Review of therapeutic options for adjuvant treatment of focal seizures in epilepsy: focus on lacosamide

Lacosamide: A Review in Focal-Onset Seizures in Patients with Epilepsy

Lacosamide (Vimpat^®) is a functionalized amino acid (available orally and intravenously) approved in the EU and the USA for use as monotherapy and adjunctive therapy for the treatment of focal-onset seizures in adults, adolescents and children aged ≥ 4 years with epilepsy. In adults and adolescents (aged ≥ 16 years), oral lacosamide as adjunctive therapy to other antiepileptic drugs was generally effective in reducing seizure frequency during short-term (up to 18 weeks) treatment, with efficacy sustained over the longer-term (up to 8 years). Moreover, patients were effectively switched from adjunctive oral lacosamide to the same dosage of intravenous lacosamide. Oral lacosamide was an effective conversion to monotherapy agent in this patient population and as monotherapy demonstrated noninferiority to carbamazepine controlled release in terms of seizure freedom. Antiepileptic benefits were maintained during longer-term (≤ 2 years) monotherapy. The antiepileptic efficacy of lacosamide in children aged ≥ 4 years has been extrapolated from data from adults and adolescents, with a similar response expected provided paediatric dosage adaptations are used and safety is demonstrated. Indeed, preliminary data demonstrated the efficacy of short-term (16 weeks) adjunctive lacosamide in patients aged ≥ 4 to < 17 years. Oral lacosamide was generally well tolerated over the short- and longer-term when administered as adjunctive therapy, a conversion to monotherapy agent and monotherapy in adults and adolescents and when administered as adjunctive therapy in children aged ≥ 4 years. Thus, lacosamide is a useful option for the management of focal-onset seizures across a broad age range, starting as early as 4 years of age.

Understanding the burden of focal epilepsy as a function of seizure frequency in the United States, Europe, and Brazil

Objective

To understand the current burden of focal epilepsy (FE) as a function of seizure frequency.

Methods

Patients were identified from the United States (2011, 2012, and 2013), five European countries (EU; France, Germany, Italy, Spain, United Kingdom) (2011 and 2013), and Brazil (2011 and 2012) National Health and Wellness Survey (NHWS), a nationally representative, Internet‐based survey of adults (18+ years). The NHWS collected data on respondents’ quality of life (QoL), health utilities, productivity loss, and healthcare resource utilization. Indirect and direct costs were calculated from the literature. Altogether, 345 of 176,093 (U.S.A.), 73 of 30,000 (United Kingdom), 53 of 30,001 (Germany), 53 of 30,000 (France), 41 of 12,011 (Spain), 37 of 17,500 (Italy), and 71 of 24,000 (Brazil) respondents self‐reported a diagnosis of FE.

Results

Many respondents (U.S.A.: 56.2%; 5EU: 41.6%; Brazil + 5EU: 40.5%) reported persistent seizures (≥1 per year). Over 60% to just over 71% of respondents with FE were treated with antiepileptic drugs (AEDs). In the United States, seizure frequency was associated with hospitalizations, indirect costs (ages 18–60), and total direct costs. For the 5EU and Brazil + 5EU, seizure frequency was associated with physical QoL, health utilities, activity impairment, and emergency room (ER) visits. Additional associations were observed for the 5EU on hospitalizations, indirect costs (ages 18–60), ER visit costs, and total direct costs and for Brazil + 5EU on absenteeism, overall work impairment, and provider visits. Costing was not performed for Brazil + 5EU.

Significance

Around half of the patients had persistent seizures despite most taking an AED in this 2011–2013 dataset. The results support the hypothesis that reducing seizures can improve productivity and reduce resource utilization and associated costs. Regional differences may reflect differences in healthcare systems and selected patient populations. Overall, the results suggest that additional treatment options are needed to improve seizure control and reduce related costs.

Emerging drugs for partial-onset epilepsy: a review of brivaracetam

There are more than 12 new antiepileptic drugs approved in the last 2 decades. Even with these newer agents, seizure remission is still unachievable in around 30% of patients with partial-onset seizures (POS). Brivaracetam (BRV) is chemically related to levetiracetam (LEV) and possesses a strong binding affinity for the synaptic vesicle protein 2A tenfold above that of LEV, and other possible modes of antiepileptic actions. BRV is now under Phase III development for POS, but data from one Phase III trial also suggested its potential efficacy for primary generalized seizures. The purpose of this review is to provide updated information on the mechanisms of action of the available antiepileptic drugs, with a focus on BRV to assess its pharmacology, pharmacokinetics, clinical efficacy, safety, and tolerability in patients with uncontrolled POS. To date, six Phase IIb and III clinical trials have been performed to investigate the efficacy, safety, and tolerability of BRV as an adjunctive treatment for patients with POS. Generally, BRV was well tolerated and did not show significant difference in safety profile, compared to placebo. The efficacy outcomes of BRV, although not consistent across trials, did indicate that BRV was a promising add-on therapy for patients with POS. In conclusion, the many favorable attributes of BRV, like its high oral efficacy, good tolerability, dosing regimen, and minimal drug interaction, make it a promising antiepileptic therapy for patients with uncontrolled partial-onset epilepsy.

Palladium-benzodiazepine derivatives as promising metallodrugs for the development of antiepileptic therapies

We synthesized two organometallic diazepam-palladium(II) derivatives by C-H activation of diazepam (DZP) with palladium salts, i.e., PdCl2 and Pd(OAc)2 (OAc=acetate). Both compounds obtained are air stable and were isolated in good yields. The anticonvulsant potential of the complexes, labeled [(DZP)PdCl]2 and [(DZP)PdOAc]2, was evaluated through two animal models: pentylenetetrazole (PTZ)- and picrotoxin (PTX)-induced convulsions. The organometallic DZP-palladium(II) acetate complex, [(DZP)PdOAc]2, significantly increased (p<0.01 or p<0.001) latencies and protected the animals against convulsions induced by PTZ and PTX, while the analogous chloro derivative, [(DZP)PdCl]2, was effective (p<0.01) only in the PTZ model. These effects appear to be mediated through the GABAergic system. The possible mechanism of action of the DZP-palladium(II) complexes was also confirmed with the use of flumazenil (FLU), a GABAA-benzodiazepine receptor complex site antagonist. Herein, we present the first report of the anticonvulsant properties of organometallic DZP-palladium(II) complexes as well as evidence that these compounds may play an important role in the study of new drugs to treat patients with epilepsy.

Cognitive effects of lacosamide as adjunctive therapy in refractory epilepsy

BACKGROUND

Lacosamide (LCM) is a novel antiepileptic drug (AED) with potential benefit as adjunctive treatment in patients with partial-onset seizures. As yet, limited information on cognitive effects of LCM is available, especially in real-life settings.

AIMS

In this open clinical prospective study, the cognitive effects of LCM were evaluated when used as adjunctive antiepileptic therapy in patients with refractory epilepsy.

METHODS

We included 33 patients aged between 16 and 74 years (mean: 37 years). All patients had a localization-related epilepsy. Patients were assessed at baseline before starting LCM treatment and during follow-up when the optimal clinical dose was achieved.

MATERIALS

Subjective complaints were evaluated using the SIDAED; effects on cognition were evaluated using the computerized visual searching task (CVST).

RESULTS

The CVST showed significant faster information processing reaction times at the second evaluation (P = 0.013), which was not correlated with seizure control, type of epilepsy, age, gender, drug load, number of concomitant drugs, dose or duration of LCM treatment. On the SIDAED, patients complained more about their cognitive function at the second evaluation (P = 0.005). For the SIDAED, a positive correlation at follow-up was found between the total severity score and higher age (r = 0.375, P = 0.031), but not with epilepsy factors or treatment characteristics.

DISCUSSION/CONLUSION

Screening of the cognitive effects of LCM showed that LCM does not have negative effects on information processing speed. As this is the most sensitive function for cognitive side effects of AEDs, LCM does not seem to induce the common negative cognitive effects. Remarkably, patients complained more, especially about their cognitive function, which is possible the 'doing better, feeling worse phenomenon'.

Antiepileptic drug effects on mood and behavior: molecular targets

With almost 100 years of clinical experience, antiepileptic drugs (AEDs) remain the mainstay of epilepsy treatment. They suppress epileptic seizures by acting on a variety of mechanisms and molecular targets involved in the regulation of neuronal excitability. These include inhibitory-GABAergic and excitatory-glutamatergic neurotransmission, as well as ion (sodium and calcium) conductance through voltage-gated channels. On the other hand, accruing evidence indicates that these mechanisms and targets are also implicated in the regulation of mood and behavior, which may explain why each AED is associated with specific psychotropic effects. These effects, however, cannot be explained solely on the basis of the known mode of action of each AED, and other mechanisms or targets are likely to be implicated. In this article, we review positive and negative effects of AEDs on mood and behavior, discuss putative underlying mechanisms, and highlight knowledge gaps which should be addressed in future studies.