Effects of adjunctive eslicarbazepine acetate on neurocognitive functioning in children with refractory focal-onset seizures

PURPOSE

This was a phase-II, randomized, double-blind (DB), placebo-controlled study aimed to evaluate neurocognitive effects of eslicarbazepine acetate (ESL) as adjunctive therapy in pediatric patients with refractory focal-onset seizures (FOS).

METHODS

Children (6-16years old) with FOS were randomized (2:1) to ESL or placebo. Treatment started at 10mg/kg/day, was up-titrated up to 30mg/kg/day (target dose), and maintained for 8weeks, followed by one-year open-label follow-up. The primary endpoint was change from baseline to the end of maintenance period in the composite Power of Attention assessed with the Cognitive Drug Research (CDR) system. Behavioral and emotional functioning and quality of life (QOL), secondary endpoints, were assessed with Child Health Questionnaire-Parent Form 50 (CHQ-PF50), Child Behavior Checklist (CBCL), and Raven's Standard Progressive Matrices (SPM). Efficacy was evaluated through changes in standardized seizure frequency (SF), responder rate, and proportion of seizure-free patients. Safety was evaluated by the incidence of treatment-emergent adverse events (TEAEs).

RESULTS

One hundred and twenty-three patients were randomized. A noninferiority analysis failed to reject the null hypothesis that the change from baseline in the Power of Attention score in the ESL group was at least 121ms inferior to the placebo group for all age groups. The CDR scores showed no differences between placebo and ESL in Power of Attention (1868.0 vs 1759.5), Continuity of Attention (1.136 vs -1.786), Quality of Working Memory (-0.023 vs -0.024), and Speed of Memory (-263.4 vs -249.6). Nonsignificant differences between placebo and ESL were seen for CHQ-PF50, CBCL scores, and Raven's SPM. Episodic Memory Index showed significant negative effect on ESL. Efficacy results favored the ESL group (SF least square [LS] means 1.98 vs 4.29). The TEAEs had a similar incidence between treatment groups (41.0% vs 47.5%).

CONCLUSIONS

Overall ESL did not produce statistically significant effects on neurocognitive and behavioral functioning in patients with epilepsy aged 6 to 16years. Additionally, ESL was effective in reducing seizure frequency and was well-tolerated.

SAFETY AND EFFICACY OF ESLICARBAZEPINE ACETATE IN ELDERLY PATIENTS

Purpose

To evaluate the safety/tolerability and efficacy of eslicarbazepine acetate (ESL) as adjunctive therapy in elderly patients with partial-onset seizures (POS).

Method

Phase III, multicentre, open-label, non-controlled study in patients aged ≥65 years with ≥2 POS during an 8-week baseline and treated with 1–2 antiepileptic drugs. Following baseline, patients entered a 26-week maintenance period. ESL was initiated at 400 mg once-daily and adjusted (400–1200 mg/day) based on individual response. Safety/tolerability evaluations included treatment-emergent adverse events (TEAEs), vital signs, 12-lead electrocardiogram and physical/neurological examinations. Efficacy evaluations included change in standardised seizure frequency (SSF; seizure frequency/4 weeks).

Results

Of the 72 patients included, 47 (65.3%) experienced 152 TEAEs; most commonly, dizziness (12.5%), somnolence (9.7%), fatigue (8.3%), convulsion (8.3%) and hyponatraemia (8.3%). Three patients died of cardiac failure, glioblastoma multiforme and ischaemic stroke (relationship unlikely/not related). Overall, 16 (22.2%) patients discontinued due to TEAEs. Incidence of clinically significant findings was low for vital signs, electrocardiogram and physical/neurological examinations. SSF decreased from 2.9 at baseline to 1.2 during the maintenance period (median relative change: –54.1%).

Conclusion

Once-daily ESL (400–1200 mg) as adjunctive therapy in elderly subjects with POS did not raise major safety concerns and was efficacious. Supported by Bial.

Distribution and pharmacokinetics of etamicastat and its N-acetylated metabolite (BIA 5-961) in dog and monkey

1. The disposition etamicastat was evaluated in the Cynomolgus monkey after intravenous and oral administration of [(14)C]-etamicastat. The pharmacokinetics of etamicastat and its N-acetylated metabolite BIA 5-961 were also evaluated in monkeys and dogs. 2. In the monkey, 7 days after intravenous and oral administration of [(14)C]-etamicastat, 76.6-91.1% of the etamicastat-related radioactivity had been excreted mainly in urine. The radioactivity peaked in plasma between 4- and 8-h post-dosing followed by a quick decline and a slow terminal phase (half-life of 68.7 h). The calculated oral bioavailability for etamicastat was 46.1%. Etamicastat was quickly absorbed in monkeys and dogs with a half-life ranging from 5.2 to 9.9 h in monkeys and 6.9 to 11.4 h in dogs over. 3. The N-acetylated metabolite of etamicastat, represented 4-7% of the extent of exposure of etamicastat in the monkey, but was not found detectable in dogs. Gender did not influence etamicastat exposure and the concentration versus time curves fitted a dose-dependent pharmacokinetics in the dog, but not in the monkey. 4. In conclusion, etamicastat is rapidly absorbed and primarily excreted via urine in monkeys. Similarly, to humans, monkeys, unlike dogs, N-acetylate etamicastat and evidence that etamicastat pharmacokinetics is less than dose proportional.

Pharmacological profile of opicapone, a third-generation nitrocatechol catechol-O-methyl transferase inhibitor, in the rat

BACKGROUND AND PURPOSE

Catechol-O-methyltransferase (COMT) is an important target in the levodopa treatment of Parkinson's disease; however, the inhibitors available have problems, and not all patients benefit from their efficacy. Opicapone was developed to overcome those limitations. In this study, opicapone's pharmacological properties were evaluated as well as its potential cytotoxic effects.

EXPERIMENTAL APPROACH

The pharmacodynamic effects of opicapone were explored by evaluating rat COMT activity and levodopa pharmacokinetics, in the periphery through microdialysis and in whole brain. The potential cytotoxicity risk of opicapone was explored in human hepatocytes by assessing cellular ATP content and mitochondrial membrane potential.

KEY RESULTS

Opicapone inhibited rat peripheral COMT with ED50 values below 1.4 mg⋅kg(-1) up to 6 h post-administration. The effect was sustained over the first 8 h and by 24 h COMT had not returned to control values. A single administration of opicapone resulted in increased and sustained plasma levodopa levels with a concomitant reduction in 3-O-methyldopa from 2 h up to 24 h post-administration, while tolcapone produced significant effects only at 2 h post-administration. The effects of opicapone on brain catecholamines after levodopa administration were sustained up to 24 h post-administration. Opicapone was also the least potent compound in decreasing both the mitochondrial membrane potential and the ATP content in human primary hepatocytes after a 24 h incubation period.

CONCLUSIONS AND IMPLICATIONS

Opicapone has a prolonged inhibitory effect on peripheral COMT, which extends the bioavailability of levodopa, without inducing toxicity. Thus, it exhibits some improved properties compared to the currently available COMT inhibitors.

Brain and peripheral pharmacokinetics of levodopa in the cynomolgus monkey following administration of opicapone, a third generation nitrocatechol COMT inhibitor

OBJECTIVE

The present study aimed at evaluating the effect of opicapone, a third generation nitrocatechol catechol-O-methyltransferase (COMT) inhibitor, on the systemic and central bioavailability of 3,4-dihydroxy-l-phenylalanine (levodopa) and related metabolites in the cynomolgus monkey.

METHODS

Four monkeys, implanted with guiding cannulas for microdialysis probes, in the substantia nigra, dorsal striatum and prefrontal cortex, were randomized in two groups that received, in a crossover design, vehicle or 100 mg/kg opicapone for 14 days. Twenty-three hours after last administration of vehicle or opicapone, animals were challenged with levodopa/benserazide (12/3 mg/kg). Extracellular dialysate and blood samples were collected over 360 min (at 30 min intervals) for the assays of catecholamine and COMT activity.

RESULTS

Opicapone increased levodopa systemic exposure by 2-fold not changing Cmax values and reduced both 3-O-methyldopa (3-OMD) exposure and Cmax values by 5-fold. These changes were accompanied by ∼76-84% reduction in erythrocyte COMT activity. In dorsal striatum and substantia nigra, opicapone increased levodopa exposure by 1.7- and 1.4-fold, respectively, reducing 3-OMD exposure by 5- and 7-fold respectively. DOPAC exposure was increased by 4-fold in the substantia nigra. In the prefrontal cortex, opicapone increased levodopa exposure and reduced 3-OMD levels by 2.3- and 2.4-fold, respectively.

CONCLUSIONS

Opicapone behaved as long-acting COMT inhibitor that markedly increased systemic and central levodopa bioavailability. Opicapone is a strong candidate to fill the unmet need for COMT inhibitors that lead to more sustained levodopa levels in Parkinson's disease patients.