Effectiveness of eslicarbazepine acetate in dependency of baseline anticonvulsant therapy: Results from a German prospective multicenter clinical practice study

Research Status, Synthesis and Clinical Application of Antiepileptic Drugs

According to the 2017 ILAE's official definition, epilepsy is a slow brain disease state characterized by recurrent episodes. Due to information released by ILAE in 2017, it can be divided into four types, including focal epilepsy, generalized epilepsy, combined generalized, and focal epilepsy, and unknown epilepsy. Since 1989, 24 new antiepileptic drugs have been approved to treat different types of epilepsy. Besides, there are a variety of antiepileptic medications under clinical monitoring. These novel antiepileptic drugs have plenty of advantages. Over the past 33 years, there have been many antiepileptic drugs on the mearket, but no one has been found that can completely cure epilepsy. In this paper, the mentioned drugs were classified according to their targets, and the essential information, and clinical studies of each drug were described. The structure-activity relationship of different chemical structures was summarized. This paper provides help for the follow-up research on epilepsy drugs.

Anticonvulsant Classes and Possible Mechanism of Actions

Epilepsy is considered one of the most common neurological disorders worldwide; it needs long-term or life-long treatment. Despite the presence of several novel antiepileptic drugs, approximately 30% patients still suffer from drug-resistant epilepsy. Subsequently, searching for new anticonvulsants with lower toxicity and better efficacy is still in paramount demand. Using target-based studies in the discovery of novel antiepileptics is uncommon owing to the insufficient information on the molecular pathway of epilepsy and complex mode of action for most of known antiepileptic drugs. In this review, we investigated the properties of anticonvulsants, types of epileptic seizures, and mechanism of action for anticonvulsants.

Synergistic effects of vagus nerve stimulation and antiseizure medication

INTRODUCTION

Vagus nerve stimulation (VNS) is an effective, non-pharmacological therapy for epileptic seizures. Until now, favorable combinations of different groups of antiseizure medication (ASM) and VNS have not been sufficiently addressed. The aim of this study was to identify the synergistic effects between VNS and different ASMs.

METHODS

We performed an observational study of patients with epilepsy who were implanted with VNS and had a stable ASM therapy during the first 2 years after the VNS implantation. Data were collected from the Mainz Epilepsy Registry. The efficacy of VNS depending on the concomitantly used ASM group/individual ASMs was assessed by quantifying the responder rate (≥ 50% seizure reduction compared to the time of VNS implantation) and seizure freedom (absence of seizures during the last 6 months of the observation period).

RESULTS

One hundred fifty one patients (mean age 45.2 ± 17.0 years, 78 females) were included in the study. Regardless of the used ASM, the responder rate in the whole cohort was 50.3% and the seizure freedom was 13.9%. Multiple regression analysis showed that combination of VNS with synaptic vesicle glycoprotein (SV2A) modulators (responder rate 64.0%, seizure freedom 19.8%) or slow sodium channel inhibitors (responder rate 61.8%, seizure freedom 19.7%) was associated with a statistically significant better responder rate and seizure freedom than combinations of VNS and ASM with other mechanism of action. Within these ASM groups, brivaracetam showed a more favorable effect than levetiracetam, whereas lacosamide and eslicarbazepine were comparable in their effects.

CONCLUSION

Our data suggest that the combination of VNS with ASMs belonging to either SV2A modulators or slow sodium channel inhibitors could be optimal to achieve a better seizure control following VNS. However, these preliminary data require further validation under controlled conditions.

Initial monotherapy with eslicarbazepine acetate for the management of adult patients with focal epilepsy in clinical practice: a meta-analysis of observational studies

AIM OF THE STUDY

To assess the effectiveness, overall tolerability of eslicarbazepine acetate (ESL) as an initial or early monotherapy treatment of adult patients with focal epilepsy under real-world practice conditions.

MATERIALS AND METHODS

We focused on real-world longitudinal studies that included or separately reported the results of at least one of the efficacy outcomes of interest. A DerSimonian-Laird random effects model was used with the presentation of the 95% confidence intervals of the estimate.

RESULTS

5 studies met our selection criteria and were included in the quantitative synthesis. All studies were observational and uncontrolled studies, and all but one were retrospective studies. The pooled proportion of patients who were seizure-free for the entire study period was 64.6% (95% CI, 45.7 to 79.8) at month 6 and 56.6% (95% CI, 50.2 to 62.8) at month 12. Pooled retention rates were 95.0% (95% CI, 90.3 to 97.5) at 6 months and 83.6% (95% CI, 73.9 to 90.1) at 12 months. The pooled proportion of patients who reported at least one adverse event was 27.2% (95% CI, 21.7 to 33.6), and the pooled proportion of patients who discontinued ESL due to adverse events was 8.9% (95% CI 6.2 to 12.6).

CONCLUSIONS

Our results suggest that initial or early monotherapy with ESL is effective and well-tolerated for the management of adult patients with focal epilepsy in clinical practice, with results that are at least similar to those reported in the pivotal randomized clinical trial of ESL monotherapy. No new safety signals with ESL have been identified in this systematic review.

Efficacy and safety of antiseizure medication in post-stroke epilepsy

BACKGROUND

Specific antiseizure medications (ASM) would improve the outcome in post-stroke epilepsy (PSE). The aim of this multicenter observational study was to compare different antiseizure monotherapies in PSE.

METHODS

We collected the data from 207 patients with PSE who did not change their initial antiseizure monotherapy during the period of 12 months. Efficacy was assessed by a standardized three month seizure frequency and seizure freedom. Safety was estimated by the reported side effects.

RESULTS

The mean three month seizure frequency was 1.9 ± 3.1 on eslicarbazepine, 2.1 ± 3.2 on lacosamide, 3.4 ± 4.4 on levetiracetam, 4.3 ± 6.8 on lamotrigine, and 5.1 ± 7.3 on valproate (p < 0.05 for eslicarbazepine or lacosamide in comparison with levetiracetam, lamotrigine and valproate, respectively). The lowest seizure frequency and the highest seizure freedom was observed on ASMs acting via the slow inactivation of sodium channels in comparison to other mechanisms of action (0.7 ± 0.9 vs 2.2 ± 2.4, p < 0.01). Among side effects, the most frequently reported were vertigo (25%) and tiredness (15.9%). They were similar in all investigated groups of ASM. The independent factors increasing seizure frequency that were identified in multiple regression analyses were increased size of infarction, cortical involvement, hemorrhagic transformation, neurological deficits at admission and functional impairment. Administration of ASM with the mechanism of action via the slow inactivation of sodium channels was an independent factor decreasing the seizure frequency.

CONCLUSION

Our data show that antiseizure medications acting via the slow inactivation of sodium channels, such as lacosamide and eslicarbazepine, are well tolerated and might be associated with better seizure control in PSE.

Eslicarbazepine Acetate as Adjunctive Therapy for Primary Generalized Tonic-Clonic Seizures in Adults: A Prospective Observational Study

BACKGROUND

Eslicarbazepine acetate (ESL), a novel sodium channel blocker, is approved for mono and adjunctive treatment of partial epileptic seizures with or without secondary generalization. Its efficacy in primary generalized seizures has not yet been evaluated.

OBJECTIVE

To evaluate the efficacy and safety of ESL in primary generalized tonic-clonic seizures (PGTCS) in an observational study.

METHODS

The data were collected from a prospective population-based register. Effectiveness was measured as relative reduction in standardized seizure frequency (SSF), responder rate (≥ 50% reduction in SSF), and seizure freedom rate at 6 and 12 months after initiation of ESL. Safety and tolerability were evaluated using patients' diaries.

RESULTS

Fifty-six adult patients with PGTCS were treated with ESL as adjunctive therapy. Of these, 30.4% (n = 17) had myoclonic seizures in addition to PGTCS. The retention rate after 12 months was 80.4% (n = 45). After initiating ESL therapy, reduction in SSF for PGTCS on ESL was 56.0% after 6 months and 56.9% after 12 months (p &lt; 0.01), whereas myoclonic seizures did not show any significant improvement in frequency. The responder rate for PGTCS was 64.3% after 6 months and 66.1% after 12 months, and seizure freedom was achieved in 32.1% and 35.7%, respectively. Forty-three patients (73.2%) reported no side effects. Among the reported side effects of ESL therapy, headache (7.1%), dizziness (8.9%), tiredness (7.1%), nausea (5.4%), and hyponatremia (5.4%) were the most prevalent.

CONCLUSIONS

Our data suggest that ESL may provide additional benefits in the treatment of patients with PGTCS and motivate randomized controlled trials in this indication.

Eslicarbazepine-induced severe hyponatremia resulted in generalized tonic-clonic seizure

Although eslicarbazepine is an anti-seizure medication, it may result in seizure worsening if its use is complicated by severe hyponatremia, even long time after commencing this medication. The treatment is a replacement for another ASM.

ABCB1 C3435T, G2677T/A and C1236T variants have no effect in eslicarbazepine pharmacokinetics

Eslicarbazepine acetate is a third-generation anti-epileptic prodrug quickly and extensively transformed to eslicarbazepine after oral administration. Reduction in seizure frequency in patients managed with eslicarbazepine is only partial in the majority of patients and many of them suffer considerable ADRs that require a change of treatment. The P-glycoprotein, encoded by the ABCB1 gene, is expressed throughout the body and can impact the pharmacokinetics of several drugs. In terms of epilepsy treatment, this transporter was linked to drug-resistant epilepsy, as it conditions drug access into the brain due to its expression at the blood-brain barrier. Therefore, we aimed to investigate the impact of three ABCB1 common polymorphisms (i.e., C3435T, or rs1045642, G2677A or rs2032582 and C1236T or rs1128503) in the pharmacokinetics and safety of eslicarbazepine. For this purpose, 22 healthy volunteers participating in a bioequivalence clinical trial were recruited. No significant relationship was observed between sex, race and ABCB1 polymorphism and eslicarbazepine pharmacokinetic variability. In contrast, ABCB1 C1236T C/C diplotype was significantly related to the occurrence of ADRs: one volunteer with this genotype suffered dizziness, somnolence and hand paresthesia, while no other volunteer suffered any of these ADRs (p < 0.045). To the best of our knowledge, this is the first study published to date evaluating eslicarbazepine pharmacogenetics. Further studies with large sample sizes are needed to compare the results obtained here.

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.

Eslicarbazepine Acetate: A Review in Focal-Onset Seizures

Eslicarbazepine acetate (Zebinix^®), a voltage-gated sodium channel blocker, is a once-daily, orally administered anti-seizure medication available in the EU for use as monotherapy in adults with newly diagnosed focal-onset seizures and as adjunctive therapy in adults, adolescents and children aged > 6 years with focal-onset seizures. In adult patients, adjunctive eslicarbazepine acetate was generally associated with a significant decrease in seizure frequency and an increase in responder rate compared with placebo. The drug was also an effective monotherapy agent in adult patients, demonstrating noninferiority to controlled-release carbamazepine, in terms of seizure freedom rates. In paediatric patients, eslicarbazepine acetate provided seizure control when administered as adjunctive therapy, with the benefits appearing to be dependent on age and dose. The antiepileptic efficacy of eslicarbazepine acetate as adjunctive therapy or as monotherapy was maintained during longer-term extension studies, with each extension study period being up to 2 years. Oral eslicarbazepine acetate was generally well tolerated when administered as adjunctive therapy or monotherapy in adult patients and when administered as adjunctive therapy in paediatric patients, with most adverse events being of mild or moderate intensity. In conclusion, with the convenience of once-daily administration, eslicarbazepine acetate is an effective and generally well-tolerated treatment option for adults, adolescents and children aged > 6 years with focal-onset seizures.