Lacosamide as adjunctive therapy for partial-onset seizures: A randomized controlled trial

Lacosamide for the treatment of epilepsy

Lacosamide is a third-generation antiepilepsy drug approved for adjunctive treatment of partial-onset seizures in adults. The pharmacology of lacosamide includes linear kinetics, complete bioavailability, and no major drug interactions. Lacosamide produces slow inactivation of neuronal sodium channels, which differentiates it from other sodium channel modulators, such as carbamazepine and phenytoin. The drug was effective with no major safety problems detected in three large placebo-controlled pivotal trials and has been released in Europe and the US at 200-400 mg/day, divided b.i.d.; an intravenous formulation is approved for temporary conversion from oral therapy. This article reviews the clinical development, pharmacology, and uses of lacosamide for treating partial-onset seizures in adults.

Ezogabine: An Evaluation of Its Efficacy and Safety as Adjunctive Therapy for Partial-Onset Seizures in Adults

Objective:

To evaluate the safety, efficacy, pharmacokinetics, pharmacodynamic properties, and clinical application of ezogabine (retigabine. INN), an antiepileptic drug approved in 2011.

Data Sources:

Published data from in vitro, animal, and clinical studies were obtained from PubMed and CINAHL searches, from January 1980 to March 31, 2012. Other relevant data regarding the safety and efficacy of ezogabine were obtained from the Food and Drug Administration and the European Medication Agency Web sites.

Study Selection and Data Extraction:

Selected articles were prospective in vitro, animal, and controlled clinical studies of ezogabine. Non-English-language articles were excluded.

Data Synthesis:

In vitro and animal studies show that ezogabine activates voltage-gated potassium channels, leading to reduction of seizure frequency by inhibiting hyperexcitability activity in the central nervous system. Additionally, ezogabine enhances γ-aminobutyric acid (GABA) activity and de novo GABA synthesis. Eight clinical studies of ezogabine have been published, 5 being Phase 1 clinical trials in healthy subjects and 3 being Phase 3 clinical trials in patients with pharmacoresistant partial-onset seizures. Phase 3 clinical trials demonstrated the safety and efficacy of ezogabine in patients with partial-onset seizures.

Conclusions:

Clinical trials have shown that ezogabine is efficacious as an adjunctive agent in patients with pharmacoresistant partial seizures. Careful monitoring of drug interactions and adverse reactions is necessary. While ezogabine is efficacious (or partial seizures, its precise role in the management of patients with epilepsy is yet to be determined.

Antiepileptic drugs 2012: recent advances and trends

There are now 24 antiepileptic drugs (AEDs) approved for use in epilepsy in the United States by the Food and Drug Administration. A literature search was conducted using PubMed, MEDLINE, and Google for all English-language articles that discuss newly approved AEDs and the use of AEDs in epilepsy in the United States from January 1, 2008, through December 31, 2011. Five new agents were identified that have come onto the market within the past 2 years. Moreover, 3 trends involving AEDs have become clinically important and must be considered by all who treat patients with epilepsy. These trends include issues of generic substitution of AEDs, pharmacogenomics predicting serious adverse events in certain ethnic populations, and the issue of the suicide risk involving the entire class of AEDs. This article discusses the most recent AEDs approved for use in the United States and the 3 important trends shaping the modern medical management of epilepsy.

Bioequivalence of intravenous and oral formulations of the antiepileptic drug lacosamide

BACKGROUND/AIMS

To evaluate the bioequivalence of intravenous and oral lacosamide (tablet), an antiepileptic drug.

METHODS

Two randomized, single-dose (200 mg) trials were conducted: a 2-way trial (study A, 15-min infusion, oral tablet) and a 3-way crossover trial (study B, 30- and 60-min infusions, oral tablet). Twenty four healthy men participated in study A and 27 in study B. Eighteen blood samples were taken before to 72 h after lacosamide administration during each treatment period, followed by a 1-week washout. Safety and the ratio of intravenous/oral lacosamide for AUC(0-tz) (area under the concentration-time curve from zero up to the last measurable plasma concentration) and C(max) (maximum plasma concentration) were evaluated.

RESULTS

For AUC(0-tz) and C(max), 90% confidence intervals for the ratio of intravenous/oral lacosamide fell within the predetermined bioequivalence range (80-125%) for 30- and 60-min infusions. In study A, all adverse events (AEs) were mild, with no discontinuations. In study B, 3 volunteers discontinued due to AEs; one serious AE (epiglottitis) was reported. No clinically relevant effects on vital signs, electrocardiograms or laboratory parameters and no AEs relating to infusion site were reported.

CONCLUSION

Intravenous infusions (15, 30 and 60 min) of 200 mg lacosamide are as well tolerated as the oral tablet. Bioequivalence was demonstrated for 30- and 60-min infusions; therefore, direct conversion from oral to intravenous lacosamide, or vice versa, is possible.

Clinical experience with oral lacosamide as adjunctive therapy in adult patients with uncontrolled epilepsy: a multicentre study in epilepsy clinics in the United Kingdom (UK)

INTRODUCTION

Lacosamide (LCS) is a new antiepileptic drug (AED) licensed in the European Union (EU) and United States (US) in 2008.

AIMS

To evaluate the efficacy and tolerability of add-on LCS in an out-patient epilepsy clinic setting to obtain useful information for everyday practice.

METHODS

We pooled data retrospectively from the case note of patients with refractory epilepsy in whom LCS had been prescribed in 19 hospitals across the United Kingdom.

RESULTS

Four hundred and three patients were included (mean age 41.9 years, 50.6% women, 18.1% with learning disabilities (LD)). Mean follow-up (FU) was 11.6 months (range one day to 42 months). Most patients (86.9%) presented with symptomatic partial epilepsy (SPE) and 80% were taking two or more antiepileptic drugs (AEDs) when LCS was added (mean 2, range 0-4). Retention rates were 80% at six months, 68% at one year and 45% at two years. The efficacy of LCS was evaluated at three months and at the final FU. At three months one hundred and eight patients (31.1%) reported ≥ 50% seizure reduction and 32 (9.2%) were seizure free. At the final FU 102 (37.5%) reported ≥ 50% seizures reduction and 28 (9.8%) were seizure free. One hundred and ninety three patients (48.7%) reported adverse effects (AEs). The most frequent were sedation and dizziness, followed by nausea. Lacosamide was discontinued in 150 patients (38%), 60 due to AEs alone.

CONCLUSION

LCS appears to be an effective and safe AED when used as adjunctive therapy in patients with refractory partial epilepsy.

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

PURPOSE

To evaluate the long-term (up to 5 years exposure) safety and efficacy of lacosamide as adjunctive therapy in patients with uncontrolled partial-onset seizures taking one to three concomitant antiepileptic drugs (AEDs) in open-label extension trial SP756 (NCT00522275).

METHODS

Patients who completed the double-blind trial SP754 (NCT00136019) were eligible to participate in this open-label extension trial (SP756). At the conclusion of trial SP754, patients had transitioned to lacosamide 200 mg/day. Subsequent dosage adjustments of lacosamide (100-800 mg/day) and/or concomitant AEDs were allowed to optimize tolerability and seizure reduction. Treatment-emergent adverse events (TEAEs), vital signs, body weight, clinical laboratory data, electrocardiography studies, and seizure frequency were evaluated.

KEY FINDINGS

A total of 308 patients received open-label lacosamide and 138 patients (44.8%) completed the long-term trial. The median modal dose (defined as the daily lacosamide dose a patient received for the longest duration during the treatment period) was 500 mg/day. The percentages of patients with lacosamide exposure >1, >2, >3, or >4 years were 75%, 63%, 54%, and 29%, respectively. Primary reasons for discontinuation were lack of efficacy (26%) and adverse events (11%). Common TEAEs (≥15%) were dizziness, headache, contusion, nausea, convulsion, nasopharyngitis, fall, vomiting, and diplopia. TEAEs that led to discontinuation in ≥1.0% of patients were dizziness (1.6%) and convulsion (1.0%). The median percent reductions from baseline of trial SP754 in 28-day seizure frequency were 53.4%, 55.2%, 58.1%, and 62.5%, respectively, for 1-, 2-, 3-, and 4-year completers. The ≥50% responder rates were 52.8%, 56.5%, 58.7%, and 62.5% for 1-, 2-, 3-, and 4-year completers, respectively. Seven of eight patients on lacosamide monotherapy for ≥12 months were deemed 50% responders. Of patients exposed to lacosamide ≥2 years, 3.1% remained seizure-free for a period ≥2 years.

SIGNIFICANCE

Long-term (up to 5 years) lacosamide treatment was generally well tolerated. The safety profile of lacosamide observed in this trial is consistent with that established in previous double-blind, placebo-controlled trials. Although the open-label trial design limits the analysis of efficacy, long-term reduction in seizure frequency and maintenance of efficacy was observed.

Cost effectiveness of lacosamide in the adjunctive treatment of patients with refractory focal epilepsy in Belgium

OBJECTIVES

Lacosamide is an anti-epileptic drug, indicated as adjunctive therapy for patients with focal seizures with or without secondary generalization. This study aims to assess the cost effectiveness of standard anti-epileptic drug therapy plus lacosamide 300 mg/day compared with standard therapy alone from the perspective of the Belgian healthcare payer.

METHODS

The treatment pathway of a hypothetical cohort of 1000 patients over 2 years was simulated using a decision tree. Data about health state probabilities, seizure frequency and utility values were taken from lacosamide trials or from the literature. Effectiveness measures included the number of seizures avoided and the number of quality-adjusted life-years gained. Unit costs were taken from national references. Resource use was estimated by a panel of eight neurologists with extensive experience in epilepsy. The price year was 2008. Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

Over a 24-month period, standard anti-epileptic drug therapy plus lacosamide led to a reduction of seven seizures, an increase of 0.038 quality-adjusted life-years and a cost decrease of &U20AC;3619 per patient compared with standard therapy alone. Using a willingness to pay of &U20AC;30 000 per quality-adjusted life-year, the net monetary benefit of standard anti-epileptic drug therapy plus lacosamide amounted to &U20AC;4754. The probability of standard anti-epileptic drug therapy plus lacosamide being cost effective was 97.3%, 99.8%, 99.9% and 100% at 6, 12 , 18 and 24 months, respectively.

CONCLUSION

In patients with difficult-to-treat epilepsy, standard anti-epileptic drug therapy plus lacosamide appears to be a cost-effective option in Belgium.

Lacosamide in refractory mixed pediatric epilepsy: a prospective add-on study

Lacosamide is a new antiepileptic drug that is currently approved by the US Food and Drug Administration (FDA) for adults 17 years or older for partial-onset seizures. The authors reviewed 21 pediatric patients (<17 years) with various seizure types who were started on oral lacosamide as part of a prospective add-on study as adjunctive therapy for refractory epilepsy. Five patients were excluded due to less than 3 months of meaningful follow-up. Maintenance dosages used ranged from 2.4 to 19.4 mg/kg/d. Eight of 16 (50%) patients had greater than 50% reduction in seizure frequency with adjunctive lacosamide therapy. Eight (50%) patients had generalized epilepsy including 4 with Lennox-Gastaut syndrome. Lacosamide was effective therapy for most seizure types but was particularly effective for partial-onset seizures. Lacosamide was effective in treating 5 of 8 (62.5%) localization-related epilepsies but only 2 of 8 (25%) generalized epilepsies, both Lennox-Gastaut syndrome patients with greater than 90% seizure reduction. None of these very refractory patients remained seizure free.

Minimizing pharmacodynamic interactions of high doses of lacosamide

OBJECTIVES

To determine whether pharmacodynamic interactions between high doses of lacosamide (400-800 mg/day) and concomitant sodium channel antiepilepsy drugs (AEDs) can be minimized in patients with drug-resistant partial-onset seizures.

MATERIALS AND METHODS

Patients were rapidly initiated with high-dose lacosamide (100 mg/week; increases to 400 to 800 mg/day), while simultaneously tapering concomitant sodium channel AEDs. Seizure frequency and side effects were evaluated at six time points: baseline, titration, 3, 6, 9 and 12 months.

RESULTS

Twenty-three patients had a baseline median of 4 seizures/month with persisting partial-onset seizures, despite previous treatment with an average of 6.8 AEDs. Mean decreases in monthly seizure frequency were as follows: 3 months 49.9% (P = 0.011), 6 months 55.4% (P = 0.010), 9 months 60.8% (P = 0.002) and 12 months 58.2% (P = 0.011). Most adverse events were mild CNS-related symptoms and occurred transiently only during titration - there was no significant relationship (χ(2) < 1.5, P > 0.1) between lacosamide dose and the presence of side effects at 3, 6, 9 or 12 months.

CONCLUSIONS

Drug-resistant patients rapidly titrated to high doses of lacosamide with simultaneous tapering of traditional sodium channel AEDs had marked reduction in CNS-related adverse events compared with patients treated in three previous pivotal trials that used fixed doses of concomitant AEDs.

Pharmacotherapy of the third-generation AEDs: lacosamide, retigabine and eslicarbazepine acetate

INTRODUCTION

The search for new, more effective antiepileptic drugs (AEDs) continues. The three most recently approved drugs, the so-called third-generation AEDs, include lacosamide, retigabine and eslicarbazepine acetate and are licensed as adjunctive treatment of partial epilepsy in adults.

AREAS COVERED

For the above three AEDs, their mechanisms of action, pharmacokinetic characteristics, drug-drug interactions, pharmacotherapeutics, dose and administration and therapeutic drug monitoring are reviewed in this paper.

EXPERT OPINION

Lacosamide and retigabine act through novel mechanisms, while eslicarbazepine acetate, a pro-drug for eslicarbazepine, acts in a similar manner to several other AEDs. All three AEDs are associated with linear pharmacokinetic and rapid absorption and undergo metabolism. Their drug-drug interaction profile is low (lacosamide and retigabine) to modest (eslicarbazepine) in propensity. At the highest approved doses for the three AEDs, responder rates were similar. The most commonly observed adverse effects compared with placebo were dizziness, headache, diplopia and nausea for lacosamide; dizziness, somnolence and fatigue for retigabine and dizziness and somnolence for eslicarbazepine acetate. The precise role that these new AEDs will have in the treatment of epilepsy and whether they will make a significant impact on the prognosis of intractable epilepsy is not yet known and will have to await further clinical experience.

Defining minimally important change in QOLIE-31 scores: estimates from three placebo-controlled lacosamide trials in patients with partial-onset seizures

The Quality of Life Inventory in Epilepsy (QOLIE-31) is a valuable tool to assess the impact of antiepileptic drugs on patients' lives, but interpretation of mean score changes can be challenging. Minimally important change (MIC) thresholds can be used to describe the proportion of clinically improved or worsened patients. Pooled data from Phase II/III trials of adjunctive lacosamide in patients with treatment-resistant partial-onset seizures were used to estimate MIC thresholds for the QOLIE-31 total score and subscales. Using multiple distribution- and anchor-based estimation methods, the optimal MIC value for the total score in this population of patients with treatment-resistant seizures was 5 points, which is lower than those previously reported in the literature for mixed populations. MIC estimates varied substantially across QOLIE-31 subscales. Taken together, these results demonstrate that intrinsic characteristics of a patient population impact what should be considered as MIC, a key consideration in the clinical interpretation of QOLIE-31 change scores.

Rational polytherapy with lacosamide in clinical practice: results of a Spanish cohort analysis RELACOVA

There has been little long-term success with polytherapy for patients with refractory partial-onset epilepsy. The rational combination of antiepileptic drugs based on their mechanism of action may help improve treatment efficacy and tolerability. Lacosamide, a novel sodium channel blocker (SCB), was investigated in 158 patients with partial-onset epilepsy in the prospective, multicenter, observational, RELACOVA cohort study conducted in Spain. After 12 months' treatment with lacosamide, 47% of patients were responders (≥50% reduction in seizure frequency) and 24% were seizure free. Lacosamide was well tolerated; dizziness was the most frequent adverse event. Efficacy was better (responder rate, 65% vs 38%; seizure free rate, 35% vs 17%) and there was a lower adverse event rate (33% vs 58%) in patients receiving non-SCBs (n=49) versus those receiving SCBs (n=104) as concomitant therapy at baseline. Further investigation of lacosamide combination therapy is warranted.

Preliminary efficacy and safety of lacosamide in children with refractory epilepsy

BACKGROUND

Despite the introduction of multiple new antiepileptic drugs (AEDs) in the past 20 years, about 30% of patients with epilepsy continue to experience uncontrolled seizures or significant side effects.

AIMS

To present our experience with lacosamide therapy in children with drug-resistant epilepsy.

METHODS

We retrospectively reviewed the medical charts of all patients receiving oral lacosamide until October 2010. Efficacy was determined according to seizure frequency during the week prior to treatment initiation and the week after the maximal dosage of lacosamide was attained.

RESULTS

Seventeen patients (10 boys) aged 1.5-16 (mean - 8 ± 4.7) years were identified. Nine patients had epilepsy attributed to a structural cause, six patients had epilepsy of unknown cause, and two had Lennox-Gastaut syndrome. Mean epilepsy duration was 5.4 ± 3.3 years. The mean number of previous AEDs was 6.6 ± 2. Lacosamide was added to the baseline AEDs in13 patients. The mean duration of follow-up was 9.1 ± 4.4 months. Six (35%) patients had at least a 50%.seizure reduction (mean - 76%). Social, behavioral, and/or motor improvement were noted in seven (41%) patients. Lacosamide was discontinued in six (35%) patients because of inefficacy. Side effects were reported in 10 (59%) patients.

CONCLUSIONS

Lacosamide seems to be effective and safe according to the data in our small cohort. Further prospective studies on lacosamide efficacy and safety in a large number of children are warranted.

New developments in the treatment of partial-onset epilepsy

Although most people presenting with partial-onset seizures will achieve control with antiepileptic medication, a considerable minority will have difficult-to-treat epilepsy that is resistant to existing medication. Over the last few years, a large number of new antiepileptic drugs have been developed. Some of these have a novel mode of action. Many of the older antiepileptic drugs act through sodium channels or by enhancement of gamma amino butyric acid (GABA). Lamotrigine has sodium-channel blocking properties but also has other important modes of action, indicated by efficacy in treating not only partial-onset but also generalized seizures. Vigabatrin and tiagabine both increase GABA activity, by inhibiting GABA transaminase and limiting GABA reuptake, respectively. The main mode of action of gabapentin and pregabalin is not via GABA but through a selective inhibitory effect on voltage-gated calcium channels containing the α(2)δ-1 subunit. Levetiracetam inhibits the recycling of SV2A (synaptic vesicle protein 2A) neurotransmitter vesicles but also has other effects, including inhibition of voltage-dependent calcium channels. Some drugs, eg, felbamate, zonisamide, and topiramate, have multiple modes of action. In many cases, although the main mode of action may have been identified, other modes of action also play a role. Two recently developed antiepileptic drugs appear to have completely novel primary modes of action; retigabine (ezogabine) and perampanel act on the potassium channel and on AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors, respectively. The hope is that antiepileptic drugs with a novel mode of action will be effective where previous drugs have failed and will not have unacceptable adverse effects. However, experience with these medications is too limited to allow any conclusions to be drawn at present.

No pharmacokinetic interaction between lacosamide and valproic acid in healthy volunteers

Two open-label, randomized, multiple-dose clinical studies evaluated the potential for pharmacokinetic interaction between the antiepileptic drugs lacosamide and valproic acid. The influence of lacosamide on valproic acid pharmacokinetics (trial A) and valproic acid on lacosamide pharmacokinetics (trial B) was investigated in 32 healthy male volunteers, 16 in each trial. Volunteers in trial A received valproic acid (300 mg bid) with randomization to either early or late addition of lacosamide (200 mg bid). Those in trial B received lacosamide (200 mg bid) with randomization to either early or late addition of valproic acid (300 mg bid). Area under the concentration-time curve during a 12-hour dosing interval at steady state (AUC(τ,ss)) and maximum steady-state plasma drug concentration (C(max,ss)) were measured for each drug alone and together and tested for equivalence. The point estimates (90% confidence intervals) for AUC(τ,ss) and C(max,ss) were 104% (99%-109%) and 101% (97%-107%), respectively, for valproic acid and 100% (98%-103%) and 101% (96%-107%), respectively, for lacosamide, which were within the generally accepted equivalence range of 80% to 125%. No changes in the rate or extent of absorption, terminal half-life, or time to maximum concentration were observed. These results suggest that lacosamide and valproic acid have no relevant pharmacokinetic drug-drug interaction.

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

Epilepsy is one of the most common serious neurological conditions worldwide, with an age-adjusted incidence of approximately 50 per 100,000 persons per year in developed countries. Antiepileptic therapy can result in long-term remission in 60-70% of patients, but many patients will require combination treatment to achieve optimal seizure control, as monotherapy is ineffective at controlling seizures in 30-53% of patients. Despite the increase in available treatment options, patient outcomes have not improved significantly and there is still a need for more effective therapies. Drugs used in the treatment of focal-onset seizures are a diverse range of compounds, and in most cases their mechanism of action is unknown or poorly defined. This review discusses the efficacy and safety of the newer adjuvant antiepileptic therapies that may improve outcomes in patients unresponsive to monotherapy, including clobazam, vigabatrin, lamotrigine, gabapentin, topiramate, tiagabine, levetiracetam, oxcarbazepine, pregabalin, zonisamide and eslicarbazepine, with focus on lacosamide. Lacosamide has been shown to exert its anticonvulsant effects predominantly by enhancement of the slow inactivation of voltage-gated sodium channels. Lacosamide is indicated for use as adjuvant treatment of focal-onset seizures in patients with epilepsy, and there is some evidence that it may also be of use in patients with status epilepticus and cancer patients with epilepsy. The efficacy of lacosamide has been assessed in three randomized, double-blind, placebo-controlled clinical trials, all of which have shown lacosamide to be effective at reducing seizure frequency and increasing 50% responder rates in patients with focal-onset seizures. Long-term lacosamide treatment is generally well tolerated and is not associated with significant drug interactions; the availability of an intravenous form of the drug also makes it particularly useful for a broad range of patients.

Lacosamide for epileptic seizures in patients with co-morbidities and unusual presentations of epilepsy

Numerous patients who are prescribed antiepileptic drugs (AEDs) for epileptic seizures are already receiving other agents for the treatment of co-morbid conditions, which frequently occur alongside epilepsy. This raises additional clinical considerations and makes the use of AEDs with good safety profiles and fewer drug-drug interactions attractive. Second and third-generation anticonvulsant drugs are associated with fewer pharmacological interactions and improved tolerability compared with first-generation drugs. Furthermore, second and third-generation anticonvulsant drugs are associated with linear pharmacokinetic profiles and differing mechanisms of action, making them ideal for pluripathological and polymedicated patients. In this report, we highlight the efficacy of one such agent, lacosamide, in five patients with co-morbidities and unusual presentations of epilepsy, including a patient with paraneoplastic encephalitis caused by microcytic lung carcinoma, one with a brain tumour and one with Alzheimer's disease, as well as a case of catamenial epilepsy and one of refractory convulsive status epilepticus. In all patients, lacosamide was associated with a substantial reduction in seizure frequency and effective control of seizure episodes. Treatment was generally well tolerated in all patients, indicating that lacosamide is an effective treatment option for a variety of patients with epileptic seizures.

Newer anticonvulsant medications in pediatric neurology

OPINION STATEMENT

Antiepileptic drugs (AEDs) are the mainstay of treatment for recurrent seizures. Uncontrolled seizures may cause medical, developmental, and psychological disturbances. The medical practitioner should thus strive to eliminate or minimize seizures. Treatment advances in epilepsy include 1) identification of the basic mechanisms of epilepsy and action of AEDs, 2) the introduction of new AEDs, and 3) the use of neurostimulation, including vagus nerve stimulation. Treatment with AEDs involves balancing each AED's efficacy against its side effects. In some patients, effective AEDs must be discontinued because of intolerable side effects. Although all AEDs have a proven efficacy, the choice of AEDs should be based on better efficacy for individual seizure types or epilepsy syndromes. Side effects also differ from drug to drug and must be taken into account. This article focuses on studies and expert opinion consensus to guide the choice of AEDs.

Add-on lacosamide: a retrospective study on the relationship between serum concentration, dosage, and adverse events

We performed a retrospective study in patients with poorly controlled epilepsy treated with add-on lacosamide (LCM) to investigate the relationship of LCM-related adverse events with LCM serum concentration and weight-dependent dosage. We collected serum concentrations, weight-related dosages, and occurrences of the seven most frequent adverse events according to the randomized double-blind, placebo-controlled trials. Seventy of 131 patients could be sufficiently evaluated. LCM serum concentrations and weight-related dosages in patients with and without typical adverse events did not differ significantly. Closer analysis of the data suggested that dizziness as the leading adverse event occurred significantly more often if LCM was combined with classic sodium channel blockers. There was a significant correlation between LCM serum concentrations and co-medication, so there is still evidence for dependent variables that might have a relevant impact in individual cases. However, our data do not allow definition of a safety range for LCM.

Adjunctive lacosamide in clinical practice: sodium blockade with a difference?

Lacosamide (LCM) was licensed in the United Kingdom in 2008 for the adjunctive treatment of partial-onset seizures. It exerts its effect by enhancing sodium channel slow inactivation. This article reports preliminary outcomes with adjunctive LCM in the everyday clinical setting. To date, 113 patients (57 males, 56 females; aged range=18-74 years, median=39 years) with uncontrolled partial-onset seizures (monthly frequency range=1-300, median=4) have been included in the audit. Patients were taking 1-4 (median=1) antiepileptic drugs (AEDs), having previously tried 1-12 (median 3) drug schedules. After 12 weeks on stable AED dosing, LCM was added, aiming at an initial target range of 200-400mg/day. Review took place every 6-8 weeks until one of four endpoints was reached: seizure freedom for ≥6 months on a given LCM dose; ≥50% (responder) or <50% (marginal benefit) seizure reduction over 6 months compared with baseline on the highest tolerated LCM dose; withdrawal of LCM because of lack of efficacy, side effects, or both. An endpoint has been reached by 65 (57.5%) patients so far. Seventeen (26.2%) have remained seizure free on a median daily LCM dose of 100mg (range=50-300 mg). Patients were more likely to become seizure free when LCM was used as a first add-on (15/36, 41.7%), compared with a later treatment schedule (1/27, 3.7%, P=0.001). With appropriate dose manipulation, patients taking traditional sodium blockers (5/26, 19.2%) were as likely to become seizure free as those taking AEDs with other mechanisms of action only (11/37, 29.7%). Fifty percent or greater seizure reduction was achieved in an additional 16 (24.6%) patients (1 monotherapy); 18 (27.7%) reported marginal benefit. Two patients were established on LCM monotherapy (one seizure free, one responder). Patients remaining on LCM were as likely to also be taking sodium blockers only (23/27, 85.1%) as AEDs with other mechanisms (26/36, 72.2%). LCM was withdrawn in 14 patients (12.3% of ongoing patients, 21.5% of those at an endpoint; 10 for side effects, 4 for lack of efficacy). The most common side effects leading to withdrawal were sedation, ataxia, and dizziness. Of the 10 with side effects, only 2 patients took concomitant sodium blockers. Patients on sodium valproate were more likely to discontinue LCM (8/21, P=0.018) than those also taking other AEDs; 5 of the 8 did so because of side effects and 3 because of lack of efficacy. In patients with partial-onset seizures, LCM is an effective and well-tolerated adjunctive AED when combined with appropriate doses of traditional sodium blockers, as well as agents with other mechanisms of action. Seizure freedom was more likely when LCM was used as a first add-on compared with a later treatment schedule. Patients also taking sodium valproate were significantly more likely to discontinue LCM compared with those taking other AEDs. These data suggest that the pharmacological effect of LCM differs importantly from that of AEDs that influence fast inactivation of the sodium channel.

Initial post marketing experience with lacosamide in adult patients with epilepsy

The outcomes of adult epilepsy patients prescribed lacosamide for additional seizure control. Responders were defined as having at least a 50% decrease in seizure frequency Sixty-seven patients were evaluated. Forty-six out of 67 patients (69%) were responders. Twelve of 14 patients not taking sodium channel-acting AEDs were responders (86%) and 34/53 patients taking sodium channel-acting AEDs were responders (64%) (difference not significant).

Early clinical experience with lacosamide as adjunctive therapy in patients with refractory focal epilepsy and nocturnal seizures

This retrospective study reports the early experience with lacosamide (LCM) as adjunctive therapy in Spanish patients with refractory focal epilepsy. Sixty patients (mean age 38.3 years, 54% women, mean epilepsy duration 27.2 years, mean seizure rate 9.7/month, and 28% with mainly nocturnal seizures) taking ≥2 antiepileptic drugs (mean 2.2) were included. LCM maintenance doses were 200, 300, 400, and 500mg/day in 31, 16, 10, and 3 patients, respectively. Patients were followed up for 13-24 months. Twenty-eight patients (47%) reported a ≥50% reduction in seizure frequency. A ≥50% reduction in seizure frequency was reported by 65% and 40% of patients in the nocturnal seizure and diurnal seizure subgroups, respectively (p>0.05). Of the 28 responders, 2 achieved stable periods of seizure freedom of 6 and 11 months after starting LCM. Twenty patients (33%) reported drug-related adverse events (AEs); the most common was dizziness (16 patients). LCM was withdrawn in 8 patients (13%). There were no serious AEs. These results support the efficacy and safety of adjunctive LCM in patients with partial-onset seizures.

Pharmacologic treatment of intractable epilepsy in children: a syndrome-based approach

The successful pharmacologic treatment of intractable childhood epilepsy is predicated upon an accurate classification of the epilepsy syndrome. The selection of an antiepileptic drug is facilitated by the knowledge of syndrome-specific efficacy, the anticipation of potential side effects, and a careful risk-benefit assessment tailored to each patient. As such, the identification of comorbidities and careful monitoring for treatment-emergent adverse events, especially cognitive and behavioral effects, is of utmost importance. Especially in refractory cases, polypharmacy may increase the likelihood of side effects, but carefully chosen combinations can result in synergistic benefit. For most epilepsy syndromes, newer antiepileptic drugs typically yield equivalent efficacy and superior tolerability. Nevertheless, continued research is needed to further contrast the syndrome-specific efficacy and tolerability of available drugs and to foster the development of new agents with superior efficacy and side effect profiles.

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.

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.

Budget impact analysis of adjunctive therapy with lacosamide for partial-onset epileptic seizures in Belgium

OBJECTIVE

This study aims to compute the budget impact of lacosamide, a new adjunctive therapy for partial-onset seizures in epilepsy patients from 16 years of age who are uncontrolled and having previously used at least three anti-epileptic drugs from a Belgian healthcare payer perspective.

METHODS

The budget impact analysis compared the 'world with lacosamide' to the 'world without lacosamide' and calculated how a change in the mix of anti-epileptic drugs used to treat uncontrolled epilepsy would impact drug spending from 2008 to 2013. Data on the number of patients and on the market shares of anti-epileptic drugs were taken from Belgian sources and from the literature. Unit costs of anti-epileptic drugs originated from Belgian sources. The budget impact was calculated from two scenarios about the market uptake of lacosamide.

RESULTS

The Belgian target population is expected to increase from 5333 patients in 2008 to 5522 patients in 2013. Assuming that the market share of lacosamide increases linearly over time and is taken evenly from all other anti-epileptic drugs (AEDs), the budget impact of adopting adjunctive therapy with lacosamide increases from €5249 (0.1% of reference drug budget) in 2008 to €242,700 (4.7% of reference drug budget) in 2013. Assuming that 10% of patients use standard AED therapy plus lacosamide, the budget impact of adopting adjunctive therapy with lacosamide is around €800,000-900,000 per year (or 16.7% of the reference drug budget).

CONCLUSIONS

Adjunctive therapy with lacosamide would raise drug spending for this patient population by as much as 16.7% per year. However, this budget impact analysis did not consider the fact that lacosamide reduces costs of seizure management and withdrawal. The literature suggests that, if savings in other healthcare costs are taken into account, adjunctive therapy with lacosamide may be cost saving.

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.

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.

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.

Atrial flutter/atrial fibrillation associated with lacosamide for partial seizures

Lacosamide (LCM) is a novel antiepileptic drug that exerts a strong antiepileptic effect via slow inactivation of voltage-gated sodium channels. LCM has been approved by the Food and Drug Administration for treatment of partial seizures at doses up to 400mg/day. Clinical trials have employed doses up to 600mg/day. LCM has been associated with atrial fibrillation at high doses (600mg/day) in patients with diabetes who had risk factors for heart disease. To our knowledge, atrial flutter or atrial fibrillation has not been reported in people with epilepsy. We report atrial flutter/atrial fibrillation at high doses of LCM (600mg/day) in a patient with epilepsy who had no significant risk factors for heart disease, which resolved following discontinuation of LCM. The literature regarding LCM-related cardiac death and arrhythmia is discussed. Physicians should be aware of the potential cardiac effects of this novel antiepileptic drug.

Therapeutic Drug Monitoring of the Newer Anti-Epilepsy Medications

In the past twenty years, 14 new antiepileptic drugs have been approved for use in the United States and/or Europe. These drugs are eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, rufinamide, stiripentol, tiagabine, topiramate, vigabatrin and zonisamide. In general, the clinical utility of therapeutic drug monitoring has not been established in clinical trials for these new anticonvulsants, and clear guidelines for drug monitoring have yet to be defined. The antiepileptic drugs with the strongest justifications for drug monitoring are lamotrigine, oxcarbazepine, stiripentol, and zonisamide. Stiripentol and tiagabine are strongly protein bound and are candidates for free drug monitoring. Therapeutic drug monitoring has lower utility for gabapentin, pregabalin, and vigabatrin. Measurement of salivary drug concentrations has potential utility for therapeutic drug monitoring of lamotrigine, levetiracetam, and topiramate. Therapeutic drug monitoring of the new antiepileptic drugs will be discussed in managing patients with epilepsy.

Therapeutic Drug Monitoring of the Newer Anti-Epilepsy Medications

In the past twenty years, 14 new antiepileptic drugs have been approved for use in the United States and/or Europe. These drugs are eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, rufinamide, stiripentol, tiagabine, topiramate, vigabatrin and zonisamide. In general, the clinical utility of therapeutic drug monitoring has not been established in clinical trials for these new anticonvulsants, and clear guidelines for drug monitoring have yet to be defined. The antiepileptic drugs with the strongest justifications for drug monitoring are lamotrigine, oxcarbazepine, stiripentol, and zonisamide. Stiripentol and tiagabine are strongly protein bound and are candidates for free drug monitoring. Therapeutic drug monitoring has lower utility for gabapentin, pregabalin, and vigabatrin. Measurement of salivary drug concentrations has potential utility for therapeutic drug monitoring of lamotrigine, levetiracetam, and topiramate. Therapeutic drug monitoring of the new antiepileptic drugs will be discussed in managing patients with epilepsy.