Long-term safety and efficacy in patients with uncontrolled partial-onset seizures treated with adjunctive lacosamide: results from a Phase III open-label extension trial

Lacosamide as adjunctive therapy in treatment-resistant epilepsy in childhood

AIMS

Lacosamide (LCM) is a novel anti-epileptic drug (AED) that enhances the slow inactivation of voltage-gated sodium channels. Its efficacy as adjunctive therapy for focal seizures is confirmed in adult placebo controlled trials with >50% reduction in seizure frequency in up to 50% patients. There is paucity of data on its efficacy and tolerance in treatment-resistant epilepsy in childhood (TREC). This study aims to assess efficacy and tolerance of LCM as adjunct therapy in TREC.

METHODS

Audit of medical records and seizure diaries in children with TREC on LCM. A response (RR) was defined as ≥50% reduction in seizure frequency.

RESULTS

Forty children (age range: 2-19 years) with TREC received LCM as add-on therapy. All had abnormal electroencephalograms, and 36 had abnormal neuroimaging. All children failed >2 AED trials, nine had trialled the ketogenic diet, five had failed the vagal nerve stimulator and 11 had failed resective epilepsy surgery. Median dose and duration of LCM therapy were 5.7 mg/kg/day and 10.5 months, respectively. RR was seen in 20% with persistence of RR in 8/36, 8/30 and 8/26 children on LCM at 3-, 6- and 9-month follow-up. Two children became seizure free. Retention on LCM was 65% at 9 months. LCM was well tolerated with minor side effects in seven children; no child discontinued LCM because of side effects.

CONCLUSION

LCM is a well-tolerated AED with RR in 20%: in 5%, it resulted in seizure freedom. LCM may be useful even in TREC when seizures have not responded to intervention with multiple modalities.

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'.

Cardiac sodium channel blockade after an intentional ingestion of lacosamide, cyclobenzaprine, and levetiracetam: Case report

CONTEXT

Lacosamide treats partial seizures by enhancing slow inactivation of voltage-gated sodium channels. The described cardiac toxicity of lacosamide in the literature to date includes atrioventricular blockade (PR prolongation), atrial flutter, atrial fibrillation, sinus pauses, ventricular tachycardia and a single cardiac arrest. We report a second case of cardiac arrest following an intentional lacosamide overdose.

CASE DETAILS

A 16 year-old female with a seizure disorder was found unresponsive in pulseless ventricular tachycardia after intentionally ingesting 4.5 g (76 mg/kg) lacosamide, 120 mg (2 mg/kg) cyclobenzaprine and an unknown amount of levetiracetam. Exact time of ingestion was unknown. Her initial electrocardiogram (ECG) demonstrated sinus tachycardia at 139 beats per minute, QRS duration 112 ms, and terminal R-wave in lead aVR > 3 mm. Despite treatment with 150 mEq of sodium bicarbonate, she had persistent EKG findings eight hours after presentation. Her serum lacosamide concentration nine hours after presentation was elevated at 22.8 μg/mL, while serum cyclobenzaprine concentration was 16 ng/mL (therapeutic: 10-30 ng/mL), and serum levetiracetam concentration was 22.7 μg/mL (therapeutic: 12-46 μg/mL). On hospital day three, ECG demonstrated resolution of the terminal R-wave with QRS of 78 ms. The patient recovered without physical or neurologic sequelae.

DISCUSSION

The patient's lacosamide, cyclobenzaprine and levetiracetam overdose was associated with QRS prolongation and terminal right axis deviation--suggesting sodium channel blockade as a likely etiology for her cardiac arrest. Cyclobenzaprine has potential for sodium channel blockade and ventricular dysrhythmias although cardiac toxicity due to cyclobenzaprine alone is rare. The combination of cyclobenzaprine with lacosamide may have resulted in cardiovascular collapse. In conclusion, overdose of lacosamide combined with therapeutic concentrations of sodium channel blocking xenobiotics may cause cardiac conduction delays and cardiac arrest.

Safety and efficacy of adjunctive lacosamide among patients with partial-onset seizures in a long-term open-label extension trial of up to 8 years

Long-term (up to 8 years of exposure) safety and efficacy of the antiepileptic drug lacosamide was evaluated in this open-label extension trial (SP615 [ClinicalTrials.gov identifier: NCT00552305]). Patients were enrolled following participation in a double-blind trial or one of two open-label trials of adjunctive lacosamide for partial-onset seizures. Dosage adjustments of lacosamide (100-800 mg/day) and/or concomitant antiepileptic drugs were allowed to optimize tolerability and seizure reduction. Of the 370 enrolled patients, 77%, 51%, and 39% had >1, >3, or >5 years of lacosamide exposure, respectively. Median lacosamide modal dose was 400mg/day. Common treatment-emergent adverse events (TEAEs) were dizziness (39.7%), headache (20.8%), nausea (17.3%), diplopia (17.0%), fatigue (16.5%), upper respiratory tract infection (16.5%), nasopharyngitis (16.2%), and contusion (15.4%). Dizziness (2.2%) was the only TEAE that led to discontinuation in >2% of patients. Ranges for median percent reductions in seizure frequency were 47-65%, and those for ≥ 50% responder rates were 49-63% for 1-, 3-, and 5-year completer cohorts. Exposure to lacosamide for up to 8 years was generally well tolerated, with a safety profile similar to previous double-blind trials, and efficacy was maintained.

Lacosamide as adjunctive therapy in refractory epilepsy in adults: a systematic review

PURPOSE

To review the evidence for efficacy and safety of lacosamide in adult patients with refractory epilepsy and refractory status epilepticus (RSE).

METHODS

A systematic literature search of MEDLINE, PubMed, EMBASE, IPA, Google and Google Scholar (through October 2014) was performed.

RESULTS

Fourteen studies assessing lacosamide in 3509 refractory epilepsy patients were included. In 3 RCTs, more patients had at least 50% reduction in seizure frequency with lacosamide compared to placebo with 38.3-41.1%, 38.1-41.2%, and 18.3-25.8%, in the 400 mg/day, 600 mg/day, and placebo groups, respectively. In non-comparative trials, 18-69% of patients achieved at least 50% reduction in seizure frequency, and 1.7-26.2% achieved seizure freedom. Non-responders were documented in two trials, with 26.2-34% having no response. Thirteen studies assessing lacosamide in 390 RSE patients were included. When assessing lacosamide's ability to terminate RSE, one comparative cohort study found no improvement in SE duration or seizure control with addition of lacosamide. Another study documented no difference compared to use of phenytoin. Eleven descriptive studies using lacosamide as add-on RSE therapy revealed seizure termination rates of 0-100% (median 64.7%). In all patients receiving lacosamide, dizziness (21.8%), vision disturbances (10.4%), drowsiness (7.4%), headache (7.0%), nausea (6.5%), and coordination problems (5.8%) were the most common adverse effects.

CONCLUSION

Based on evidence to date, adjunctive lacosamide is a treatment option to reduce seizure frequency in patients with refractory epilepsy and terminate seizures in patients with RSE. The safety information summary can be used to advise patients of potential adverse effects.

Update on the use of lacosamide in the treatment of partial-onset seizures

ABSTRAT: 

Lacosamide has a novel mechanism of action, namely selective enhancement of slow inactivation of voltage-gated sodium channels. Trial data and clinical experience indicate that it is effective in the treatment of partial-onset seizures, and that it is well tolerated. Pivotal early clinical trials demonstrated median percent reductions in seizure frequency ranging from 26 to 35.3% in the 200 mg/day, from 36.4 to 39% in the 400 mg/day, and from 37.8 to 40% in the 600 mg/day treatment groups. Dose-related adverse events were similar in the early clinical trials, and were mainly CNS complaints including dizziness, nausea, vomiting, fatigue, ataxia, abnormal vision, diplopia and nystagmus. Because of the dose-dependent adverse events and lack of additional efficacy at the 600 mg/day daily dose, lacosamide has been approved as an adjunctive treatment at recommended daily doses of 200–400 mg/day.

Determining minimally important change thresholds for the Seizure Severity Questionnaire (SSQ)

The Seizure Severity Questionnaire (SSQ) was developed to evaluate changes in seizure severity and bothersomeness. Determination of a threshold value reflecting meaningful patient benefit on the SSQ would improve clinical interpretation of scale results. The objective of this analysis was to define a minimally important change (MIC) threshold for the SSQ, using data from patients with treatment-resistant partial-onset seizures from two clinical trials (N=776). Minimally important change thresholds were calculated using standard anchor-based methods, with the Patient Global Impression of Change (PGIC) score as the anchor with the categories of 'much improved,' 'minimally improved,' 'much worsened,' and 'minimally worsened' combined. The calculated MIC thresholds (range: 0.34 to 0.50) suggest that a 0.48-point change in the SSQ total score reflects a clinically meaningful change in seizure severity from the patients' perspective.

Sensitivity testing of the Seizure Severity Questionnaire (SSQ)

The sensitivity of the Seizure Severity Questionnaire (SSQ) was evaluated using pooled data from open-label extensions of two clinical trials in patients with partial-onset seizures. The SSQ includes questions relating to frequency and helpfulness of warning signs as well as frequency, severity, and bothersomeness of ictal and postictal effects. Differences between mean change from baseline for each SSQ item for responders and nonresponders were described and compared between patients solely with complex partial seizures (CPSs: responders, n=166; nonresponders, n=127) and those solely with secondarily generalized partial seizures (SGPSs: responders, n=26; nonresponders, n=24) at baseline. Seizure Severity Questionnaire total score and individual SSQ items related to ictal movement, consciousness, bothersomeness of postictal effects, and frequency of postictal emotional effects showed differentiation between seizure type responders. These data provide further validation of the SSQ by demonstrating its sensitivity in describing treatment effects.

Lacosamide: a review of its use as adjunctive therapy in the management of partial-onset seizures

Lacosamide (Vimpat(®)) is a functionalized amino acid available orally (as a syrup or tablet) and as an intravenous infusion. It is believed to exert its antiepileptic effect by selectively enhancing the slow inactivation of voltage-gated sodium channels. Lacosamide is approved in several countries worldwide as an adjunctive therapy for the treatment of partial-onset seizures; however, prescribing regulations differ between countries. This article reviews the use of lacosamide as indicated in adults and adolescents (aged 16-18 years) in the EU, where it is approved in this patient population as an adjunctive therapy to other AEDs in the treatment of partial-onset seizures, with or without secondary generalization. In three randomized, double-blind, placebo-controlled, multicentre studies in adults and adolescents (aged 16-18 years) with partial-onset seizures, adjunctive therapy with oral lacosamide (administered for an initial titration period followed by 12 weeks' maintenance therapy) generally reduced the frequency of seizures to a significantly greater extent than placebo, with antiepileptic efficacy sustained following longer-term treatment (up to 8 years) in this patient population. Oral and intravenous lacosamide were generally well tolerated in clinical studies, with the majority of adverse events being mild or moderate in severity. Very common adverse reactions following adjunctive therapy with oral lacosamide included diplopia, dizziness, headache and nausea; the tolerability profile of intravenous lacosamide appeared consistent with that of oral lacosamide, although intravenous administration was associated with local adverse events, such as injection site discomfort or pain, irritation and erythema. Thus, oral and intravenous lacosamide as an adjunctive therapy to other AEDs provides a useful option in the treatment of patients with partial-onset seizures.

Development of lacosamide for the treatment of partial-onset seizures

Lacosamide is an antiepileptic drug (AED) available in multiple formulations that was first approved in 2008 as adjunctive therapy for partial-onset seizures (POS) in adults. Unlike traditional sodium channel blockers affecting fast inactivation, lacosamide selectively enhances sodium channel slow inactivation. This mechanism of action results in stabilization of hyperexcitable neuronal membranes, inhibition of neuronal firing, and reduction in long-term channel availability without affecting physiological function. Lacosamide has a well-characterized and favorable pharmacokinetic profile, including a fast absorption rate, minimal or no interaction with cytochrome P-450 izoenzymes, and a low potential for drug-drug interactions. Lacosamide clinical development included three placebo-controlled, double-blind, randomized trials conducted in more than 1300 patients, each demonstrating safety and efficacy of lacosamide compared to placebo as adjunctive therapy for adults with POS. The clinical use of lacosamide may broaden, pending results of trials evaluating its use as monotherapy for POS in adults, as treatment for epilepsy in pediatric subjects, and as adjunctive treatment for uncontrolled primary generalized tonic-clonic seizures in those with idiopathic generalized epilepsy.