Binding characteristics of brivaracetam, a selective, high affinity SV2A ligand in rat, mouse and human brain: Relationship to anti-convulsant properties

A single exposure to brivaracetam or perampanel does not cause cell death in neonatal rats

Introduction

Exposure to a range of anti-seizure medications (ASMs) during early brain development adversely impacts neurodevelopmental outcomes in both animal models and in clinical studies. Many ASMs, including phenobarbital, phenytoin, valproate (VPA), and benzodiazepines, are associated with acute neurotoxicity (cell death), impaired synaptic development, and long-term behavioral changes following gestational or neonatal exposure in animals. This is mirrored in clinical studies which show lasting neurodevelopmental deficits following early-life or gestational exposure to these drugs. Brivaracetam (BRV) and perampanel (PER) are two newer generation anti-seizure medications and are of interest based on their mechanisms of action (SV2A modulator, AMPA antagonist, respectively), as other drugs with these mechanisms of action do not trigger acute neurotoxicity. Both BRV and PER show anti-seizure efficacy in developing animals, but potential neurotoxicity of these drugs is unexplored.

Methods

To address this gap, we treated postnatal day (P)7 Sprague-Dawley rats with BRV (20, 40, 80 mg/kg) and PER (0.1, 0.9, 2.7 mg/kg), and assessed the induction of cell death across a range of vulnerable brain regions 24 h after exposure. Cell death was assessed using pathogreen staining.

Results

In each of the regions examined (dorsal striatum, nucleus accumbens, motor cortex, cingulate cortex, lateral thalamus, septum, hippocampus), VPA, which served as a positive control, significantly increased cell death as measured by the numer of pathogreen positive cells. By contrast, neither BRV nor PER increased the number of pathogreen positive cells in any region examined.

Discussion

Our results suggest that BRV and PER may have a positive safety profile-at least with respect to acute induction of cell death - and therefore may offer a safer option for the treatment of early life seizures.

Assessment of cerebral drug occupancy in humans using a single PET-scan: A [11C]UCB-J PET study

PURPOSE

Here, we evaluate a PET displacement model with a Single-step and Numerical solution in healthy individuals using the synaptic vesicle glycoprotein (SV2A) PET-tracer [11C]UCB-J and the anti-seizure medication levetiracetam (LEV). We aimed to (1) validate the displacement model by comparing the brain LEV-SV2A occupancy from a single PET scan with the occupancy derived from two PET scans and the Lassen plot and (2) determine the plasma LEV concentration-SV2A occupancy curve in healthy individuals.

METHODS

Eleven healthy individuals (five females, mean age 35.5 [range: 25-47] years) underwent two 120-min [11C]UCB-J PET scans where an LEV dose (5-30 mg/kg) was administered intravenously halfway through the first PET scan to partially displace radioligand binding to SV2A. Five individuals were scanned twice on the same day; the remaining six were scanned once on two separate days, receiving two identical LEV doses. Arterial blood samples were acquired to determine the arterial input function and plasma LEV concentrations. Using the displacement model, the SV2A-LEV target engagement was calculated and compared with the Lassen plot method. The resulting data were fitted with a single-site binding model.

RESULTS

SV2A occupancies and VND estimates derived from the displacement model were not significantly different from the Lassen plot (p = 0.55 and 0.13, respectively). The coefficient of variation was 14.6% vs. 17.3% for the Numerical and the Single-step solution in Bland-Altman comparisons with the Lassen plot. The average half maximal inhibitory concentration (IC50), as estimated from the area under the curve of the plasma LEV concentration, was 12.5 µg/mL (95% CI: 5-25) for the Single-Step solution, 11.8 µg/mL (95% CI: 4-25) for the Numerical solution, and 6.3 µg/mL (95% CI: 0.08-21) for the Lassen plot. Constraining Emax to 100% did not significantly improve model fits.

CONCLUSION

Plasma LEV concentration vs. SV2A occupancy can be determined in humans using a single PET scan displacement model. The average concentration of the three computed IC50 values ranges between 6.3 and 12.5 µg/mL. The next step is to use the displacement model to evaluate LEV occupancy and corresponding plasma concentrations in relation to treatment efficacy.

CLINICAL TRIAL REGISTRATION

NCT05450822. Retrospectively registered 5 July 2022 https://clinicaltrials.gov/ct2/results? term=NCT05450822&Search=Search.

Presynaptic antiseizure medications - basic mechanisms and clues for their rational combinations

Among clinically highly efficient antiseizure medications (ASMs) there are modifiers of the presynaptic release machinery. Of them, levetiracetam and brivaracetam show a high affinity to the synaptic vesicle protein type 2 A (SV2A), whereas pregabalin and gabapentin are selective ligands for the α2δ1 subunits of the voltage-gated calcium channels. In this paper, we present recent progress in understanding the significance of presynaptic release machinery in the neurochemical mechanisms of epilepsy and ASMs. Furthermore, we discuss whether the knowledge of the basic mechanisms of the presynaptically acting ASMs might help establish a rational polytherapy for drug-resistant epilepsy.

Single intravenous and oral dose pharmacokinetics of the antiseizure medication brivaracetam in healthy cats

The number of available antiseizure medications with demonstrated efficacy in cats is limited. As such, there is a need to evaluate the pharmacokinetics of newer medications so that proper dosing regimens can be made. Brivaracetam (BRV) is a more potent analogue of levetiracetam, and is Food and Drug Administration approved for use in people. The goal of this study was to describe the pharmacokinetics of intravenous and oral doses of BRV in healthy cats. A cross-over study involving eight healthy cats, that were administered 10 mg of BRV intravenously as a bolus and orally in the fasted state. Blood samples were collected over 24 h. Analysis was performed using liquid chromatography-mass spectrometry. Data were subjected to non-compartmental analysis. Median (min-max) of maximal concentration, time to maximal concentration, area under the curve, elimination half-life and oral absolute bioavailability were 902 (682-1036) ng/mL, 0.6 (0.5-2.0) h, 6.4 (5.2-7.2) h, 8145 (6669-9351) ng × h/mL and 100% (85-110) respectively. BRV appeared to be well tolerated by all cats. A single dose of BRV is well tolerated both orally and intravenously. Maximal concentrations are produced rapidly and within the human reference interval considered to be therapeutic.

Time-course of drug-related psychiatric and behavioral treatment-emergent adverse events during brivaracetam treatment in adults with focal-onset seizures

OBJECTIVE

We previously analyzed data from three phase lll trials of adjunctive brivaracetam (BRV) in adults showing that the incidence and prevalence of drug-related central nervous system treatment-emergent adverse events (TEAEs) quickly peaked and decreased over several weeks following BRV treatment initiation. However, that analysis did not assess psychiatric and behavioral side effects which can occur with antiseizure medication (ASM) treatment. Here, we investigate the time-course of psychiatric and behavioral TEAEs by week of BRV treatment and how these TEAEs were managed.

METHODS

Data were pooled from three trials (N01252 [NCT00490035]; N01253 [NCT00464269]; N01358 [NCT01261325]) in adult patients (≥16 years of age) with focal-onset seizures receiving BRV adjunctive therapy. This post hoc analysis reports data on the incidence and prevalence of drug-related psychiatric or behavioral TEAEs over time in patients who received BRV doses of 50-200 mg/day (without titration) or placebo (PBO) during the 12-week treatment period. A logistic regression model was used to determine if psychiatric or behavioral comorbid conditions were predictors for drug-related psychiatric or behavioral TEAEs, or BRV discontinuation due to psychiatric or behavioral TEAEs.

RESULTS

A total of 803 patients received BRV 50-200 mg/day, and 459 patients received PBO. Drug-related psychiatric or behavioral TEAEs were reported by 11.0 % of patients during adjunctive BRV treatment (PBO: 4.8 %) with onset early after BRV initiation (median time to onset of first drug-related psychiatric or behavioral TEAE: 15 days). Incidence peaked at week 1 and decreased over the first 4 weeks following BRV initiation. Prevalence peaked at week 4 and then remained stable between weeks 5-12. In an analysis excluding patients on concomitant levetiracetam (BRV: n = 744; PBO: n = 422), the incidence of drug-related psychiatric or behavioral TEAEs was similar to the incidence in the overall population. The most common drug-related psychiatric or behavioral TEAEs were irritability, insomnia, depression, and anxiety. Only 2 % of patients discontinued BRV due to psychiatric or behavioral TEAEs (PBO: 1.3 %), while most patients on BRV who reported drug-related psychiatric or behavioral TEAEs did not require a change in dose (84.1 %; PBO: 63.6 %). A history of psychiatric or behavioral comorbid conditions (not ongoing at BRV initiation) was not associated with an increased likelihood of drug-related psychiatric or behavioral TEAEs, or BRV discontinuation due to psychiatric or behavioral TEAEs. Ongoing psychiatric or behavioral comorbid conditions at BRV initiation increased the likelihood of drug-related psychiatric or behavioral TEAEs, but not the likelihood of BRV discontinuation due to psychiatric or behavioral TEAEs.

CONCLUSIONS

Drug-related psychiatric and behavioral TEAEs occurred early during BRV treatment, and most patients did not require a change in BRV dose. These data can help guide clinician monitoring and patient expectations after starting BRV.

Narrative Review of Brivaracetam: Preclinical Profile and Clinical Benefits in the Treatment of Patients with Epilepsy

One third of patients with epilepsy will continue to have uncontrolled seizures despite treatment with antiseizure medications (ASMs). There is therefore a need to develop novel ASMs. Brivaracetam (BRV) is an ASM that was developed in a major drug discovery program aimed at identifying selective, high-affinity synaptic vesicle protein 2A (SV2A) ligands, the target molecule of levetiracetam. BRV binds to SV2A with 15- to 30-fold higher affinity and greater selectivity than levetiracetam. BRV has broad-spectrum antiseizure activity in animal models of epilepsy, a favorable pharmacokinetic profile, few clinically relevant drug-drug interactions, and rapid brain penetration. BRV is available in oral and intravenous formulations and can be initiated at target dose without titration. Efficacy and safety of adjunctive BRV (50-200 mg/day) treatment of focal-onset seizures was demonstrated in three pivotal phase III trials (NCT00490035/NCT00464269/NCT01261325), including in patients who had previously failed levetiracetam. Efficacy and safety of adjunctive BRV were also demonstrated in adult Asian patients with focal-onset seizures (NCT03083665). In several open-label trials (NCT00150800/NCT00175916/NCT01339559), long-term safety and tolerability of adjunctive BRV was established, with efficacy maintained for up to 14 years, with high retention rates. Evidence from daily clinical practice highlights BRV effectiveness and tolerability in specific epilepsy patient populations with high unmet needs: the elderly (≥ 65 years of age), children (< 16 years of age), patients with cognitive impairment, patients with psychiatric comorbid conditions, and patients with acquired epilepsy of specific etiologies (post-stroke epilepsy/brain tumor related epilepsy/traumatic brain injury-related epilepsy). Here, we review the preclinical profile and clinical benefits of BRV from pivotal trials and recently published evidence from daily clinical practice.

Efficacy, safety, and tolerability of adjunctive brivaracetam in adult Asian patients with uncontrolled focal-onset seizures: A phase III randomized, double-blind, placebo-controlled trial

OBJECTIVE

Evaluate efficacy, safety, and tolerability of adjunctive brivaracetam (BRV) in adult Asian patients with focal-onset seizures (FOS).

METHODS

Phase III, randomized, double-blind, placebo-controlled study (EP0083; NCT03083665) evaluating BRV 50 mg/day and 200 mg/day in patients (≥16-80 years) with FOS with/without secondary generalization (focal to bilateral tonic-clonic seizures) despite current treatment with 1 or 2 concomitant antiseizure medications. Following an 8-week baseline, patients were randomized 1:1:1 to placebo, BRV 50 mg/day, or BRV 200 mg/day, and entered a 12-week treatment period. Efficacy outcomes: percent reduction over placebo in 28-day FOS frequency (primary); 50% responder rate in FOS frequency; median percent reduction in FOS frequency from baseline; seizure freedom during treatment period (secondary). Primary safety endpoints: incidences of treatment-emergent adverse events (TEAEs); TEAEs leading to discontinuation; serious TEAEs.

RESULTS

In this study, 448/449 randomized patients (mean age, 34.5 years; 53.8% female) received ≥1 dose of study medication (placebo/BRV 50 mg/BRV 200 mg/day: n = 149/151/148). Percent reduction over placebo in 28-day adjusted FOS frequency was 24.5% (p = 0.0005) and 33.4% (p < 0.0001) with BRV 50 mg/day and 200 mg/day, respectively, 50% responder rate was 19.0%, 41.1%, and 49.3% with placebo, BRV 50 mg/day, and BRV 200 mg/day, respectively (p < 0.0001 for both BRV groups vs. placebo). Median percent reduction in FOS frequency from baseline was 21.3%/38.9%/46.7% in patients on placebo/BRV 50 mg/BRV 200 mg/day, respectively. Overall, 0, 7 (4.6%), and 10 (6.8%) patients were classified as seizure-free during the treatment period on placebo, BRV 50 mg/day, and BRV 200 mg/day, respectively (p = 0.0146/p = 0.0017 for BRV 50 mg/200 mg/day vs. placebo, respectively). TEAE incidences were similar between patients on placebo (58.4%) and all patients receiving BRV (58.5%); TEAE incidences for BRV 50 mg/day and BRV 200 mg/day were 57.0% and 60.1%, respectively. Overall, 0.7% of patients on placebo and 2.0% of all patients on BRV reported serious TEAEs (incidences for BRV 50 mg/day and BRV 200 mg/day were 1.3% and 2.7%, respectively), 20.1% of patients on placebo and 33.1% of all patients on BRV reported drug-related TEAEs (incidences for BRV 50 mg/day and BRV 200 mg/day were 26.5% and 39.9%, respectively), and 4.7% of patients on placebo and 3.0% of all patients on BRV discontinued due to TEAEs (discontinuation incidences for BRV 50 mg/day and BRV 200 mg/day were 2.6% and 3.4%, respectively).

SIGNIFICANCE

Adjunctive BRV was efficacious and well tolerated in adult Asian patients with FOS. Efficacy and safety profiles were consistent with BRV studies in predominantly non-Asian populations.

PLAIN LANGUAGE SUMMARY

Brivaracetam is used to treat partial or focal seizures in people with epilepsy. Most studies with brivaracetam tablets have involved people from non-Asian racial backgrounds. In this study, 449 Asian adults with epilepsy took part. One third took 50 mg of brivaracetam, one third took 200 mg of brivaracetam, and one third took a placebo each day for 12 weeks. On average, those who took brivaracetam had fewer seizures than those given the placebo. Most of the side effects were mild and the number and type of side effects seen were as expected for this medication.

Exploring the Interactions between two Ligands, UCB-J and UCB-F, and Synaptic Vesicle Glycoprotein 2 Isoforms

In silico modeling was applied to study the efficiency of two ligands, namely, UCB-J and UCB-F, to bind to isoforms of the synaptic vesicle glycoprotein 2 (SV2) that are involved in the regulation of synaptic function in the nerve terminals, with the ultimate goal to understand the selectivity of the interaction between UCB-J and UCB-F to different isoforms of SV2. Docking and large-scale molecular dynamics simulations were carried out to unravel various binding patterns, types of interactions, and binding free energies, covering hydrogen bonding and nonspecific hydrophobic interactions, water bridge, π-π, and cation-π interactions. The overall preference for bonding types of UCB-J and UCB-F with particular residues in the protein pockets can be disclosed in detail. A unique interaction fingerprint, namely, hydrogen bonding with additional cation-π interaction with the pyridine moiety of UCB-J, could be established as an explanation for its high selectivity over the SV2 isoform A (SV2A). Other molecular details, primarily referring to the presence of π-π interactions and hydrogen bonding, could also be analyzed as sources of selectivity of the UCB-F tracer for the three isoforms. The simulations provide atomic details to support future development of new selective tracers targeting synaptic vesicle glycoproteins and their associated diseases.

Brivaracetam exposure-response predictions in pediatric patients from age 1 month: Extrapolation of levetiracetam adult-pediatric scaling to brivaracetam

BACKGROUND

An adult population pharmacokinetic/pharmacodynamic (PK/PD) model for the antiseizure medication (ASM) brivaracetam (BRV) was previously extended to children aged 4-16 years by using a pediatric BRV population PK model. Effects were scaled using information from a combined adult-pediatric PK/PD model of a related ASM, levetiracetam (LEV).

OBJECTIVE

To scale an existing adult population PK/PD model for BRV to children aged 1 month to < 4 years using information from a combined adult-pediatric PK/PD model for LEV, and to predict the effective dose of BRV in children aged 1 month to < 4 years using the adult BRV PK/PD model modified for the basal seizure rate in children.

MATERIAL AND METHODS

An existing adult population PK/PD model for BRV was scaled to children aged from 1 month to < 4 years using information from a combined adult-pediatric PK/PD model for LEV, an ASM binding to the same target protein as BRV. An existing adult-pediatric PK/PD model for LEV was extended using data from UCB study N01009 (NCT00175890) to include children as young as 1 month of age. The BRV population PK model was updated with data up to 180 days after first administration from BRV pediatric studies N01263 (NCT00422422) and N01266 (NCT01364597). PK and PD simulations for BRV were performed for a range of mg/kg doses to predict BRV effect in pediatric participants, and to provide dosing recommendations.

RESULTS

The extended adult-pediatric LEV PK/PD model was able to describe the adult and pediatric data using the same PD model parameters in adults and children and supported the extension of the adult BRV PK/PD model to pediatric patients aged 1 month to < 4 years. Simulations predicted exposures similar to adults receiving BRV 100 mg twice daily (b.i.d.), when using 3 mg/kg b.i.d. for weight < 10 kg, 2.5 mg/kg b.i.d. for weight ≥ 10 kg and < 20 kg, and 2 mg/kg b.i.d. for weight ≥ 20 kg in children aged 1 month to < 4 years. PK/PD simulations show that maximum BRV response is expected to occur with 2-3 mg/kg b.i.d. dosing of BRV in children aged 1 month to < 4 years, with an effective dose of 1 mg/kg b.i.d. for some participants.

CONCLUSION

Development of an adult-pediatric BRV PK/PD model allowed characterization of the exposure-response relationship of BRV in children aged 1 to < 4 years, providing a maximal dose allowance based on weight.

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.

Structural basis for antiepileptic drugs and botulinum neurotoxin recognition of SV2A

More than one percent of people have epilepsy worldwide. Levetiracetam (LEV) is a successful new-generation antiepileptic drug (AED), and its derivative, brivaracetam (BRV), shows improved efficacy. Synaptic vesicle glycoprotein 2a (SV2A), a putative membrane transporter in the synaptic vesicles (SVs), has been identified as a target of LEV and BRV. SV2A also serves as a receptor for botulinum neurotoxin (BoNT), which is the most toxic protein and has paradoxically emerged as a potent reagent for therapeutic and cosmetic applications. Nevertheless, no structural analysis on AEDs and BoNT recognition by full-length SV2A has been available. Here we describe the cryo-electron microscopy structures of the full-length SV2A in complex with the BoNT receptor-binding domain, BoNT/A2 HC, and either LEV or BRV. The large fourth luminal domain of SV2A binds to BoNT/A2 HC through protein-protein and protein-glycan interactions. LEV and BRV occupy the putative substrate-binding site in an outward-open conformation. A propyl group in BRV creates additional contacts with SV2A, explaining its higher binding affinity than that of LEV, which was further supported by label-free spectral shift assay. Numerous LEV derivatives have been developed as AEDs and positron emission tomography (PET) tracers for neuroimaging. Our work provides a structural framework for AEDs and BoNT recognition of SV2A and a blueprint for the rational design of additional AEDs and PET tracers.

Efficacy, tolerability and safety of add-on third-generation antiseizure medications in treating focal seizures worldwide: a network meta-analysis of randomised, placebo-controlled trials

Background

Adjunctive newer antiseizure medications (ASMs) are being used in patients with treatment-resistant focal-onset seizures (FOS). An updated network meta-analysis (NMA) was necessary to compile evidence in this critical area.

Methods

We systematically searched PubMed, Embase, Cochrane Library, Web of Science, and Scopus from their inception until 17 January 2024, evaluating the efficacy, tolerability, and safety of rufinamide (RUF), brivaracetam (BRV), cenobamate (CNB), eslicarbazepine (ESL), lacosamide (LCM), retigabine (RTG), and perampanel (PER) as adjunctive treatments for FOS. Efficacy outcomes included seizure response and seizure freedom. Tolerability was assessed by discontinuation due to adverse events (AEs). Safety outcomes were evaluated based on the number of patients experiencing at least one AE and serious adverse events (SAEs). This review is registered with PROSPERO (CRD42023485130).

Findings

A total of 29 studies involving 11,750 participants were included. For seizure response, all ASMs were significantly superior to placebo, with RTG ranking highest, followed by CNB. Considering dosage, CNB 400 mg/d was top-ranked, followed by RTG 1200 mg/d. For seizure freedom, BRV was highest-ranked, followed by CNB, with BRV 100 mg/d leading, followed by CNB 400 mg/d. Regarding tolerability, LCM 600 mg/d had the lowest ranking, followed by CNB 400 mg/d. For the safety outcome of AEs, ESL 1200 mg/d was ranked lowest, followed by CNB 400 mg/d. Regarding SAEs, LCM 400 mg/d was ranked lowest, followed by RTG 1200 mg/d.

Interpretation

ASMs at different dosages have varying efficacy and tolerability profiles. We have provided hierarchical rankings of ASMs for efficacy and safety outcomes. Our findings offer the most comprehensive evidence available to inform patients, families, physicians, guideline developers, and policymakers about the choice of ASMs in patients with treatment-resistant FOS.

Funding

None.

In vivo imaging of synaptic density in neurodegenerative disorders with positron emission tomography: A systematic review

Positron emission tomography (PET) with radiotracers that bind to synaptic vesicle glycoprotein 2 A (SV2A) enables quantification of synaptic density in the living human brain. Assessing the regional distribution and severity of synaptic density loss will contribute to our understanding of the pathological processes that precede atrophy in neurodegeneration. In this systematic review, we provide a discussion of in vivo SV2A PET imaging research for quantitative assessment of synaptic density in various dementia conditions: amnestic Mild Cognitive Impairment and Alzheimer's disease, Frontotemporal dementia, Progressive supranuclear palsy and Corticobasal degeneration, Parkinson's disease and Dementia with Lewy bodies, Huntington's disease, and Spinocerebellar Ataxia. We discuss the main findings concerning group differences and clinical-cognitive correlations, and explore relations between SV2A PET and other markers of pathology. Additionally, we touch upon synaptic density in healthy ageing and outcomes of radiotracer validation studies. Studies were identified on PubMed and Embase between 2018 and 2023; last searched on the 3rd of July 2023. A total of 36 studies were included, comprising 5 on normal ageing, 21 clinical studies, and 10 validation studies. Extracted study characteristics were participant details, methodological aspects, and critical findings. In summary, the small but growing literature on in vivo SV2A PET has revealed different spatial patterns of synaptic density loss among various neurodegenerative disorders that correlate with cognitive functioning, supporting the potential role of SV2A PET imaging for differential diagnosis. SV2A PET imaging shows tremendous capability to provide novel insights into the aetiology of neurodegenerative disorders and great promise as a biomarker for synaptic density reduction. Novel directions for future synaptic density research are proposed, including (a) longitudinal imaging in larger patient cohorts of preclinical dementias, (b) multi-modal mapping of synaptic density loss onto other pathological processes, and (c) monitoring therapeutic responses and assessing drug efficacy in clinical trials.

The impact of brivaracetam on cognitive processes and anxiety in various experimental models

BACKGROUND

Memory deficits and anxiety symptoms are undesirable effects that occur in epilepsy patients. They may be associated with the pathophysiology of the disease but also with anticonvulsant therapy. Brivaracetam (BRV) is one of the newest antiseizure drugs. It acts as a ligand for synaptic vesicle glycoprotein 2A (SV2A), which may play a significant role in cognitive processes. Although BRV has a favorable safety profile, its central side effects remain unclear. Hence, this study aimed to evaluate the effect of BRV on various types of memory and anxiety in rats.

METHODS

BRV was given to adult male Wistar rats (n = 80) via gastric tube as a single dose (6 mg/kg or 20 mg/kg) or chronically (6 mg/kg). The effect of the drug on spatial memory was evaluated in the Morris water maze (MWM), fear-learning by passive avoidance (PA), and recognition memory with novel object recognition (NOR). The elevated plus maze (EPM) was used to assess anxiety-like behaviors.

RESULTS

The impact of BRV on memory is dose-dependent and mainly high doses may alter retrieval memory and fear-learning. Sub-chronic administration also impaired retrieval and spatial memory in animals. Moreover, chronic BRV may increase anxiety levels in rats but did not affect recognition memory.

CONCLUSIONS

BRV may cause transient memory deficits as well as anxiety disturbances. However, the results are varied and depend on the type of memory, used dose, and duration of administration.

Rapid switching from levetiracetam to brivaracetam in pharmaco-resistant epilepsy in people with and without intellectual disabilities: a naturalistic case control study

BACKGROUND

Approximately one quarter of people with an intellectual disability (PwID) have epilepsy of whom nearly three-quarters are pharmaco-resistant. There are higher reported neuropsychiatric side-effects to anti-seizure medication (ASM) in this group. Levetiracetam (LEV) is a first-line ASM with a stronger association with neuropsychiatric symptoms for PwID than other ASMs. Brivaracetam (BRV) is a newer ASM. Recent studies suggest a beneficial effect of swapping people who experience neuropsychiatric events with LEV to BRV. However, there is limited evidence of this for PwID. This evaluation analyses real world outcomes of LEV to BRV swap for PwID compared to those without ID.

METHODS

We performed a multicentre, retrospective review of clinical records. Demographic, clinical characteristics and reported adverse events of patients switched from LEV to BRV (2016-2020) were recorded at 3 months pre and 6- and 12-month post-BRV initiation. Outcomes were compared between PwID and those without and summarised using cross-tabulations and logistic regression models. A Bonferroni correction was applied.

RESULTS

Of 77 participants, 46 had ID and 52% had a past psychiatric illness. 71% participants switched overnight from LEV to BRV. Seizure reduction of > 50% was seen in 40% patients. Psychiatric illness history was predictive of having neuropsychiatric side-effects with LEV but not BRV (p = 0.001). There was no significant difference for any primary outcomes between PwID versus without ID.

CONCLUSIONS

Switching from LEV to BRV appears as well tolerated and efficacious in PwID as those without ID with over 90% still on BRV after 12 months.

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.

Real-life evidence about the use of intravenous brivaracetam in urgent seizures: The BRIV-IV study

PURPOSE

Urgent seizures are a medical emergency for which new therapies are still needed. This study evaluated the use of intravenous brivaracetam (IV-BRV) in an emergency setting in clinical practice.

METHODS

BRIV-IV was a retrospective, multicenter, observational study. It included patients ≥18 years old who were diagnosed with urgent seizures (including status epilepticus (SE), acute repetitive seizures, and high-risk seizures) and who were treated with IV-BRV according to clinical practice in 14 hospital centers. Information was extracted from clinical charts and included in an electronic database. Primary effectiveness endpoints included the rate of IV-BRV responder patients, the rate of patients with a sustained response without seizure relapse in 12 h, and the time between IV-BRV administration and clinical response. Primary safety endpoints were comprised the percentage of patients with adverse events and those with adverse events leading to discontinuation.

RESULTS

A total of 156 patients were included in this study. The mean age was 57.7 ± 21.5 years old with a prior diagnosis of epilepsy for 57.1% of patients. The most frequent etiologies were brain tumor-related (18.1%) and vascular (11.2%) epilepsy. SE was diagnosed in 55.3% of patients. The median time from urgent seizure onset to IV treatment administration was 60.0 min (range: 15.0-360.0), and the median time from IV treatment to IV-BRV was 90.0 min (range: 30.0-2400.0). Regarding dosage, the mean bolus infusion was 163.0 ± 73.0 mg and the mean daily dosage was 195.0 ± 87.0 mg. A total of 77.6% of patients responded to IV-BRV (66.3% with SE vs. 91% other urgent seizures) with a median response time of 30.0 min (range: 10.0-60.0). A sustained response was achieved in 62.8% of patients. However, adverse events were reported in 14.7%, which were predominantly somnolence and fatigue, with 4.5% leading to discontinuation. Eighty-six percent of patients were discharged with oral brivaracetam.

CONCLUSION

IV-BRV in emergency settings was effective, and tolerability was good for most patients. However, a larger series is needed to confirm the outcomes.

Design and evaluation of gastro-swelling/gastro-floating sustained-release tablets of brivaracetam for epilepsy therapy

To prolong the absorption of the drug and achieve the effect of gastric retention, new brivaracetam tablets together with the characteristics of rapid swelling and sustained floating have been developed here. The tablets were optimized and prepared by direct compression techniques using Kollidon® SR and cross-linked polyvinylpyrrolidone (PVPP) XL as the matrix and disintegrant respectively, and carbomer 71G NF and polyethylene oxide (PEO) N60K as the gel materials to achieve sustained release effect. The characteristics of static expansion, floating time, drug release and dynamic swelling performance in vitro of the tablets were evaluated. The optimized formulations (F5 and F10) exhibited satisfactory swelling and floating properties, mechanical strength, and in vitro sustained-release characteristic with diffusion and matrix erosion mechanisms. X-ray images of beagle dogs showed that the tablet F5 could be retained in the stomach for more than 6 h. Furthermore, the pharmacokinetic studies in volunteers exhibited that the bioavailability of F5 and F10 was 95.70% (90% CI, 83.80%-109.28%) and 103.39% (90% CI, 87.61%-122.01%), respectively, relative to commercial tablets, with Tmax prolonged, demonstrating an excellent sustained-release effect. Therefore, the present system can reduce dosing frequency and improve patient compliance, which is expected to be a promising treatment option for epilepsy patients.

The efficacy and tolerability of adjunctive brivaracetam for the treatment of adult epilepsy: An Australian multi-center retrospective real-world observational cohort study

OBJECTIVE

Assess the efficacy and tolerability of add-on therapy brivaracetam (BRV) in adult patients with epilepsy in a real-world setting.

METHODS

This multi-center retrospective observational cohort study examined all adult patients who commenced on BRV at 11 Australian epilepsy centers between 2017 and 2020. Primary outcomes were seizure response (≥50% reduction in frequency) and seizure freedom 12 months post BRV commencement, and tolerability. We report three approaches to missing data (complete case analysis, CCA; last observation carried forward, LOCF; and intention to treat, ITT). Secondary outcomes included the durability of early BRV response and continuous seizure freedom from BRV initiation. Subgroup analysis examined patients with focal and generalized epilepsy and patients with refractory (≥4 prior ASMs) and highly refractory (≥7 prior ASMs) epilepsy. Outcomes were also assessed at 'personalized' seizure outcome time points based on baseline seizure frequency.

RESULTS

Baseline and follow-up data were available for 228 patients. The mean age was 41.5 years (IQR 30, 50). Most had focal epilepsy (188/228, 82.5%). Median number of previous ASMs was 4 (2, 7), and concomitant ASMs 2 (2, 3). Twelve-month responder rate was: 46.3% using CCA (95% CI 34.0, 58.9); 39.5% using LOCF (33.1, 46.1); and 15.4% using ITT (10.9, 20.7). Twelve-month seizure freedom was: 23.9% using CCA (14.3, 35.9); 24.6% using LOCF (19.1, 30.7); and 7.9% using ITT (4.7, 12.1). The most frequent adverse effects were sedation or cognitive slowing (33/228, 14.5%), irritability or aggression (16/228, 7.0%), and low mood (14/228, 6.1%). Outcomes were similar using continuous outcome definitions and 'personalized' outcome assessment time points. Early responses were highly durable, with 3-month response maintained at all subsequent time points at 83%, and seizure freedom maintained at 85%. Outcomes were similar in focal (n = 187) and generalizsed (n = 25) subgroups. Outcomes were similar in refractory patients (n = 129), but lower in the highly refractory group (n = 62), however improvement with BRV was still observed with 12-month seizure freedom of 8.3% using CCA (1.0, 27), 6.5% using LOCF (1.8, 15.7); and 3.2% using ITT (0.4, 11.2).

CONCLUSIONS

Meaningful real-world responder and seizure freedom rates can be still observed in a refractory epilepsy population. Brivaracetam response can occur early and appears to be maintained with minimal later relapse. The results should be interpreted with caution given the retrospective nature of the study and the quantities of missing data at later time points.

Brivaracetam or levetiracetam in status epilepticus?: Lessons from the photosensitivity model

First, a short history is given of the use of the EEG as a biomarker of efficacy in anti-seizure medication (ASM) development. The generalized epileptiform EEG response to Intermittent Photic Stimulation (IPS), the photoparoxysmal EEG response or PPR, in particular, is a reliable reproducible measure since the 1950s. Over time, a "Photosensitivity Model", testing within the same patients the impact of potential new oral ASMs, along with dose-ranging data, on PPRs, has been developed successfully. The classical Photosensitivity Model consists of IPS and blood sampling for ASM measurement performed hourly between 8 AM and 5 PM over three consecutive days. This single-blind, placebo-controlled, pharmacokinetic-pharmacodynamic (PK/PD) Model is now commonly utilized as a Proof-of-Concept Phase 2a trial. For Generalized Tonic-Clonic Status Epilepticus (GTCSE), it is especially relevant to know the time for CNS entry and effect minutes after i.v. ASM treatment, since "time is brain". We, therefore, adapted successfully the Model to a time-efficient Model with the determination of photosensitivity ranges in minutes after equivalent doses of iv brivaracetam (BRV) and levetiracetam (LEV). This modified design allows one to monitor the time to CNS effect (i.e., PPR elimination) of a quickly-acting FDA-approved ASM given i.v., a crucial element in status epilepticus treatment. This paper was presented at the 8th London-Innsbruck Colloqium on Status Epilepticus and Acute Seizures held in September 2022.

BRIVEST: A 'real-world' observational, single-centre study investigating the efficacy, safety and tolerability of Brivaracetam

OBJECTIVE

Via measures of efficacy, tolerability, and safety, this open-label, single-center study assessed the overall effectiveness of Brivaracetam (BRV) for the treatment of epilepsy in the context of 'real-world' clinical practice.

METHODS

Unselected consecutive patients were recruited and stratified into 3 cohorts with either fully prospective, fully retrospective or mixed data collection, dependent on whether their BRV prescriptions were historical, current, or pending. Prospective data were obtained at baseline, 3 and 6 months, and at 6-month intervals thereafter, from patient interviews and seizure diaries, and retrospective data from medical records. Efficacy variables were derived from seizure-related changes, and tolerability and safety variables from reported treatment-emergent adverse events (TEAEs), BRV withdrawal, and changes to questionnaire scores. Additionally, we investigated treatment outcomes for those with previous levetiracetam (LEV) use, a history of psychiatric comorbidity, a learning disability, and of older age.

RESULTS

One hundred and nine patients (58.7% female, mean age 42 years, range: 18 to 72) were included, 59 with prospective follow-up for a minimum of 6 (47 patients, excluding those who withdrew) and a maximum of 24 months (2 patients). Of the full cohort, 87.2% had drug-resistant epilepsy. Retention: At the study end, the median treatment duration was 384 days (range: 6 to 1514 days), and BRV retention was 68.8%. Kaplan-Meier survival functions predicted retention rates of 74.0% and 70.0% at 6 and 12 months respectively.

EFFICACY

At the last follow-up, there was a ≥ 50% responder rate of 30.8%, with 12.1% seizure-free. Seizure frequency categories improved in 31.4% of patients, remained the same in 44.2%, and worsened in 24.4%. Monthly tonic-clonic seizure frequency had significantly decreased, and of those reporting these seizures, 58.3% showed reductions and 25.0% showed complete tonic-clonic seizure freedom.

TOLERABILITY

91.7% of patients reported at least 1 TEAE, with fatigue (30.3%), irritability (29.4%), and depression/low mood (28.4%) as the most common. Only 58.4% of all TEAEs were persistent. Brivaracetam discontinuation due to side effects occurred in 27.5% of the cohort. Depression and anxiety scores remained stable over time, and quality-of-life scores improved. Subgroups: Measures of BRV efficacy and tolerability did not differ according to previous LEV exposure. Tolerability profiles of those with learning disabilities, histories of psychiatric comorbidities, and older age did not greatly differ from the rest of the cohort. Of note, specific history of depression predicted the reporting of suicidal ideation.

CONCLUSION

The BRIVEST study provides real-world evidence of the effectiveness of BRV, suggesting that neither drug-resistant epilepsy nor previous LEV failure should preclude its use. Furthermore, BRV appears to be well-tolerated, even among those from vulnerable patient populations.

Drug characteristics derived from kinetic modeling: combined 11C-UCB-J human PET imaging with levetiracetam and brivaracetam occupancy of SV2A

BACKGROUND

Antiepileptic drugs, levetiracetam (LEV) and brivaracetam (BRV), bind to synaptic vesicle glycoprotein 2A (SV2A). In their anti-seizure activity, speed of brain entry may be an important factor. BRV showed faster entry into the human and non-human primate brain, based on more rapid displacement of SV2A tracer ¹¹C-UCB-J. To extract additional information from previous human studies, we developed a nonlinear model that accounted for drug entry into the brain and binding to SV2A using brain ¹¹C-UCB-J positron emission tomography (PET) data and the time-varying plasma drug concentration, to assess the kinetic parameter K₁ (brain entry rate) of the drugs.

METHOD

Displacement (LEV or BRV p.i. 60 min post-tracer injection) and post-dose scans were conducted in five healthy subjects. Blood samples were collected for measurement of drug concentration and the tracer arterial input function. Fitting of nonlinear differential equations was applied simultaneously to time-activity curves (TACs) from displacement and post-dose scans to estimate 5 parameters: K₁ (drug), K₁(¹¹C-UCB-J, displacement), K₁(¹¹C-UCB-J, post-dose), free fraction of ¹¹C-UCB-J in brain (f_ND(¹¹C-UCB-J)), and distribution volume of ¹¹C-UCB-J (V_T(UCB-J)). Other parameters (K_D(drug), K_D(¹¹C-UCB-J), f_P(drug), f_P(¹¹C-UCB-J, displacement), f_P(¹¹C-UCB-J, post-dose), f_ND(drug), k_off(drug), k_off(¹¹C-UCB-J)) were fixed to literature or measured values.

RESULTS

The proposed model described well the TACs in all subjects; however, estimates of drug K₁ were unstable in comparison with ¹¹C-UCB-J K₁ estimation. To provide a conservative estimate of the relative speed of brain entry for BRV vs. LEV, we determined a lower bound on the ratio BRV K₁/LEV K₁, by finding the lowest BRV K₁ or highest LEV K₁ that were statistically consistent with the data. Specifically, we used the F test to compare the residual sum of squares with fixed BRV K₁ to that with floating BRV K₁ to obtain the lowest possible BRV K₁; the same analysis was performed to find the highest LEV K₁. The lower bound of the ratio BRV K₁/LEV K₁ was ~ 7.

CONCLUSIONS

Under appropriate conditions, this advanced nonlinear model can directly estimate entry rates of drugs into tissue by analysis of PET TACs. Using a conservative statistical cutoff, BRV enters the brain at least sevenfold faster than LEV.

Efficacy and tolerability of brivaracetam monotherapy in childhood and juvenile absence epilepsy: An innovative adaptive trial design

OBJECTIVE

Despite introduction of several antiseizure medications over the past two decades, treatment options for childhood absence epilepsy (CAE) and juvenile absence epilepsy (JAE) remain limited. We report the innovative adaptive design of an ongoing phase 2/3 trial to evaluate efficacy, safety, and tolerability of brivaracetam (BRV) monotherapy in patients 2-25 years of age with CAE or JAE.

METHODS

N01269 (ClinicalTrials.gov: NCT04666610; start: July 2021; expected completion: 2024) is a randomized, dose-finding and confirmatory, double-blind, placebo-controlled, parallel-group, multicenter trial. The trial consists of a dose-selection and assessment for futility stage, followed by an optimal-dose stage after interim analysis. Both stages include an up to 2-week screening period, a 2-week placebo-controlled period, and an 11-week active treatment period (10 weeks of initial treatment followed by a 24-hour electroencephalogram [EEG] and an additional week of active treatment for 24-hour EEG assessment). Patients who are absence seizure-free will enter an up to 4-week randomized withdrawal period. Efficacy assessments will be based on 24-hour EEG and seizure diaries.

SIGNIFICANCE

This two-stage adaptive trial design allows investigation of two potentially efficacious BRV doses, where one dose is dropped in favor of the other dose with a better benefit-risk profile. This allows for a combined phase 2 dose-finding and phase 3 confirmatory efficacy trial, which reduces the number of patients needed to be recruited and reduces trial duration. A randomized withdrawal period is included to evaluate sustainability of treatment effect over time and to allow for placebo control while minimizing placebo exposure. Use of EEG capture in addition to seizure diaries offers a robust mechanism of detecting seizure activity and measuring treatment effect. Positive efficacy and safety/tolerability data may support the use of BRV as monotherapy for CAE or JAE, providing another treatment option and representing long-delayed progress in the treatment of absence seizures in these populations.

Treatment and care of women with epilepsy before, during, and after pregnancy: a practical guide

Women with epilepsy (WWE) wishing for a child represent a highly relevant subgroup of epilepsy patients. The treating epileptologist needs to delineate the epilepsy syndrome and choose the appropriate anti-seizure medication (ASM) considering the main goal of seizure freedom, teratogenic risks, changes in drug metabolism during pregnancy and postpartum, demanding for up-titration during and down-titration after pregnancy. Folic acid or vitamin K supplements and breastfeeding are also discussed in this review. Lamotrigine and levetiracetam have the lowest teratogenic potential. Data on teratogenic risks are also favorable for oxcarbazepine, whereas topiramate tends to have an unfavorable profile. Valproate needs special emphasis. It is most effective in generalized seizures but should be avoided whenever possible due to its teratogenic effects and the negative impact on neuropsychological development of in utero-exposed children. Valproate still has its justification in patients not achieving seizure freedom with other ASMs or if a woman decides to or cannot become pregnant for any reason. When valproate is the most appropriate treatment option, the patient and caregiver must be fully informed of the risks associated with its use during pregnancies. Folate supplementation is recommended to reduce the risk of major congenital malformations. However, there is insufficient information to address the optimal dose and it is unclear whether higher doses offer greater protection. There is currently no general recommendation for a peripartum vitamin K prophylaxis. During pregnancy most ASMs (e.g. lamotrigine, oxcarbazepine, and levetiracetam) need to be increased to compensate for the decline in serum levels; exceptions are valproate and carbamazepine. Postpartum, baseline levels are reached relatively fast, and down-titration is performed empirically. Many ASMs in monotherapy are (moderately) safe for breastfeeding and women should be encouraged to do so. This review provides a practically oriented overview of the complex management of WWE before, during, and after pregnancy.

Imaging of Synaptic Density in Neurodegenerative Disorders

PET technology has produced many radiopharmaceuticals that target specific brain proteins and other measures of brain function. Recently, a new approach has emerged to image synaptic density by targeting the synaptic vesicle protein 2A (SV2A), an integral glycoprotein in the membrane of synaptic vesicles and widely distributed throughout the brain. Multiple SV2A ligands have been developed and translated to human use. The most successful of these to date is 11C-UCB-J, because of its high uptake, moderate metabolism, and effective quantification with a 1-tissue-compartment model. Further, since SV2A is the target of the antiepileptic drug levetiracetam, human blocking studies have characterized specific binding and potential reference regions. Regional brain SV2A levels were shown to correlate with those of synaptophysin, another commonly used marker of synaptic density, providing the basis for SV2A PET imaging to have broad utility across neuropathologic diseases. In this review, we highlight the development of SV2A tracers and the evaluation of quantification methods, including compartment modeling and simple tissue ratios. Mouse and rat models of neurodegenerative diseases have been studied with small-animal PET, providing validation by comparison to direct tissue measures. Next, we review human PET imaging results in multiple neurodegenerative disorders. Studies on Parkinson disease and Alzheimer disease have progressed most rapidly at multiple centers, with generally consistent results of patterns of SV2A or synaptic loss. In Alzheimer disease, the synaptic loss patterns differ from those of amyloid, tau, and 18F-FDG, although intertracer and interregional correlations have been found. Smaller studies have been reported in other disorders, including Lewy body dementia, frontotemporal dementia, Huntington disease, progressive supranuclear palsy, and corticobasal degeneration. In conclusion, PET imaging of SV2A has rapidly developed, and qualified radioligands are available. PET studies on humans indicate that SV2A loss might be specific to disease-associated brain regions and consistent with synaptic density loss. The recent availability of new 18F tracers, 18F-SynVesT-1 and 18F-SynVesT-2, will substantially broaden the application of SV2A PET. Future studies are needed in larger patient cohorts to establish the clinical value of SV2A PET and its potential for diagnosis and progression monitoring of neurodegenerative diseases, as well as efficacy assessment of disease-modifying therapies.

Method Development and Validation of a Novel UHPLC Coupled with MS/MS System for the Estimation of Brivaracetam in Human (K2EDTA) Plasma Samples and its Application to Pharmacokinetic Study

Background:

Brivaracetam is a novel antiepileptic drug clinically approved for the treatment of partial onset seizures in adults and adolescents. It has some abuse potential and assigns to Schedule V category under the Controlled Substance Act by the Drug Enforcement Administration. It is essential to develop a faster, simple, and highly sensitive method for the quantification of Brivaracetam in human plasma by employing simple liquid-liquid extraction.

Objective:

The objective of this study is to develop and validate a novel UHPLC-MS/MS method for the estimation of brivaracetam in human plasma samples and application to pharmacokinetic study.

Methods:

An ultra-high-pressure liquid chromatography-tandem mass spectrometry method was developed and validated according to current regulatory guidelines for bioanalytical methods. Sample processing (50 μL) involved only a simple liquid-liquid extraction by ethyl acetate as extraction solvent. Brivaracetam-d7 was used as an internal standard. The chromatographic analysis was performed by a Unisol C18 (4.6 X 100 mm, 5μm) column using 0.1% formic acid in water/acetonitrile (20/80 V/V) as an isocratic mobile phase, at a flow rate of 1.0 mL/min with a run time of 2.2 min. Brivaracetam and its internal standard Brivaracetam D7 were detected and quantified in positive ion mode using multiple reaction monitoring transitions at m/z 213.100→168.100 and m/z 220.000→175.100, respectively. The developed method was applied to assess pharmacokinetic parameters like Cmax, Tmax, t1/2 and AUC for Brivaracetam in healthy, male, and adult humans.

Results:

The method was validated over a concentration range of 20.000 ng/mL to 4000. 000 ng/mL. Both intra- and inter-assay precision and accuracy were <15% for all quality control samples. No matrix effect was observed. Pharmacokinetic results showed that test formulation is bioequivalent with reference formulation.

Conclusion:

The present assay is faster, highly sensitive and simpler than previously published analytical reports for brivaracetam in human plasma samples and is suitable for pharmacokinetic evaluation of any marketed formulation.

Connectivity Mapping Using a Novel sv2a Loss-of-Function Zebrafish Epilepsy Model as a Powerful Strategy for Anti-epileptic Drug Discovery

Synaptic vesicle glycoprotein 2A (SV2A) regulates action potential-dependent neurotransmitter release and is commonly known as the primary binding site of an approved anti-epileptic drug, levetiracetam. Although several rodent knockout models have demonstrated the importance of SV2A for functional neurotransmission, its precise physiological function and role in epilepsy pathophysiology remains to be elucidated. Here, we present a novel sv2a knockout model in zebrafish, a vertebrate with complementary advantages to rodents. We demonstrated that 6 days post fertilization homozygous sv2a^–/– mutant zebrafish larvae, but not sv2a^+/– and sv2a^+/+ larvae, displayed locomotor hyperactivity and spontaneous epileptiform discharges, however, no major brain malformations could be observed. A partial rescue of this epileptiform brain activity could be observed after treatment with two commonly used anti-epileptic drugs, valproic acid and, surprisingly, levetiracetam. This observation indicated that additional targets, besides Sv2a, maybe are involved in the protective effects of levetiracetam against epileptic seizures. Furthermore, a transcriptome analysis provided insights into the neuropathological processes underlying the observed epileptic phenotype. While gene expression profiling revealed only one differentially expressed gene (DEG) between wildtype and sv2a^+/– larvae, there were 4386 and 3535 DEGs between wildtype and sv2a^–/–, and sv2a^+/– and sv2a^–/– larvae, respectively. Pathway and gene ontology (GO) enrichment analysis between wildtype and sv2a^–/– larvae revealed several pathways and GO terms enriched amongst up- and down-regulated genes, including MAPK signaling, synaptic vesicle cycle, and extracellular matrix organization, all known to be involved in epileptogenesis and epilepsy. Importantly, we used the Connectivity map database to identify compounds with opposing gene signatures compared to the one observed in sv2a^–/– larvae, to finally rescue the epileptic phenotype. Two out of three selected compounds rescued electrographic discharges in sv2a^–/– larvae, while negative controls did not. Taken together, our results demonstrate that sv2a deficiency leads to increased seizure vulnerability and provide valuable insight into the functional importance of sv2a in the brain in general. Furthermore, we provided evidence that the concept of connectivity mapping represents an attractive and powerful approach in the discovery of novel compounds against epilepsy.

Tolerability and efficacy of adjunctive brivaracetam in adults with focal seizures by concomitant antiseizure medication use: pooled results from three Phase 3 trials

Objective

This study was undertaken to evaluate safety/tolerability and efficacy of adjunctive brivaracetam (BRV) in patients on one or two concomitant antiseizure medications (ASMs) and in patients on one specific concomitant ASM.

Methods

Post hoc analysis was made of double‐blind trials (N01252/NCT00490035, N01253/NCT00464269, and N01358/NCT01261325) in adults with focal seizures randomized to BRV (50–200 mg/day; approved therapeutic dose range for adults) or placebo with concomitant ASM regimen unchanged throughout a 12‐week evaluation period. Outcomes were analyzed in patients on one or two concomitant ASMs, and those on concomitant carbamazepine (CBZ), lamotrigine (LTG), oxcarbazepine (OXC), or valproate (VPA) only.

Results

Patients randomized to BRV with one or two concomitant ASMs, respectively (n = 181/557), reported similar incidences of treatment‐emergent adverse events (TEAEs; 68.0%/66.4%), drug‐related TEAEs (41.4%/41.5%), and TEAEs leading to discontinuation (6.6%/5.4%). Respective values for patients randomized to placebo with one or two concomitant ASMs (n = 95/331) were 60.0%/60.7% (TEAEs), 32.6%/30.2% (drug‐related TEAEs), and 2.1%/4.5% (TEAEs leading to discontinuation). The incidences of TEAEs, drug‐related TEAEs, and TEAEs leading to discontinuation by specific concomitant ASM (CBZ, LTG, OXC, VPA) were similar to the overall incidences in patients taking one concomitant ASM. In patients on one or two concomitant ASMs, respectively, 50% responder rates were numerically higher on BRV (42.3%/36.8% [n = 175/511]) versus placebo (18.3%/19.5% [n = 93/298]). Patients with one or two ASMs on BRV (n = 175/509) versus placebo (n = 92/298) also had numerically higher 100% responder rates (BRV, 9.1%/4.5%; placebo, 1.1%/.3%) and seizure freedom (6.9%/3.7%; 1.1%/0). For patients taking concomitant CBZ, LTG, OXC, or VPA, efficacy was numerically higher with BRV (n = 54/30/27/27) versus placebo (n = 34/13/10/14–15; 50% responder rates: BRV, 31.5%/30.0%/40.7%/70.4%; placebo, 17.6%/7.7%/20.0%/33.3%; 100% responder rates: BRV, 5.6%/10.0%/11.1%/11.1%; placebo, 0 for all; seizure freedom: BRV, 3.7%/6.7%/7.4%/11.1%; placebo, 0 for all).

Significance

Therapeutic doses of BRV were efficacious and well tolerated regardless of the number of concomitant ASMs (one or two) or specific concomitant ASM (CBZ, LTG, OXC, VPA).

Levetiracetam Mechanisms of Action: From Molecules to Systems

Epilepsy is a chronic disease that affects millions of people worldwide. Antiepileptic drugs (AEDs) are used to control seizures. Even though parts of their mechanisms of action are known, there are still components that need to be studied. Therefore, the search for novel drugs, new molecular targets, and a better understanding of the mechanisms of action of existing drugs is still crucial. Levetiracetam (LEV) is an AED that has been shown to be effective in seizure control and is well-tolerable, with a novel mechanism of action through an interaction with the synaptic vesicle protein 2A (SV2A). Moreover, LEV has other molecular targets that involve calcium homeostasis, the GABAergic system, and AMPA receptors among others, that might be integrated into a single mechanism of action that could explain the antiepileptogenic, anti-inflammatory, neuroprotective, and antioxidant properties of LEV. This puts it as a possible multitarget drug with clinical applications other than for epilepsy. According to the above, the objective of this work was to carry out a comprehensive and integrative review of LEV in relation to its clinical uses, structural properties, therapeutical targets, and different molecular, genetic, and systemic action mechanisms in order to consider LEV as a candidate for drug repurposing.

Intravenous Brivaracetam in the Management of Acute Seizures in the Hospital Setting: A Scoping Review

Background

Clinical considerations for drug treatment of acute seizures involve variables such as safety, tolerability, drug-drug interactions, dosage, route of administration, and alterations in pharmacokinetics because of critical illness. Therapy options that are easily and quickly administered without dilution, well tolerated, and effective are needed for the treatment of acute seizures. The objective of this review is to focus on the clinical considerations relating to the use of intravenous brivaracetam (IV BRV) for the treatment of acute seizures in the hospital, focusing on critically ill patients.

Methods

This was a scoping literature review of PubMed from inception to April 13, 2021, and search of the American Academy of Neurology (AAN) 2021 Annual Meeting website for English language publications/conference abstracts reporting the results of IV BRV use in hospitalized patients, particularly in the critical care setting. Outcomes of interest relating to the clinical pharmacology, safety, tolerability, efficacy, and effectiveness of IV BRV were reviewed and are discussed.

Results

Twelve studies were included for analysis. One study showed that plasma concentrations of IV BRV 15 min after the first dose were similar between patients receiving IV BRV as bolus or infusion. IV BRV was generally well tolerated in patients with acute seizures in the hospital setting, with a low incidence of individual TEAEs classified as behavioral disorders. IV BRV demonstrated efficacy and effectiveness and had a rapid onset, with clinical and electrophysiological improvement in seizures observed within minutes. Although outside of the approved label, findings from several studies suggest that IV BRV reduces seizures and is generally well tolerated in patients with status epilepticus.

Conclusions

IV BRV shows effectiveness, and is generally well tolerated in the management of acute seizures in hospitalized patients where rapid administration is needed, representing a clinically relevant antiseizure medication for potential use in the critical care setting.

Brivaracetam Modulates Short-Term Synaptic Activity and Low-Frequency Spontaneous Brain Activity by Delaying Synaptic Vesicle Recycling in Two Distinct Rodent Models of Epileptic Seizures

Brivaracetam (BRV) is an anti-seizure drug for the treatment of focal and generalized epileptic seizures shown to augment short-term synaptic fatigue by slowing down synaptic vesicle recycling rates in control animals. In this study, we sought to investigate whether altered short-term synaptic activities could be a pathological hallmark during the interictal periods of epileptic seizures in two well-established rodent models, as well as to reveal BRV's therapeutic roles in altered short-term synaptic activities and low-frequency band spontaneous brain hyperactivity in these models. In our study, the electrophysiological field excitatory post-synaptic potential (fEPSP) recordings were performed in rat hippocampal brain slices from the CA1 region by stimulation of the Schaffer collateral/commissural pathway with or without BRV (30 μM for 3 h) in control or epileptic seizure (induced by pilocarpine (PILO) or high potassium (h-K⁺)) models. Short-term synaptic activities were induced by 5, 10, 20, and 40-Hz stimulation sequences. The effects of BRV on pre-synaptic vesicle mobilization were visually assessed by staining the synaptic vesicles with FM1-43 dye followed by imaging with a two-photon microscope. In the fEPSP measurements, short-term synaptic fatigue was found in the control group, while short-term synaptic potentiation (STP) was detected in both PILO and h-K⁺ models. STP was decreased after the slices were treated with BRV (30 μM) for 3 h. BRV also exhibited its therapeutic benefits by decreasing abnormal peak power (frequency range of 8-13 Hz, 31% of variation for PILO model, 25% of variation for h-K⁺ model) and trough power (frequency range of 1-4 Hz, 66% of variation for PILO model, 49% of variation for h-K⁺ model), and FM1-43 stained synaptic vesicle mobility (64% of the variation for PILO model, 45% of the variation for h-K⁺ model) in these epileptic seizure models. To the best of our knowledge, this was the first report that BRV decreased the STP and abnormal low-frequency brain activities during the interictal phase of epileptic seizures by slowing down the mobilization of synaptic vesicles in two rodent models. These mechanistic findings would greatly advance our understanding of BRV's pharmacological role in pathomechanisms of epileptic seizures and its treatment strategy optimization to avoid or minimize BRV-induced possible adverse side reactions.

Brivaracetam prevents the development of epileptiform activity when administered early after cortical neurotrauma in rats

OBJECTIVES

There is no effective therapy to prevent the development of posttraumatic epilepsy (PTE). Recently, we reported that administration of the antiseizure medication (ASM) levetiracetam (LEV) shortly after trauma prevented the development of epileptiform activity in two experimental models of neurotrauma. However, the time window for effective intervention with LEV may be too narrow for most clinical settings. Using the controlled cortical impact (CCI) injury model, the current study tested whether early administration of brivaracetam (BRV), an ASM with 20 times the affinity of LEV for the SV2A synaptic vesicle protein, could improve upon the antiepileptogenic action observed with LEV.

METHODS

Rats (postnatal day [P] 24-32) subjected to CCI injury were given a single dose of BRV (21 or 100 mg/kg, i.p.) at one of three post-injury time points: immediately (0-2 minutes), 30 minutes, or 60 minutes. Control animals received only vehicle (0.9% saline). Posttraumatic electrographic epileptiform activity was assayed ex vivo from coronal neocortical slices collected proximal to the injury (four per rat) 3-4 weeks after injury. In this model, ictal-like burst discharges occur spontaneously or can be evoked in an "all or none" manner with applied electrical stimulation within the first 2 weeks after injury.

RESULTS

A single dose of BRV administered to rats up to 60 minutes after traumatic brain injury (TBI) significantly reduced the development of posttraumatic epileptiform activity by (1) inhibiting the development of both evoked and spontaneous epileptiform activity, (2) raising the threshold for stimulus-evoked epileptiform discharges, and (3) reducing the intensity of epileptiform bursts that arise after cortical neurotrauma.

SIGNIFICANCE

Clinically there has been little success preventing the development of posttraumatic epilepsy. The results of this study support the hypothesis that early intervention with BRV has the potential to prevent or reduce posttraumatic epileptogenesis, and that there may be a limited time window for successful prophylactic intervention.

Clinical and Economic Outcomes of Intravenous Brivaracetam Compared With Levetiracetam for the Treatment of Seizures in United States Hospitals

Background: Seizures are common among hospitalized patients. Levetiracetam (LEV), a synaptic vesicle protein 2A (SV2A) ligand, is a common intravenous (IV) anti-seizure medication option in hospitals. Brivaracetam (BRV), a selective SV2A ligand for treatment of focal seizures in patients ≥16 years, has greater binding affinity, higher lipophilicity, and faster brain entry than IV LEV. Differences in clinical outcomes and associated costs between IV BRV and IV LEV in treating hospitalized patients with seizure remain unknown.

Objectives: To compare the clinical outcomes, costs, and healthcare resource utilization between patients with seizure treated with IV BRV and those with IV LEV within hospital setting.

Design/Methods: A retrospective cohort analysis was performed using chargemaster data from 210 United States hospitals in Premier Healthcare Database. Adult patients (age ≥18 years) treated intravenously with LEV or BRV (with or without BZD) and a seizure discharge diagnosis between July 1, 2016 and December 31, 2019 were included. The cohorts were propensity score-matched 4:1 on baseline characteristics. Outcomes included intubation rates, intensive care unit (ICU) admission, length of stay (LOS), all-cause and seizure-related readmission, total hospitalization cost, and in-hospital mortality. A multivariable regression analysis was performed to determine the association between treatment and main outcomes adjusting for unbalanced confounders.

Results: A total of 450 patients were analyzed (IV LEV, n = 360 vs. IV BRV, n = 90). Patients treated with IV BRV had lower crude prevalence of ICU admission (14.4 vs. 24.2%, P < 0.05), 30-day all-cause readmission (1.1 vs. 6.4%, P = 0.06), seizure-related 30-day readmission (0 vs. 4.2%, P < 0.05), similar mean total hospitalization costs ($13,715 vs. $13,419, P = 0.91), intubation (0 vs. 1.1%, P = 0.59), and in-hospital mortality (4.4 vs. 3.9%, P = 0.77). The adjusted odds for ICU admission (adjusted odds ratio [_aOR] = 0.6; 95% confidence interval [CI]:0.31, 1.16; P = 0.13), 30-day all-cause readmission (_aOR = 0.17; 95% CI:0.02, 1.24; P = 0.08), and in-hospital mortality (_aOR = 1.15; 95% CI:0.37, 3.58, P = 0.81) were statistically similar between comparison groups.

Conclusion: The use of IV BRV may provide an alternative to IV LEV for management of seizures in hospital setting due to lower or comparable prevalence of ICU admission, intubation, and 30-day seizure-related readmission. Additional studies with greater statistical power are needed to confirm these findings.

Reactive metabolites of the anticonvulsant drugs and approaches to minimize the adverse drug reaction

Several generations of antiepileptic drugs (AEDs) are available in the market for the treatment of seizures, but these are amalgamated with acute to chronic side effects. The most common side effects of AEDs are dose-related, but some are idiosyncratic adverse drug reactions (ADRs) that transpire due to the formation of reactive metabolite (RM) after the bioactivation process. Because of the adverse reactions patients usually discontinue the medication in between the treatment. The AEDs such as valproic acid, lamotrigine, phenytoin etc., can be categorized under such types because they form the RM which may prevail with life-threatening adverse effects or immune-mediated reactions. Hepatotoxicity, teratogenicity, cutaneous hypersensitivity, dizziness, addiction, serum sickness reaction, renal calculi, metabolic acidosis are associated with the metabolites of drugs such as arene oxide, N-desmethyldiazepam, 2-(1-hydroxyethyl)-2-methylsuccinimide, 2-(sulphamoy1acetyl)-phenol, E-2-en-VPA and 4-en-VPA and carbamazepine-10,11-epoxide, etc. The major toxicities are associated with the moieties that are either capable of forming RM or the functional groups may itself be too reactive prior to the metabolism. These functional groups or fragment structures are typically known as structural alerts or toxicophores. Therefore, minimizing the bioactivation potential of lead structures in the early phases of drug discovery by a modification to low-risk drug molecules is a priority for the pharmaceutical companies. Additionally, excellent potency and pharmacokinetic (PK) behaviour help in ensuring that appropriate (low dose) candidate drugs progress into the development phase. The current review discusses about RMs in the anticonvulsant drugs along with their mechanism vis-a-vis research efforts that have been taken to minimize the toxic effects of AEDs therapy.

Brivaracetam in treating epileptic encephalopathy and refractory focal epilepsies in patients under 14 years of age

Objectives

To analyze the efficacy and safety of Brivaracetam in pediatric patients with epileptic encephalopathy or unresponsive focal epilepsy.

Materials & Methods

This retrospective study included eight pediatric patients with EE or unresponsive focal epilepsy. Inclusion criteria: (1) ≤14 years, (2) history of refractory epilepsy, (3) at least one month of continuous therapy with BRV, and (4) at least six months of follow-up. Exclusion criteria: (1) variation of concomitant antiepileptic drugs during the previous and/or subsequent four weeks of the BRV introduction, (2) levetiracetam in therapy, (3) epilepsy secondary to the progressive cerebral disease, tumor, or any other progressive neurodegenerative diseases, and (4) a status epilepticus a month before screening or during the baseline period. The efficacy of BRV was defined as ≥50% of seizure frequency reduction at the end of the follow-up, compared to baseline.

Results:

All patients showed ≥50% seizure frequency reduction, of whom 37.5% were seizure-free, 25% had a frequency reduction of ≥75%, and 37.5% had frequency reduction of ≥ 50%. All patients with an epilepsy onset >12 months and epilepsy duration of ≤6 years were seizure-free. The maximum effect was achieved at 2 mg/kg/day, and focal seizures revealed a better response than epileptic encephalopathy. A remarkably positive effect of the Brivaracetam was noticed in patients with encephalopathy regarding the status epilepticus during sleep; however, no relevant side-effects were noted.

Conclusion:

Brivaracetam was an effective and well-tolerated treatment in pediatric patients with epileptic encephalopathy or unresponsive focal epilepsy, especially for the epilepsy onset >12 months and the epilepsy duration ≤6 years. The total effect was not dose-dependent. Brivaracetam could represent an indication of encephalopathy regarding the status epilepticus during sleep.

Loss of Hippocampal Calretinin and Parvalbumin Interneurons in the 5XFAD Mouse Model of Alzheimer's Disease

The deposition of amyloid-β peptides in the form of extracellular plaques and neuronal degeneration belong to the hallmark features of Alzheimer’s disease (AD). In addition, impaired calcium homeostasis and altered levels in calcium-binding proteins seem to be associated with the disease process. In this study, calretinin- (CR) and parvalbumin- (PV) positive gamma-aminobutyric acid-producing (GABAergic) interneurons were quantified in different hippocampal subfields of 12-month-old wild-type mice, as well as in the transgenic AD mouse models 5XFAD and Tg4-42. While, in comparison with wild-type mice, CR-positive interneurons were mainly reduced in the CA1 and CA2/3 regions in plaque-bearing 5XFAD mice, PV-positive interneurons were reduced in all analyzed subfields including the dentate gyrus. No reduction in CR- and PV-positive interneuron numbers was detected in the non-plaque-forming Tg4-42 mouse, although this model has been previously demonstrated to harbor a massive loss of CA1 pyramidal neurons. These results provide information about hippocampal interneuron numbers in two relevant AD mouse models, suggesting that interneuron loss in this brain region may be related to extracellular amyloid burden.

Preclinical In Vitro and In Vivo Characterization of Synaptic Vesicle 2A-Targeting Compounds Amenable to F-18 Labeling as Potential PET Radioligands for Imaging of Synapse Integrity

PURPOSE

Current synaptic vesicle 2A (SV2A) positron emission tomography (PET) imaging agents include the nanomolar affinity probes [¹¹C]UCB-J and [¹⁸F]UCB-H derived from the anti-epileptic drug levitaracetam (Keppra®). An industry-utilized "de-risking" approach was used to carry out initial pharmacological characterization and to assess potential next-generation candidates amenable to F-18 radiolabeling for preliminary evaluation.

PROCEDURES

Radioligand binding methods were employed in mammalian brain homogenates to determine the SV2A affinity (K_d) and maximal binding capacity (B_max) of [³H]UCB-J. Novel leads were then screened to identify compounds minimally with comparable binding affinities with UCB-J in order to select a F-18-labeled candidate for subsequent in vivo assessment in rat. In parallel, mammalian brain tissue section autoradiography was performed to assess specific SV2A distribution.

RESULTS

[³H]UCB-J bound with high affinity to a single population of sites in the rat brain (K_d = 2.6 ± 0.25 nM; B_max = 810 ± 25 fmol/mg protein) and control human cortex (K_d = 2.9 ± 0.54 nM; B_max = 10,000 ± 640 fmol/mg protein). Distribution of specific SV2A binding was shown to be homogeneous throughout the rodent brain and primarily in gray matter regions of rodent and human brain sections. Analog screening identified MNI-1038, MNI-1126/SDM-8, and SDM-2 as having comparable binding affinities with the currently available PET ligands. Subsequent [¹⁸F]MNI-1126/[¹⁸F]SDM-8 dynamic micro-PET imaging in rats revealed in vivo uptake and accumulation in the brain with favorable kinetics. Chase studies using 30 mg/kg levetiracetam confirmed that in vivo brain uptake of [¹⁸F]MNI-1126/[¹⁸F]SDM-8 was reversible.

CONCLUSIONS

Taken together, these data suggest [¹⁸F]MNI-1126/[¹⁸F]SDM-8 (since renamed as [¹⁸F]SynVesT-1) characterized via an in vitro screening cascade provided a measurable in vivo SV2A specific signal in the rodent brain. This tracer as well as the close analog [¹⁸F]SDM-2 (since renamed as [¹⁸F]SynVesT-2) is currently undergoing further evaluation in preclinical and clinical studies.

Effect of Number of Previous Antiseizure Medications on Efficacy and Tolerability of Adjunctive Brivaracetam for Uncontrolled Focal Seizures: Post Hoc Analysis

INTRODUCTION

The aim was to evaluate the efficacy and tolerability of adjunctive brivaracetam (BRV) in adults with severely drug-resistant focal seizures versus adults with less drug-resistant disease.

METHODS

Data were pooled from patients with focal seizures on 1-2 concomitant antiseizure medications (ASMs) randomized to BRV 50, 100, 200 mg/day, or placebo in 3 phase 3 trials (N01252 [NCT00490035], N01253 [NCT00464269], and N01358 [NCT01261325]) with a 12-week treatment period. Outcomes were assessed in patients with ≥ 5 and 0-4 previous ASMs (stopped before trial drug initiation).

RESULTS

In ≥ 5 previous ASMs subgroup (BRV 50, 100, 200 mg/day: n = 26, n = 137, n = 120; placebo: n = 151), percentage reduction over placebo in 28-day adjusted focal seizure frequency was 13.0% for 50 mg/day (p = 0.38), 18.1% for 100 mg/day (p = 0.006), 19.8% for 200 mg/day (p = 0.004), and 17.0% for all BRV-treated patients (p = 0.001). The 50% responder rate was 26.9%, 29.9%, 30.0%, and 29.7% for BRV 50, 100, 200, and 50-200 mg/day, respectively (placebo: 13.2%); odds ratios versus placebo were statistically significant (p < 0.05) for BRV 100, 200, and 50-200 mg/day. In 0-4 previous ASMs subgroup (BRV 50, 100, 200 mg/day: n = 135, n = 195, n = 129; placebo: n = 267), all BRV dosages showed statistically significant (1) percentage reduction over placebo in 28-day adjusted focal seizure frequency (21.4-28.7%); (2) differences from placebo in median percentage reduction in 28-day adjusted focal seizure frequency from baseline (35.5-45.9%; placebo: 21.3%); and (3) odds ratios versus placebo (favoring BRV) for 50% responder rates. In BRV-treated patients, treatment-emergent adverse event (TEAE) incidence (73.8% [217/294] vs. 64.6% [329/509]) and discontinuation due to TEAEs (10.5% vs. 4.5%) were higher in the ≥ 5 versus 0-4 previous ASMs subgroup; serious TEAEs were rare in both subgroups (≥ 5 previous ASMs: 3.1%; 0-4 previous ASMs: 2.9%).

CONCLUSION

Adjunctive BRV showed efficacy and was generally well tolerated in adults with focal seizures independent of the number of previous ASMs.

Long-term efficacy and tolerability of adjunctive brivaracetam in adults with focal to bilateral tonic-clonic (secondary generalized) seizures: Post hoc pooled analysis

This post hoc analysis was conducted to evaluate the efficacy, tolerability, and health-related quality of life during long-term adjunctive brivaracetam (BRV) treatment in adult patients with focal to bilateral tonic-clonic seizures (FBTCS). Patients (≥ 16 years) were included in this post hoc analysis if they were randomized to BRV or placebo in double-blind, placebo-controlled (N01252 [NCT00490035], N01253 [NCT00464269], N01358 [NCT01261325]; core) trials, and received adjunctive BRV in the corresponding long-term follow-up (N01125 [NCT00175916], N01199 [NCT00150800], N01379 [NCT01339559]) trials, and reported FBTCS during the 8-week prospective baseline (core trial). Efficacy (concomitant levetiracetam excluded) and tolerability (concomitant levetiracetam included) were assessed from the first day of BRV in patients who initiated BRV at 50-200 mg/day. Two hundred and eighty-four patients reported FBTCS during baseline (core trials) and were included in the Efficacy Set. Patients (mean age of 37.0 years; 51.8% male; mean epilepsy duration of 22.4 years; median baseline frequency of 2.8 FBTCS per 28 days) received BRV for a median treatment duration of 2.5 years (range< 0.1-11.3) at a median modal dose of 150 mg/day. BRV was discontinued by 175 (61.6%) patients, most commonly (≥ 10% of patients) due to adverse event (18.3%), lack of efficacy (18.3%), and consent withdrawn (11.6%); the median time to discontinuation of BRV due to any reason was 358.5 days. The Kaplan-Meier (KM)-estimated retention on BRV at 1, 3, and 5 years, were 69.3%, 48.2%, and 37.3%, respectively. The KM-estimated proportion of patients not discontinuing BRV due to lack of efficacy or adverse event were 80.0%, 63.9%, and 57.2% at 1, 3, and 5 years, respectively. Overall, the median percentage reduction in FBTCS frequency from baseline was 76.2%, and the 50% and 75% responder rates for FBTCS were 68.7% and 50.7%, respectively, which were sustained over time across completer cohorts. Sustained 50%, 75%, and 100% response in FBTCS from day 1 of adjunctive BRV treatment during the entire first year was estimated for 32.5%, 21.1%, and 15.0% of patients, respectively (KM analysis), and showed maintenance or improvement in the response to BRV over time. For patients with ≥ 1 year of BRV exposure, 51.3% were free from FBTCS for ≥ 1 year during any time of the treatment period, and 22.8% of patients did not report FBTCS during the first year from the first day of treatment. Clinically meaningful improvements in total Patient Weighted Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) score were reported by 43.6% and 46.4% of patients after 1 and 2 years of treatment, respectively. The largest improvements in the QOLIE-31-P score, with > 50% of patients reporting a clinically meaningful improvement, were observed in the seizure worry and daily activities/social functioning subscales after 1 and 2 years of BRV treatment. Overall, 278/313 (88.8%; Safety Set) patients reported at least one treatment-emergent adverse event (TEAE), 170 (54.3%) had a drug-related TEAE, 88 (28.1%) had a serious TEAE, and 55 (17.6%) discontinued BRV due to a TEAE. Overall, long-term adjunctive BRV was generally well tolerated and reduced the frequency of FBTCS in adults, with 22.8% of patients (who completed ≥ 1 year of treatment) not reporting any FBTCS during the first year from the first day of BRV treatment.

Brivaracetam: How Well Does It Fare as an Anti-Epileptic? A Review

Objectives

Epilepsy is a common neurological ailment contributing to significant disability. About one-third of all epilepsy patients would be refractory to two or more medications. Brivaracetam (BRV) is one of the newer anti-seizure medications on which extensive data is available, but its efficacy as an early add-on agent (first/second adjuvant) is unclear. The principal objective of this review is to assess the efficacy of BRV as an early add-on agent in refractory Focal Onset Seizures (FOS) and its pharmacology and usage in various clinical situations associated with seizures.

Methods

We searched two databases, Medline and Cochrane Central, for papers on BRV and FOS, and selected six studies with randomized parallel control design to extract the data for a meta-analysis. We also did a comprehensive review of the available literature on its pharmacology and usage in various clinical scenarios associated with seizures.

Results

For the meta-analysis, we extracted 145 articles; six studies fulfilled the selection criteria that gave us data on 1938 patients who received Brivaracetam as an early add-on agent in FOS. The Risk Ratio (RR) (95% CI) for 50% responders across the trials was 1.88 (1.55-2.29). Similarly, the overall RR (95% CI) was 5.82 (2.15-15.70) for seizure freedom.

Conclusion

Our analysis provides moderate evidence for Brivaracetam as an effective agent as an early adjuvant in FOS. Its efficacy for several other indications needs further clinical trials and evaluation.

Brivaracetam Retention Rate and Seizure Outcomes in Patients with Drug-Resistant Focal Epilepsy Included in the Medical Need Program in Belgium: A Real-World, Multicenter, Chart Review

Background

New treatments are needed for patients with drug-resistant epilepsy to improve seizure control without decreasing quality of life.

Objective

In Belgium, a Medical Need Program (MNP) was initiated to make a new antiepileptic drug (brivaracetam; high-affinity synaptic vesicle protein 2A ligand) available as adjunctive therapy to treat focal seizures in patients failing treatment with three or more different antiepileptic drugs. This is a real-world chart review of the majority of patients (71%) enrolled in the MNP.

Patients and Methods

Retention and seizure outcomes of brivaracetam adjunctive treatment were evaluated in 175 patients aged ≥ 16 years enrolled in the MNP between June 2016 and May 2017 at six centers; 95.4% were previously/concomitantly treated with levetiracetam. Safety events data were also collected.

Results

In this highly drug-resistant population, 85.8%, 73.9%, and 64.9% of patients remained on brivaracetam, while seizure frequency decreased from baseline in 32.0%, 37.1%, and 37.3% of patients after 3, 6, and 9 months’ treatment, respectively. Patients achieving 3-month seizure freedom increased from 3.2% after 3 months’ treatment to 10.2% and 10.7% after 6 and 9 months’ treatment, respectively. Six-month seizure freedom was achieved by 5.7% of patients at any time. Qualitative evaluation of seizures by physicians demonstrated 44.2%, 38.8%, and 43.2% of patients improved and 42.8%, 50.9%, and 50.6% remained unchanged during 3, 6, and 9 months’ follow-up, respectively. No safety signals were identified.

Conclusions

Retention was high during 9 months of brivaracetam treatment in drug-resistant patients, including those previously/concomitantly treated with levetiracetam; 3-month seizure freedom increased from 3.2% after 3 months to 10.7% after 9 months of treatment.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40801-021-00246-7.

Quantification of SV2A Binding in Rodent Brain Using [18F]SynVesT-1 and PET Imaging

PURPOSE

Synapse loss is a hallmark of Alzheimer's disease (AD) and correlates with cognitive decline. The validation of a noninvasive in vivo imaging approach to quantify synapse would greatly facilitate our understanding of AD pathogenesis and assist drug developments for AD. As animal models of neurodegenerative and neuropsychiatric disorders play a critical role in the drug discovery and development process, a robust, objective, and translational method for quantifying therapeutic drug efficacy in animal models will facilitate the drug development process. In this study, we tested the quantification reliability of the SV2A PET tracer, [¹⁸F]SynVesT-1, in a mouse model of AD (APP/PS1) and wild-type controls, and developed a simplified quantification method to facilitate large cohort preclinical imaging studies.

PROCEDURES

We generated nondisplaceable binding potential (BP_ND) and distribution volume ratio (DVR) values using the simplified reference tissue model (SRTM) on the 90-min dynamic PET imaging data, with brain stem and cerebellum as the reference region, respectively. Then, we correlated the standardized uptake value ratio (SUVR)-1 and SUVR averaged from different imaging windows with BP_ND and DVR, using brain stem and cerebellum as the reference region, respectively. We performed homologous competitive binding assay and autoradiographic saturation binding assay using [¹⁸F]SynVesT-1 to calculate the B_max and K_d.

RESULTS

Using brain stem as the reference region, the averaged SUVR-1 from 30 to 60 min postinjection correlated well with the BP_ND calculated using SRTM. Using cerebellum as the reference region, the averaged SUVR from 30 to 60 min postinjection correlated well with the SRTM DVR. From the homologous competitive binding assay and autoradiographic saturation binding assay, the calculated the B_max and K_d were 4.5-18 pmol/mg protein and 9.8-19.6 nM, respectively, for rodent brain tissue.

CONCLUSIONS

This simplified SUVR method provides reasonable SV2A measures in APP/PS1 mice and their littermate controls. Our data indicate that, in lieu of a full 90-min dynamic scan, a 30-min static PET scan (from 30 to 60 min postinjection) would be sufficient to provide quantification data on SV2A expression, equivalent to the data generated from kinetic modeling. The methods developed here are readily applicable to the evaluation of therapeutic effects of novel drugs in this rodent model using [¹⁸F]SynVesT-1 and small animal PET.

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.

Behavioral adverse events with brivaracetam, levetiracetam, perampanel, and topiramate: A systematic review

PURPOSE

To understand the currently available post-marketing real-world evidence of the incidences of and discontinuations due to the BAEs of irritability, anger, and aggression in people with epilepsy (PWE) treated with the anti-seizure medications (ASMs) brivaracetam (BRV), levetiracetam (LEV), perampanel (PER), and topiramate (TPM), as well as behavioral adverse events (BAEs) in PWE switching from LEV to BRV.

METHODS

A systematic review of published literature using the Cochrane Library, PubMed/MEDLINE, and Embase was performed to identify retrospective and prospective observational studies reporting the incidence of irritability, anger, or aggression with BRV, LEV, PER, or TPM in PWE. The incidences of these BAEs and the rates of discontinuation due to each were categorized by ASM, and where possible, weighted means were calculated but not statistically assessed. Behavioral and psychiatric adverse events in PWE switching from LEV to BRV were summarized descriptively.

RESULTS

A total of 1500 records were identified in the searches. Of these, 44 published articles reporting 42 studies met the study criteria and were included in the data synthesis, 7 studies were identified in the clinical trial database, and 5 studies included PWE switching from LEV to BRV. Studies included a variety of methods, study populations, and definitions of BAEs. While a wide range of results was reported across studies, weighted mean incidences were 5.6% for BRV, 9.9% for LEV, 12.3% for PER, and 3.1% for TPM for irritability; 3.3%* for BRV, 2.5% for LEV, 2.0% for PER, and 0.2%* for TPM for anger; and 2.5% for BRV, 2.6% for LEV, 4.4% for PER, and 0.5%* for TPM for aggression. Weighted mean discontinuation rates were 0.8%* for BRV, 3.4% for LEV, 3.0% for PER, and 2.2% for TPM for irritability and 0.8%* for BRV, 2.4% for LEV, 9.2% for PER, and 1.2%* for TPM for aggression. There were no discontinuations for anger. Switching from LEV to BRV led to improvement in BAEs in 33.3% to 83.0% of patients (weighted mean, 66.6%). *Denotes only 1 study.

CONCLUSIONS

This systematic review characterizes the incidences of irritability, anger, and aggression with BRV, LEV, PER, and TPM, and it provides robust real-world evidence demonstrating that switching from LEV to BRV may improve BAEs. While additional data remain valuable due to differences in methodology (which make comparisons difficult), these results improve understanding of the real-world incidences of discontinuations due to these BAEs in clinical practice and can aid in discussions and treatment decision-making with PWE.

Long-term safety, efficacy, and quality of life during adjunctive brivaracetam treatment in patients with uncontrolled epilepsy: An open-label follow-up trial

OBJECTIVES

The primary objective of this long-term follow-up (LTFU) trial was to evaluate the long-term safety and tolerability of brivaracetam (BRV). The secondary objective was to evaluate the maintenance of efficacy of BRV (including quality of life) over time.

METHODS

This open-label, multicenter, flexible-dose trial (N01379 [NCT01339559]) was conducted in adults (≥16 years) with focal or generalized-onset seizures, who had participated in a placebo (PBO)-controlled trial of adjunctive BRV (N01258: NCT01405508 or N01358: NCT01261325).

RESULTS

Seven hundred and sixty-six patients received BRV in this LTFU trial (753 had focal seizures and 13 had generalized-onset seizures). Kaplan-Meier-estimated retention was 71.9% at 12 months, and 53.7% at 36 months. Treatment-emergent adverse events (TEAEs) were reported by 643 (83.9%) patients, most commonly headache (104 [13.6%] patients) and dizziness (100 [13.1%] patients). Two hundred and fifty-seven (33.6%) patients had drug-related TEAEs, most commonly somnolence (49 [6.4%] patients) and dizziness (41 [5.4%] patients). Permanent discontinuation of BRV due to TEAEs occurred in 91 (11.9%) patients. Patients with focal seizures had a median percentage reduction in focal seizure frequency of 52.0% and 51.7% were 50% responders (sustained over time); 26.0% were seizurefree for 6 months, and 17.9% were seizurefree for 12 months. 42.4% of patients at 12 months and 46.8% at 24 months had clinically meaningful improvements in Patient Weighted Quality of Life in Epilepsy Questionnaire 31 total score.

CONCLUSIONS

In this select group of patients who entered the LTFU trial, BRV was generally safe and well tolerated. Results indicate the long-term efficacy of BRV in patients with focal seizures.

Simple and efficient method for the quantification of antiepileptic drugs in human plasma by using magnetic graphene oxide-β-cyclodextrin composite as a sorbent

Background

In recent days, solid-phase extraction methods are widely utilized for the extraction of drug molecules from plasma samples due to their easy operating procedures and low matrix effect. The trace-level solid-phase extraction of three structurally related antiepileptic drugs brivaracetam (BVC), eslicarbazepine acetate (ESL), and carbamazepine (CBZ) was investigated by using a magnetic porous material graphene oxide-β-cyclodextrin (MGO-CD). Morphology, magnetic properties, and structure of the synthesized MGO-CD were characterized by using FT-IR, SEM, XRD, and VSM.

Results

Solid-phase extraction (SPE) methods were used to extract the analytes from human plasma. Different extraction solvents such as acetonitrile (ACN), methanol (MeOH), acetone, chloroform (CHCl3), tertiary butyl diethyl ether (TBDE), and ethyl acetate (EtOAc) with variable polarities were used to extract drug molecules from MGO-CD. The linearity analysis showed good correlation coefficient values (R2) of 0.9989, 0.9995, and 0.9982 for BVC, ESL, and CBZ respectively. The LOD and LOQ ranges were found to be 6.14–28.32 ng mL−1 and 20.45–94.31 ng mL−1 respectively.

Conclusion

The high accuracy and precision made the developed HPLC method with MGO-CD a suitable alternative for the bioequivalence study of BVC, ESL, and CBZ in human plasma. This developed HPLC-UV method has good efficiency for recoveries and good linearity and is simple to handle. And also, it gave low retention time for the three antiepileptic drugs within 8 min. It provides high efficiency for the extraction of trace-level substances from human plasma.

The pharmacokinetics of [18F]UCB-H revisited in the healthy non-human primate brain

Background

Positron Emission Tomography (PET) imaging of the Synaptic Vesicle glycoprotein (SV) 2A is a new tool to quantify synaptic density. [¹⁸F]UCB-H was one of the first promising SV2A-ligands to be labelled and used in vivo in rodent and human, while limited information on its pharmacokinetic properties is available in the non-human primate. Here, we evaluate the reliability of the three most commonly used modelling approaches for [¹⁸F]UCB-H in the non-human cynomolgus primate, adding the coupled fit of the non-displaceable distribution volume (V_ND) as an alternative approach to improve unstable fit. The results are discussed in the light of the current state of SV2A PET ligands.

Results

[¹⁸F]UCB-H pharmacokinetic data was optimally fitted with a two-compartment model (2TCM), although the model did not always converge (large total volume of distribution (V_T) or large uncertainty of the estimate). 2TCM with coupled fit K₁/k₂ across brain regions stabilized the quantification, and confirmed a lower specific signal of [¹⁸F]UCB-H compared to the newest SV2A-ligands. However, the measures of V_ND and the influx parameter (K₁) are similar to what has been reported for other SV2A ligands. These data were reinforced by displacement studies using [¹⁹F]UCB-H, demonstrating only 50% displacement of the total [¹⁸F]UCB-H signal at maximal occupancy of SV2A. As previously demonstrated in clinical studies, the graphical method of Logan provided a more robust estimate of V_T with only a small bias compared to 2TCM.

Conclusions

Modeling issues with a 2TCM due to a slow component have previously been reported for other SV2A ligands with low specific binding, or after blocking of specific binding. As all SV2A ligands share chemical structural similarities, we hypothesize that this slow binding component is common for all SV2A ligands, but only hampers quantification when specific binding is low.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-021-00777-8.