Gaetano Zaccara

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.

Health-related quality of life of patients with epilepsy is heavily influenced by antiepileptic drug (AED) tolerability. However, an accepted method for precise assessment of AED-induced adverse events (AEs) has not yet been established. Assessment of tolerability and of the frequency of predefined AEs among drug-resistant epilepsy patients through an analysis of placebo-treated patients from randomized controlled studies (RCTs) performed in patients with partial onset epilepsies (POS) and evaluation of factors which may influence the occurrence of AEs in these patients are the objectives of this study. We searched all double-blind, placebo-controlled trials investigating any AED on adult patients with POS and extracted both for patients treated with placebo and for those treated with the active drug, number of patients, number of responders, number of patients withdrawing because of AEs, number of patients with AEs, and number of patients with 11 predefined AEs. We also explored the effect of multiple factors on AEs reporting. Seventy-nine RCTs were included in our study with 12,594 patients, 6,793 of whom randomized to placebo. In placebo-treated patients, overall responder rate was 15.2 %, proportion of placebo-treated patients withdrawing because of AEs was 3.9 %, and proportion of patients with AE was 60.3 %. The four most frequently reported AEs were headache (12.4 %) somnolence (8.6 %), dizziness (8.2 %), and fatigue (7.9 %). Several factors were found to influence these outcomes. Several factors influence AEs’ appearance in RCTs. Among the most important, we found the expectations of patients and doctors and their attitudes on the positive or negative effect of a drug.

Summary: Objectives: To assess the comparative efficacy and safety of pregabalin and levetiracetam for the reduction of seizure frequency in patients with partial seizures.Methods: This was a randomized, double‐blind, flexible‐dose, parallel‐group noninferiority study of pregabalin and levetiracetam (randomized 1:1) as adjunctive treatment in adult patients with refractory partial seizures. The study included a 6‐week baseline phase, 4‐week dose‐escalation phase, and 12‐week maintenance phase. The primary endpoint was the proportion of patients with a ≥50% reduction in 28‐day seizure rate during the 12‐week maintenance phase, as compared with baseline. Noninferiority of pregabalin was declared if the lower limit of the 95% confidence interval (CI) for the difference in responder rates was greater than the prespecified noninferiority margin of −12%. A key secondary endpoint was the percent change from baseline in 28‐day seizure rate during the dose‐escalation and maintenance phases.Results: Five hundred nine patients were randomized to pregabalin (n = 254) or levetiracetam (n = 255) and 418 (208 pregabalin, 210 levetiracetam) completed the maintenance phase. With both pregabalin and levetiracetam, the proportion of patients with a ≥50% reduction in 28‐day seizure rate was 0.59 (difference between groups [95% CI], 0.00 [−0.08 to 0.09]). Because the lower bound of the 95% CI was greater than the prespecified noninferiority margin of −12%, pregabalin was not inferior to levetiracetam. There was no significant difference between pregabalin and levetiracetam in the percent change in 28‐day seizure rate (median difference [95% CI], 4.1 [−2.6 to 10.9], p = 0.3571). In a post hoc analysis, the proportion of patients who were seizure‐free for the maintenance phase was lower with pregabalin (8.4%) than with levetiracetam (16.2%), p = 0.0155. Safety profiles were similar and consistent with prior trials.Significance: These results indicate that pregabalin is noninferior, and has a similar tolerability, to levetiracetam as adjunctive therapy in reducing seizure frequency in patients with partial seizures.A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.

Network meta-analysis (NMA) is a new technique that allows multiple treatment comparisons and provides estimates of effect sizes for all possible pair-wise comparisons. Several NMAs of antiepileptic drug (AED) efficacy and tolerability in individuals with refractory focal epilepsy, however, came to non-specific and, in some cases, divergent conclusions. We review some clinical factors that may be responsible for these inconsistent findings. A major issue is the small number of individuals included in the meta-analyses with consequent wide confidence intervals and lack of ability to achieve significant results. Further issues are lack of robustness of the measured efficacy outcome—the responder ratio (the percentage of individuals with a >50 % improvement in seizure frequency); the selection of randomized studies (RCTs) included, i.e., the inclusion of studies with heterogeneous populations (children and adults); and inclusion of people treated with different doses of the experimental drug. Some methods of analysing data from RCTs, such as the last observation carried forward (LOCF) analysis, the choice of different phases of the study to compare to baseline, and the year in which the trial was conducted, selectively affect measurement of efficacy outcomes. Titration speed and other methodological aspects selectively affect tolerability. Several factors restrict the analysis of clinically useful estimates of the comparative efficacy of AEDs, while analysis of tolerability may be easier to accomplish.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in the postsynaptic membrane are involved in fast excitatory signaling in the brain and their activation may lead to the firing of action potentials. Talampanel and perampanel were the first noncompetitive AMPA receptor antagonists to be tested as add-on drugs in patients with refractory partial seizures, and were found to be effective in improving seizure control. Due to an unfavorable kinetic and tolerability profile, talampanel clinical development in the field of epilepsy was discontinued early while perampanel has been recently approved in Europe and the USA as adjunctive therapy for adults with partial seizures with or without secondary generalization. The recommended perampanel starting dose is 2 mg/day once daily, which can be increased up to the recommended maintenance dose of 4-8 mg/day. Increments should be of 2 mg/day and based on clinical response and tolerability. Titration should be performed at 1-week intervals or at lower speed and a 12-mg daily dose should be considered after careful evaluation. To date, no serious and/or idiosyncratic adverse effects have been associated with this agent. Most frequently reported adverse effects are dizziness, ataxia, aggression, irritability, vertigo, somnolence, fatigue, headache and gait disturbance. Weight increase is the only non-neurological adverse effects associated with perampanel.