Plasma lacosamide monitoring in children with epilepsy: Focus on reference therapeutic range and influencing factors

Therapeutic Drug Monitoring for Lacosamide in Chinese Pediatric Patients with Epilepsy: Focus on Clinical Effectiveness, Tolerability and Drug Interactions

Objective: To investigate the effectiveness and tolerability of lacosamide (LCM) and to select a better reference range for its concentration in plasma for Chinese pediatric patients with epilepsy. In addition, it is necessary to evaluate the potential determinates of LCM concentration. Methods: Pediatric epilepsy patients using LCM were retrospective included. The clinical data of these patients were retrospectively reviewed, and the effectiveness at 3, 6, and 12 months after treatment was assessed. Drug concentrations from routine therapeutic drug monitoring (TDM) were also obtained. The trough concentration-to-dose ratio (C0/dose ratio) of LCM was compared among patients with various potential influencing factors. In addition, a new reference range was established based on the range in which the majority of patients were located and the proportion of responders within this range. Results: A total of 153 pediatric epilepsy patients were finally included. The frequency of seizures decreased by ≥50% was 74.7%, 73.0%, and 71.2% at 3, 6, and 12 months, respectively. Adverse events (AEs) occurred in 53 patients, and most AEs were mild and moderate. The TDM data showed that it is reasonable to recommend using 2.5 to 6.5 µg/mL as the reference range. The C0/dose ratio was significantly associated with weight, but those aged 4 to 12 were significantly lower than those aged >12 years. In addition, LCM-antiepileptic drug (AED) interactions were observed. Oxcarbazepine and perampanel significantly decreased the C0/dose ratio of LCM. Conclusions: LCM was efficacious in reducing seizure frequency and well tolerated in pediatric patients with epilepsy. The reference range 2.5-6.5 µg/mL, for routine LCM monitoring may be more applicable. As complex LCM-AED interactions were observed, it is necessary to monitor the plasma concentration.

Efficacy and Blood Levels of Lacosamide in Patients with Focal Epilepsy

Objectives: The aim of this paper is to analyze clinical targets for lacosamide (LCM) blood levels in patients with focal epilepsy. Referring to the LCM optimal range will encourage us to think about the importance and usefulness of measuring its blood levels. Methods: A total of 101 (45 female, 56 male) patients were treated with LCM. Blood sampling was performed 1 month after the start of oral medication (the levels reached a steady state) if the LCM treatment had been continued, and then 6 and 12 months after. The efficacy of LCM was evaluated by the reduction in the epileptic seizure rate (RR) at the time of blood sampling. The patients were classified as effective cases (seizure reduction rate ≥ 50%) and ineffective cases (<50%). The actual level, the calculated peak/trough levels, and the levels for each type of seizure were investigated. A statistical analysis was performed using Spearman's rank correlation coefficient and the Wilcoxon signed-rank test. Results: A positive correlation was seen between blood levels and dosage (r = 0.446). However, the blood levels and RR showed no correlation. The blood levels were higher in effective cases than in ineffective cases at all time points (measurement p < 0.001, peak p = 0.013, trough p = 0.001). Because the range was set so that the effective and ineffective groups did not overlap, the optimal range of LCM was found to be 8.0-10.5 µg/mL. Conclusions: Measuring and calculating blood levels of LCM and adjusting the dosage to reach the optimal range are recommended. Moreover, the optimal range for LCM was determined as a therapeutic target.

CYP2C19 genotype and sodium channel blockers in lacosamide-treated children with epilepsy: two major determinants of trough lacosamide concentration or clinical response

Background

The widespread clinical use of lacosamide (LCM) has revealed significant individual differences in clinical response, with various reported influencing factors. However, it remains unclear how genetic factors related to the disposition and clinical response of LCM, as well as drug-drug interactions (DDIs), exert their influence on pediatric patients with epilepsy.

Objectives

To evaluate the impact of genetic variations and DDIs on plasma LCM concentrations and clinical response.

Design

Patients with epilepsy treated with LCM from June 2021 to March 2023 in the Children's Hospital of Nanjing Medical University were included in the analysis.

Methods

The demographic information and laboratory examination data were obtained from the hospital information system. For the pharmacogenetic study, the left-over blood specimens, collected for routine plasma LCM concentration monitoring, were used to perform genotyping analysis for the selected 26 single nucleotide polymorphisms from 14 genes. The trough concentration/daily dose (C 0/D) ratio and efficacy outcomes were compared.

Results

Patients achieved 90.1% and 68.9% responder rates in LCM mono- and add-on therapy, respectively. The genetic variant in the CYP2C19 *2 (rs4244285) was associated with a better responsive treatment outcome (odds ratio: 1.82; 95% confidence interval: 1.05-3.15; p = 0.031). In monotherapy, 36% of patients were CYP2C19 normal metabolizers (NMs), 49% were intermediate metabolizers (IMs), and 15% were poor metabolizers (PMs) carrying CYP2C19 *2 or *3. Of note, the C 0/D ratios of IMs and PMs were 9.1% and 39.6% higher than those of NMs, respectively. Similar results were in the add-on therapy group, and we also observed a substantial decrease in the C 0/D ratio when patients were concomitant with sodium channel blockers (SCBs).

Conclusion

This study was the first to confirm that CYP2C19 *2 or *3 variants impact the disposition and treatment response of LCM in children with epilepsy. Moreover, concomitant with SCBs, particularly oxcarbazepine, also decreased plasma LCM concentration.

Clinical Analysis of Lacosamide Monotherapy in the Treatment of Self-Limited Epilepsy with Centrotemporal Spikes

Objective

To evaluate the efficacy and safety of lacosamide (LCM) monotherapy in the treatment of self-limited epilepsy with centrotemporal spikes (SeLECTS).

Methods

In this study, 89 children with SeLECTS who were treated with LCM monotherapy in the Children's Hospital Affiliated to Soochow University from June 2019 to June 2021 were included. Clinical seizures and spike wave index (SWI) on video EEG during slow-wave sleep were evaluated before and after treatment. The role of LCM monotherapy in improving SWI, controlling clinical seizures and improving cognition was analyzed, and corresponding adverse reactions were documented.

Results

There were 52 males and 37 females in this group, with an average age of 7.6 ± 2.1 years. The total effective rate was 93.83% and at 18 months of treatment, the cumulative control rate was 85.19%, the retention rate was 91.01% and the effective rate in terms of EEG spike index was 72.92%, all of which showed a high rate; there was no statistically significant difference in intelligence quotient before and after treatment (P > 0.05). In addition, it was found in the study that the earlier the age of onset, the less obvious the improvement in SWI after LCM treatment; the lower the baseline seizure frequency, the more significant the improvement in SWI after LCM treatment.

Conclusion

LCM monotherapy had curative effect and adverse reactions for SeLECTS, with no negative impact on cognition. These significant findings indicate that LCM is likely to become a widely prescribed ASM for the treatment of SeLECTS. Meanwhile, the onset age and baseline seizure frequency had certain value in judging prognosis and predicting curative effect.