Adjunctive lacosamide for partial-onset seizures: Efficacy and safety results from a randomized controlled trial

Lacosamide as adjunctive therapy for partial-onset epileptic seizures: a review of the clinical and economic literature

OBJECTIVE

This article provides a short but comprehensive pharmacotherapeutic update of adjunctive therapy with lacosamide for partial-onset seizures in adult patients.

RESEARCH DESIGN AND METHODS

PubMed, Centre for Reviews and Dissemination databases, Cochrane Database of Systematic Reviews, EconLit were searched from January 1999 to September 2010. Studies evaluating intravenous lacosamide were excluded because this article focuses on chronic adjunctive therapy.

RESULTS

Three randomised, multicentre, double-blind, placebo-controlled trials have investigated the efficacy of lacosamide in 1300 adults with epilepsy. The median percent reduction in seizure frequency per 28 days from baseline to maintenance was 18.4% for placebo, 33.3% for lacosamide 200 mg/day (p < 0.01), 36.8% for 400 mg/day (p < 0.001), 39.4% for 600 mg/day. The percentage of patients attaining a seizure frequency reduction of ≥50% was 22.6% with placebo, 34.1% with lacosamide 200 mg/day (p < 0.05), 39.7% with lacosamide 400 mg/day (p < 0.001), 39.6% with lacosamide 600 mg/day. Three open-label extension studies showed that long-term treatment with lacosamide produced sustained efficacy in and was well-tolerated by patients. Three economic evaluations used a similar design to determine the cost effectiveness of lacosamide from the healthcare payer perspective in Sweden, Finland and Belgium. These studies showed that standard anti-epileptic drug therapy plus lacosamide is likely to constitute a cost-effective alternative. The budget impact of introducing lacosamide is likely to be limited.

CONCLUSIONS

The evidence on lacosamide was limited and studies suffered from a number of methodological limitations. Lacosamide appears to be a safe, efficacious and cost-effective adjunctive therapy for partial-onset epileptic seizures in adult patients. However, these results need to be validated by studies that explore the impact of lacosamide in real-life clinical practice.

Experience with lacosamide in a series of children with drug-resistant focal epilepsy

We report our pediatric experience with lacosamide, a new antiepileptic drug, approved by the US Food and Drug Administration as adjunctive therapy in focal epilepsy in patients more than 17 years old. We retrospectively reviewed charts for lacosamide use and seizure frequency outcome in patients with focal epilepsy (Wilcoxon signed rank test). Sixteen patients (7 boys) were identified (median dose 275 mg daily, 4.7 mg/kg daily; mean age 14.9 years, range 8-21 years). Patients were receiving a median of 2 antiepileptic drugs (interquartile range [IQR] 1.7-3) in addition to having undergone previous epilepsy surgery (n=3), vagus nerve stimulation (n=9), and ketogenic diet (n=3). Causes included structural (encephalomalacia and diffuse encephalitis, 1 each; stroke in 2) and genetic abnormalities (Aarskog and Rett syndromes, 1 each) or cause not known (n=10). Median seizure frequency at baseline was 57 per month (IQR 7-75), and after a median follow-up of 4 months (range 1-13 months) of receiving lacosamide, it was 12.5 per month (IQR 3-75), (P<0.01). Six patients (37.5%; 3 seizure free) were classified as having disease that responded to therapy (≥50% reduction seizure frequency) and 10 as having disease that did not respond to therapy (<50% in 3; increase in 1; unchanged in 6). Adverse events (tics, behavioral disturbance, seizure worsening, and depression with suicidal ideation in 1 patient each) prompted lacosamide discontinuation in 4/16 (25%). This retrospective study of 16 children with drug-resistant focal epilepsy demonstrated good response to adjunctive lacosamide therapy (median seizure reduction of 39.6%; 37.5% with ≥50% seizure reduction) without severe adverse events.

Fluctuation of lacosamide serum concentrations during the day and occurrence of adverse drug reactions--first clinical experience

PURPOSE

To obtain better understanding of the effect of lacosamide (LCM) in clinical practice, laboratory and clinical data of 17 patients under treatment with LCM as an add-on antiepileptic drug (AED) were retrospectively evaluated.

METHODS

Total LCM serum concentrations were obtained at hourly intervals for up to 5h and 8h after morning dose. Adverse drug reactions (ADR) were assessed.

RESULTS

LCM serum concentrations showed high fluctuations during the day with a steep increase within the first 3h after intake (mean 87.8%; range: 44.4-149.0%) under b.i.d. Mean trough and peak concentrations of LCM were 5.0 μg/ml (range: 1.8-9.5 μg/ml) and 9.7 μg/ml (range: 4.0-18.3 μg/ml), respectively; mean dose 353 mg/d (range: 200-600mg/d). Twelve patients showed ADRs. After conversion to t.i.d. or dose reduction LCM serum concentration showed lower fluctuations during the day and a lower increase after intake (mean: 50.0%, range: 27.1-66.7%); peak LCM was 9.4 μg/ml (range: 4.7-11.6 μg/ml), mean dose 388 mg/d (range: 300-500 mg/d). These interventions led to amelioration of the ADR.

CONCLUSION

Changing the dose regimen from two to three times daily could reduce fluctuations of LCM during the day and improve tolerability of LCM in patients with ADR.

Efficacy and tolerability of oral lacosamide as adjunctive therapy in pediatric patients with pharmacoresistant focal epilepsy

The results of adjunctive lacosamide treatment in 18 pediatric patients with pharmacoresistant focal epilepsy are reported. All had severe forms of focal epilepsy with or without secondary generalization and were concurrently receiving one to three other antiepileptic drugs. Lacosamide was administered orally, and final dose, after slow titration, ranged between 1.7 and 10 mg/kg. Mean treatment duration was 8 months (range=3 weeks-17 months). Treatment efficacy was assessed at two time points with a 1-year interval. The reported greater than 50% reduction in seizure frequency was 36% in the initial short-term and 20% in the following long-term assessment. Side effects, mostly somnolence and irritability, were reported by 39% of patients in both evaluations. Our data suggest that lacosamide treatment in pediatric patients is safe at doses up to 10 mg/kg/day without any major side effects, but studies in larger series are needed to validate and extend these findings.

Atrioventricular block following lacosamide intoxication

Lacosamide (LCM) is a novel anticonvulsant that modulates voltage-dependent sodium channels. Although it is known to cause a slight, dose-dependent prolongation of the PR interval on the ECG, third-degree atrioventricular (AV) block has been described as an adverse event in only a few patients participating in diabetic neuropathic pain studies and in no patient with epilepsy. We describe an 89-year old patient with decreased renal function and taking two other negative dromotropic agents who accidentally received two intravenous boli of 400 mg LCM within 6 hours. She had a normal PQ interval before and after the first dose of LCM and developed a reversible complete AV block approximately 30 minutes after the second bolus. We conclude that particular caution must be exercised when using very high doses of LCM in patients with significant cardial and renal risk factors.

Pharmacotherapy of epilepsy: newly approved and developmental agents

This article discusses seven newly available antiepileptic drugs (AEDs) and agents in phase III development. Lacosamide, licensed as an adjunctive treatment for partial-onset seizures, primarily acts by enhancing sodium channel slow inactivation. At daily doses of 200-600 mg, the drug significantly reduced partial-onset seizures in adults with refractory epilepsy. The most common adverse effects are CNS related. Rufinamide, available as adjunctive treatment for seizures associated with Lennox-Gastaut syndrome, has an unclear mechanism of action, although it does block voltage-dependent sodium channels. Coadministration of valproic acid significantly increases rufinamide circulating concentrations. The drug has been shown to have efficacy for partial-onset, primary generalized tonic-clonic, tonic-atonic, absence and atypical absence seizures. Adverse effects are mainly somnolence, nausea and vomiting. Eslicarbazepine acetate, a carbamazepine analogue, was recently licensed as adjunctive treatment for partial-onset seizures. Eslicarbazepine acetate acts at voltage-gated sodium channels, although the precise mechanism of action is unclear. The drug had efficacy for partial-onset seizures in three randomized, double-blind, placebo-controlled studies, using 400, 800 or 1200 mg/day. Adverse effects include dizziness and somnolence. Retigabine (ezogabine) exerts its anticonvulsant effect through the opening of neuronal voltage-gated potassium channels. Following significant seizure reduction rates at dosages of 600, 900 and 1200 mg/day, license applications have been submitted for its use as adjunctive treatment for patients with partial-onset seizures. Dose-related adverse effects include somnolence, confusion and dizziness. Brivaracetam is the n-propyl analogue of levetiracetam. Mixed results have been obtained in phase III studies in patients with partial-onset seizures, and further trials in children, patients with photosensitive epilepsy and patients with partial-onset seizures are ongoing. Dizziness, headache and somnolence are the most common adverse effects reported. Perampanel was designed as an AMPA-type glutamate receptor antagonist. Following encouraging results from phase II studies in patients with refractory partial-onset seizures, recruitment for phase III trials is almost complete. Ganaxolone is a neurosteroid with potent antiepileptic activity that modulates GABA(A) receptors in the CNS. Ganaxolone has shown promise in a variety of seizure types. Dizziness and somnolence have been reported in some patients. The availability of new AEDs has widened the choices for clinicians treating patients with epilepsy. However, given the minimal improvement in prognosis and disappointing efficacy outcomes in double-blind, placebo-controlled, dose-ranging regulatory trials, it seems unlikely that these novel agents will have a major impact on outcomes for people with epilepsy.

The acute and chronic effects of the novel anticonvulsant lacosamide in an experimental model of status epilepticus

The effective management of status epilepticus (SE) continues to be a therapeutic challenge. The aim of this study was to investigate the efficacy of lacosamide treatment in an experimental model of self-sustaining SE. Rats were treated with lacosamide (3, 10, 30 or 50mg/kg) either 10 min (early treatment) or 40 min (late treatment) after the initiation of perforant path stimulation. Early lacosamide treatment significantly and dose-dependently reduced acute SE seizure activity; late treatment showed only a non-significant trend toward reduced seizure activity. Early lacosamide treatment also dose-dependently reduced the number of spontaneous recurrent seizures following a 6-week waiting period, with 70% reduction at the highest dose tested (50mg/kg); there was also a significant reduction in the number of spikes and the cumulative time spent in seizures. Late treatment with high-dose lacosamide (30-50mg/kg) reduced the number of animals that developed spontaneous recurrent seizures (33% vs 100% in controls, P<.05), but did not significantly reduce seizure severity or frequency in rats that developed spontaneous recurrent seizures. The results presented here suggest that lacosamide deserves investigation for the clinical treatment of SE. Potential for disease modification in this rat model of self-sustaining SE will require further studies.

Factors determining response to antiepileptic drugs in randomized controlled trials. A systematic review and meta-analysis

PURPOSE

Because of the lack of head-to-head adjunctive-therapy trials of antiepileptic drugs (AEDs) in refractory partial epilepsy, meta-analyses of placebo-controlled randomized controlled trials (RCTs) represent a potentially important source of evidence to guide treatment decisions. However, such indirect comparisons raise various methodologic issues that may hamper their relevance.

METHODS

All RCTs in adult refractory partial epilepsy were analyzed to assess whether efficacy outcomes are influenced by: characteristics of patients and trials ; use of last observation carried forward (LOCF) analysis; evaluation period (entire period versus maintenance period); and year of publication. A meta-analysis of these AEDs was then performed taking these factors into consideration.

KEY FINDINGS

Sixty-three RCTs evaluating 20 AEDs were included. The following variables influenced efficacy estimates: (1) responder rates correlated positively with duration of the entire treatment period (p = 0.038); (2) response to placebo was significantly greater in the maintenance period than in the entire treatment period (p = 0.005); (3) responder rates increased over the years both for AEDs (p < 0.001) and for placebo (p = 0.001); (4) LOCF analysis overestimated responder rates for AEDs (p < 0.001) and for placebo (p = 0.001) compared with completer-based analysis, and the overestimation correlated positively with withdrawal rates (p < 0.001). A meta-analysis of available data showed large differences in efficacy ranking in relation to dose selection and type of analysis, but these were mostly nonsignificant due to statistical power limitations.

SIGNIFICANCE

Several methodologic issues hamper the relevance of indirect comparisons of AEDs in the adjunctive-therapy of refractory partial epilepsy. Some of these issues could be overcome by improved standardization in the reporting of efficacy outcomes.

Lacosamide in the treatment of acute recurrent seizures and periodic epileptiform patterns in critically ill patients

We investigated the safety, tolerability, and effectiveness of lacosamide (LCM) in patients with acute recurrent seizures or with periodic epileptiform activity captured during continuous EEG monitoring. A total of 17 patients received LCM; 12 patients received LCM as a second or third antiepileptic drug (AED), one patient as a fourth AED, and one patient as a fifth AED. No additional AEDs were introduced after LCM in 15 patients. Twelve patients responded to LCM with improvement in the seizures or periodic epileptiform activity. Two patients required further AED management or burst suppression. No adverse effects, including symptomatic bradycardia and allergic reactions, were seen for intravenous infusion dosages up to 300 mg. Eleven patients were eventually discharged on LCM. LCM is an important new AED in the add-on treatment of acute recurrent seizures and periodic epileptiform activity in critically ill patients.

Lacosamide neurotoxicity associated with concomitant use of sodium channel-blocking antiepileptic drugs: a pharmacodynamic interaction?

Lacosamide is a new antiepileptic drug (AED) apparently devoid of major pharmacokinetic interactions. Data from a small postmarketing assessment suggest people who had lacosamide co-prescribed with a voltage-gated sodium channel (VGSC)-blocking AED seemed more likely to discontinue lacosamide because of tolerability problems. Among 39 people with refractory epilepsy who developed neurotoxicity (diplopia, dizziness, drowsiness) on lacosamide treatment given in combination with VGSC-blocking AEDs, we identified 7 (17.9%) without any changes in serum levels of other AEDs in whom the symptoms were ameliorated by dose reduction of the concomitant VGSC-blocking AED. Symptoms in these people seem to have arisen from a pharmacodynamic interaction between lacosamide and other VGSC-blocking AEDs. Slow-inactivated VGSCs targeted by lacosamide might be more sensitive to the effects of conventional VGSC-blocking AEDs. Advising people to reduce concomitantly the conventional VGSC-blocking AEDs during lacosamide uptitration in cases of neurotoxicity might improve the tolerability of combination treatment.

Does lacosamide aggravate Lennox-Gastaut syndrome? Report on three consecutive cases

Lennox-Gastaut syndrome is an intractable epileptic encephalopathy, with most patients experiencing daily seizures despite therapy with multiple antiepileptic drugs. New treatments need to be tested to define their efficacy in this syndrome. Lacosamide is a new antiepileptic drug recently approved for the treatment of partial-onset seizures. We describe three patients with Lennox-Gastaut syndrome resistant to conventional antiepileptic drugs whose seizures were aggravated by lacosamide.

New drugs for pediatric epilepsy

The last 2 decades have witnessed an unprecedented period of new antiepileptic drug (AED) development. Newer-generation AEDs have been developed with the intention of improving the ease of use, decreasing drug interactions, decreasing adverse side effects, and identifying drugs with unique mechanisms of action, some of which may bear relevance to potential neuroprotective activity. Drug trials have also been refined in some cases to evaluate AED efficacy in children and against distinct epilepsy syndromes. This progress provides many new treatment options for the child neurologist facing children with epilepsy but also introduces the burden of determining appropriate AED choices. Here we highlight 6 new antiepileptic medications recently approved or pending approval for use in the United States: lacosamide, rufinamide, vigabatrin, retigabine, brivaracetam, and clobazam. For each of these medications, we present information regarding the history of drug development, proposed mechanism(s) of action, pharmacokinetics and recommended dosing, evidence for clinical efficacy, tolerability, and when, available, any unique features that are relevant for the pediatric population.

A pooled analysis of lacosamide clinical trial data grouped by mechanism of action of concomitant antiepileptic drugs

BACKGROUND

Lacosamide, a new antiepileptic drug (AED) with a different pharmacological action that enhances sodium channel slow inactivation, is approved for the adjunctive treatment of partial-onset seizures in adults. Previous analyses of pooled phase II/III trials have demonstrated that lacosamide provides additional efficacy when added to a broad range of AEDs.

OBJECTIVE

To further evaluate the efficacy and safety of lacosamide by grouping patients based upon the sodium channel-blocking properties of their concomitant AEDs.

STUDY DESIGN

Post hoc exploratory analyses were performed on pooled data in which patients were grouped based upon inclusion or non-inclusion of at least one 'traditional' sodium channel-blocking AED (defined as carbamazepine, lamotrigine, oxcarbazepine and phenytoin derivatives) as part of their concomitant AED regimen.

SETTING

Data pooled from previously conducted phase II/III clinical trials of lacosamide.

PATIENTS

Adult patients with partial-onset seizures with or without secondary generalization (N = 1308).

INTERVENTION

Four- to six-week Titration Phase followed by 12-week maintenance treatment with adjunctive lacosamide (Vimpat®) [200, 400 or 600 mg/day] or placebo.

MAIN OUTCOME MEASURE

Efficacy variables included change in seizure frequency per 28 days and the proportion of patients experiencing a ≥50% reduction in seizure frequency (50% responder rate) from Baseline to the Maintenance Phase. The proportion of patients experiencing a ≥75% reduction in seizure frequency from Baseline to the Maintenance Phase (75% responder rate) was also assessed. Safety parameters assessed were treatment-emergent adverse events (TEAEs) and discontinuation due to TEAEs. Additional safety assessments were changes in ECG and laboratory parameters as well as vital signs (including bodyweight).

RESULTS

Of 1308 patients in the pooled phase II/III population, the majority (82%) were using at least one 'traditional' sodium channel-blocking concomitant AED. In this subgroup of patients, adjunctive lacosamide showed significant reductions in seizure frequency (p < 0.01, all dosages) and significantly greater 50% and 75% responder rates (p < 0.01 for 400 mg/day; p < 0.01 [50% responder rate] and p < 0.05 [75% responder rate] for 600 mg/day) compared with placebo; these effects were similar to the results seen in the pooled phase II/III population. TEAEs and discontinuations due to TEAEs in this subgroup were dose related and similar to the pooled phase II/III population. In the remaining subgroup of patients, i.e. those not taking 'traditional' sodium channel-blocking AEDs as part of their concomitant AED regimen (n = 231; 18%), a pronounced, dose-related seizure reduction was observed with lacosamide (p < 0.01, 400 and 600 mg/day for median percent seizure reduction and 50% or 75% responder rates). Also in this group, incidences of TEAEs were low, and discontinuations due to TEAEs did not appear to increase with dose. Analyses of ECG, laboratory and vital signs (including bodyweight) assessments did not identify abnormalities in either subgroup that were outside of the known safety profile of lacosamide observed in the pooled phase II/III population.

CONCLUSION

In this post hoc exploratory analysis, adjunctive lacosamide demonstrated significant seizure reduction over placebo regardless of the inclusion of 'traditional' sodium channel blockers in the concomitant AED regimen. Future prospective studies evaluating single AED combinations (e.g. lacosamide plus one other drug) are needed to better evaluate the potential for additive or synergistic effects of lacosamide in combination with AEDs not considered 'traditional' sodium channel blockers.

Examining the clinical utility of lacosamide: pooled analyses of three phase II/III clinical trials

BACKGROUND

Lacosamide is an antiepileptic drug (AED) approved for the adjunctive treatment of partial-onset seizures in adults. Completed phase II/III clinical trials of lacosamide provide a valuable opportunity to evaluate clinically relevant aspects of the resulting large patient pool.

OBJECTIVE

To provide insight into the clinical utility of lacosamide by performing a priori-defined and post hoc analyses on a large, pooled patient population.

STUDY DESIGN

Pooled data from three randomized, double-blind, multicentre, placebo-controlled phase II/III trials.

PATIENTS

Adult patients with partial-onset seizures with or without secondary generalization (N = 1294).

INTERVENTION

Four- to six-week titration followed by 12-week maintenance treatment with lacosamide (Vimpat®) 200, 400 or 600 mg/day or placebo.

MAIN OUTCOME MEASURE

A priori-defined primary efficacy variables for the pooled analysis were change in seizure frequency per 28 days and the proportion of patients experiencing a ≥50% reduction in seizure frequency (50% responder rate) from Baseline to the Maintenance Phase; a priori-defined secondary efficacy variables were the proportion of patients achieving a ≥75% reduction in seizure frequency from Baseline to the Maintenance Phase (75% responder rate), the proportion of Maintenance Phase completers remaining seizure free throughout the entire Maintenance Phase and the percentage of seizure-free days during the Maintenance Phase for patients entering the Maintenance Phase. The pooled analyses of the change in seizure frequency, and 50% and 75% responder rates were performed with an intent-to-treat (ITT) approach, including all patients receiving at least one dose of trial medication and having at least one post-baseline efficacy assessment. Similar analyses of the two primary efficacy variables and 75% responder rates were also performed using a modified ITT population (ITTm) that included ITT patients who entered the Maintenance Phase. Additional post hoc efficacy analyses were an evaluation of onset of efficacy and assessment of efficacy in patients grouped by prior surgical history and individual concomitant AED use. In addition, pharmacokinetic-pharmacodynamic modelling was performed, and safety data were assessed.

RESULTS

In this pooled analysis of 1294 difficult-to-treat patients, all three dosages of lacosamide (200, 400 and 600 mg/day) showed a significant improvement compared with placebo for median percent seizure reduction (ITT and ITTm; p < 0.05 for 200 mg/day, p < 0.001 for 400 and 600 mg/day), as well as for 50% responder rate (ITT and ITTm; p < 0.05 for 200 mg/day, p < 0.001 for 400 and 600 mg/day). Evaluation of 75% responder rate in the phase II/III pooled population showed that a significantly higher proportion of patients randomized to lacosamide 400 or 600 mg/day achieved a ≥75% reduction in seizure frequency compared with placebo (ITT and ITTm; p < 0.001); statistical significance was not observed for lacosamide 200 mg/day (ITT and ITTm). A total of 2.7%, 3.3% and 4.8% of patients completing the Maintenance Phase in the lacosamide 200, 400 and 600 mg/day groups, respectively, experienced no seizures throughout the entire Maintenance Phase (placebo group = 0.9%). The mean change from baseline in the percentage of seizure-free days in patients entering the Maintenance Phase for the phase II/III pool was 8.0%, 11.6% and 14.7% with lacosamide 200 (p = 0.077), 400 (p < 0.001) and 600 (p < 0.001) mg/day groups, respectively, compared with 6.1% in the placebo group. The onset of efficacy relative to placebo was evident by the first week of treatment with lacosamide. Efficacy was similar in lacosamide-treated patients reporting prior surgical intervention for epilepsy compared to lacosamide-treated patients with no prior surgical intervention. Lacosamide showed a reduction in seizures, regardless of the concomitant AEDs used. The preferred pharmacokinetic-pharmacodynamic model (E(max)) supported the therapeutic dose range of lacosamide, and no additional safety concerns were identified in the phase II/III pooled analysis.

CONCLUSIONS

Results of these a priori-defined and post hoc pooled data analyses from phase II/III trials demonstrate that lacosamide effectively reduces seizures in patients at all three dosages evaluated with an early onset of efficacy, regardless of patient surgical history and concomitant AED regimen.

A high-performance liquid chromatography assay to monitor the new antiepileptic drug lacosamide in patients with epilepsy

A simple high-performance liquid chromatographic micromethod is described for the quantitation of the new antiepileptic drug lacosamide in serum of patients. Serum (100 microL) was first precipitated with 10 microL 60% perchloric acid and 10 microL supernatant injected directly into the high-performance liquid chromatograph. Chromatographic separation was achieved by use of a steel cartridge column (125 x 3 mm inside diameter) packed with Hypersil BDS C-18, at 40 degrees C, and with a gradient elution system comprising methanol, formic acid and water. The eluent was monitored at 215 nm by diode array detection and the calibration curve was linear in the range of 10 to 250 micromol/L. Recovery ranged from 99% to 106%. The limit of quantification was 1 micromol/L and the intrabatch and interbatch coefficients of variation were less than 5%. No interference from commonly prescribed antiepileptic drugs (clobazam, clonazepam, carbamazepine, carbamazepine-10,11-epoxide, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, phenobarbital, phenytoin, primidone, pregabalin, valproic acid, and vigabatrin) was observed, so the method can be used to routinely monitor lacosamide in patients on polytherapy antiepileptic drug regimens.

Lacosamide and epilepsy

We will review all available studies on the use of lacosamide in the treatment of partial-onset seizures. The available evidence includes two open-label studies and three randomized controlled trials evaluating the safety and efficacy of oral lacosamide. One open-label study and one randomized controlled trial evaluating the safety and tolerability of intravenous lacosamide was also identified. Lacosamide was found to be efficacious with significant reduction in seizure frequency dosed 400-600 mg daily. Moreover, its adverse drug effects were mild and infrequently reported in the literature. Findings suggest that lacosamide is an effective agent for adjunctive treatment of refractory partial-onset seizures.

Saliva and serum lacosamide concentrations in patients with epilepsy

PURPOSE

Lacosamide is a new antiepileptic drug that has a novel mechanism of action, linear pharmacokinetics, and proven efficacy in the adjunctive treatment of partial-onset seizures. We ascertained the relationship between serum and saliva lacosamide concentrations so as to determine whether saliva may be a useful alternative to serum for therapeutic drug monitoring.

METHODS

Blood samples were obtained from 98 people with intractable epilepsy (51 male; mean age 43 ± 12; range 19-76 years) prescribed lacosamide as adjunctive therapy. For 48 patients, concurrent saliva samples were also collected. Lacosamide concentrations in serum (free and total) and in saliva were determined by high performance liquid chromatography (HPLC).

RESULTS

Linear regression analysis showed a good correlation between lacosamide dose and both total (r(2) = 0.825; n = 32) and free (r(2) = 0.815; n = 29) serum concentrations, and lacosamide serum total and free concentrations were linearly related (r(2) = 0.721; n = 97). There was also a good correlation between saliva lacosamide and both total (r(2) = 0.842; n = 49) and free (r(2) = 0.828; n = 47) serum lacosamide concentrations. Based on the saliva data, the protein binding of lacosamide in serum is calculated to be 87 ± 4% and is comparable to the value calculated by direct measurement of the free and total lacosamide concentration in serum (91 ± 4%).

DISCUSSION

These data support the use of saliva as a viable alternative to serum for monitoring lacosamide therapy in patients with epilepsy.

Effect of antiepileptic drugs on the postictal state. A critical overview

Although postictal events contribute to seizure severity and thus affect quality of life, the effect of antiepileptic drugs (AEDs) on the postictal state is not well known. This review assesses the available evidence from randomized controlled trials on the effect of AEDs on postictal events. The instruments used in AED trials include postictal items of The Liverpool Seizure Severity Scale (LSSS) and Seizure Severity Scale (SSQ) and postictal recovery of electroencephalography (EEG) background activity. The effect of AEDs on postictal components of LSSS, if documented separately or at all, was either too small to be clinically significant (for lamotrigine) or not different from that of controls (topiramate, valproate). However, lacosamide showed improvement on the SSQ over placebo, and levetiracetam was associated with a speedier postictal recovery of EEG background activity compared with placebo. Although measuring the effect of AEDs on postictal state is of great clinical interest, the limited evidence found in this review suggests that further work is needed to evaluate current instruments used to assess AED-associated changes in postictal events.

Lacosamide for the prevention of partial onset seizures in epileptic adults

Lacosamide is a newly registered antiepileptic drug with dual mechanisms of action. It selectively enhances slow inactivation of voltage-gated sodium channels, resulting in stabilization of hyperexcitable neuronal membranes and inhibition of repetitive neuronal firing. It also binds to a collapsing-response mediator protein-2, CRMP2. Lacosamide has a favorable pharmacokinetic profile; is rapidly and completely absorbed, has a relatively long elimination half-life of 13 hours which allows twice-daily administration, linear pharmacokinetics, and has low potential for drug interactions and renal elimination. Both oral and intravenous formulations of lacosamide are being developed. In placebo-controlled clinical trials, lacosamide was effective in seizure reduction as adjunctive therapy in patients with uncontrolled partial-onset seizures. Lacosamide was generally well tolerated. The most frequently reported adverse events in placebo-controlled trials were dizziness, headache, nausea, and diplopia. Intravenous lacosamide has a comparably good safety profile.

Lacosamide: new adjunctive treatment option for partial-onset seizures

IMPORTANCE OF THE FIELD

Epilepsy is one of the most common neurological disorders, affecting up to 2% of the population worldwide. Studies show that patients with refractory seizures have higher morbidity and mortality rates, as well as a poorer quality of life, than those with controlled seizures. Therefore, treatment that reduces the frequency of seizures may improve patients' quality of life. Lacosamide (LCM) is a recently approved anticonvulsant in Europe and the USA which offers new mechanisms of action and favorable safety profiles. Efficacy data have shown fast onset of anticonvulsant effects and significant reduction of partial-onset seizures as adjunctive therapy at LCM 200 and 400 mg/day, even in a severely refractory population.

AREAS COVERED IN THIS REVIEW

This article reviews three pivotal clinical trials of LCM, including its efficacy and tolerability over 7 years. In addition, LCM's key pharmacodynamics and pharmacokinetics from a search of the literature are reviewed in detail. This article also includes recent publications on the safety and use of intravenous LCM solution for patients with epilepsy.

WHAT THE READER WILL GAIN

This article provides comprehensive review of efficacy and safety information of LCM along with comprehensive pharmacokinetic information, which includes absolute bioavailability, low protein binding, lack of hepatic enzyme induction or inhibition, and low potential for drug-drug interactions.

TAKE HOME MESSAGE

Considering the fact that more than 30% of epilepsy patients remain refractory despite various antiepileptic drugs, LCM may provide added benefit to patients with refractory seizures.

Update on anticonvulsant drugs

In 2009, the US Food and Drug Administration approved three medications for the treatment of epilepsy: rufinamide, lacosamide, and vigabatrin. In addition, extended-release formulations of lamotrigine and levetiracetam were approved recently. When added to the dozen medications for treating epilepsy, the choice is a luxury in terms of additional options, but also a challenge for practitioners to use them all with expertise. Recently, there has been much interest surrounding medications for epilepsy and their possible association with osteoporosis, safety during pregnancy, biological equivalence to generic versions, and possible association with higher rates of suicidality. This review discusses these issues and provides a current overview for the medical management of epilepsy.

Lacosamide: what can be expected from the next new antiepileptic drug?

Adjunctive Lacosamide for Partial-Onset Seizures: Efficacy and Safety Results from a Randomized Controlled Trial. Halasz P, Kalviainen R, Mazurkiewicz-Beldzińska M, Rosenow F, Doty P, Hebert D, Sullivan T; SP755 Study Group. Epilepsia 2009;50(3):443–453. PURPOSE: To evaluate the efficacy and safety of lacosamide (200 and 400 mg/day) when added to one to three concomitant antiepileptic drugs (AEDs) in patients with uncontrolled partial-onset seizures. METHODS: This multicenter, double-blind, placebo-controlled trial randomized patients (age 16–70 years) with partial-onset seizures with or without secondary generalization to placebo, lacosamide 200, or lacosamide 400 mg/day. The trial consisted of an 8-week baseline, a 4-week titration, and a 12-week maintenance period. RESULTS: Four hundred eighty-five patients were randomized and received trial medication. Among these, 87% were taking two or more concomitant AEDs. Median percent reduction in seizure frequency per 28 days from baseline to maintenance period (intent-to-treat, ITT) was 20.5% for placebo, 35.3% for lacosamide 200 mg/day ( p = 0.02), and 36.4% for 400 mg/day ( p = 0.03). In the per protocol population, the reductions were 35.3% for lacosamide 200 mg/day ( p = 0.04) and 44.9% for 400 mg/day ( p = 0.01) compared to placebo (25.4%). The 50% responder rate for lacosamide 400 mg/day (40.5%) was significant ( p = 0.01) over placebo (25.8%), but was not for 200 mg/day (35.0%). In the per protocol population, the 50% responder rate for lacosamide 400 mg/day (46.3%) was significant ( p < 0.01) compared with the placebo responder rate (27.5%). Dose-related adverse events (AEs) included dizziness, nausea, and vomiting. Clinically relevant changes in the mean plasma concentrations of commonly used AEDs were not observed. DISCUSSION: Results of this trial demonstrated the efficacy and tolerability of adjunctive lacosamide 200 and 400 mg/day and support that lacosamide may be an advantageous option for the treatment of partial-onset seizures in patients with epilepsy.

Lacosamide as treatment of epileptic seizures - cost utility results for Sweden

OBJECTIVES

To calculate cost per additional quality-adjusted life-year (QALY) for lacosamide as adjunctive treatment for patients with uncontrolled partial-onset seizures as compared to no adjunctive treatment.

MATERIALS AND METHODS

A decision-tree simulation model was constructed to calculate the number of seizures and health-care utilization for treated and untreated with lacosamide, respectively. Prices from 2007 were used for all costs.

RESULTS

All results were calculated for a 24-, 18-, 12- and 6-months follow-up. The cost per additional QALY was estimated to euro 27,641 (24 months). Using a willingness-to-pay threshold for a QALY of euro 50,000 the net marginal value of using lacosamide was estimated to about euro 850,000 per 1000 patients.

CONCLUSIONS

The estimated cost per QALY gained falls within the range of reported estimates of the willingness-to-pay for an additional QALY. The results imply that lacosamide is cost-effective in the treatment of uncontrolled partial-onset seizures (1 euro approximately 9.6 SEK).

Lacosamide intoxication in attempted suicide

The anticonvulsant drug lacosamide selectively enhances slow inactivation of voltage-gated sodium channels and has been shown to be an effective add-on treatment for partial-onset seizures. Common adverse events (frequency 10%) of lacosamide doses up to 600 mg/day include nonspecific central nervous system effects (e.g., dizziness, ataxia, diplopia, and somnolence). There are no human data regarding the safety of very high dosages of lacosamide. We report the clinical course of a patient with bitemporal epilepsy who ingested 12 g of lacosamide, 56 g of gabapentin, 2g of topiramate, and 2.8 g of zonisamide during a suicide attempt. The patient was found comatose and experienced repeated generalized tonic-clonic seizures, aspiration with subsequent pneumonia, hypotension, and an increase in PR interval. Complete physical recovery occurred after several days of supportive treatment. We conclude that intoxication with lacosamide, in combination with overdoses of multiple AEDs, can be survived without sequelae, even after ingestion of 12 g lacosamide.

New treatment option for partial-onset seizures: efficacy and safety of lacosamide

More than 30% of epilepsy patients remain refractory despite the advent of new antiepileptic drugs (AEDs) over two decades. Although a small percentage of these refractory patients may become seizure free when a new AED is added, combined administration of AEDs or the application of novel AEDs is the most common therapeutic option when surgical treatment cannot be offered. The most recently approved AED in Europe and the USA is lacosamide (LCM), which offers new mechanisms of action and favorable safety profiles. This article reviews LCM's molecular mechanisms of action, pharmacokinetic profiles as well as efficacy and safety from phase II and III clinical trials. In addition, comparison between LCM and other existing AEDs is discussed.

New and investigational antiepileptic drugs

In the last fifteen years, new antiepileptic medications have been offered for the treatment of patients with epilepsy. Nevertheless, despite optimal medical treatment, up to 30% of patients still experience recurrent seizures and the challenge for new, more efficacious and better-tolerated drugs continues. New antiepileptic drugs include the evolution of pre-existing drugs and new compounds identified through the investigation of additional molecular targets, such as SV2A synaptic vesicle protein, voltage-gated potassium channels, ionotropic and metabotropic glutamate receptors, and gap junctions. This paper reviews the available information on various classes of molecules that are in the pipeline as well as on the innovative approaches to the treatment of epilepsy.

Six months of postmarketing experience with adjunctive lacosamide in patients with pharmacoresistant focal epilepsy at a tertiary epilepsy center in Germany

We report our 6 months of experience with adjunctive lacosamide in 25 patients with pharmacoresistant focal epilepsy. Baseline characteristics of our patients were similar to those of the populations in the three clinical trials that evaluated lacosamide for refractory focal epilepsy. One patient experienced sustained seizure freedom for 5 months; two more patients had nonsustained periods of seizure freedom of 1 and 4 months. A total of eight patients (32%) reported a greater than 50% reduction in seizure frequency. Thirteen patients (52%) reported side effects during the titration, mostly dizziness, fatigue, nausea, and gait instability. In five patients (20%), these disappeared during the maintenance phase and/or with dose reduction. Two patients lost more than 10% of their body weight. Otherwise, in terms of efficacy and adverse effects, our data mirror the profile of lacosamide described in the three clinical trials. Substantial weight loss may occur in individual patients.

Lacosamide: an adjunctive agent for partial-onset seizures and potential therapy for neuropathic pain

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, and safety of lacosamide, a new agent for use as adjunctive treatment in partial-onset seizures and a potential agent for treatment of neuropathic pain.

DATA SOURCES

A MEDLINE search (1966-July 2009) was conducted using the key words lacosamide, harkoseride, SPM-927, ADD-234037, epilepsy, anticonvulsant, and neuropathic pain. Bibliographies of all articles retrieved were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

All studies including humans and published in English with data describing lacosamide for the adjunctive treatment of partial-onset seizures and for treatment of neuropathic pain were reviewed.

DATA SYNTHESIS

Lacosamide is a functionalized amino acid molecule that selectively enhances the slow inactivation of voltage-gated sodium channels and interacts with the collapsin-response mediator protein-2. With its bioavailability of approximately 100%, minimal protein binding, and few drug-drug interactions, lacosamide has a favorable pharmacokinetic profile. Recent data suggest that lacosamide may have a role as adjunctive treatment of partial-onset seizures. Open-label studies showed a 14-47% reduction in seizure frequency, while placebo-controlled trials demonstrated a 26-40% reduction in seizure frequency. The 50% responder rates ranged from 32.7% to 41.2% with varying doses of lacosamide. Although lacosamide use is not approved by the Food and Drug Administration for treatment of neuropathic pain, studies demonstrated reductions of 2.01-3.60 in pain scale scores. The most common adverse effects, occurring in greater than 10% of subjects in the clinical trials, include arthralgia, ataxia, blurred vision, diplopia, dizziness, fatigue, headache, injection site pain (only in intravenous studies), nausea, tremor, upper respiratory tract infection, and vomiting.

CONCLUSIONS

Lacosamide is an effective agent for adjunctive treatment of refractory partial-onset seizures. Its exact role in the treatment of neuropathic pain needs to be determined.

No pharmacokinetic interaction between lacosamide and carbamazepine in healthy volunteers

Lacosamide is a new antiepileptic drug for adjunctive treatment of adult partial-onset seizures. Two open-label, multiple-dose clinical trials were conducted to evaluate the potential for pharmacokinetic interaction between lacosamide and carbamazepine. The influence of carbamazepine on lacosamide pharmacokinetics (trial A) and lacosamide on carbamazepine pharmacokinetics (trial B) was investigated in 19 (trial A) and 18 (trial B) healthy male participants. Trial A participants received lacosamide 200 mg bid alone and with carbamazepine 200 mg bid. Trial B participants received carbamazepine 200 mg bid alone and with lacosamide 200 mg bid. Pharmacokinetic parameters, area under the concentration-time curve during a dosage interval at steady state (AUC(tau,ss)), and maximum steady-state plasma drug concentration during a dosage interval (C(max,ss)) of lacosamide, carbamazepine, and carbamazepine-10,11-epoxide were measured and compared for each drug alone and together. The AUC(tau,ss) and C(max,ss) point estimates (combined vs sole treatment) showed relative bioavailability of approximately 100% for both drugs. All 90% confidence intervals of AUC(tau,ss) and C(max,ss) were within the generally accepted bioequivalence ranges of 80% to 125%. No changes in rate or extent of absorption or terminal half-life were observed. These results suggest that lacosamide and carbamazepine have a low potential for pharmacokinetic drug-drug interaction in clinical use.

The anti-epileptic drug lacosamide (Vimpat) has anxiolytic property in rodents

Lacosamide ((R)-2-acetamido-N-benzyl-3-methoxypropionamide; formerly harkoseride, SPM 927; Vimpat), has been recently approved by US and European regulatory authorities for use as add-on therapy for partial-onset seizures in adults. Because a number of anti-epileptic drugs are used to treat conditions beyond epilepsy, including anxiety, in the present study we investigated the anxiolytic potential of lacosamide in a conditioned emotional response (CER) model in rat, and the mouse marble burying assay. In each test lacosamide produced a significant effect consistent with anxiolysis, i.e. lacosamide increased suppression ratio in the CER test, and reduced the number of marbles buried in the marble burying assay. The doses necessary for an anxiolytic effect were higher than those necessary for efficacy in seizure tests conducted in the same species. For example in the mouse, the lacosamide oral ED(50) in the maximal electroshock seizure (MES) and 6 Hz tests was 5.3 and 9.6 mg/kg respectively, and the minimal effective dose in the marble burying assay was 30 mg/kg. In both seizure and anxiety tests, the (S)-enantiomer of lacosamide was inactive suggesting a similar mechanism of action, possibly use-dependent inhibition of sodium channel function (Errington et al., 2008). Efficacy in the CER model was equivalent to diazepam and pregabalin (Lyrica). In tests of side-effects, lacosamide had no effect on choice accuracy in the delayed match to position task of working memory, although at the 30 mg/kg dose, response rates and response latencies were significantly affected. In sum, the present results identify for the first time, an anxiolytic potential of lacosamide.

Lacosamide as treatment for partial epilepsy: mechanisms of action, pharmacology, effects, and safety

Lacosamide (LCM) is a novel agent that has been developed as an antiepileptic drug. In vitro studies suggest that LCM modulates voltage-gated sodium channels by enhancing their slow inactivation. In addition, LCM seems to interact with collapsin-response mediator protein 2 and thus may mediate neuronal plasticity. LCM has an elimination half-life of 13 hours, no relevant protein binding, and does not induce or inhibit enzymes of the cytochrome P450 system. No clinically significant drug-drug interactions have been discovered as yet. Experimental data suggest anticonvulsant as well as analgesic effects. Large clinical studies have demonstrated its efficacy for treatment of patients with partial seizures. LCM is well tolerated, and the most common adverse events are unspecific central nervous system and gastrointestinal effects such as dizziness, vertigo, nausea, and headache. LCM is approved for treatment of partial seizures with or without secondary generalization in the United States and the European Union within a dose range of 200 to 400 mg per day, administered twice daily. In addition to the oral formulations, an intravenous infusion solution is available.

Lacosamide: a new approach to target voltage-gated sodium currents in epileptic disorders

The mechanism of action of several antiepileptic drugs (AEDs) rests on their ability to modulate the activity of voltage-gated sodium currents that are responsible for fast action potential generation. Recent data indicate that lacosamide (a compound with analgesic and anticonvulsant effects in animal models) shares a similar mechanism. When compared with other AEDs, lacosamide has the unique ability to interact with sodium channel slow inactivation without affecting fast inactivation. This article reviews these findings and discusses their relevance within the context of neuronal activity seen during epileptiform discharges generated by limbic neuronal networks in the presence of chemical convulsants. These seizure-like events are characterized by sustained discharges of sodium-dependent action potentials supported by robust depolarizations, thus providing synchronization within neuronal networks. Generally, AEDs such as phenytoin, carbamazepine and lamotrigine block sodium channels when activated. In contrast, lacosamide facilitates slow inactivation of sodium channels both in terms of kinetics and voltage dependency. This effect may be relatively selective for repeatedly depolarized neurons, such as those participating in seizure activity in which the persistence of sodium currents is more pronounced and promotes neuronal excitation. The clinical effectiveness of lacosamide has been demonstrated in randomized, double-blind, parallel-group, placebo-controlled, adjunctive-therapy trials in patients with refractory partial seizures. Further studies should determine whether the effects of lacosamide in animal models and in clinical settings are fully explained by its selective action on sodium current slow inactivation or whether other effects (e.g. interactions with the collapsin-response mediator protein-2) play a contributory role.