore the pharmacokinetics of BRV and drug interactions between BRV and rifampin (RIF), a CYP2C19 inducer, based on CYP2C19 genetic polymorphisms. A PBPK model of BRV was developed in the general population and in individuals with different CYP2C19 phenotypes by adjusting catalytic rate constants (k_cat), and the model was validated with observed clinical data. The model was then extrapolated to predict BRV steady-state plasma concentration in individuals with different CYP2C19 phenotypes, with or without coadministration of RIF. The developed model adequately described BRV exposure in the abovementioned populations. The predicted steady-state area under the curve (AUC_τ-ss) increases by 20% in heterozygous extensive metabolizers (hEMs) and 55% in poor metabolizers (PMs), compared to homozygous extensive metabolizer (EMs). When coadministered with RIF, the model predicted the most significant magnitude of drug-drug interaction (DDI) in EMs, while the exposure change of BRV was minimal in PMs. Referencing the recommended concentration for therapeutic drug monitoring (TDM), we concluded that the current clinical maintenance dose of BRV is acceptable regardless of CYP2C19 polymorphisms and coadministration with RIF.

[Brivaracetam - A Good Alternative in the Acute Treatment of Trigeminal Neuralgia]

Brivaracetam - A Good Alternative in the Acute Treatment of Trigeminal Neuralgia Abstract. In trigeminal neuralgia there is brief neuropathic pain in the supply area of the trigeminal nerve. A distinction is made between classic, symptomatic, and idiopathic trigeminal neuralgia. Only a few drugs are available for acute treatment. In the presented case series, we report on five patients with trigeminal neuralgia of various origins who responded well to treatment with brivaracetam. Brivaracetam binds to the synaptic vesicle protein 2A, which is also found on nerves and nerve roots. SV2 regulates the exocytotic release of neurotransmitters, which may explain the effect of brivaracetam on neuropathic pain. The use of brivaracetam can be helpful in the short-term therapy of paroxysmal pain with trigeminal neuralgia. Further studies are required to demonstrate this effect and to rule out a placebo effect.

An update on brivaracetam for the treatment of pediatric partial epilepsy

Introduction: Brivaracetam (BRV) is an antiseizure medication (ASM), which has been approved as an adjunctive treatment in adults and pediatric patients aged four years and older with focal onset seizures. It is a second-generation levetiracetam (LEV) derivative, sharing the same mechanism of action, binding synaptic vesicles 2A (SV2A). BRV shows higher binding affinity and selectivity and higher brain permeability than LEV.Areas covered: This article reviews randomized controlled trials, retrospective and prospective studies published up to December 2020, searched in electronic databases MEDLINE, EMBASE and the Clinical Trial Database and provide an overview of efficacy, safety and tolerability of BRV in pediatric patients with partial epilepsy. Furthermore, the authors provide their expert opinion on the drug and give their future perspectives.Expert opinion: The analysis of the literature data has demonstrated the safety and efficacy of BRV in pediatric patients, with more evidence in children aged 4 to 16 years with an onset of focal seizures. However, a positive response was also achieved in patients affected by some encephalopathic epilepsies. Comparative efficacy studies between BRV and other ASMs, in addition to well-designed RCTs that include larger pediatric populations are needed to better define the role and potentiality of this ASM.

Economic and social cost of epilepsy in Poland: 5-year analysis

INTRODUCTION

Epilepsy affects nearly 50 million people around the world. As a common and chronic disease generates a high cost burden for healthcare system and patients.

AIM

We aimed to determine the most current direct and indirect costs of epilepsy in Poland from the social perspective for the years 2014-2018, to analyze the changes of expenditures over time, indicate trends and to determine key cost-drivers.

MATERIAL AND METHODS

Direct and indirect costs using a top-down approach were estimated based on the public institutions' data for the ICD-10 codes G40 and G41. Direct costs included pharmacotherapy, hospitalizations, outpatient specialist care and rehabilitation. A human capital approach was used to estimate loss of productivity due to sick leaves and long-term inability to work.

RESULTS

Annual total direct and indirect costs related to epilepsy accounted for EUR 410 million in 2014 and decreased in subsequent years to EUR 361 million in 2018. The indirect costs were dominant (76-83% of total costs) and in the majority related to the long-term absenteeism (87-92% of total indirect costs). In 2014-2018, patients with epilepsy generated EUR 341 million to EUR 282 million of indirect costs. Annual direct costs for patients with epilepsy were EUR 69 million in 2014 and increased to EUR 80 million in 2018. The biggest expenses were the costs of drugs (> 50%) and hospitalizations (~ 40%).

CONCLUSIONS

Epilepsy is an expensive disorder in terms of consumption of resources and social costs. Decision-makers should take it under special consideration.

The Integrated Effects of Brivaracetam, a Selective Analog of Levetiracetam, on Ionic Currents and Neuronal Excitability

Brivaracetam (BRV) is recognized as a novel third-generation antiepileptic drug approved for the treatment of epilepsy. Emerging evidence has demonstrated that it has potentially better efficacy and tolerability than its analog, Levetiracetam (LEV). This, however, cannot be explained by their common synaptic vesicle-binding mechanism. Whether BRV can affect different ionic currents and concert these effects to alter neuronal excitability remains unclear. With the aid of patch clamp technology, we found that BRV concentration dependently inhibited the depolarization-induced M-type K⁺ current (I_K(M)), decreased the delayed-rectifier K⁺ current (I_K(DR)), and decreased the hyperpolarization-activated cation current in GH3 neurons. However, it had a concentration-dependent inhibition on voltage-gated Na⁺ current (I_Na). Under an inside-out patch configuration, a bath application of BRV increased the open probability of large-conductance Ca²⁺-activated K⁺ channels. Furthermore, in mHippoE-14 hippocampal neurons, the whole-cell I_Na was effectively depressed by BRV. In simulated modeling of hippocampal neurons, BRV was observed to reduce the firing of the action potentials (APs) concurrently with decreases in the AP amplitude. In animal models, BRV ameliorated acute seizures in both OD-1 and lithium-pilocarpine epilepsy models. However, LEV had effects in the latter only. Collectively, our study demonstrated BRV’s multiple ionic mechanism in electrically excitable cells and a potential concerted effect on neuronal excitability and hyperexcitability disorders.

[Brivaracetam-A good alternative for the treatment of muscle cramps]

BACKGROUND

Muscle cramps are suddenly occurring involuntary, mostly painful contractions of a single muscle, rarely of a muscle group. They can be idiopathic or occur in various neuromuscular diseases and can sometimes substantially impair the quality of life due to the frequency and strength. Only a few drugs are available for the effective treatment of cramps.

RESULTS

In this case series we report on five patients with cramps of different origin who responded well to treatment with brivaracetam.

DISCUSSION

Brivaracetam is actually used for the treatment of epileptic seizures. It binds to the synaptic vesicle protein 2A (SV2A), which also occurs in nerves and nerve roots. The SV2A regulates the exocytotic release of neurotransmitters, which could explain the effect of brivaracetam on muscle cramps.

CONCLUSION

Further studies are needed to demonstrate the effect of brivaracetam on muscle cramps.

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.

Treatment with brivaracetam in children - The experience of a pediatric epilepsy center

INTRODUCTION

The new anticonvulsant brivaracetam is a levetiracetam analog which binds to the synaptic vesicle protein 2A, and inhibits excitatory neurotransmitters' release. Brivaracetam was Food and Drug Administration (FDA) and European Medicine Agency (EMA) approved in 2016 as adjunctive treatment for focal onset seizures in patients over 16 years of age, and in 2018 for children over four years of age. Our aim was to describe effectiveness and tolerability in real-life pediatric epilepsy clinic.

METHODS

Cross-sectional retrospective chart review of patients under 20 years of age, treated with brivaracetam. Positive response to treatment was considered when 50% decrease in seizure frequency was noted. In responders to levetiracetam, positive effect was regarded if switching to brivaracetam maintained at least the same seizure control.

RESULTS

Thirty-one patients (67.7% males), aged 13.8 ± 4.07 (6.9-20 years), were treated with brivaracetam 3.8 mg/kg ± 1.8. Age of onset of epilepsy was 5.7 ± 3.7 years; 20 patients had focal epilepsies; and 11 had epileptic syndromes (5 - Lennox-Gastaut, 3 - myoclonic absence, 3 - myoclonic-atonic). Responder rate was 45.2%, with no statistical difference under and over 16 years of age (40% vs. 54.5%, Fisher's exact test). Eight patients had better response to seizures compared to levetiracetam. Gender, duration of epilepsy, and dosage did not affect epilepsy control. Six patients had seizure aggravation. Adverse effects were rare: mild somnolence (6.4%), psychosis (3.2%), and nausea (3.2%).

CONCLUSION

Brivaracetam is an effective add-on treatment in focal, as well as generalized seizures in children, with negligible side effects, including children who failed previously on levetiracetam. Seizure exacerbation may occur, but it's reason is unclear.

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.

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.

Pharmacotherapy for Refractory and Super-Refractory Status Epilepticus in Adults

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

Improving the catalytic efficiency and stereoselectivity of a nitrilase from Synechocystis sp. PCC6803 by semi-rational engineering en route to chiral γ-amino acids

Simultaneously improving activity and stereoselectivity of a nitrilase to catalyze the desymmetrization of 3-substituted glutaronitriles is presented.

A New Chemoenzymatic Synthesis of the Chiral Key Intermediate of the Antiepileptic Brivaracetam

Brivaracetam is a new anticonvulsant compound, recently approved as an antiepileptic drug. This drug substance presents a 4-substituted pyrrolidone structure: the (4R)-configuration of the stereocenter present on the heterocyclic ring is the main target of the synthesis. The described method allows to prepare the suitable optically pure 2-substituted primary alcohol by means of a Pseudomonas fluorescens lipase-catalyzed transesterification. The obtained (2R)-alcohol was easily transformed into the (3R)-3-propylbutyrolactone, an advanced intermediate of brivaracetam. The described synthetic pathway is completed with the chromatographic methods and the NMR analyses necessary to establish the chemical and the optical purity of the intermediates and of the final lactone.