Bioequivalence of intravenous and oral formulations of the antiepileptic drug lacosamide

Lacosamide dosing in patients receiving continuous renal replacement therapy

BACKGROUND

Lacosamide is one of the anticonvulsants used in critically ill patients. This study aimed to suggest appropriate lacosamide dosing regimens in critically ill patients receiving continuous renal replacement therapy (CRRT) via Monte Carlo simulations.

METHODS

Mathematical models were created using published demographic and pharmacokinetics in adult critically ill patients. CRRT modalities with different effluent rates were added into the models. Lacosamide regimens were evaluated on the probability of target attainment (PTA) using pharmacodynamic targets of trough concentrations and area under the curve within a range of 5-10 mg/L and 80.25-143 and 143-231 mg*h/L for the initial 72 h-therapy, respectively. Optimal regimens were defined from regimens that yielded the highest PTA. Each dosing regimen was tested in a group of different 10,000 virtual patients.

RESULTS

Our results revealed the optimal lacosamide dosing regimen of 300-450 mg/day is recommended for adult patients receiving both CRRT modalities with 20-25 effluent rates. The dose of 600 mg/day was suggested in higher effluent rate of 35 mL/kg/h. Moreover, a patient with body weight > 100 kg was less likely to attain the targets.

CONCLUSIONS

Volume of distribution, total clearance, CRRT clearance and body weight were significantly contributed to lacosamide dosing. Clinical validation of the finding is strongly indicated.

Safety and tolerability of short-term infusions of intravenous lacosamide in pediatric patients with epilepsy: An open-label, phase 2/3 trial

OBJECTIVE

The objective of this study is to evaluate the safety and tolerability of intravenous (IV) lacosamide infusion in patients aged ≥1 month to <17 years with epilepsy.

METHODS

This Phase 2/3 open-label trial (EP0060; NCT02710890) enrolled patients in two age cohorts (cohort 1: ≥8 to <17 years; cohort 2: ≥1 month to <8 years). Eligible patients were receiving oral lacosamide as adjunctive treatment or monotherapy (in an open-label long-term trial or by prescription) or were not receiving lacosamide before enrolment. Patients initiated IV lacosamide (2-12 mg/kg/day or 100-600 mg/day; 15-60 minutes infusion) as a replacement for oral lacosamide or as adjunctive treatment. The primary outcomes were treatment-emergent adverse events (TEAEs) and discontinuations due to TEAEs.

RESULTS

In total, 103 patients were enrolled and completed the trial; 55 patients were included in cohort 1 (≥8 to <17 years), 48 in cohort 2 (≥1 month to <8 years). During the 4 weeks before screening, 74 (71.8%) patients had focal seizures, 12 (11.7%) had generalized seizures, and two (1.9%) had unclassified seizures. Most patients (74 [71.8%]) initiated lacosamide as adjunctive IV treatment. The mean overall duration of exposure to IV lacosamide was 1.18 days. Seventy-nine (76.7%) patients had one IV lacosamide infusion, 20 (19.4%) had two, one (1.0%) had three, and three (2.9%) had 10 infusions. Overall, five (4.9%) patients had a total of seven TEAEs. The only TEAEs reported in two or more patients were increased blood triglycerides (two [1.9%]). No serious or severe TEAEs were reported, and no patients discontinued due to TEAEs. No TEAEs were considered drug-related by the investigator. No consistent or clinically relevant treatment-related changes from baseline were observed for hematology, clinical chemistry parameters, vital signs, or 12-lead electrocardiograms.

SIGNIFICANCE

IV lacosamide was generally well tolerated in pediatric patients (≥1 month to <17 years) with epilepsy, and no new safety concerns were identified.

IMI2-PainCare-BioPain-RCT2 protocol: a randomized, double-blind, placebo-controlled, crossover, multicenter trial in healthy subjects to investigate the effects of lacosamide, pregabalin, and tapentadol on biomarkers of pain processing observed by non-invasive neurophysiological measurements of human spinal cord and brainstem activity

Background

IMI2-PainCare-BioPain-RCT2 is one of four similarly designed clinical studies aiming at profiling a set of functional biomarkers of drug effects on specific compartments of the nociceptive system that could serve to accelerate the future development of analgesics. IMI2-PainCare-BioPain-RCT2 will focus on human spinal cord and brainstem activity using biomarkers derived from non-invasive neurophysiological measurements.

Methods

This is a multisite, single-dose, double-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD) and pharmacokinetic (PK) study in healthy subjects. Neurophysiological biomarkers of spinal and brainstem activity (the RIII flexion reflex, the N13 component of somatosensory evoked potentials (SEP) and the R2 component of the blink reflex) will be recorded before and at three distinct time points after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol), and placebo, given as a single oral dose in separate study periods. Medication effects on neurophysiological measures will be assessed in a clinically relevant hyperalgesic condition (high-frequency electrical stimulation of the skin), and in a non-sensitized normal condition. Patient-reported outcome measures (pain ratings and predictive psychological traits) will also be collected; and blood samples will be taken for pharmacokinetic modelling. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split between the two primary endpoints, namely the percentage amplitude changes of the RIII area and N13 amplitude under tapentadol. Remaining treatment arm effects on RIII, N13 and R2 recovery cycle are key secondary confirmatory analyses. Complex statistical analyses and PK-PD modelling are exploratory.

Discussion

The RIII component of the flexion reflex is a pure nociceptive spinal reflex widely used for investigating pain processing at the spinal level. It is sensitive to different experimental pain models and to the antinociceptive activity of drugs. The N13 is mediated by large myelinated non-nociceptive fibers and reflects segmental postsynaptic response of wide dynamic range dorsal horn neurons at the level of cervical spinal cord, and it could be therefore sensitive to the action of drugs specifically targeting the dorsal horn. The R2 reflex is mediated by large myelinated non-nociceptive fibers, its circuit consists of a polysynaptic chain lying in the reticular formation of the pons and medulla. The recovery cycle of R2 is widely used for assessing brainstem excitability. For these reasons, IMI2-PainCare-BioPain-RCT2 hypothesizes that spinal and brainstem neurophysiological measures can serve as biomarkers of target engagement of analgesic drugs for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification.

Trial registration

This trial was registered on 02 February 2019 in EudraCT (2019-000755-14).

IMI2-PainCare-BioPain-RCT1: study protocol for a randomized, double-blind, placebo-controlled, crossover, multi-center trial in healthy subjects to investigate the effects of lacosamide, pregabalin, and tapentadol on biomarkers of pain processing observed by peripheral nerve excitability testing (NET)

Background

Few new drugs have been developed for chronic pain. Drug development is challenged by uncertainty about whether the drug engages the human target sufficiently to have a meaningful pharmacodynamic effect. IMI2-PainCare-BioPain-RCT1 is one of four similarly designed studies that aim to link different functional biomarkers of drug effects on the nociceptive system that could serve to accelerate the future development of analgesics. This study focusses on biomarkers derived from nerve excitability testing (NET) using threshold tracking of the peripheral nervous system.

Methods

This is a multisite single-dose, subject and assessor-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD), and pharmacokinetic (PK) study in healthy subjects. Biomarkers derived from NET of large sensory and motor fibers and small sensory fibers using perception threshold tracking will be obtained before and three times after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol) and placebo, given as a single oral dose with at least 1 week apart. Motor and sensory NET will be assessed on the right wrist in a non-sensitized normal condition while perception threshold tracking will be performed bilaterally on both non-sensitized and sensitized forearm skin. Cutaneous high-frequency electrical stimulation is used to induce hyperalgesia. Blood samples will be taken for pharmacokinetic purposes and pain ratings as well as predictive psychological traits will be collected. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split across the two primary outcomes: strength-duration time constant (SDTC; a measure of passive membrane properties and nodal persistent Na+ conductance) of large sensory fibers and SDTC of large motor fibers comparing lacosamide and placebo. The key secondary endpoint is the SDTC measured in small sensory fibers. Remaining treatment arm effects on key NET outcomes and PK modelling are other prespecified secondary or exploratory analyses.

Discussion

Measurements of NET using threshold tracking protocols are sensitive to membrane potential at the site of stimulation. Sets of useful indices of axonal excitability collectively may provide insights into the mechanisms responsible for membrane polarization, ion channel function, and activity of ionic pumps during the process of impulse conduction. IMI2-PainCare-BioPain-RCT1 hypothesizes that NET can serve as biomarkers of target engagement of analgesic drugs in this compartment of the nociceptive system for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification.

Trial registration

This trial was registered 25/06/2019 in EudraCT (2019-000942-36).

IMI2-PainCare-BioPain-RCT3: a randomized, double-blind, placebo-controlled, crossover, multi-center trial in healthy subjects to investigate the effects of lacosamide, pregabalin, and tapentadol on biomarkers of pain processing observed by electroencephalography (EEG)

Background

IMI2-PainCare-BioPain-RCT3 is one of four similarly designed clinical studies aiming at profiling a set of functional biomarkers of drug effects on the nociceptive system that could serve to accelerate the future development of analgesics, by providing a quantitative understanding between drug exposure and effects of the drug on nociceptive signal processing in human volunteers. IMI2-PainCare-BioPain-RCT3 will focus on biomarkers derived from non-invasive electroencephalographic (EEG) measures of brain activity.

Methods

This is a multisite single-dose, double-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD) and pharmacokinetic (PK) study in healthy subjects. Biomarkers derived from scalp EEG measurements (laser-evoked brain potentials [LEPs], pinprick-evoked brain potentials [PEPs], resting EEG) will be obtained before and three times after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol) and placebo, given as a single oral dose in separate study periods. Medication effects will be assessed concurrently in a non-sensitized normal condition and a clinically relevant hyperalgesic condition (high-frequency electrical stimulation of the skin). Patient-reported outcomes will also be collected. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split between LEP and PEP under tapentadol. Remaining treatment arm effects on LEP or PEP or effects on EEG are key secondary confirmatory analyses. Complex statistical analyses and PK-PD modeling are exploratory.

Discussion

LEPs and PEPs are brain responses related to the selective activation of thermonociceptors and mechanonociceptors. Their amplitudes are dependent on the responsiveness of these nociceptors and the state of the pathways relaying nociceptive input at the level of the spinal cord and brain. The magnitude of resting EEG oscillations is sensitive to changes in brain network function, and some modulations of oscillation magnitude can relate to perceived pain intensity, variations in vigilance, and attentional states. These oscillations can also be affected by analgesic drugs acting on the central nervous system. For these reasons, IMI2-PainCare-BioPain-RCT3 hypothesizes that EEG-derived measures can serve as biomarkers of target engagement of analgesic drugs for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification.

Trial registration

This trial was registered 25/06/2019 in EudraCT (2019%2D%2D001204-37).

Is Therapeutic Drug Monitoring of Lacosamide Needed in Patients with Seizures and Epilepsy?

Lacosamide is an antiepileptic drug (AED) that has linear pharmacokinetics, predictable blood concentrations, and few drug interactions, setting it apart from other AEDs that require vigorous therapeutic drug monitoring (TDM) such as phenytoin and carbamazepine. However, there have been reports of altered lacosamide pharmacokinetics in some populations. The purpose of this review is to determine whether lacosamide pharmacokinetics are altered in certain patient populations, suggesting the need for TDM. A literature search of Medline, Scopus, Embase, and Cochrane trials was conducted on January 3, 2019 (and then updated on September 2, 2019) to search for articles relevant to the TDM or pharmacokinetics of lacosamide. A total of 56 relevant articles were found and included in this review. Dose of lacosamide is linearly correlated with plasma concentrations and efficacy. However, currently there is no well-established reference range. Overall, the recommended reference ranges varied from 2.2 to 20 mg/L. Lacosamide has very few clinically relevant drug-drug interactions; however, there seems to be a significant drug interaction between lacosamide and enzyme-inducer AEDs. Based on available literature, it appears that lacosamide pharmacokinetics may be altered in severe renal dysfunction, in patients on dialysis and with extremes of age. More evidence is currently needed on lacosamide pharmacokinetics in pregnancy and critical illness. While it is not practical to utilize TDM for all patients, TDM may be useful in patients taking enzyme-inducer AEDs, in patients with decreased renal function or on dialysis, and older adults.

Pharmacology of lacosamide: From its molecular mechanisms and pharmacokinetics to future therapeutic applications

Epilepsy is one of the most common brain disorders, affecting more than 50 million people worldwide. Although its treatment is currently symptomatic, the last generation of anti-seizure drugs is characterized by better pharmacokinetic profiles, efficacy, tolerability and safety. Lacosamide is a third-generation anti-seizure drug that stands out due to its good efficacy and safety profile. It is used with effectiveness in the treatment of partial-onset seizures with or without secondary generalization, primary generalized tonic-clonic seizures and off-label in status epilepticus. Despite scarcely performed until today, therapeutic drug monitoring of lacosamide is proving to be advantageous by allowing the control of inter and intra-individual variability and promoting a successful personalized therapy, particularly in special populations. Herein, the pharmacology, pharmacokinetics, and clinical data of lacosamide were reviewed, giving special emphasis to the latest molecular investigations underlying its mechanism of action and therapeutic applications in pathologies besides epilepsy. In addition, the pharmacokinetic characteristics of lacosamide were updated, as well as current literature concerning the high pharmacokinetic variability observed in special patient populations and that must be considered during treatment individualization.

Selective quantification of lacosamide in human plasma using UPLC-MS/MS: Application to pharmacokinetic study in healthy subjects with different doses

A practical, sensitive, and robust UPLC-MS/MS method was developed and validated to quantify lacosamide in human plasma. A simple one-step protein precipitation was used to extract lacosamide and labeled lacosamide-13C, D3 as an internal standard (IS) from 150-μL plasma. The extracts were analyzed on an Eclipse Plus C18 column (50 × 2.1 mm, 1.8 μm) using 0.1% formic acid in water and methanol:acetonitrile (50:50, v/v) under gradient conditions. The extracts were quantified on LCMS-8040 using electrospray ionization source operated in positive ionization and multiple reaction monitoring modes. The method showed good linearity from 0.02 to 20 μg/mL, which was adequate to cover lacosamide concentration assayed in formulations with different strengths. The bioanalytical assay was fully validated as per current regulatory guidelines. The intra-batch and inter-batch precision values of lacosamide were less than 4.6%. Lacosamide was found to be stable at different storage conditions. The extraction recoveries and IS-normalized matrix factors for lacosamide ranged from 97.17 to 99.68% and from 0.973 to 1.012, respectively. The validated method was successfully applied to a pharmacokinetic study with three lacosamide formulations (50, 100, and 200 mg) in 36 healthy subjects. The assay reliability was determined by reanalysis of 81 subject samples.

Lacosamide Pharmacokinetics in a Critically Ill Patient During Continuous Renal Replacement Therapy

The objective of this study is to describe the pharmacokinetics of lacosamide in a critically ill adult during continuous venovenous hemofiltration (CVVH). A 78-year-old male developed sepsis and acute kidney injury following cardiac surgery. He was initially treated with intermittent hemodialysis but developed nonconvulsive status epilepticus at the end of the first session and was subsequently initiated on CVVH. In addition to lorazepam boluses, levetiracetam, and midazolam infusion, he was loaded with lacosamide 400 mg intravenously and started on 200 mg intravenously twice daily as maintenance therapy. Noncompartmental modeling of lacosamide pharmacokinetics revealed significant extracorporeal removal, a volume of distribution of 0.69 L/kg, elimination half-life of 13.6 hours, and peak and trough concentrations of 7.4 and 3.7 mg/L, respectively (goal trough, 5-10 mg/L). We found significant extracorporeal removal of serum lacosamide during CVVH, which was higher than previously reported. This led to subtherapeutic concentrations and decreased overall antiepileptic drug exposure. The relationship between serum lacosamide concentrations and clinical efficacy is not well understood; thus, therapeutic drug monitoring is not routinely recommended. Yet, we demonstrated that measuring serum lacosamide concentrations in the critically ill population during continuous renal replacement therapy may be useful to individualize dosing programs. Further pharmacokinetic studies of lacosamide may be necessary to generate widespread dosing recommendations.

Intravenous lacosamide (LCM) in status epilepticus (SE): Weight-adjusted dose and efficacy

BACKGROUND

Some studies suggest higher efficacy of lacosamide (LCM) in status epilepticus (SE) with higher loading doses; however, this weight-adjusted dose has not been evaluated.

OBJECTIVE

The objective was to evaluate the relationship between loading weight-adjusted dose and efficacy of LCM in SE.

METHODS

A group of patients with SE treated with LCM from Spanish hospitals was examined retrospectively. Demographic data, type of SE, etiology, response rate, last antiepileptic drug (AED) used, treatment line in which LCM was used, total loading dose, and weight-adjusted dose were collected.

RESULTS

One hundred sixty-five cases of SE were collected; 87 (52.7%) patients had nonconvulsive SE. Mean age was 64.2 ± 17.2 and 60.6% (n = 100) were men. Regarding etiology, SE was considered as acute symptomatic in 85 (51.5%), remote symptomatic in 51 (30.9%), progressive symptomatic in 10 (6.1%), and cryptogenic in 19 (11.5%). Lacosamide was used as the third drug in 46.1%, and as a second option in 28%. In 115 patients, clonazepam had been used as the first option, and no benzodiazepines had been administered in the remaining 50. The median loading dose was 400 mg (100-600 mg), and the weight-adjusted dose was 5 mg/kg (3-6 mg/kg). The response rate was 63.3%, and 55.1% responded within the first 12 h. Efficacy was significantly higher in patients who had taken benzodiazepines at LCM loading doses >5.3 mg/kg (p = 0.006). This relationship was maintained independent of using other concomitant AEDs. However, if benzodiazepines were not taken, this relationship was not found.

CONCLUSIONS

In adults with benzodiazepine-resistant SE, the response rate to LCM was higher, with weight-adjusted doses above 5.3 mg/kg.

Lacosamide in status epilepticus: Systematic review of current evidence

OBJECTIVE

The intravenous formulation of lacosamide (LCM) and its good overall tolerability and safety favor the use in status epilepticus (SE). The aim of this systematic review was to identify and evaluate studies reporting on the use of LCM in SE.

METHODS

We performed a systematic literature search of electronic databases using a combined search strategy from 2008 until October 2016. Using a standardized assessment form, information on the study design, methodologic framework, data sources, efficacy, and adverse events attributed to LCM were extracted from each publication and systematically reported.

RESULTS

In total, 522 SE episodes (51.7% female) in 486 adults and 36 children and adolescents were evaluated with an overall LCM efficacy of 57%. Efficacy was comparable between use in nonconvulsive (57%; 82/145) and generalized-convulsive (61%; 30/49; p = 0.68) SE, whereas overall success rate was better in focal motor SE (92%; 34/39, p = 0.013; p < 0.001). The efficacy with later positioning of LCM decreased from 100% to 20%. The main adverse events during treatment of SE are dizziness, abnormal vision, diplopia, and ataxia. Overall, lacosamide is well tolerated and has no clinically relevant drug-drug interactions.

SIGNIFICANCE

The available data regarding the use of LCM in SE are promising, with a success rate of 57%. The strength of LCM is the lack of interaction potential and the option for intravenous use in emergency situations requiring rapid uptitration.

The efficacy of lacosamide as monotherapy and adjunctive therapy in focal epilepsy and its use in status epilepticus: clinical trial evidence and experience

Lacosamide (LCM) is approved for anticonvulsive treatment in focal epilepsy and exhibits its function through the slow inactivation of voltage-gated sodium channels (VGSCs). LCM shows comparable efficacy with other antiepileptic drugs (AEDs) licensed in the last decade: in three randomized placebo-controlled trials, significant median seizure reduction rates of 35.2% for 200 mg/day, 36.4-39% for 400 mg/day and 37.8-40% for 600 mg/day were reported. Likewise, 50% responder rates were 38.3-41.1% for 400 mg/day and 38.1-41.2% for 600 mg/day. Similar rates were reported in post-marketing studies. The main adverse events (AEs) are dizziness, abnormal vision, diplopia and ataxia. Overall, LCM is well tolerated and has no clinically-relevant drug-drug interactions. Due to the drug's intravenous availability, its use in status epilepticus (SE) is increasing, and the available data are promising.

Safety and tolerability of lacosamide as adjunctive therapy for adults with partial-onset seizures: Analysis of data pooled from three randomized, double-blind, placebo-controlled clinical trials

OBJECTIVE

The objective of this study was to describe a priori protocol-defined analyses to evaluate the safety and tolerability of adjunctive oral lacosamide (200-600 mg/day) in adults (ages 16-70 years) with partial-onset seizures (POS) using data pooled from three similarly designed randomized, double-blind, placebo-controlled trials (SP667, SP754 [NCT00136019], SP755 [NCT00220415]).

METHODS

Patients with POS (≥2 years' duration, ≥2 previous antiepileptic drugs [AEDs]) uncontrolled by a stable dosing regimen of 1-3 concomitant AEDs were randomized to treatment with lacosamide at doses of 200 mg/day, 400 mg/day, or 600 mg/day, or placebo. Studies comprised a 4- to 6-week titration phase to target dose followed by a 12-week maintenance phase. Safety outcomes included treatment-emergent adverse events (TEAEs) of particular relevance to patients with POS, overall TEAEs, and discontinuations due to TEAEs. Post hoc analyses included evaluation of TEAEs potentially related to cognition and TEAEs leading to discontinuation analyzed by concomitant AEDs.

RESULTS

One thousand three hundred eight patients were randomized to and received treatment; 944 to lacosamide and 364 to placebo. Most patients (84.4%) were taking 2 or 3 concomitant AEDs. The most common drug-associated TEAEs (reported by ≥5% of patients in any lacosamide dose group and with an incidence at least twice that reported for placebo during the treatment phase) were dizziness (30.6% for lacosamide vs 8.2% for placebo), nausea (11.4% vs 4.4%), and diplopia (10.5% vs 1.9%). Common drug-associated TEAEs generally appeared to be dose-related, and the incidence of each was lower during the 12-week maintenance phase than during the titration phase. Most TEAEs were either mild or moderate in intensity; severe TEAEs were predominantly observed with lacosamide 600 mg/day. No individual serious TEAE occurred in ≥1% of all lacosamide-treated patients. Treatment-emergent adverse events led to discontinuation in 8.1%, 17.2%, and 28.6% of the lacosamide 200-, 400-, and 600-mg/day groups, respectively (vs 4.9% of placebo). Few TEAEs were related to rash, weight loss/gain, changes in clinical chemistry parameters, or psychiatric disturbances, or were seizure-related. The odds of reporting any potential cognition-related TEAE vs placebo increased with dose and were similar between lacosamide doses of 200 and 400mg/day and placebo (odds ratio 1.3, 95% confidence interval 0.7-2.4). Discontinuations due to TEAEs based on most commonly used AEDs taken in combination with lacosamide (all doses combined) were carbamazepine (15.3% [51/334] vs 3.9% [5/129] placebo), lamotrigine (19.2% [56/291] vs 4.3% [5/117]), and levetiracetam (10.1% [28/278] vs 3.9% [4/103]).

CONCLUSIONS

The safety and tolerability profile of adjunctive lacosamide in this detailed evaluation was similar to that observed in the individual double-blind trials. Adjunctive lacosamide was associated with TEAEs related to the nervous system and gastrointestinal tract, predominantly during titration.

Acute or chronic use of lacosamide does not alter its distribution between serum and cerebrospinal fluid

OBJECTIVE

The site of action for antiepileptic drugs (AEDs) is within the brain; however, cerebrospinal fluid (CSF) concentration is highly variable. Lacosamide (LCM) is approved by the U.S. Food and Drug Administration (FDA) for treatment of partial-onset seizures in adults, and has linear pharmacokinetics in serum. Penetration across the blood-brain barrier (BBB) is unknown. This study aims to provide additional insights into the pharmacokinetics of LCM.

METHODS

Thirty adults undergoing craniotomy for treatment of intractable epilepsy or brain tumor were recruited and were either taking LCM long term (group 1, n = 15), or were LCM naive, receiving LCM as prophylaxis for surgery (group 2, n = 15). All patients received one intravenous (IV) dose (15 min infusion) immediately prior to craniotomy. CSF and arterial blood were collected simultaneously following craniotomy. LCM concentrations were measured in serum and CSF.

RESULTS

LCM concentration differences between groups 1 and 2 for both CSF and serum were statistically significant (p ≤ 0.0005), but there was no statistically significant difference in CSF/serum ratios (group 1 = 0.726 ± 0.231; group 2 = 0.556 ±0.241; p = 0.0585). LCM concentration in serum correlated positively with CSF concentration in group 1 (Pearson r = 0.8527, p < 0.0001). The time interval between the end of dose delivery and sample collection correlated positively with the CSF/serum ratio for the drug-naive group (Pearson r = 0.6525; p = 0.0084). Treatment with other AEDs did not affect LCM distribution between serum and CSF.

SIGNIFICANCE

Although chronic dosing resulted in higher LCM concentrations in serum and CSF compared to drug-naive patients, the CSF/serum ratio was not affected by LCM pretreatment. These data suggest that LCM serum concentration may reliably predict CSF concentration.

Advances in epilepsy treatment: lacosamide pharmacokinetic profile

Lacosamide (LCM) is a functionalized amino acid specifically developed for use as an antiepileptic drug (AED) and is currently indicated as adjunctive treatment for partial-onset seizures in adults with focal epilepsy (maximum approved dose 400 mg/day). Characterization of the pharmacokinetic profile is an important aspect in the development of LCM. Studies in healthy subjects and in patients with focal epilepsy have established that LCM has several favorable pharmacokinetic characteristics, including rapid absorption and high oral bioavailability not affected by food, linear and dose-proportional pharmacokinetics, low inter- and intraindividual variability, low plasma protein binding, renal elimination, and a low potential for clinically relevant pharmacokinetic drug-drug interactions both with AEDs and other common medications. Studies have demonstrated bioequivalence among the three LCM formulations (oral tablets, oral solution, and solution for intravenous (IV) infusion), allowing direct conversion to or from oral and IV administration without titration. Thus, the favorable and predictable pharmacokinetic profile and bioequivalence of LCM formulations, coupled with the low potential for clinically relevant pharmacokinetic drug-drug interactions, make LCM an easy-to-use adjunctive treatment for the management of patients with focal epilepsy.

Single-dose oral lacosamide in refractory simple partial status epilepticus: case report and review

OBJECTIVES

This study aimed to present 2 patients with simple partial refractory status epilepticus (RSE) treated with a single oral lacosamide (LCM) dose and to review the literature on this topic.

METHOD

A retrospective description of 2 patients with simple partial RSE treated with 300 mg of LCM per os (p.o.) and a literature review were done.

RESULTS

Both patients responded to single-dose oral LCM treatment with seizure cessation after 30 minutes.

CONCLUSIONS

This is the first report on successful treatment of simple partial RSE with a single-dose of LCM p.o.. Oral LCM might represent an option for treatment of patients presenting with simple partial RSE.

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

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

Absorption, disposition, metabolic fate and elimination of the anti-epileptic drug lacosamide in humans: mass balance following intravenous and oral administration

The absorption, distribution, metabolism and elimination of the anti-epileptic drug lacosamide were determined in 10 healthy male volunteers following intravenous or oral administration in a single-center, open-label, single-dose trial. Volunteers were randomized to receive either a continuous intravenous infusion of 100 mg (40 μCi) [¹⁴C]-lacosamide administered over 60 min, or a 100 mg (40 μCi) [¹⁴C]-lacosamide dose given as an oral solution. During the infusion, total radioactivity concentrations reached peak levels at 1 h post dose followed by a decline of 71 % within 24 h. More than 97 % of radioactivity was excreted within 168 h; 96.8 % in urine and 0.3 % in feces. Following oral administration, total radioactivity concentrations increased to peak levels within 0.5 h followed by a decline of 65 % within 24 h. Approximately 94.6 % of radioactivity was excreted within 168 h after oral administration, 94.2 % by the kidneys and 0.4% in feces. A comparison of AUC values (po/iv) of unchanged lacosamide indicates a high absolute bioavailability. The metabolic profile was analyzed using pooled urine samples, and following intravenous and oral administration, respectively, a total of 38 and 34 % unchanged lacosamide, 28 and 28 % of the desmethyl metabolite and 19 and 17 % of a polar fraction were measured. Additional metabolites were identified only in small amounts (<3 %). In plasma at maximum concentration, most of the total radioactivity was found as unchanged drug after intravenous and oral dose. The plasma concentration curves of total radioactivity following intravenous and oral administration were similar.