Pharmacokinetics and tolerability of eslicarbazepine acetate and oxcarbazepine at steady state in healthy volunteers

A real-world pharmacovigilance analysis of eslicarbazepine acetate using the FDA adverse events reporting system (FAERS) database from 2013 (Q4) to 2024 (Q1)

Background

The approval of eslicarbazepine acetate (ESL) by the Food and Drug Administration (FDA) in 2013 marked an advancement in the treatment of adult patients with partial-onset seizures. However, there still remains a paucity of real-world studies regarding the adverse events (AEs) associated with this compound. The principal aim of the present study was to scrutinize ESL-related AEs by leveraging data from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database.

Methods

By extracting all available data since the FDA approval of ESL (2013Q4-2024Q1), disproportionality analysis was performed using reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN) and multi-item gamma Poisson shrinker (MGPS) algorithms. AE signals that simultaneously met the requirements of all four algorithms were identified as significant positive signals. Demographic information, time of onset and gender-specific signal detection were also examined. In addition, a special screening process for designated medical events (DME) was implemented to focus on the evaluation and comparison of safety signals within DME and System Organ Classification (SOC) level, as well as SMQ (Standardised MedDRA Queries) level. Stratified analysis by logistic regression is employed to examine the variations across different gender (male and female) and age groups (<18 years old, 18-64 years old, >65 years old).

Results

A total of 5,719 AE reports and 1,907 reported cases were obtained. ESL related AEs were identified in relation to 27 SOCs, among which the significant positive SOCs were nervous system disorders, injury poisoning and procedural complications, etc. There were 86 severely disproportional preferred terms that complied with the four algorithms. Most AEs occurred within the first month after treatment. According to the 86 valuable positive signals with DME screening results, 3 signals of dermatitis exfoliative, stevens-johnson syndrome, drug reaction with eosinophilia and systemic symptoms were consistent with PT signals on the DME-list, with the 3 PTs focusing on skin and subcutaneous tissue disorders and hypersensitivity. Males are more commonly affected by seizures than females. Seizures, hyponatremia, and confusional states were more frequently observed in the elderly population, while aggression, irritability, DRESS (drug reaction with eosinophilia and systemic symptoms), and abnormal behavior were found to be more common in the pediatric population. Both the children and elderly groups exhibited a higher proportion of agitation than the adult group.

Conclusion

Our research enhances the safety and tolerability profile of ESL, but the clinical use of ESL should be noticed and avoided in relation to AEs since it raises the risk of dermatitis exfoliative, stevens-johnson syndrome. Particular attention should be paid to DRESS in children and hyponatremia in the elderly.

Overnight switch from carbamazepine to eslicarbazepine in a real-life clinical scenario: a retrospective study

BACKGROUND

Carbamazepine (CBZ) is a first-choice anti-seizure medication (ASM) whose efficacy is often invalidated by adverse effects (AEs). Eslicarbazepine (ESL) is a structural derivative of CBZ with better pharmacokinetic/tolerability profiles. We describe our experience of the overnight CBZ to ESL switch in people with epilepsy (PwE) to improve seizure control, AEs, and ASMs adherence.

METHODS

We retrospectively included 19 PwE (12 females, 53 ± 21 years old) who underwent CBZ to ESL overnight switch due to single/multiple issues: poor efficacy (pEff, N = 8, 42%), tolerability (pToll, N = 11, 58%), adherence (pAdh, N = 2, 10%). 9/19 (47%) had psychiatric comorbidities. Clinical variables, seizure frequency, and AEs were recorded at switch time (T0) after 3.5 ± 3 (T1) and 6.5 ± 1.5 months (T2).

RESULTS

At T1, in pEff group, 1/8 (13%) was seizure free, 2/8 (25%) were responders (> 50% seizure reduction), 2/8 (25%) had no seizure changes, 3/8 (37%) had seizure worsening; the latter were those with the most severe epilepsy and encephalopathy. In pToll group, all PwE experienced AEs disappearance/amelioration. In pAdh group, all PwE reported adherence amelioration. Four dropouts. At T2, no changes were recorded within groups, while in the whole sample, 6/15 (40%) were responders, and 4/15 (27%) were seizure-free. No one complained of Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation psychiatric worsening, while 6/19 (32%) experienced mood/behavior benefits.

CONCLUSIONS

CBZ to ESL overnight switch offers an opportunity to improve efficacy, tolerability, adherence, and psychiatric symptoms.

Assessing the Effectiveness of Eslicarbazepine Acetate in Reducing Audiogenic Reflex Seizures in the GASH/Sal Model of Epilepsy

Eslicarbazepine acetate (ESL) is a third-generation antiepileptic drug indicated as monotherapy for adults with newly diagnosed epilepsy and as adjunctive therapy for the treatment of partial seizures. Our aim was to assess the effectiveness and safety of both acute and repeated ESL administration against reflex audiogenic seizures, as shown by the Genetic Audiogenic Seizures Hamster from Salamanca (GASH/Sal). Animals were subject to the intraperitoneal administration of ESL, applying doses of 100, 150 and 200 mg/kg for the acute study, whereas a daily dose of 100 mg/kg was selected for the subchronic study, which lasted 14 days. In both studies, the anticonvulsant effect of the therapy was evaluated using neuroethological methods. To assess the safety of the treatment, behavioral tests were performed, hematological and biochemical liver profiles were obtained, and body weight was monitored. In addition, the ESL levels in blood were measured after the acute administration of a 200 mg/kg dose. Treatment with ESL caused a reduction in seizure severity. No statistically significant differences were detected between the selected doses or between the acute or repeated administration of the drug. To summarize, the intraperitoneal administration of ESL is safe and shows an anticonvulsant effect in the GASH/Sal.

Thirteen years of experience with eslicarbazepine acetate in the United Kingdom and Republic of Ireland: A safety perspective

OBJECTIVE

Eslicarbazepine acetate (ESL) is a once-daily oral antiseizure medication. Its safety and tolerability from clinical trials have been mostly confirmed by real-world data. The main purpose of this report is to provide an overview of the safety profile of ESL in the United Kingdom (UK) and Republic of Ireland (ROI).

METHODS

Safety data were obtained from the UK and ROI post-marketing sources (October 2009-April 2022) by the marketing authorization holder. All individual reports were included in the Argus Safety™ database. All adverse events (AEs) were coded using MedDRA® version 24.1. Only valid cases (meeting the minimum pharmacovigilance reporting requirements) were included.

RESULTS

During 13 years of ESL marketing, with cumulative estimated exposure of 2 210 395 patients-years, 183 reports were received. A total of 402 AEs were reported for the 155 valid reports. The most common reported AEs (≥6% of total reported), per system organ class (SOC), were: nervous system disorders (23.4%), injury, poisoning, and procedural complications (18.9%), general disorders and administration site conditions (12.9%), psychiatric disorders (12.7%) and gastrointestinal disorders (6.7%). The most frequently reported (≥2% of total reported) AEs were: seizure (4.5%), hyponatremia (4.2%), dizziness (2.7%), rash, fatigue (2.5% each), and somnolence (2.0%). Twenty-six percent of events were classified as serious (including six fatal cases).

SIGNIFICANCE

The current analysis supports the known safety profile of ESL, as generally well-tolerated with most AEs being non-serious. The most common AEs were considered either expected according to the disease itself or to the reference safety information. ESL continues to be a relevant medication in the treatment of partial (focal-onset) epilepsy, as also confirmed by the 2022 NICE guidelines.

Quantitative Evaluation of the Contribution of Each Aldo-Keto Reductase and Short-Chain Dehydrogenase/Reductase Isoform to Reduction Reactions of Compounds Containing a Ketone Group in the Human Liver

Enzymes of the aldo-keto reductase (AKR) and short-chain dehydrogenase/reductase superfamilies are involved in the reduction of compounds containing a ketone group. In most cases, multiple isoforms appear to be involved in the reduction of a compound, and the enzyme(s) that are responsible for the reaction in the human liver have not been elucidated. The purpose of this study was to quantitatively evaluate the contribution of each isoform to reduction reactions in the human liver. Recombinant cytosolic isoforms were constructed, i.e., AKR1C1, AKR1C2, AKR1C3, AKR1C4, and carbonyl reductase 1 (CBR1), and a microsomal isoform, 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1), and their contributions to the reduction of 10 compounds were examined by extrapolating the relative expression of each reductase protein in human liver preparations to recombinant systems quantified by liquid chromatography-mass spectrometry. The reductase activities for acetohexamide, doxorubicin, haloperidol, loxoprofen, naloxone, oxcarbazepine, and pentoxifylline were predominantly catalyzed by cytosolic isoforms, and the sum of the contributions of individual cytosolic reductases was almost 100%. Interestingly, AKR1C3 showed the highest contribution to acetohexamide and loxoprofen reduction, although previous studies have revealed that CBR1 mainly metabolizes them. The reductase activities of bupropion, ketoprofen, and tolperisone were catalyzed by microsomal isoform(s), and the contributions of HSD11B1 were calculated to be 41%, 32%, and 104%, respectively. To our knowledge, this is the first study to quantitatively evaluate the contribution of each reductase to the reduction of drugs in the human liver. SIGNIFICANCE STATEMENT: To our knowledge, this is the first study to determine the contribution of aldo-keto reductase (AKR)-1C1, AKR1C2, AKR1C3, AKR1C4, carbonyl reductase 1, and 11β-hydroxysteroid dehydrogenase type 1 to drug reductions in the human liver by utilizing the relative expression factor approach. This study found that AKR1C3 contributes to the reduction of compounds at higher-than-expected rates.

The pharmacokinetic, safety, and tolerability profiles of eslicarbazepine acetate are comparable between Korean and White subjects

Eslicarbazepine acetate (ESL) is a prodrug antiseizure medication for the treatment of focal seizures. ESL shows a well-established pharmacokinetic (PK)-pharmacodynamic relationship and has similar extrinsic epilepsy-related factors across ethnicities. This study evaluated and compared ESL safety, tolerability, and PK characteristics between Korean and White subjects. A randomized, double-blind, placebo-controlled, single- and multiple-dose escalation study was conducted in healthy Korean and White adults. Participants randomly received a single dose and multiple oral doses of ESL (400-1600 mg) or placebo once daily for 11 days at a ratio of 8:2. Serial blood samples were collected to determine the plasma concentration of ESL and its metabolites (eslicarbazepine, [R-licarbazepine and oxcarbazepine). Safety and tolerability were assessed throughout the study. A total of 29 Korean and 20 White subjects completed the study. The PK profiles of the metabolites of ESL were similar between Korean and White subjects. The geometric mean ratio (90% confidence interval) of Korean to White subjects for the area under the concentration-time curve within a dosing interval of eslicarbazepine was 1.06 (0.97-1.17) and 0.96 (0.87-1.06) after multiple oral doses of 400 and 1600 mg ESL, respectively. Other PK parameters were also similar between the two ethnic groups. ESL was well-tolerated in healthy Korean and White subjects, and its PK characteristics were similar between the two ethnic groups. The results of this study support to use the same dosage regimen of ESL in both White and Korean patients with seizures.

Pharmacokinetic variability of eslicarbazepine in real clinical practice

INTRODUCTION

Eslicarbazepine acetate (ESL) is a sodium channel blocker indicated for partial-onset seizures with or without secondary generalization, at a single daily dose. There are very few publications on the levels of ESL metabolites in real clinical practice.

OBJECTIVE

To describe the serum levels of licarbazepine (main metabolite of ESL) in patients with refractory epilepsy in real clinical practice. To evaluate the influence of age, sex, and polytherapy on levels and adverse effects.

METHODS

This study involved a retrospective analysis of patients diagnosed with epilepsy treated with ESL for whom plasma levels of licarbazepine were available, measured by spectrophotometry.

RESULTS

Sixty-four patients were included. One patient had licarbazepine levels of 0 (admitted not taking the drug) was not analyzed. Mean licarbazepine levels of 7.66 µg/mL (400 mg/day dose), 16.56 µg/mL (800-mg dose), and 20.80 µg/mL (1200 mg) were significantly different. There was a significant correlation between daily dose and serum levels (p < 0.05) and between the concentration/dose ratio and lower to higher doses (p < 0.05). Pharmacokinetic variability (coefficient of variation for the concentration/dose ratio) was 33.2%. We found a decrease in the concentration/dose ratio in the 1200 mg/day dose, compared to lower doses. We did not find differences by sex or intake of other antiepileptic inducers or metabolic inhibitors. Fifteen patients (23.8%) had mild nonsymptomatic hyponatremia.

CONCLUSION

These results suggest that it is not necessary to routinely determine licarbazepine levels. In specific cases, licarbazepine levels can be useful to assess adherence to treatment and for personalized dose adjustment.

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.

Bioequivalence and switchability of generic antiseizure medications (ASMs): A re-appraisal based on analysis of generic ASM products approved in Europe

The safety of switching between generic products of antiseizure medications (ASMs) continues to be a hot topic in epilepsy management. The main reason for concern relates to the uncertainty on whether, and when, two generics found to be bioequivalent to the same brand (reference) product are bioequivalent to each other, and the risk of a switch between generics resulting in clinically significant changes in plasma ASM concentrations. This article addresses these concerns by discussing the distinction between bioequivalence and statistical testing for significant difference, the importance of intra-subject variability in interpreting bioequivalence studies, the stricter regulatory bioequivalence requirements applicable to narrow-therapeutic-index (NTI) drugs, and the extent by which currently available generic products of ASMs comply with such criteria. Data for 117 oral generic products of second-generation ASMs approved in Europe by the centralized, mutual recognition or decentralized procedure were analyzed based on a review of publicly accessible regulatory assessment reports. The analysis showed that for 99% of generic products assessed (after exclusion of gabapentin products), the 90% confidence intervals (90% CIs) of geometric mean ratios (test/reference) for AUC (area under the drug concentration vs time curve) were narrow and wholly contained within the acceptance interval (90%-111%) applied to NTI drugs. Intra-subject variability for AUC was <10% for 53 (88%) of the 60 products for which this measure was reported. Many gabapentin generics showed broader, 90% CIs for bioequivalence estimates, and greater intra-subject variability, compared with generics of other ASMs. When interpreted within the context of other available data, these results suggest that any risk of non-bioequivalence between these individual generic products is small, and that switches across these products are not likely to result in clinically relevant changes in plasma drug exposure. The potential for variability in exposure when switching across generics is likely to be greatest for gabapentin.

Safety, tolerability and effectiveness of transition to eslicarbazepine acetate from carbamazepine or oxcarbazepine in clinical practice

PURPOSE

To assess the efficacy, safety and tolerability of eslicarbazepine acetate (ESL) in patients transitioning from carbamazepine or oxcarbazepine to ESL in clinical practice, by analysing data from the Euro-Esli study.

METHODS

Euro-Esli was a pooled analysis of 14 European clinical practice studies. Effectiveness assessments included responder rate (≥50 % seizure frequency reduction) and seizure freedom rate (seizure freedom at least since prior visit), assessed after 3, 6 and 12 months of ESL treatment, and at the last visit. Safety and tolerability were assessed throughout follow-up by evaluating adverse events (AEs) and ESL discontinuation due to AEs, respectively. Data were analysed for cohorts of patients who transitioned from carbamazepine and oxcarbazepine to ESL either due to lack of efficacy or poor tolerability.

RESULTS

Euro-Esli included 2058 patients, of whom 233 (11.3 %) transitioned from carbamazepine to ESL and 134 (6.5 %) transitioned from oxcarbazepine to ESL. After 12 months of ESL treatment, responder and seizure freedom rates for patients transitioning from carbamazepine due to lack of efficacy (n = 163) were 70.0 % and 30.9 %, respectively. Corresponding values for patients transitioning from oxcarbazepine due to lack of efficacy (n = 90) were 57.1 % and 25.0 %, respectively. Among patients who transitioned from carbamazepine and oxcarbazepine to ESL due to poor tolerability (n = 64 and n = 61, respectively), 26.6 % and 39.5 % experienced AEs, and 8.3 % and 6.8 % discontinued ESL due to AEs, respectively.

CONCLUSION

ESL was efficacious and generally well tolerated in patients transitioning from carbamazepine or oxcarbazepine in clinical practice due to inadequate seizure control or intolerable AEs with these agents.

Development and validation of a specific and sensitive LC-MS/MS method for determination of eslicarbazepine in human plasma and its clinical pharmacokinetic study

In this work, we developed and validated the specific, sensitive and simple LC-MS/MS method for quantification of eslicarbazepine in human plasma. The analyte samples were prepared through a simple one-step protein precipitation method by acetonitrile. The chromatographic separation was operated on an economical Hanbon ODS-2 C18 column (150 mm × 2.1 mm, 10 μm) with isocratic elution using 10 mM ammonium acetate containing 0.01% formic acid and acetonitrile (72:28, v/v) as the mobile phase at the flow rate of 0.5 mL/min. The mass quantification was carried on the multiple reaction monitoring (MRM) of the transitions of m/z 255.1 → 194.1 for eslicarbazepine and m/z 446.1 → 321.1 for glipizide (the internal standard), respectively. The established method was validated with acceptable specificity, linearity, accuracy, precision, extraction recovery, matrix effect and stability in accordance with FDA regulations. At last, the validated method was successfully applied to determination of eslicarbazepine in human plasma obtained from clinical study.

Eslicarbazepine Acetate: A New Improvement on a Classic Drug Family for the Treatment of Partial-Onset Seizures

Eslicarbazepine acetate is a new anti-epileptic drug belonging to the dibenzazepine carboxamide family that is currently approved as adjunctive therapy and monotherapy for partial-onset (focal) seizures. The drug enhances slow inactivation of voltage-gated sodium channels and subsequently reduces the activity of rapidly firing neurons. Eslicarbazepine acetate has few, but some, drug–drug interactions. It is a weak enzyme inducer and it inhibits cytochrome P450 2C19, but it affects a smaller assortment of enzymes than carbamazepine. Clinical studies using eslicarbazepine acetate as adjunctive treatment or monotherapy have demonstrated its efficacy in patients with refractory or newly diagnosed focal seizures. The drug is generally well tolerated, and the most common side effects include dizziness, headache, and diplopia. One of the greatest strengths of eslicarbazepine acetate is its ability to be administered only once per day. Eslicarbazepine acetate has many advantages over older anti-epileptic drugs, and it should be strongly considered when treating patients with partial-onset epilepsy.

Safety Profile of Eslicarbazepine Acetate as Add-On Therapy in Adults with Refractory Focal-Onset Seizures: From Clinical Studies to 6 Years of Post-Marketing Experience

INTRODUCTION

Eslicarbazepine acetate was first approved in the European Union in 2009 as adjunctive therapy in adults with partial-onset seizures with or without secondary generalization.

OBJECTIVE

The objective of this study was to review the safety profile of eslicarbazepine acetate analyzing the data from several clinical studies to 6 years of post-marketing surveillance.

METHODS

We used a post-hoc pooled safety analysis of four phase III, double-blind, randomized, placebo-controlled studies (BIA-2093-301, -302, -303, -304) of eslicarbazepine acetate as add-on therapy in adults. Safety data of eslicarbazepine acetate in special populations of patients aged ≥65 years with partial-onset seizures (BIA-2093-401) and subjects with moderate hepatic impairment (BIA-2093-111) and renal impairment (BIA-2093-112) are also considered. The incidences of treatment-emergent adverse events, treatment-emergent adverse events leading to discontinuation, and serious adverse events were analyzed. The global safety database of eslicarbazepine acetate was analyzed for all cases from post-marketing surveillance from 1 October, 2009 to 21 October, 2015.

RESULTS

From a pooled analysis of four phase III studies, it was concluded that the incidence of treatment-emergent adverse events, treatment-emergent adverse events leading to discontinuation, and adverse drug reactions were dose dependent. Dizziness, somnolence, headache, and nausea were the most common treatment-emergent adverse events (≥10% of patients) and the majority were of mild-to-moderate intensity. No dose-dependent trend was observed for serious adverse events and individual serious adverse events were reported in less than 1% of patients. Hyponatremia was classified as a possibly related treatment-emergent adverse event in phase III studies (1.2%); however, after 6 years of post-marketing surveillance it represents the most frequently (10.2%) reported adverse drug reaction, with more than half of these cases occurring with eslicarbazepine acetate at daily doses of 1200 mg. Other adverse drug reactions reported in post-marketing surveillance are seizure (5.8%), dizziness (4.1%), rash (2.6%), and fatigue (2.1%). The safety profile of eslicarbazepine acetate in renal and hepatic impairment subjects (phase I studies) and in elderly patients (phase III study) did not raise any specific concern.

CONCLUSION

After 6 years of post-marketing surveillance, eslicarbazepine acetate maintains a similar safety profile to that observed in pivotal clinical studies.

Assessment of efficacy and safety of eslicarbazepine acetate for the treatment of trigeminal neuralgia

BACKGROUND

Antiepileptic drugs are the first-line treatment for trigeminal neuralgia (TN). Carbamazepine and oxcarbazepine are the most studied with well-known efficacy. Eslicarbazepine acetate is a third-generation antiepileptic drug that has not previously been evaluated for the treatment of TN. We aim to assess the efficacy, tolerability and safety of eslicarbazepine for TN.

DESIGN AND METHODS

Retrospective, open-label, multicentric, intention-to-treat study. We included patients older than 18 years who met the ICHD-3 beta diagnostic criteria for TN. We evaluated the variation of intensity and frequency of pain paroxysms before and after treatment with eslicarbazepine. Secondary objectives assessed were tolerability and safety of eslicarbazepine.

RESULTS

Eighteen patients were included, 15 women, mean age 65.2 years old, mean follow-up 21.1 months. The mean number of drugs tested before eslicarbazepine was 2; 10 patients used eslicarbazepine as monotherapy. After the treatment with ESL, the median of pain intensity improved from 9.5 to 2.5 (p < 0.001) and the median of pain paroxysms frequency improved from 70 episodes per week to 0.37 (p < 0.001). Responder rate was 88.9%; 44.4% became asymptomatic after treatment. Sixty-one per cent of patients presented some adverse event; four patients discontinued eslicarbazepine for this reason. Despite this, 16 patients (88.9%) noticed a good subjective tolerance to eslicarbazepine. The retention rate at 6 months was 77.8% and at 12 months 61.1%.

CONCLUSIONS

Our study supports the hypothesis that eslicarbazepine acetate is an effective, safe and well-tolerated treatment for the treatment of TN. Further studies are warranted to corroborate these results.

SIGNIFICANCE

Eslicarbazepine acetate has shown to be an effective, safe and well-tolerated drug for TN. This is the first study that evaluated the efficacy of this drug on TN in humans.

Eslicarbazepine acetate in epilepsies with focal and secondary generalised seizures: systematic review of current evidence

INTRODUCTION

Eslicarbazepine acetate (ESL) is a third-generation antiepileptic drug (AED) approved for adjunctive treatment in adults, children, and adolescents with focal-onset seizures. Recently ESL was approved for initial monotherapy in adults. The intention of this article is to review current evidence for ESL and to summarise its pharmacological profile in comparison to other AEDs of the dibenzazepine group. Areas covered: We performed a systematic literature search in electronic databases (MEDLINE database, Cochrane Central Register of Controlled Trials, Excerpta Medica dataBASE) using a combined search strategy including the following keywords: eslicarbazepine, epilepsy and seizure. The search was performed from 2000 until December 2017. Using a standardised assessment form, information on the study design, methodological framework, data sources and efficacy and adverse events attributed to ESL were extracted from each publication and systematically reported. Expert commentary: ESL is an effective, safe and well tolerated third-generation AED for the treatment of focal epilepsies. During therapy, especially serum sodium levels and possible interactions with other substances have to be monitored. As of yet, long-term experience is still needed to make severe late-occurring adverse events unlikely and to obtain data regarding its use in pregnancy.

The Impact of Pharmacokinetic Interactions With Eslicarbazepine Acetate Versus Oxcarbazepine and Carbamazepine in Clinical Practice

BACKGROUND

Eslicarbazepine acetate (ESL) is a new anti-epileptic drug (AED) chemically related to oxcarbazepine (OXC) and carbamazepine (CBZ) and is increasingly used in clinical practice. The purpose of the study was to investigate 2-way pharmacokinetic interactions between ESL and other AEDs as compared to OXC and CBZ.

METHODS

Anonymous data regarding age, gender, use of AEDs, daily doses and serum concentration measurements of ESL, OXC, CBZ and lamotrigine (LTG) and other AEDs were retrieved from 2 therapeutic drug monitoring (TDM) databases in Norway. Drugs were categorized according to their known potential for interactions. Concentration/dose (C/D) ratios were calculated.

RESULTS

Data from 1100 patients were available. The C/D ratios of ESL and OXC were unchanged in combination with enzyme-inducing AEDs or valproate (VPA). The C/D ratio of CBZ decreased by 40% and 22% in combination with other enzyme-inducing AEDs or VPA, respectively, pointing to an increased clearance. ESL demonstrated no significant enzyme-inducing effect on LTG metabolism although there was a 20% and 34% decrease in the C/D ratio of LTG in combination with OXC and CBZ, respectively.

CONCLUSIONS

Possible pharmacokinetic interactions have been studied for ESL as compared to OXC and CBZ. The pharmacokinetics of ESL is not affected by enzyme-inducing AEDs or VPA and does not affect the metabolism of LTG in contrast to OXC and CBZ. The study demonstrates the value of using TDM databases to explore the potential for pharmacokinetic interactions of new AEDs.

Pooled efficacy and safety of eslicarbazepine acetate as add-on treatment in patients with focal-onset seizures: Data from four double-blind placebo-controlled pivotal phase III clinical studies

Purpose

Pooled evaluation of the key efficacy and safety profile of eslicarbazepine acetate (ESL) added‐on to stable antiepileptic therapy in adults with focal‐onset seizures.

Methods

Data from 1703 patients enrolled in four phase III double‐blind, randomized, placebo‐controlled studies were pooled and analyzed. Following a 2 week titration period, ESL was administered at 400 mg, 800 mg, and 1200 mg once‐daily doses for 12 weeks (maintenance period). Pooled efficacy variable was standardized (/4 weeks) seizure frequency (SSF) analyzed over the maintenance period as reduction in absolute and relative SSF and proportion of responders (≥50% reduction in SSF). Pooled safety was analyzed by means of adverse events and clinical laboratory assessments.

Results

SSF was significantly reduced with ESL 800 mg (P < 0.0001) and 1200 mg (P < 0.0001) compared to placebo. Median relative reduction in SSF was 33.4% for ESL 800 mg and 37.8% for 1200 mg (placebo: 17.6%), and responder rate was 33.8% and 43.1% (placebo: 22.2%). ESL was more efficacious than placebo regardless of gender, geographical region, epilepsy duration, age at time of diagnosis, seizure type, and type of concomitant antiepileptic drugs (AED). Incidence of adverse events (AEs) and AEs leading to discontinuation was dose dependent. Most common AEs (>10% patients) were dizziness, somnolence, and nausea. The incidence of treatment‐emergent AEs (dizziness, somnolence, ataxia, vomiting, and nausea) was lower in patients who began taking ESL 400 mg (followed by 400 mg increments to 800 or 1200 mg) than in those who began taking ESL 600 mg or 800 mg.

Conclusions

Once‐daily ESL 800 mg and 1200 mg showed consistent results across all efficacy and safety endpoints, independent of study population characteristics and type of concomitant AEDs. Treatment initiated with ESL 400 mg followed by 400 mg increments to 800 or 1200 mg provides optimal balance of efficacy and tolerability.

Population pharmacokinetics of oxcarbazepine and its monohydroxy derivative in epileptic children

AIMS

Oxcarbazepine is an antiepileptic drug with an activity mostly due to its monohydroxy derivative metabolite (MHD). A parent-metabolite population pharmacokinetic model in children was developed to evaluate the consistency between the recommended paediatric doses and the reference range for trough concentration (C_trough ) of MHD (3-35 mg l^-1 ).

METHODS

A total of 279 plasma samples were obtained from 31 epileptic children (age 2-12 years) after a single dose of oxcarbazepine. Concentration-time data were analysed with Monolix 4.3.2. The probability to obtain C_trough between 3-35 mg l^-1 was determined by Monte Carlo simulations for doses ranging from 10 to 90 mg kg^-1  day^-1 .

RESULTS

A parent-metabolite model with two compartments for oxcarbazepine and one compartment for MHD best described the data. Typical values for oxcarbazepine clearance, central and peripheral distribution volume and distribution clearance were 140 l h^-1  70 kg^-1 , 337 l 70 kg^-1 , 60.7 l and 62.5 l h^-1 , respectively. Typical values for MHD clearance and distribution volume were 4.11 l h^-1  70 kg^-1 and 54.8 l 70 kg^-1 respectively. Clearances and distribution volumes of oxcarbazepine and MHD were related to body weight via empirical allometric models. Enzyme-inducing antiepileptic drugs (EIAEDs) increased MHD clearance by 29.3%. Fifty-kg children without EIAEDs may need 20-30 mg kg^-1  day^-1 instead of the recommended target maintenance dose (30-45 mg kg^-1  day^-1 ) to obtain C_trough within the reference range. By contrast, 10-kg children with EIAEDs would need 90 mg kg^-1  day^-1 instead of the maximum recommended dose of 60 mg kg^-1  day^-1 .

CONCLUSION

This population pharmacokinetic model of oxcarbazepine supports current dose recommendations, except for 10-kg children with concomitant EIAEDs and 50-kg children without EIAEDs.

Overnight switching from oxcarbazepine to eslicarbazepine acetate: an observational study

OBJECTIVES

There are clinical situations where it might be appropriate to switch patients from immediate-release oxcarbazepine (OXC) to eslicarbazepine acetate (ESL). We investigated the effects of transitioning patients overnight from OXC to ESL.

MATERIALS AND METHODS

A retrospective, single-center study was conducted in which patients with drug-resistant focal epilepsy on a stable dose of immediate-release OXC for at least 4 weeks were switched overnight to ESL. Patients were switched because they experienced persistent seizures with OXC but were unable to tolerate increased OXC dosing due to adverse events. Tolerability was assessed using the Adverse Events Profile (AEP), quality of life was assessed using the Quality of Life in Epilepsy Inventory 10 (QOLIE-10), and alertness was assessed as reaction time using a subtest of the Test Battery for Attention Performance version 2.3. Assessments were performed immediately prior to and 5 days after switching from OXC to ESL (days 0 and 5, respectively).

RESULTS

The analysis included 21 patients (12 women, 9 men; mean age 36 years). After switching from OXC to ESL, there were significant improvements in mean scores for AEP (P<.001), QOLIE-10 (P=.001), and alertness (P<.05). Adverse Events Profile total scores improved for 21/21 (100.0%) patients, QOLIE-10 total scores improved for 17/21 (81.0%) patients, and alertness scores improved for 16/21 (76.2%) patients.

CONCLUSIONS

In this short-term, single-center study, an overnight switch from twice-daily OXC to once-daily ESL in patients with drug-resistant focal epilepsies resulted in improvements in side effects, quality of life, and alertness.

[Anticonvulsant add-on therapy with Eslicarbazepine acetate : Results of the EPOS-study in adults in Germany]

BACKGROUND

Due to inadequate seizure control achieved with antiepileptic drug (AED) monotherapy and the considerable side effects at high required doses, patients with partial-onset seizures (POS) often require AED combination therapy. Eslicarbazepine acetate (ESL) is licensed as an add-on therapy for POS and has a favorable tolerability profile.

OBJECTIVES

To investigate retention, utilization, reported efficacy, safety and tolerability as well as effects on health-related quality of life using ESL as an add-on treatment to an established monotherapy in a real-world adult population with POS in Germany.

PATIENTS AND METHODS

A subgroup analysis was performed on the data derived from the German study sites that had participated in an international, non-interventional, open-label study conducted in eight European countries (eslicarbazepine acetate in partial-onset seizures, EPOS). Adult patients with POS whose physician had decided to prescribe add-on treatment with ESL to an established monotherapy were followed over a total period of approximately six months (three visits: baseline and after periods of approximately three and six months). Data collection included patient retention, reported efficacy, safety and tolerability as well as quality of life (QOLIE-10).

RESULTS AND DISCUSSION

The subgroup analysis included 104 patients which had been enrolled at 38 German study sites. After 6 months, retention of ESL add-on therapy was 86.5 %, with 44.7 % of patients reporting seizure freedom over the 3 months prior to this visit. The overall tolerability of ESL add-on therapy was favorable: 32 adverse events (AE) were reported in 20 patients (19.2 %), while only two events in two patients were considered serious. No new safety signals were detected.

Eslicarbazepine acetate: its effectiveness as adjunctive therapy in clinical trials and open studies

Eslicarbazepine acetate (ESL) is a once-daily antiepileptic drug that is approved as adjunctive therapy in adults with focal-onset seizures. Following oral administration, ESL is rapidly metabolized to its active metabolite, eslicarbazepine, which acts primarily by enhancing slow inactivation of voltage-gated sodium channels. The efficacy and safety/tolerability of ESL in the adjunctive setting were established in a comprehensive Phase III program (n = 1702 randomized patients) and this evidence has been supported by several open studies (n = 864). ESL treatment has demonstrated improvements in health-related quality of life, in both randomized clinical trials and open studies. ESL has also been shown to be usually well tolerated and efficacious when used in the adjunctive setting in elderly patients. The effectiveness of ESL as the only add-on to antiepileptic drug monotherapy has been demonstrated in a multinational study (n = 219), subgroup analyses of which have also shown it to be efficacious and generally well tolerated in patients who had previously not responded to carbamazepine therapy. Open studies have also demonstrated improvements in tolerability in patients switched overnight from oxcarbazepine to ESL. Due to differences in pharmacokinetics, pharmacodynamics, and metabolism, there may be clinical situations in which it is appropriate to consider switching patients from oxcarbazepine or carbamazepine to ESL.

Pharmacokinetic variability, efficacy and tolerability of eslicarbazepine acetate-A national approach to the evaluation of therapeutic drug monitoring data and clinical outcome

BACKGROUND

Eslicarbazepine acetate (ESL) is a new antiepileptic drug (AED), still insufficiently studied regarding pharmacokinetic variability, efficacy and tolerability. The purpose of this study was to evaluate therapeutic drug monitoring (TDM) data in Norway and relate pharmacokinetic variability to clinical efficacy and tolerability in a long-term clinical setting in patients with refractory epilepsy.

METHODS

This retrospective observational study included TDM-data from the main laboratories and population data from the Norwegian Prescription Database in Norway, in addition to clinical data from medical records of adult patients using ESL for up to three years, whenever possible.

RESULTS

TDM-data from 168 patients were utilized for assessment of pharmacokinetic variability, consisting of 71% of the total number of patients in Norway using ESL, 2011-14. Median daily dose of ESL was 800mg (range 400-1600mg), and median serum concentration of ESL was 53μmol/L (range 13-132μmol/L). Inter-patient variability of ESL was extensive, with 25-fold variability in concentration/dose ratios. Additional clinical data were available from 104 adult patients out of the 168, all with drug resistant focal epilepsy. After 1, 2 and 3 years follow-up, the retention rate of ESL was 83%, 72% and 64%, respectively. ESL was generally well tolerated as add-on treatment, but sedation, cognitive impairment and hyponatremia were reported. Hyponatremia (sodium <137mmol/L) was present in 36% of the patients, and lead to discontinuation in three.

CONCLUSION

Pharmacokinetic variability of ESL was extensive and the demonstration of usefulness of TDM requires further studies. In patients with drug resistant focal Epilepsy, the high retention rate indicated good efficacy and tolerability. Hyponatremia was observed in one third of the patients. The present results point to a need for individualization of treatment and TDM may be useful.

Practical guidance and considerations for transitioning patients from oxcarbazepine or carbamazepine to eslicarbazepine acetate--Expert opinion

There is currently a lack of guidance on methodology and special considerations for transitioning patients from oxcarbazepine (OXC) or carbamazepine (CBZ) to eslicarbazepine acetate (ESL), if deemed clinically necessary. An advisory panel of epilepsy experts was convened to share their experience on the use of adjunctive ESL in clinical practice and to provide practical recommendations to help address this gap. When changing over from OXC to ESL, an OXC:ESL dose ratio of 1:1 should be employed to calculate the ESL target dose, and the changeover can take place overnight. No changes to comedication are required. Since CBZ has a different mechanism of action to ESL and is a stronger inducer of cytochrome P450 (CYP) enzymes, the transitioning of patients from CBZ to ESL requires careful consideration on a patient-by-patient basis. In general, a CBZ:ESL dose ratio of 1:1.3 should be employed to calculate the ESL target dose, and patients should be transitioned over a minimum period of 1-2weeks. Special considerations include adjustment of titration schedule and target dose in elderly patients and those with hepatic or renal impairment and potential adjustment of comedications metabolized by CYP enzymes. In summary, due to structural distinctions between ESL, OXC, and CBZ, which affect mechanism of action and tolerability, there are clinical situations in which it may be appropriate to consider transitioning patients from OXC or CBZ to ESL. Changing patients over from OXC to ESL is generally more straightforward than transitioning patients from CBZ to ESL, which requires careful consideration.

Assessment of the efficacy and safety of eslicarbazepine acetate in acute mania and prevention of recurrence: experience from multicentre, double-blind, randomised phase II clinical studies in patients with bipolar disorder I

BACKGROUND

Eslicarbazepine acetate (ESL) is an anticonvulsant approved as an adjunctive therapy in adults with partial-onset seizures.

OBJECTIVE

To evaluate the efficacy, safety and tolerability of ESL in the treatment of acute mania and prevention of recurrence in bipolar disorder I.

METHODS

Two 3-week multicentre, double-blind, randomised, placebo-controlled studies in acute mania (study BIA-2093-203: dose titrated by response, ESL 600-1800mg or 800-2400mg, once-daily; study BIA-2093-204: fixed doses of 600, 1200 and 1800mg, once-daily) were followed by a recurrence prevention study consisting of a 2-week open-label period (900mg, once-daily) continued by a double-blind, parallel-group, fixed dose (300, 900 and 1800mg, once-daily) period for a minimum of 6 months. The primary endpoint was changed from baseline until the end of the 3-week treatment period in Young Mania Rating Scale (YMRS) in studies BIA-2093-203 and BIA-2093-204, and the proportion of patients showing no worsening according to the Clinical Global Impressions - Bipolar Version (CGI-BP) over Part II in study BIA-2093-205.

RESULTS

In study BIA-2093-203 (n=160, ITT), neither dose group was statistically different from placebo in the primary endpoint, though the ESL 800-2400mg showed a greater reduction in YMRS score (p=0.0523). CGI-BP score changes for mania and overall bipolar illness indicate a significant improvement in patient symptomatology for the ESL 800-2400mg group (from preceding and worst phase) and for ESL 600-1800mg group (from worst phase only) when compared to placebo. Study BIA-2093-204 (n=38) results were inconclusive due to premature termination caused by recruitment difficulties. In study BIA-2093-205 (n=85, ITT), at least 50% of patients showed no worsening in all treatment groups (p=0.250). ESL adverse events were mostly of mild and moderate intensities and consistent with previously reported observations for ESL.

CONCLUSION

ESL treatment was not significantly different from placebo in manic patients in the primary outcome, but secondary outcomes may be suggestive of efficacy. The recurrence prevention study provides preliminary support for efficacy of ESL in patients recovered from an acute manic episode.

Eslicarbazepine acetate for the treatment of focal epilepsy: an update on its proposed mechanisms of action

Eslicarbazepine acetate (ESL) is a once daily antiepileptic drug (AED) approved by the European Medicines Agency (EMA), the Food and Drug Administration (FDA) and Health Canada as an adjunctive therapy in adults with partial-onset seizures (POS). In humans and in relevant animal laboratory species, ESL undergoes extensive first pass hydrolysis to its major active metabolite eslicarbazepine that represents ∼95% of circulating active moieties. ESL and eslicarbazepine showed anticonvulsant activity in animal models. ESL may not only suppress seizure activity but may also inhibit the generation of a hyperexcitable network. Data reviewed here suggest that ESL and eslicarbazepine demonstrated the following in animal models: (1) the selectivity of interaction with the inactive state of the voltage-gated sodium channel (VGSC), (2) reduction in VGSC availability through enhancement of slow inactivation, instead of alteration of fast inactivation of VGSC, (3) the failure to cause a paradoxical upregulation of persistent Na(+) current (I NaP), and (4) the reduction in firing frequencies of excitatory neurons in dissociated hippocampal cells from patients with epilepsy who were pharmacoresistant to carbamazepine (CBZ). In addition, eslicarbazepine effectively inhibited high- and low-affinity hCaV3.2 inward currents with greater affinity than CBZ. These preclinical findings may suggest the potential for antiepileptogenic effects; furthermore, the lack of effect upon KV7.2 outward currents may translate into a reduced potential for eslicarbazepine to facilitate repetitive firing.

Clinical utility of eslicarbazepine: current evidence

Eslicarbazepine acetate (ESL) is a new antiepileptic drug whose mechanism of action is blockade of the voltage-gated sodium channel (VGSC). However, in respect to carbamazepine and oxcarbazepine, the active ESL metabolite (eslicarbazepine) affects slow inactivation of VGSC and has a similar affinity for the inactivated state and a lower affinity for the resting state of the channel. This new antiepileptic drug has been recently approved in Europe (trade name Zebinix) and in the United States (trade name Stedesa) for adjunctive treatment in adult subjects with partial-onset seizures, with or without secondary generalization. Following oral administration, ESL is rapidly and extensively metabolized by hepatic esterases to eslicarbazepine. This active metabolite has a linear pharmacokinetic profile, a low binding to plasma proteins (<40%), and a half-life of 20-24 hours and is mainly excreted by kidneys in an unchanged form or as glucuronide conjugates. ESL is administered once a day and has a low potential for drug-drug interactions. Efficacy and safety of this drug in patients with focal seizures have been assessed in four randomized clinical trials, and responder rates (percentage of patients with a ≥50% improvement of their seizures) ranged between 17% and 43%. Adverse events were usually mild to moderate, and the most common were dizziness, somnolence, diplopia, abnormal coordination, blurred vision, vertigo, headache, fatigue, nausea, and vomiting. ESL may be considered an interesting alternative to current antiepileptic drugs for the treatment of drug-resistant focal epilepsies. Additionally, it is under investigation in children with focal epilepsies, in patients with newly diagnosed focal epilepsies, and also in other neurological and psychiatric disorders.

Eslicarbazepine and the enhancement of slow inactivation of voltage-gated sodium channels: a comparison with carbamazepine, oxcarbazepine and lacosamide

This study aimed at evaluating the effects of eslicarbazepine, carbamazepine (CBZ), oxcarbazepine (OXC) and lacosamide (LCM) on the fast and slow inactivated states of voltage-gated sodium channels (VGSC). The anti-epileptiform activity was evaluated in mouse isolated hippocampal slices. The anticonvulsant effects were evaluated in MES and the 6-Hz psychomotor tests. The whole-cell patch-clamp technique was used to investigate the effects of eslicarbazepine, CBZ, OXC and LCM on sodium channels endogenously expressed in N1E-115 mouse neuroblastoma cells. CBZ and eslicarbazepine exhibit similar concentration dependent suppression of epileptiform activity in hippocampal slices. In N1E-115 mouse neuroblastoma cells, at a concentration of 250 μM, the voltage dependence of the fast inactivation was not influenced by eslicarbazepine, whereas LCM, CBZ and OXC shifted the V0.5 value (mV) by -4.8, -12.0 and -16.6, respectively. Eslicarbazepine- and LCM-treated fast-inactivated channels recovered similarly to control conditions, whereas CBZ- and OXC-treated channels required longer pulses to recover. CBZ, eslicarbazepine and LCM shifted the voltage dependence of the slow inactivation (V0.5, mV) by -4.6, -31.2 and -53.3, respectively. For eslicarbazepine, LCM, CBZ and OXC, the affinity to the slow inactivated state was 5.9, 10.4, 1.7 and 1.8 times higher than to the channels in the resting state, respectively. In conclusion, eslicarbazepine did not share with CBZ and OXC the ability to alter fast inactivation of VGSC. Both eslicarbazepine and LCM reduce VGSC availability through enhancement of slow inactivation, but LCM demonstrated higher interaction with VGSC in the resting state and with fast inactivation gating.

Eslicarbazepine acetate: a review of its use as adjunctive therapy in refractory partial-onset seizures

Eslicarbazepine acetate (Aptiom(®), Zebinix(®)) is approved for the adjunctive treatment of partial-onset seizures in adults aged ≥18 years. Adjunctive therapy with oral eslicarbazepine acetate 800 or 1,200 mg once daily was associated with a significantly lower standardized seizure frequency (primary endpoint) than placebo in patients aged ≥18 years with refractory partial-onset seizures in three, randomized, double-blind, multinational, phase III trials. In a fourth randomized, double-blind, multinational, phase III trial in patients aged ≥16 years with refractory partial-onset seizures, adjunctive eslicarbazepine acetate 1,200 mg once daily, but not 800 mg once daily, was associated with a significantly lower standardized seizure frequency (primary endpoint). Responder rates were significantly higher with eslicarbazepine acetate 1,200 mg once daily than with placebo in these four trials, and with eslicarbazepine acetate 800 mg once daily than with placebo in two trials. The efficacy of eslicarbazepine acetate was maintained in the longer term, according to the results of 1-year extension studies. Adjunctive therapy with oral eslicarbazepine acetate was generally well tolerated in patients with refractory partial-onset seizures, with most adverse events being of mild to moderate severity. In conclusion, eslicarbazepine acetate is a useful option for the adjunctive treatment of patients with refractory partial-onset seizures.