Pharmacokinetics of eslicarbazepine acetate in patients with moderate hepatic impairment

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.

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.

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.

Safety, Tolerability and Efficacy of Eslicarbazepine Acetate as Adjunctive Therapy in Patients Aged ≥ 65 Years with Focal Seizures

BACKGROUND

The incidence of epilepsy is high within the first few years of life, stabilizes over the second through fifth decades, and then rises again. Treatment of elderly patients with antiepileptic drugs (AEDs) is complicated by increased sensitivity to drug effects, altered pharmacokinetics and an increased risk for drug interactions due to polytherapy. On the other hand, the safety and efficacy data of AEDs attained during clinical development programmes are relatively limited for this age group.

OBJECTIVE

The aim of this study was to evaluate the safety, tolerability and efficacy of eslicarbazepine acetate (ESL) as adjunctive therapy in patients aged ≥ 65 years with focal-onset seizures (FOS).

METHODS

This was an international, multicentre, open-label, non-controlled, single-arm, post-European approval commitment study with flexible doses of ESL between 400 and 1200 mg/day. Seventy-two elderly patients with at least two FOS in the prior 4 weeks, and treated with one or two AEDs, were enrolled. The study consisted of an 8-week baseline, followed by a 26-week treatment period during which the investigator was allowed to up- or down-titrate the ESL dose, and a 4-week follow-up period. Safety and tolerability were assessed as well as mental sedation, cognitive mental state and suicidal ideation. Efficacy was assessed based on patient diaries regarding the absolute and relative changes in seizure frequency, change in intellectual impairment and quality of life.

RESULTS

Overall, 47 (65.3%) patients experienced 152 treatment-emergent adverse events (TEAEs). The most frequent were dizziness (12.5%), somnolence (9.7%), fatigue, convulsion and hyponatraemia (8.3% each). All patients that experienced hyponatraemia (6/72) recovered without sequelae. Three patients died during the study (due to cardiac failure, glioblastoma multiforme and ischaemic stroke, all considered unrelated to ESL). Overall, 16 (22.2%) patients discontinued prematurely due to TEAEs. The incidences of clinically significant findings were low for vital signs, ECG, physical and neurological examinations. No TEAEs of hypothyroidism were reported; however, 24 (33.3%) patients presented post-baseline shifts from normal to decreased free T4 levels (not clinically significant). ESL decreased standardized seizure frequency from a mean of 4.8 seizures at baseline to 3.6 seizures at endpoint (p > 0.05); and mean number of days with seizures significantly decreased from 4.1 (baseline) to 2.8 at endpoint (p = 0.0408).

CONCLUSION

ESL taken once daily (400-1200 mg) as adjunctive therapy in patients aged ≥ 65 years was found to be safe, well tolerated and efficacious (EudraCT number: 2009-012587-14).

Exposure-safety and efficacy response relationships and population pharmacokinetics of eslicarbazepine acetate

Objectives

Eslicarbazepine acetate (ESL) is a once‐daily (QD) oral antiepileptic drug (AED) for focal‐onset seizures (FOS). Pharmacokinetic (PK) and pharmacodynamic (PD) models were developed to assess dose selection, identify significant AED drug interactions, and quantitate relationships between exposure and safety and efficacy outcomes from Phase 3 trials of adjunctive ESL.

Methods

Eslicarbazepine (the primary active metabolite of ESL) population PK was evaluated using data from 1351 subjects enrolled in 14 studies (11 Phase 1 and three Phase 3 studies) after multiple oral doses ranging from 400 to 1200 mg. Population PK and PD models related individual eslicarbazepine exposures to safety outcomes and efficacy responses.

Results

Eslicarbazepine PK was described by a one‐compartment model with linear absorption and elimination. The probability of a treatment‐emergent adverse event (TEAE; dizziness, headache, or somnolence) was higher with an initial dose of ESL 800 mg than with an initial dose of ESL 400 mg QD. Body weight, sex, region, and baseline use of carbamazepine (CBZ) or lamotrigine were also found to influence the probability of TEAEs. Eslicarbazepine exposure influenced serum sodium concentration, standardized seizure frequency, and probability of response; better efficacy outcomes were predicted in patients not from Western Europe (WE; vs WE patients) and those not taking CBZ (vs taking CBZ) at baseline.

Conclusions

Pharmacokinetic and PK/PD modeling were implemented during the development of ESL for adjunctive treatment of FOS in adults. This quantitative approach supported decision‐making during the development of ESL, and contributed to dosing recommendations and labeling information related to drug interactions.

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.

An Updated Overview on Therapeutic Drug Monitoring of Recent Antiepileptic Drugs

Given the distinctive characteristics of both epilepsy and antiepileptic drugs (AEDs), therapeutic drug monitoring (TDM) can make a significant contribution to the field of epilepsy. The measurement and interpretation of serum drug concentrations can be of benefit in the treatment of uncontrollable seizures and in cases of clinical toxicity; it can aid in the individualization of therapy and in adjusting for variable or nonlinear pharmacokinetics; and can be useful in special populations such as pregnancy. This review examines the potential for TDM of newer AEDs such as eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, perampanel, pregabalin, rufinamide, retigabine, stiripentol, tiagabine, topiramate, vigabatrin, and zonisamide. We describe the relationships between serum drug concentration, clinical effect, and adverse drug reactions for each AED as well as the different analytical methods used for serum drug quantification. We discuss retrospective studies and prospective data on the serum drug concentration-efficacy of these drugs and present the pharmacokinetic parameters, oral bioavailability, reference concentration range, and active metabolites of newer AEDs. Limited data are available for recent AEDs, and we discuss the connection between drug concentrations in terms of clinical efficacy and nonresponse. Although we do not propose routine TDM, serum drug measurement can play a beneficial role in patient management and treatment individualization. Standardized studies designed to assess, in particular, concentration-efficacy-toxicity relationships for recent AEDs are urgently required.

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.

Antiepileptic Drugs and Liver Disease

Acute, symptomatic seizures or epilepsy may complicate the course of hepatic disease. Choosing the most appropriate antiepileptic drug in this setting represents a difficult challenge, as most medications are metabolized by the liver. This article focuses on the acute and chronic treatment of seizures in patients with advanced liver disease and reviews the hepatotoxic potential of specific antiepileptic drugs. Newer antiepileptic drugs without, or with minimal, hepatic metabolism, such as levetiracetam, lacosamide, topiramate, gabapentin, and pregabalin should be used as first-line therapy. Medications undergoing extensive hepatic metabolism, such as valproic acid, phenytoin, and felbamate should be used as drugs of last resort. In special circumstances, as in patients affected by acute intermittent porphyria, exposure to most antiepileptic drugs could precipitate attacks. In this clinical scenario, bromides, levetiracetam, gabapentin, and vigabatrin constitute safe choices. For the treatment of status epilepticus, levetiracetam and lacosamide, available in intravenous preparations, are good second-line therapies after benzodiazepines fail to control seizures. Hepatotoxicity is also a rare and unexpected side effect of some antiepileptic drugs. Drugs such as valproic acid, phenytoin, and felbamate, have a well-recognized association with liver toxicity. Other antiepileptic drugs, including phenobarbital, benzodiazepines, ethosuximide, and the newer generations of antiepileptic drugs, have only rarely been linked to hepatotoxicity. Thus physicians should be mindful of the pharmacokinetic profile and the hepatotoxic potential of the different antiepileptic drugs available to treat patients affected by liver disease.

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.

The Pharmacology and Toxicology of Third-Generation Anticonvulsant Drugs

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

Eslicarbazepine Acetate Monotherapy: A Review in Partial-Onset Seizures

Eslicarbazepine acetate (Aptiom(®)) is a once-daily, orally administered antiepileptic drug (AED) approved previously in the EU, USA and several other countries for use as adjunctive therapy for the treatment of partial-onset seizures. Based on the findings of two randomized, dose-blinded, conversion-to-monotherapy phase III trials in patients with uncontrolled partial epilepsy, the US license for eslicarbazepine acetate has recently been expanded to include use as monotherapy for partial-onset seizures. The pivotal trials demonstrated that seizure control following conversion from other AEDs was superior for eslicarbazepine acetate monotherapy (1200 or 1600 mg once daily) compared with a pseudo-placebo historical control. Other efficacy outcomes appeared to support the benefit of treatment, with up to 10 % of patients remaining seizure free and up to 46 % of patients experiencing a ≥50 % reduction from baseline in standardized seizure frequency during the monotherapy periods of the trials. Eslicarbazepine acetate monotherapy was generally well tolerated, with most treatment-emergent adverse events being mild to moderate in severity. Its tolerability profile was generally consistent with the established profile of the drug based on its use as adjunctive therapy. Thus, once-daily eslicarbazepine acetate, either as monotherapy or adjunctive therapy, represents a useful option for the treatment of patients with partial-onset seizures. The recent licensing of the drug in the USA as monotherapy expands the range of treatment options for patients with partial-onset seizures and increases the opportunity to tailor therapy to the individual patient.

Eslicarbazepine acetate for the treatment of partial epilepsy

INTRODUCTION

Eslicarbazepine acetate (ESL) is a third generation AED structurally related to carbamazepine and oxcarbazepine, but without several of the drawbacks associated with these compounds. ESL is completely metabolized to its eslicarbazpine, which selectively binds inactivated voltage-gated sodium channels and thus selectively reduces the activity of rapidly firing (epileptic) neurons. In addition, ESL has pharmacokinetic properties allowing once daily dosing.

AREAS COVERED

This review summarizes data from the initial phase I to III studies, which demonstrated efficacy of ESL as add-on treatment in partial onset epilepsy, and more recent studies that demonstrate efficacy of ESL as monotherapy. Real-life observational studies are also reviewed, and seem to confirm the notion of ESL as a well-tolerated AED. As a new AED, ESL needs to be subject to close monitoring regarding long-term adverse events. Future independent studies will most likely clarify the role of ESL in the management of partial onset seizures.

EXPERT OPINION

The role of ESL in management of partial onset seizures is discussed, as is the need for close monitoring and evaluation for broad-spectrum pharmacodynamics properties. The characteristics of the molecule and efficacy and safety profiles seem, however, very promising.

A Pharmacokinetic Study Comparing Eslicarbazepine Acetate Administered Orally as a Crushed or Intact Tablet in Healthy Volunteers

The relative bioequivalence of crushed versus intact eslicarbazepine acetate (ESL) tablets (800 mg) administered orally in healthy adults was evaluated in an open-label, randomized, 2-period crossover study with a 5-day washout between treatments. Sample blood levels of eslicarbazepine and (R)-licarbazepine were determined; pharmacokinetic parameters were derived for eslicarbazepine. Bioequivalence was established if the 90% confidence intervals (CIs) for the geometric mean treatment ratios of eslicarbazepine AUC(0-∞) and Cmax were within the prespecified 80%-125% range. Twenty-seven subjects in the intent-to-treat population (n = 28) completed both treatment periods. Eslicarbazepine exposure measures were similar for crushed versus intact ESL tablets: average Cmax , 11 700 versus 11 500 ng/mL; AUC(0-∞) , 225 000 versus 234 000 ng·h/mL; AUC(0-last) , 222 000 versus 231 000 ng·h/mL, respectively. Geometric least squares mean ratios (90%CIs) comparing eslicarbazepine exposure measures were within the 80%-125% range (Cmax , 102.63% [97.07%-108.51%]; AUC(0-∞) , 96.72% [94.36%-99.13%]; AUC0-last , 96.69% [94.24%-99.21%]). In conclusion, ESL administered orally as a crushed tablet sprinkled on applesauce, or intact were bioequivalent in healthy subjects. Eslicarbazepine bioavailability was not significantly altered by crushing, indicating that ESL tablets can be administered intact or crushed.

Update on the role of eslicarbazepine acetate in the treatment of partial-onset epilepsy

Eslicarbazepine acetate (ESL) is a once daily new third generation antiepileptic drug that shares the basic chemical structure of carbamazepine and oxcarbazepine - a dibenzazepine nucleus with the 5-carboxamide substituent, but is structurally different at the 10,11-position. ESL is a pro-drug metabolized to its major active metabolite eslicarbazepine. Despite the fact that the exact mechanism of action has not been fully elucidated, it is thought to involve inhibition of voltage-gated sodium channels (VGSC). ESL inhibits sodium currents in a voltage-dependent way by an interaction predominantly with the inactivated state of the VGSC, thus selectively reducing the activity of rapidly firing (epileptic) neurons. ESL reduces VGSC availability through enhancement of slow inactivation. In Phase III studies, adjunctive therapy with ESL 800 or 1,200 mg/day leads to a significant decrease in the seizure frequency in adults with refractory partial onset epilepsy. Based on these results, ESL has been approved in Europe (by the European Medicines Agency) and in the United States (by the US Food and Drug Administration) as add-on therapy. Data on efficacy and safety have been confirmed by 1-year extension and real life observational studies. Recently, based on results from two randomized, double-blind, historical control Phase III trials, ESL received US Food and Drug Administration approval also as a monotherapy for patients with partial onset epilepsy. In the pediatric setting, encouraging results have been obtained suggesting its potential role in the management of epileptic children. Overall ESL was generally well tolerated. The most common adverse events were dizziness, somnolence, headache, nausea, diplopia, and vomiting. Adverse events can be minimized by appropriate titration. In conclusion, ESL seems to overcome some drawbacks of the previous antiepileptic drugs, suggesting a major role of ESL in the management of focal onset epilepsy for both new onset and refractory cases, either as monotherapy or as adjunctive treatment.

Efficacy and safety of conversion to monotherapy with eslicarbazepine acetate in adults with uncontrolled partial-onset seizures: a historical-control phase III study

Background

Eslicarbazepine acetate (ESL, Aptiom®) is a once-daily (QD) anticonvulsant, approved as adjunctive treatment of partial-onset seizures (POS). It is extensively converted after oral administration to eslicarbazepine, and is believed to exert its effect through inhibition of voltage-gated sodium channels. The possible role of ESL as monotherapy to treat POS has not yet been established.

Methods

This study was an 18-week, multicenter, randomized double-blind trial of gradual conversion to ESL monotherapy in adults with POS not well controlled by 1–2 antiepileptic drugs (AEDs), using historical data as the control. The study comprised an 8-week baseline period, a 2-week titration period, a 6-week AED conversion period, a 10-week monotherapy period, and either a 1-week taper period or optional entry to an open-label extension study. The primary endpoint compared the Kaplan–Meier (KM)-estimated 112-day exit rate with a threshold value calculated from the historical controls.

Results

There were 172 randomized patients; 154 (90%) entered the AED conversion period and 121 (70%) completed the study. The KM-estimated exit rates [confidence interval (CI)] were 15.6% [8.1–28.7%] for ESL 1200 mg, and 12.8% [7.5–21.5%] for ESL 1600 mg. The upper limits of the 95% CI KM-estimates were below the pre-specified threshold for historical control of 65.3%, indicating that ESL was efficacious in reducing seizure-related exits, compared with historical control. During the 18-week double-blind treatment period, median reductions in standardized seizure frequency occurred with ESL 1200 mg (36.1%) and ESL 1600 mg (47.5%). The responder rates (a 50% or greater reduction in seizure frequency from baseline) during the 18-week double-blind period and the monotherapy period, respectively, were 35.2% and 38.9% for ESL 1200 mg, and 46.0% and 46.0% for ESL 1600 mg. The overall adverse event profile was consistent with the known safety profile of ESL.

Conclusions

These findings indicate that ESL monotherapy (1200 and 1600 mg QD) was efficacious and well tolerated in this study.

Trial registration

NCT01091662; EudraCT No. 2010-018684-42.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-015-0305-5) contains supplementary material, which is available to authorized users.

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.

Efficacy and safety of conversion to monotherapy with eslicarbazepine acetate in adults with uncontrolled partial-onset seizures: a randomized historical-control phase III study based in North America

Objective

To assess the efficacy and safety of eslicarbazepine acetate (ESL) as monotherapy in North American patients with partial‐onset seizures (POS).

Methods

This multicenter, randomized, double‐blind “withdrawal to monotherapy” study used historical control data as the comparator. Adults with POS medically uncontrolled by one to two antiepileptic drugs gradually converted to ESL monotherapy. Following an 8‐week baseline period, patients were randomized 2:1 to receive ESL 1,600 mg (n = 128) or 1,200 mg QD (n = 65) for 18 weeks. The primary end point was the proportion of patients meeting predefined exit criteria (signifying worsening seizure control). Treatment was considered effective if the 95% upper confidence limit (UCL) for the Kaplan‐Meier estimated exit rate was lower than the exit rate threshold calculated from the historical control (65.3%).

Results

Kaplan‐Meier estimated exit rates were: ESL 1,600 mg, 28.7% (95% CI 21.2–38.1%) and 1,200 mg, 44.4% (32.5–58.3%). The difference between doses was not significant (p = 0.07). For both doses, the 95% UCLs for the exit rate were ˂65.3%; ESL monotherapy was considered superior to the historical control. There was no statistically significant increase in the risk of study exit related to carbamazepine use. Nine (7.6%) and five patients (8.3%) remained seizure‐free during the 10‐week monotherapy period, while taking ESL 1,600 and 1,200 mg, respectively. The reductions in median standardized seizure frequency (seizures per 28 days) between baseline and the 18‐week treatment period were: ESL 1,600 mg, 42% and 1,200 mg, 31%. Treatment‐emergent adverse events (TEAEs) occurring in ≥10% of patients were dizziness, headache, fatigue, somnolence, nausea, and nasopharyngitis. The TEAE most frequently leading to discontinuation was hyponatremia (2.1%).

Significance

ESL was efficacious and well tolerated as monotherapy in North American patients, and led to a reduction in seizure frequency. Exit rates for ESL 1,600 and 1,200 mg QD were superior to the historical control; the difference in exit rates between doses was not statistically significant.

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 acetate as adjunctive therapy in patients with uncontrolled partial-onset seizures: Results of a phase III, double-blind, randomized, placebo-controlled trial

Objective

To evaluate the efficacy and safety of adjunctive eslicarbazepine acetate (ESL) in patients with refractory partial-onset seizures.

Methods

This randomized, placebo-controlled, double-blind, parallel-group, phase III study was conducted at 173 centers in 19 countries, including the United States and Canada. Eligible patients were aged ≥16 years and had uncontrolled partial-onset seizures despite treatment with 1–2 antiepileptic drugs (AEDs). After an 8-week baseline period, patients were randomized to once-daily placebo (n = 226), ESL 800 mg (n = 216), or ESL 1,200 mg (n = 211). Following a 2-week titration period, patients received ESL 800 or 1,200 mg once-daily for 12 weeks. Seizure data were captured and documented using event-entry or daily entry diaries.

Results

Standardized seizure frequency (SSF) during the maintenance period (primary end point) was reduced with ESL 1,200 mg (p = 0.004), and there was a trend toward improvement with ESL 800 mg (p = 0.06), compared with placebo. When data for titration and maintenance periods were combined, ESL 800 mg (p = 0.001) and 1,200 mg (p < 0.001) both reduced SSF. There were no statistically significant interactions between treatment response and geographical region (p = 0.38) or diary version (p = 0.76). Responder rate (≥50% reduction in SSF) was significantly higher with ESL 1,200 mg (42.6%, p < 0.001) but not ESL 800 mg (30.5%, p = 0.07) than placebo (23.1%). Incidence of treatment-emergent adverse events (TEAEs) and TEAEs leading to discontinuation increased with ESL dose. The most common TEAEs were dizziness, somnolence, nausea, headache, and diplopia.

Significance

Adjunctive ESL 1,200 mg once-daily was more efficacious than placebo in adult patients with refractory partial-onset seizures. The once-daily 800 mg dose showed a marginal effect on SSF, but did not reach statistical significance. Both doses were well tolerated. Efficacy assessment was not affected by diary format used.

Effects of eslicarbazepine acetate on acute and chronic latrunculin A-induced seizures and extracellular amino acid levels in the mouse hippocampus

Background

Latrunculin A microperfusion of the hippocampus induces acute epileptic seizures and long-term biochemical changes leading to spontaneous seizures. This study tested the effect of eslicarbazepine acetate (ESL), a novel antiepileptic drug, on latrunculin A-induced acute and chronic seizures, and changes in brain amino acid extracellular levels. Hippocampi of Swiss mice were continuously perfused with a latrunculin A solution (4 μM, 1 μl/min, 7 h/day) with continuous EEG and videotape recording for 3 consecutive days. Microdialysate samples were analyzed by HPLC and fluorescence detection of taurine, glycine, aspartate, glutamate and GABA. Thereafter, mice were continuously video monitored for two months to identify chronic spontaneous seizures or behavioral changes. Control EEG recordings (8 h) were performed in all animals at least once a week for a minimum of one month.

Results

Oral administration of ESL (100 mg/kg), previous to latrunculin A microperfusion, completely prevented acute latrunculin A-induced seizures as well as chronic seizures and all EEG chronic signs of paroxysmal activity. Hippocampal extracellular levels of taurine, glycine and aspartate were significantly increased during latrunculin A microperfusion, while GABA and glutamate levels remained unchanged. ESL reversed the increases in extracellular taurine, glycine and aspartate concentrations to basal levels and significantly reduced glutamate levels. Plasma and brain bioanalysis showed that ESL was completely metabolized within 1 h after administration to mainly eslicarbazepine, its major active metabolite.

Conclusion

ESL treatment prevented acute latrunculin A-induced seizures as well as chronic seizures and all EEG chronic signs of paroxysmal activity, supporting a possible anti-epileptogenic effect of ESL in mice.

Pharmacokinetic of antiepileptic drugs in patients with hepatic or renal impairment

Many factors influence choice of antiepileptic drugs (AEDs), including efficacy of the drug for the indication (epilepsy, neuropathic pain, affective disorder, migraine), tolerability, and toxicity. The first-generation AEDs and some newer AEDs are predominately eliminated by hepatic metabolism. Other recent AEDs are eliminated by renal excretion of unchanged drug or a combination of hepatic metabolism and renal excretion. The effect of renal and hepatic disease on the dosing will depend on the fraction of the AED eliminated by hepatic and/or renal excretion, the metabolic isozymes involved, as well as the extent of protein binding, if therapeutic drug monitoring is used. For drugs that are eliminated by renal excretion, methods of estimating creatinine clearance can be used to determine dose adjustments. For drugs eliminated by hepatic metabolism, there are no specific markers of liver function that can be used to provide guidance in dosage adjustments. Based on studies with probe drugs, the hepatic metabolic enzymes are differentially affected depending on the cause and severity of hepatic disease, which can aid in predicting dose adjustment when clinical data are not available. Several AEDs are also associated with laboratory markers of mild hepatic dysfunction and, rarely, more severe hepatic injury. In contrast, the risk of renal injury from AEDs is generally low. In general, co-morbid hepatic or renal diseases influence the decision for the selection of an AED. For some patients dosing changes to their existing AEDs may be appropriate. For others, a change to another AED may be a better option.

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.

Advances in anti-epileptic drug testing

In the past twenty-one years, 17 new antiepileptic drugs have been approved for use in the United States and/or Europe. These drugs are clobazam, ezogabine (retigabine), eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, perampanel, pregabalin, rufinamide, stiripentol, tiagabine, topiramate, vigabatrin and zonisamide. Therapeutic drug monitoring is often used in the clinical dosing of the newer anti-epileptic drugs. The drugs with the best justifications for drug monitoring are lamotrigine, levetiracetam, oxcarbazepine, stiripentol, and zonisamide. Perampanel, stiripentol and tiagabine are strongly bound to serum proteins and are candidates for monitoring of the free drug fractions. Alternative specimens for therapeutic drug monitoring are saliva and dried blood spots. Therapeutic drug monitoring of the new antiepileptic drugs is discussed here for managing patients with epilepsy.

Clinical pharmacokinetics of new-generation antiepileptic drugs at the extremes of age: an update

Epilepsies occur across the entire age range, and their incidence peaks in the first years of life and in the elderly. Therefore, antiepileptic drugs (AEDs) are commonly used at the extremes of age. Rational prescribing in these age groups requires not only an understanding of the drugs' pharmacodynamic properties, but also careful consideration of potential age-related changes in their pharmacokinetic profile. The present article, which updates a review published in 2006 in this journal, focuses on recent findings on the pharmacokinetics of new-generation AEDs in neonates, infants, children, and the elderly. Significant new information on the pharmacokinetics of new AEDs in the perinatal period has been acquired, particularly for lamotrigine and levetiracetam. As a result of slow maturation of the enzymes involved in glucuronide conjugation, lamotrigine elimination occurs at a particularly slow rate in neonates, and becomes gradually more efficient during the first months of life. In the case of levetiracetam, elimination occurs primarily by renal excretion and is also slow at birth, but drug clearance increases rapidly thereafter and can even double within 1 week. In general, infants older than 2-3 months and children show higher drug clearance (normalized for body weight) than adults. This pattern was confirmed in recent studies that investigated the pediatric pharmacokinetics of several new AEDs, including levetiracetam, rufinamide, stiripentol, and eslicarbazepine acetate. At the other extreme of age, in the elderly, drug clearance is generally reduced compared with younger adults because of less efficient drug-metabolizing activity, decreased renal function, or both. This general pattern, described previously for several AEDs, was confirmed in recent studies on the effect of old age on the clearance of felbamate, levetiracetam, pregabalin, lacosamide, and retigabine. For those drugs which are predominantly eliminated by renal excretion, aging-related pharmacokinetic changes could be predicted by measuring creatinine clearance (CLCR). Overall, most recent findings confirm that age is a major factor influencing the pharmacokinetic profile of AEDs. However, pharmacokinetic variability at any age can be considerable, and the importance of other factors should not be disregarded. These include genetic factors, co-morbidities, and drug interactions, particularly those caused by concomitantly administered AEDs which induce or inhibit drug-metabolizing enzymes.

Use of antiepileptic drugs in hepatic and renal disease

The use of antiepileptic drugs in patients with renal or hepatic disease is common in clinical practice. Since the liver and kidney are the main organs involved in the elimination of most drugs, their dysfunction can have important effects on the disposition of antiepileptic drugs. Renal or hepatic disease can prolong the elimination of the parent drug or an active metabolite leading to accumulation and clinical toxicity. It can also affect the protein binding, distribution, and metabolism of a drug. The protein binding of anionic acidic drugs, such as phenytoin and valproate, can be reduced significantly by renal failure, causing difficulties in the interpretation of total serum concentrations commonly used in clinical practice. Dialysis can further modify the pharmacokinetic parameters or result in significant removal of the antiepileptic drugs. Antiepileptic drugs that are eliminated unchanged by the kidneys or undergo minimal metabolism include gabapentin, pregabalin, vigabatrin, and topiramate when used as monotherapy. Drugs eliminated predominantly by biotransformation include phenytoin, valproate, carbamazepine, tiagabine, and rufinamide. Drugs eliminated by a combination of renal excretion and biotransformation include levetiracetam, lacosamide, zonisamide, primidone, phenobarbital, ezogabine/retigabine, oxcarbazepine, eslicarbazepine, ethosuximide, and felbamate. Drugs in the latter group can be used cautiously in patients with either renal or liver failure. Antiepileptic drugs that are at high risk of being extracted by hemodialysis include ethosuximide, gabapentin, lacosamide, levetiracetam, pregabalin and topiramate. The use of antiepileptic drugs in the presence of hepatic or renal disease is complex and requires great familiarity with the pharmacokinetics of these agents. Closer follow-up of the patients and more frequent monitoring of serum concentrations are required to optimize clinical outcomes.

Evaluation of neurotoxic and neuroprotective pathways affected by antiepileptic drugs in cultured hippocampal neurons

In this study we evaluated the neurotoxicity of eslicarbazepine acetate (ESL), and of its in vivo metabolites eslicarbazepine (S-Lic) and R-licarbazepine (R-Lic), as compared to the structurally-related compounds carbamazepine (CBZ) and oxcarbazepine (OXC), in an in vitro model of cultured rat hippocampal neurons. The non-related antiepileptic drugs (AEDs) lamotrigine (LTG) and sodium valproate (VPA) were also studied. We assessed whether AEDs modulate pro-survival/pro-apoptotic pathways, such as extracellular-regulated kinase (ERK1/2), Akt and stress activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK). We found that neither ESL nor its metabolites, CBZ or LTG, up to 0.3mM, for 24h of exposure, decreased cell viability. OXC was the most toxic drug decreasing cell viability in a concentration-dependent manner, leading to activation of caspase-3 and PARP cleavage. VPA caused the appearance of the apoptotic markers, but did not alter cell viability. ESL, S-Lic and OXC decreased the levels of phospho-ERK1/2 and of phospho-Akt, when compared to basal levels, whereas CBZ decreased phospho-SAPK/JNK and phospho-Akt levels. LTG and VPA increased the phosphorylation levels of SAPK/JNK. These results suggest that ESL and its main metabolite S-Lic, as well as CBZ, LTG and VPA, are less toxic to hippocampal neurons than OXC, which was the most toxic agent.

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

PURPOSE

Investigate the pharmacokinetics of once-daily (QD; 900 mg) and twice-daily (BID; 450 mg) regimens of eslicarbazepine acetate (ESL) and BID (450 mg) regimen of oxcarbazepine (OXC) at steady state in healthy volunteers.

METHODS

Single-center, open-label, randomized, three-way (n = 12) crossover studies in healthy volunteers.

KEY FINDINGS

Mean eslicarbazepine Cmax,ss (in μm) following ESL QD (87.3) was 33.3% higher (p < 0.05) compared to ESL BID (65.5) and 82.1% higher (p < 0.05) compared to OXC BID (48.0). The mean area under the curve (AUC)ss,0-τ (in μmol h/L) following the last dose of an 8-day repeated dosing was 1156.3, 1117.6, and 968.4 for ESL QD, ESL BID, and OXC BID, respectively. The ratio eslicarbazepine plasma exposure (μmol h/L) to ESL daily-dose (μmol) was 0.381 (1156.3:3037.3), 0.368 (1117.6:3037.3), and 0.271 (968.4:3567.6) for ESL-QD, ESL-BID, and OXC-BID, respectively, which translates into a 40.6% increase in the ability of ESL-QD compared to OXC-BID to deliver into the plasma their major active entity eslicarbazepine. The extent of plasma exposure to ESL minor metabolites: (R)-licarbazepine and oxcarbazepine after ESL-QD was 71.5% and 61.1% lower, respectively, than after OXC-BID. Twenty, 24 and 38 treatment emergent adverse events were reported with ESL-QD, ESL-BID, and OXC-BID, respectively.

SIGNIFICANCE

ESL-QD resulted in 33.3% higher peak plasma concentration (Cmax,ss ) of eslicarbazepine and similar extent of plasma exposure (AUCss,0-τ ) when compared to ESL-BID, which may contribute to the efficacy profile reported with once-daily ESL. In comparison to OXC-BID, administration of ESL-QD resulted in 40.6% increase in the delivery of eslicarbazepine into the plasma as well as a significantly lower systemic exposure to (R)-licarbazepine and oxcarbazepine.

Bioequivalence of eslicarbazepine acetate from two different sources of its active product ingredient in healthy subjects

PURPOSE

To compare the bioavailability (BA) and pharmacokinetic (PK) properties and to demonstrate the bioequivalence (BE) between two active product ingredient (API) sources of eslicarbazepine acetate (ESL) in healthy volunteers.

DESIGN, SUBJECTS AND METHODS

Forty healthy male and female subjects aged 18-40 years were randomized to treatment with 400 or 800 mg ESL marketed (MF) formulation [current active pharmaceutical ingredient (API) source] and 400 or 800 mg ESL to-be-marketed (TBM) formulation (new API source) under a gender-balanced, two-period, two-sequence crossover open-label study design. Subjects were assigned to receive either 400 or 800 mg ESL dose strengths, and each was randomly administered on two occasions--either a single oral tablet of MF or a single oral tablet of TBM--separated by a washout period of at least 7 days. Formulations were to be considered bioequivalent if, for both 400 or 800 mg ESL dosage strengths, the test (TBM)/reference (MF) geometric mean ratios (GMR) and 90% confidence intervals (90% CI) of the area under the plasma concentration-time curve (AUC) and peak plasma concentration (Cmax) were within the predetermined range of 80-125%.

RESULTS

Test/reference GMR (90% CI) for the Cmax and AUC was respectively 100% (94-109%) and 96% (94-98%) following 400 mg ESL and 100% (95-105%) and 100% (97-103%) following 800 mg ESL.

CONCLUSION

Oral tablet formulations of either 400 or 800 mg ESL from the new API source were found to be bioequivalent to the corresponding marketed Zebinix® formulation according to the regulatory definition of bioequivalence.

Effect of eslicarbazepine acetate on the pharmacokinetics of a combined ethinylestradiol/levonorgestrel oral contraceptive in healthy women

OBJECTIVE

To investigate the effect of once-daily (QD) eslicarbazepine acetate (ESL) 800 mg and 1,200 mg administration on pharmacokinetics of a combined ethinylestradiol/levonorgestrel oral contraceptive (OC) in women of childbearing potential.

METHODS

Two two-way, crossover, two-period, randomized, open-label studies were performed in 20 healthy female subjects, each. In one period (ESL+OC period), subjects received ESL 800 mg QD in one study and ESL 1200 mg QD in the other study, for 15 days; concomitantly with the Day 14 ESL dose, an oral single dose of 30 μg ethinylestradiol and 150 μg levonorgestrel was administered. In the other period (OC alone), a single dose of 30 μg ethinylestradiol and 150 μg levonorgestrel was administered. Three weeks or more separated the periods. An analysis of variance (ANOVA) was used to test for differences between pharmacokinetic parameters of 30 μg ethinylestradiol and 150 μg levonorgestrel following ESL+OC and OC alone, and 90% confidence intervals (90%CI) for the ESL+OC/OC alone geometric mean ratio (GMR) were calculated.

RESULTS

ESL significantly decreased the systemic exposure to both ethinylestradiol and levonorgestrel. GMR (90%CI) for AUC0-24 of ethinylestradiol were 68% (64%; 71%) following 1,200 mg ESL and 75% (71%; 79%) following 800 mg ESL. GMR (90%CI) for AUC0-24 of levonorgestrel were 76% (68%; 86%) following 1,200 mg ESL and 89% (82%; 97%) following 800 mg ESL.

CONCLUSIONS

A clinically relevant dose-dependent effect of ESL administration on the pharmacokinetics of ethinylestradiol and levonorgestrel was observed. Therefore, to avoid inadvertent pregnancy, women of childbearing potential should use other adequate methods of contraception during treatment with ESL, and, in case ESL treatment is discontinued, until CYP3A4 activity returns to normal.

A review of eslicarbazepine acetate (Stedesa®)

Eslicarbazepine acetate is an anticonvulsant medication approved in Europe for adjunctive therapy in adults with partial-onset seizures. FDA approval is expected shortly for use in the United States. This article reviews the pharmacologic and pharmacokinetic profile of eslicarbazepine acetate, and factors that should be considered when using this medication.

Steady-state plasma and cerebrospinal fluid pharmacokinetics and tolerability of eslicarbazepine acetate and oxcarbazepine in healthy volunteers

PURPOSE

To evaluate the pharmacokinetics and tolerability of once-daily eslicarbazepine acetate (ESL) and twice-daily oxcarbazepine (OXC) and their metabolites in cerebrospinal fluid (CSF) and plasma following repeated oral administration.

METHODS

Single-center, open-label, randomized, parallel-group study in healthy volunteers. Volunteers in ESL group (n = 7) received 600 mg on days 1-3 and 1,200 mg on days 4-9, once daily. Volunteers in the OXC group (n = 7) received 300 mg on days 1-3 and 600 mg on days 4-9, twice daily. Plasma and CSF sampling was performed following the last dose.

KEY FINDINGS

Eslicarbazepine was the major drug entity in plasma and CSF, accounting for, respectively, 93.84% and 91.96% of total exposure in the ESL group and 78.06% and 76.42% in the OXC group. The extent of exposure to drug entities R-licarbazepine and oxcarbazepine was approximately four-fold higher with OXC as compared with ESL. There was relatively little fluctuation from peak-to-trough (ratio) in the CSF for both eslicarbazepine (ESL = 1.5; OXC = 1.2) and R-licarbazepine (ESL = 1.2; OXC = 1.2). In contrast, oxcarbazepine showed larger differences between peak and trough (ESL = 3.1; OXC = 6.4). A total of 84 and 24 treatment-emergent adverse events (TEAEs) were reported with OXC and ESL, respectively.

SIGNIFICANCE

In comparison to OXC, administration of ESL resulted in more eslicarbazepine, less R-licarbazepine, and less oxcarbazepine in plasma and CSF, which may correlate with the tolerability profile reported with ESL. The smaller peak-to-trough fluctuation of eslicarbazepine in CSF (a measure of sustained delivery to the brain) than in plasma supports once-daily dosing of ESL.