Safety, tolerability and pharmacokinetic profile of BIA 2-093, a novel putative antiepileptic agent, during first administration to humans

The ROME (Retrospective Observational Multicenter study on Eslicarbazepine) study: Efficacy and behavioural effects of Eslicarbazepine acetate as adjunctive therapy for adults with partial onset seizures in real life

PURPOSE

Eslicarbazepine acetate (ESL) is a third-generation member of the dibenzazepine family approved in 2009 by the European Medicines Agency with the indication of adjunctive therapy in adult people with partial-onset seizures (PPOS). We aimed at assessing the ESL impact on seizure frequency and quality of life in PPOS with a particular attention to sleepiness and depression.

METHODS

We evaluated 50 adult PPOS (>18 years; 48 ± 14 years-old; 23 males) treated with adjunctive ESL for ≥2months with a retrospective multi-centric design. Clinical files of the last 2 years were reviewed checking for monthly seizure frequency, treatment retention rate, adverse drug reactions (ADRs), concomitant anti-epileptic drugs and behavioural scales for sleepiness (Stanford Sleepiness Scale, SSS, and Epworth Sleepiness Scale, ESS), depression (Beck Depression Inventory-II, BDI) and overall quality of life (QOLIE-31).

RESULTS

At the end of 96 ± 28 days of ESL treatment, the mean seizure reduction was 56%; 60% of patients had seizure reduction above 50%, with a 31% of the whole population becoming seizure free. We reported 16 ADRs with 4 hyponatremia. Retention rate was 76%. Patient reported less sleepiness after ESL (SSS, p = 0.031; ESS, p = 0.0000002). Before ESL, 38% of patients had pathologic BDI scores, which normalized in most of them (73%) after ESL (BDI improvement, p = 0.000012). These scores resulted in an amelioration of quality of life (QOLIE-31, p = 0.000002).

CONCLUSIONS

ESL is a safe and effective anti-epileptic drug in a real life scenario, with an excellent behavioural profile for the overall quality of life and, in particular, for sleepiness and depression.

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.

Two-year follow-up with eslicarbazepine acetate: a consecutive, retrospective, observational study

PURPOSE

Eslicarbazepine acetate (ESL) is a new generation voltage-gated sodium channel blocker. It has completed one phase II clinical trial and three phase III clinical trials, two of which with 1-year open label extensions. ESL was approved in 2009 by the European Medicines Agency as adjunctive therapy in adults with partial-onset seizures with or without secondary generalization. It is marketed in Portugal since April 1st 2010. Despite good safety and efficacy shown in clinical trials, little is known about its effectiveness in a clinical day-to-day setting. Our purpose was to assess the post-marketing experience with ESL in our centre, in terms of safety and efficacy profile, and ascertain whether the results were comparable to the published data.

METHODS

This is a retrospective, consecutive, single-centre 2-year observational study. All the patients who initiated treatment with ESL between April 1st 2010 and October 31st 2011 at Hospital de Santo António were consecutively included. Data was collected on demographics, clinical features, adverse events and treatment response, using a standardized data form. Follow-up data was considered until October 31st 2013. Efficacy analysis was performed using an "intention to treat" approach.

KEY FINDINGS

We included 152 patients, 74 (48.7%) female. Mean age was 38.5 years-old (sd=14.2). Eight patients were less than 18 years old. Mean epilepsy duration was 26.8 (sd=13.1) years and mean seizure frequency in the previous 3 months was 19.7 seizures per month. At baseline, about 57.9% of all patients were taking ≤2 concomitant AEDs. The total adverse rate was 42.1% (64/152), with 50.0% (32/64) leading to treatment discontinuation. The most frequent adverse events were dizziness and somnolence/slowness. Adverse events were higher in regimens including carbamazepine, and mean age was higher in the patients reporting adverse events. Retention rates as estimated by Kaplan-Meyer curves were 82.9%, 71.3%, 65.1% and 62.8%, respectively, at 6, 12, 18 and 24 months. Retention time was not influenced by gender, diagnosis, age or epilepsy duration. Fifty-six patients (36.8%) dropped out of treatment, 32 (57.1%) due to adverse events, 19 (33.9%) due to lack of efficacy and 5 (8.9%) for other reasons. At 6,12,18 and 24 months, the responder rates were 25.7%, 25.7%, 19.0% and 17.1%, respectively and favourable global clinical impression rates were 27.7%, 19.7%, 17.8% and 16.5%.

SIGNIFICANCE

This is the first study reporting follow-up data for up to 2 years in patients treated with ESL in the setting of daily clinical practice. The retention rates in our study are sustained throughout the 2 years of follow-up, and at 6 and 12 months are globally comparable to those of phase III trials and open-label extensions. The adverse event rate is also comparable to previous studies, and no new safety issues attributable to ESL were found. Responder rates were lower than those of previous studies, even though efficacy results must be interpreted with caution given the different study design. Thus, ESL appears to be a clinically useful add-on AED, with good safety profile and high retention rates, even in a very refractory group of patients like the presented cohort.

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.

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.

Safety, Tolerability, and Pharmacokinetic Profile of BIA 2-093, a Novel Putative Antiepileptic, in a Rising Multiple-Dose Study in Young Healthy Humans

This was a double-blind, randomized, placebo-controlled study to investigate rising oral doses of BIA 2-093 (S-(-)-10-acetoxy-10,11-dihydro-5H-dibenz/b,f/azepine-5-carboxamide), a putative new antiepileptic drug. Within each of 4 dosage groups of 8 healthy male adult subjects, 2 subjects were randomized to receive placebo, and the remaining 6 subjects were randomized to receive BIA 2-093 (200 mg bid, 400 mg qd, 800 mg qd, and 1200 mg qd) for 8 days. Concentrations of BIA 2-093 in plasma or urine were generally not measurable. Median maximum plasma concentrations of the major metabolite (licarbazepine, (+/-)-10,11-dihydro-10-hydroxy-5H-dibenz/b,f/azepine-5-carboxamide) were attained (t(max)) at 2 to 3 h postdose; thereafter, plasma concentrations declined with a mean apparent terminal half-life of 9 to 13 h following repeated dosing. The extent of systemic exposure to licarbazepine increased in an approximately dose-proportional manner following single and repeated administration. Licarbazepine accumulated in plasma following repeated administration of BIA 2-093; the mean extent of accumulation (R(O), calculated from AUC(0-tau) (day 8)/AUC(0-tau) (day 1)) was 3.0 after repeated, twice-daily dosing and 1.4 to 1.7 after once-daily dosing. Steady-state plasma licarbazepine concentrations were attained at 4 to 5 days of once- or twice-daily dosing, consistent with an effective half-life on the order of 20 to 24 h. The mean renal clearance of licarbazepine from plasma was approximately 20 to 30 mL/min, which is low compared with the glomerular filtration rate. The total amount of licarbazepine recovered in urine was approximately 20% within 12 h postdose and 40% within 24 h postdose. All adverse events were mild in severity, except for 1 case of somnolence of moderate severity, which occurred in a subject receiving 1200 mg BIA 2-093. The incidence of adverse events was similar between all treatment groups, including placebo. There were no serious adverse events. In conclusion, BIA 2-093 was well tolerated and appeared to be rapidly and extensively metabolized to licarbazepine following single and repeated administration to healthy young subjects.

A review of eslicarbazepine acetate for the adjunctive treatment of partial-onset epilepsy

Eslicarbazepine acetate (ESL) is a novel antiepileptic drug indicated for the treatment of partial-onset seizures. Structurally, it belongs to the dibenzazepine family and is closely related to carbamazepine and oxcarbazepine. Its main mechanism of action is by blocking the voltage-gated sodium channel. ESL is a pro-drug that is rapidly metabolized almost exclusively into S-licarbazepine, the biologically active drug. It has a favorable pharmacokinetic and drug-drug interaction profile. However, it may induce the metabolism of oral contraceptives and should be used with caution in females of child-bearing age. In the pre-marketing placebo-controlled clinical trials ESL has proven effective as adjunctive therapy in adult patients with refractory of partial-onset seizures. Best results were observed on a single daily dose between 800 and 1200 mg. In general, ESL was well tolerated, with most common dose-related side effects including dizziness, somnolence, headache, nausea and vomiting. Hyponatremia has been observed (0.6%–1.3%), but the incidence appears to be lower than with the use of oxcarbazepine. There is very limited information on the use of ESL in children or as monotherapy.

Update on treatment of partial onset epilepsy: role of eslicarbazepine

Partial epilepsy comprises simple partial seizures, complex partial seizures, and secondarily generalized seizures, and covers more than 60% of patients with epilepsy. Antiepileptic drugs are generally considered to be the major therapeutic intervention for epilepsy but, despite a broad range of commonly used antiepileptic drugs, approximately 30% of adult patients and approximately 25% of children with epilepsy have inadequate seizure control. Eslicarbazepine acetate (ESL) is a novel voltage-gated sodium channel-blocking agent with presumed good safety and efficacy for adjunctive treatment of patients with drug-resistant partial epilepsy. ESL is a prodrug of eslicarbazepine (the active entity responsible for pharmacologic effects), and is rapidly and extensively hydrolyzed during first pass by liver esterases after oral administration. The half-life of eslicarbazepine at steady-state plasma concentrations is 20-24 hours, compatible with once-daily administration. ESL 800 mg and 1200 mg significantly reduces seizure frequency and shows a favorable safety profile in adult patients with drug-resistant partial-onset seizures, as demonstrated in previous Phase II and III trials. In children, ESL showed a clear dose-dependent decrease in seizure frequency with good tolerability. The most commonly reported adverse events associated with ESL are dizziness, somnolence, nausea, diplopia, headache, vomiting, blurred vision, vertigo, and fatigue. In conclusion, these characteristics suggest that ESL might be a valid and well tolerated treatment option for patients with drug-resistant partial-onset epilepsy. The convenience of once-daily dosing and a short, simple titration regimen would be of special interest for children, although conclusive published data are lacking to date. Hence, there is an urgent need to establish the therapeutic value of ESL in this special population in the near future.

Eslicarbazepine acetate: a new option for the treatment of focal epilepsy

BACKGROUND

Epilepsy is a neurological condition with an increased probability of seizure occurrence through time. Although many anti-epileptic drugs (AEDs) exist, they fail to treat seizures in 30% of patients with epilepsy. For these patients, new AEDs potentially more efficacious and safe are developed.

OBJECTIVE

To evaluate the effectiveness of eslicarbazepine acetate (ESL) in the treatment of patients with refractory epilepsy.

METHODS

A review of the literature was carried out using PubMed central. A direct contact with the drug manufacturer and developer was made.

RESULTS/CONCLUSION

ESL is an AED that acts by inhibiting voltage-gated sodium channels. It has proved efficacious in the treatment of patients with refractory focal-onset epilepsy with a good safety profile. Evaluation of its use for treating other epileptic syndromes and its role as an initial treatment option for patients with epilepsy is warranted.

Simultaneous and enantioselective liquid chromatographic determination of eslicarbazepine acetate, S-licarbazepine, R-licarbazepine and oxcarbazepine in mouse tissue samples using ultraviolet detection

Herein is reported, for the first time, a simple and reliable chiral reversed-phase liquid chromatographic method coupled to ultraviolet (UV) detection for simultaneous determination of eslicarbazepine acetate (ESL) and its metabolites, S-licarbazepine (S-LC), R-licarbazepine (R-LC) and oxcarbazepine (OXC), in mouse plasma and brain, liver and kidney tissue homogenates. All analytes and the internal standard were extracted from plasma and tissue homogenates by a solid-phase extraction procedure using Waters Oasis hydrophilic-lipophilic balance cartridges. The chromatographic separation was performed by isocratic elution with water/methanol (88:12, v/v), pumped at a flow rate of 0.7 mL min(-1), on a LichroCART 250-4 ChiraDex (beta-cyclodextrin, 5 microm) column at 30 degrees C. The UV detector was set at 225 nm. Calibration curves were linear (r2 > or = 0.996) in the ranges 0.4-8 microg mL(-1), 0.1-1.5 microg mL(-1) and 0.1-2 microg mL(-1) for ESL and OXC and in the ranges 0.4-80 microg mL(-1), 0.1-15 microg mL(-1) and 0.1-20 microg mL(-1) for R-LC and S-LC in plasma, brain and liver/kidney homogenates, respectively. The overall precision not exceeded 11.6% (%CV) and the accuracy ranged from -3.79 to 3.84% (%bias), considering all analytes in all matrices. Hence, this method will be a useful tool to characterize the pharmacokinetic disposition of ESL in mice.

Eslicarbazepine Acetate: A Double-blind, Add-on, Placebo-controlled Exploratory Trial in Adult Patients with Partial-onset Seizures

OBJECTIVE

To explore the efficacy and safety of eslicarbazepine acetate (BIA 2-093), a new antiepileptic drug, as adjunctive therapy in adult patients with partial epilepsy.

METHODS

A multicenter, double-blind, randomized, placebo-controlled study was conducted in 143 refractory patients aged 18-65 years with >or=4 partial-onset seizures/month. The study consisted of a 12-week treatment period followed by a 1-week tapering off. Patients were randomly assigned to one of three groups: treatment with eslicarbazepine acetate once daily (QD, n=50), twice daily (BID, n=46), or placebo (PL, n=47). The daily dose was titrated from 400 mg to 800 mg and to 1,200 mg at 4-week intervals. The proportion of responders (patients with a >or=50% seizure reduction) was the primary end point.

RESULTS

The percentage of responders versus baseline showed a statistically significant difference between QD and PL groups (54% vs. 28%; 90% CI =-infinity, -14; p=0.008). The difference between the BID (41%) and PL did not reach statistical significance (90% CI =-infinity, -1; p=0.12). A significantly higher proportion of responders in weeks 5-8 was found in the QD group than in the BID group (58% vs. 33%, respectively, p=0.022). At the end of the 12-week treatment, the number of seizure-free patients in the QD and BID groups was 24%, which was significantly different from the PL group. The incidence of adverse events was similar between the treatment groups and no drug-related serious adverse events occurred.

CONCLUSION

Eslicarbazepine acetate was efficacious and well tolerated as an adjunctive therapy of refractory epileptic patients.

Effect of gender on the pharmacokinetics of eslicarbazepine acetate (BIA 2-093), a new voltage-gated sodium channel blocker

PURPOSE

To determine the effect of gender on the pharmacokinetics of eslicarbazepine acetate, a novel voltage-gated sodium channel blocker in the development for the treatment of epilepsy and bipolar disorder.

METHODS

Single-centre, open-label, parallel-group study in 12 female and 12 male healthy subjects. The study consisted of a single-dose (600 mg) period and a multiple-dose (600 mg, once-daily, for 8 days) period, separated by 4 days.

RESULTS

Eslicarbazepine acetate was rapidly and extensively metabolized to eslicarbazepine (S-licarbazepine), the main active metabolite. Following a single-dose, arithmetic mean eslicarbazepine maximum plasma concentrations (C(max)) and area under the plasma concentration-time curve over 24 h (AUC(0-24)) and from 0 to infinity (AUC(0-infinity)) were, respectively, 9.3 microg/ml, 128.5 microg h/ml and 171.9 microg h/ml in male subjects and 10.1 microg/ml, 150.1 microg h/ml and 205.0 microg h/ml in female subjects. At steady-state, C(max), AUC(0-24) and AUC(0-infinity) were 15.5 microg/ml, 207.8 microg h/ml and 295.8 microg h/ml in male subjects, and 16.8 microg/ml, 214.5 microg h/ml and 295.2 microg h/ml in female subjects. Steady-state plasma concentrations were attained at 4 to 5 days of administration in both groups. Eslicarbazepine C(max), AUC(0-24) and AUC(0-infinity) female:male geometric mean ratios (90%CI) were, respectively, 1.09 (0.94; 1.24), 1.16 (1.00; 1.33) and 1.17 (0.99; 1.38) following single-dose, and 1.10 (0.97; 1.25), 1.04 (0.92; 1.17) and 1.01 (0.88; 1.16) at steady-state.

CONCLUSION

At steady-state, the pharmacokinetic profile of eslicarbazepine acetate was not affected by gender.

Eslicarbazepine acetate (BIA 2-093)

Eslicarbazepine acetate (ESL) [(S)-(--)-10-acetoxy-10,11-dihydro-5H-dibenz[b,f]azepine-5-carboxamide], formerly known as BIA 2-093, is a novel central nervous system (CNS)-active compound with anticonvulsant activity. It behaves as a voltage-gated sodium channel (VGSC) blocker and is currently under clinical development for the treatment of epilepsy and bipolar disorder. ESL shares with carbamazepine and oxcarbazepine the dibenzazepine nucleus bearing the 5-carboxamide substitute, but is structurally different at the 10,11-position. This molecular variation results in differences in metabolism, preventing the formation of toxic epoxide metabolites such as carbamazepine-10,11 epoxide. In pharmacokinetic studies in humans, ESL was rapidly and extensively metabolized to eslicarbazepine (S-licarbazepine), which is responsible for pharmacological activity. ESL has been tested in patients with refractory partial-onset seizures and was found to be efficacious and well tolerated. Monotherapy studies in adult epileptic patients and add-on studies in epileptic children are in the planning process. The efficacy and safety data appear to be very promising considering the refractory nature of the epileptic population enrolled in studies to date. Results of ongoing phase III studies in adult epileptic patients are expected to be available in 2007 and are required to define the position of ESL in the therapy of patients with epilepsy.

Anticonvulsant effect of eslicarbazepine acetate (BIA 2-093) on seizures induced by microperfusion of picrotoxin in the hippocampus of freely moving rats

Eslicarbazepine acetate (BIA 2-093, S-(-)-10-acetoxy-10,11-dihydro-5H-dibenzo/b,f/azepine-5-carboxamide) is a novel antiepileptic drug, now in Phase III clinical trials, designed with the aim of improving efficacy and safety in comparison with the structurally related drugs carbamazepine (CBZ) and oxcarbazepine (OXC). We have studied the effects of oral treatment with eslicarbazepine acetate on a whole-animal model in which partial seizures can be elicited repeatedly on different days without changes in threshold or seizure patterns. In the animals treated with threshold doses of picrotoxin, the average number of seizures was 2.3+/-1.2, and average seizure duration was 39.5+/-8.4s. Pre-treatment with a dose of 30 mg/kg 2h before picrotoxin microperfusion prevented seizures in the 75% of the rats. Lower doses (3 and 10mg/kg) did not suppress seizures, however, after administration of 10mg/kg, significant reductions in seizures duration (24.3+/-6.8s) and seizure number (1.6+/-0.34) were found. No adverse effects of eslicarbazepine acetate were observed in the behavioral/EEG patterns studied, including sleep/wakefulness cycle, at the doses studied.

New antiepileptic drugs that are second generation to existing antiepileptic drugs

In the last decade, 10 new antiepileptic drugs (AEDs) have been introduced that offer appreciable advantages in terms of their favourable pharmacokinetics, improved tolerability and lower potential for drug interactions. However, despite the large therapeutic range of old and new AEDs, approximately 30% of the patients with epilepsy are still not seizure free and, consequently, there is a substantial need to develop new AEDs. The new AEDs currently in development can be divided into two categories: drugs with completely new chemical structures such as lacosamide (formally harkoseride), retigabine, rufinamide and talampanel; and drugs that are derivatives or analogues of existing AEDs that can be regarded as second-generation or follow-up compounds of established AEDs. This article focuses on the second category and thus critically reviews the following second-generation compounds: eslicarbazepine acetate or BIA-2-093 and 10-hydroxy carbazepine (carbamazepine derivatives); valrocemide and NPS 1776 (isovaleramide; valproic acid derivatives); pregabalin and XP13512 (gabapentin derivatives); brivaracetam (ucb 34714) and seletracetam (ucb 44212; levetiracetam derivatives); and fluorofelbamate (a felbamate derivative). In addition, a series of valproic acid derivatives that are currently in preclinical stage has also been evaluated because some lead compounds of this series have a promising potential to become new antiepileptics and CNS drugs. For any of these follow-up compounds to become a successful second generation to an existing AED, it has to be more potent, safer and possess favourable pharmacokinetics, including low potential for pharmacokinetic and pharmacodynamic drug interactions.

Effect of Food on the Pharmacokinetic Profile of Eslicarbazepine Acetate (BIA 2-093)

OBJECTIVE

To investigate the effect of food on the pharmacokinetics of eslicarbazepine acetate (BIA 2-093), a new voltage-gated sodium channel antagonist.

MATERIAL AND METHODS

Single-centre, open-label, randomised, two-way crossover study in 12 healthy subjects. The study consisted of two consecutive treatment periods separated by a washout of 14 days or more. In each of the study periods subjects were administered a single dose of eslicarbazepine acetate 800 mg following either a standard high-fat content meal or 10 hours of fasting.

RESULTS

Eslicarbazepine acetate was rapidly and extensively metabolised to BIA 2-005. Maximum BIA 2-005 plasma concentrations (C(max)) in fed (test) and fasting (reference) conditions were, respectively, 12.8 +/- 1.8 microg/mL and 11.3 +/- 1.9 microg/mL, and the areas under the plasma concentration time curve from 0 to infinity (AUC(infinity)) were, respectively, 242.5 +/- 32.1 microg.h/mL and 243.6 +/- 31.1 microg.h/mL (arithmetic mean +/- SD). The point estimate (PE) and 90% confidence interval (90% CI) of the test/reference C(max )geometric mean ratio were 1.14 and 1.04, 1.25, respectively; for the AUC(infinity) ratio, the PE and 90% CI were 1.00 and 0.95, 1.04, respectively. Bioavailability of eslicarbazepine acetate administered in fed and fasting conditions was similar and bioequivalence is accepted for both AUC(infinity) and C(max) because the 90% CI lies within the acceptance range of 0.80-1.25. No statistically significant differences were found in time of occurrence of C(max).

CONCLUSION

The presence of food had no significant effect on the pharmacokinetics of eslicarbazepine acetate and therefore this new voltage-gated sodium channel antagonist may be administered without regard to meals.

Eslicarbazepine Acetate (BIA 2-093)

PURPOSE

To investigate the bioavailability and bioequivalence of three different formulations of eslicarbazepine acetate (BIA 2-093): 50 mg/mL oral suspension (test 1), 200mg tablets (test 2) and 800mg tablets (reference).

DESIGN, SUBJECTS AND METHODS

Single-centre, open-label, randomised, three-way crossover study in 18 healthy subjects. The study consisted of three consecutive periods separated by a washout period of 7 days or more. Each subject received a single dose of eslicarbazepine acetate 800mg on three different occasions: 16mL of oral 50 mg/mL suspension, four 200mg tablets or one 800mg tablet.

RESULTS

Eslicarbazepine acetate was rapidly and extensively metabolised to BIA 2-005. Maximum BIA 2-005 plasma concentrations (Cmax) and area under the plasma concentration-time curve from time 0 to infinity (AUCinfinity) were, respectively (arithmetic mean +/- SD), 18.0 +/- 4.6 microg/mL and 325.7 +/- 64.9 microg x h/mL for test 1, 16.0 +/- 4.0 microg/mL and 304.2 +/- 66.0 microg x h/mL for test 2, and 17.0 +/- 4.1 microg/mL and 301.1 +/- 60.0 microg x h/mL for the reference formulation. Point estimate (PE) and 90% confidence intervals (CIs) for AUCinfinity test 1/reference geometric mean ratio were 1.09 and 1.01, 1.15; for Cmax ratio, PE and 90% CI were 1.07 and 0.97, 1.15. When test 2 and the reference formulations were compared, the PE and 90% CI were 0.99 and 0.94, 1.07 for the AUCinfinity ratio, and 0.94 and 0.86, 1.02 for the Cmax ratio. Bioequivalence of test versus reference formulations is thus accepted for both AUCinfinity and Cmax because the 90% CIs lie within the acceptance range of 0.80-1.25.

CONCLUSION

The pharmacokinetic profiles of eslicarbazepine acetate oral 50 mg/mL suspension, 200mg tablet and 800mg tablet formulations were essentially similar, and the formulations can be considered bioequivalent.

Neurotoxicity Induced by Antiepileptic Drugs in Cultured Hippocampal Neurons: A Comparative Study between Carbamazepine, Oxcarbazepine, and Two New Putative Antiepileptic Drugs, BIA 2-024 and BIA 2-093

PURPOSE

Newly designed antiepileptic drugs (AEDs) are being evaluated for their efficacy in preventing seizures and for their toxic profiles. We investigated and compared the toxic effects of two dibenz[b,f]azepine derivatives with anticonvulsant activity, 10,11-dihydro-10-hydroxyimino-5H-dibenz[b,f]azepine-5-carboxamide (BIA2-024) and (S)-(-)-10-acetoxy-10,11-dihydro-5H-dibenz[b,f] azepine-5-carboxamide (BIA2-093), with the structurally related compounds carbamazepine (CBZ) and oxcarbazepine (OXC), both in current use for the treatment of epilepsy.

METHODS

Primary rat hippocampal neurons were used to evaluate neuronal morphology and biochemical changes induced by the AEDs used in this study. Immunocytochemical staining against MAP-2 was used to evaluate neuronal morphology. Reactive oxygen species (ROS) and changes in mitochondrial membrane potential (Psim) were measured by fluorescence techniques. Intracellular adenosine triphosphate (ATP) levels were quantified by high-performance liquid chromatography (HPLC).

RESULTS

Hippocampal neurons treated for 24 h with CBZ or OXC (300 microM) showed degeneration and swelling of neurites, but this effect was not observed in neurons treated with BIA 2-024 or BIA 2-093 (300 microM). ROS production also was increased in neurons treated with OXC, but not in neurons treated with the other AEDs. ATP levels were significantly decreased only in neurons treated with OXC, although the energy charge was not altered. Furthermore, OXC led to a decrease of Psim.

CONCLUSIONS

In all parameters assayed, OXC was more toxic than the other AEDs used. Because the new putative AEDs have previously been shown to have an efficacy in preventing seizures similar to that of CBZ and OXC, and are less toxic to neuronal cells, they may be considered as alternatives to the current available therapies for the treatment of epilepsy.

Progress report on new antiepileptic drugs: a summary of the Seventh Eilat Conference (EILAT VII)

The Seventh Eilat Conference on New Antiepileptic Drugs (AEDs) (EILAT VII) took place in Villasimius, Sardinia, Italy from the 9th to 13th May 2004. Basic scientists, clinical pharmacologists and neurologists from 24 countries attended the conference,whose main themes included advances in pathophysiology of drug resistance, new AEDs in pediatric epilepsy syndromes, modes of AED action and spectrum of adverse effects and a re-appraisal of comparative responses to AED combinations. Consistent with previous formats of this conference, the central part of the conference was devoted to a review of AEDs in development, as well as updates on second-generation AEDs. This article summarizes the information presented on drugs in development, including atipamezole, BIA-2-093, fluorofelbamate, NPS 1776, pregabalin, retigabine, safinamide, SPM 927, stiripentol, talampanel,ucb 34714 and valrocemide (TV 1901). Updates on felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine,topiramate, vigabatrin, zonisamide, new oral and parenteral formulations of valproic acid and SPM 927 and the antiepileptic vagal stimulator device are also presented.