Impact of ABCB1 Polymorphisms on Lacosamide Serum Concentrations in Uygur Pediatric Patients With Epilepsy in China

Pharmacogenetic insights into ABCB1, ABCC2, CYP1A2, and CYP2B6 variants with epilepsy susceptibility among Egyptian Children: A retrospective case-control study

BACKGROUND

Pediatric epilepsy is a complicated neuropsychiatric disorder that is characterized by recurrent seizures and unusual synchronized electrical activities within brain tissues. It has a substantial effect on the quality of life of children, thus understanding of the hereditary considerations influencing epilepsy susceptibility and the response to antiepileptic medications is crucial. This study focuses on assessing the correlation of the ABCB1, ABCC2, CYP1A2, and CYP2B6 genetic polymorphisms with the susceptibility to epileptic seizures and their contributions to antiepileptic medication throughout the course of the disease.

METHODS

This study included 134 Egyptian epileptic children, comprising 67 drug-responsive and 67 drug-resistant patients, along with 124 healthy controls matching for age, gender, and geographical district. Genotyping of the rs2032582, rs717620, rs2273697, rs762551, and rs3745274 variants was performed using the PCR technique. Statistical analyses, including haplotype, multivariate, logistic regression, and bioinformatics approaches, were conducted to evaluate the associations within the disease.

RESULTS

The ABCC2*rs717620 (T allele) revealed an increased risk of epilepsy compared to healthy controls (OR = 2.12, p-value < 0.001), with the rs717620 (C/T + T/T genotypes) showing significant differences between drug-responsive and drug-resistant patients (p-value < 0.05). Moreover, the ABCC2*rs2273697 (A allele) indicated a decreased risk of epileptic seizures compared to healthy controls (OR = 0.51, p-value = 0.033), with the rs2273697 (G/A + A/A genotypes) indicating a significant association with drug-resistant patients (OR = 0.21, p-value = 0.002). The rs717620*T/rs2273697*G haplotype was significantly correlated with an elevated risk of epileptic seizures within drug-responsive patients (OR = 2.26, p-value = 0.019). Additionally, the CYP1A2*rs762551 (A allele) represented a protective effect against epilepsy susceptibility (OR = 0.50, p-value < 0.001), with the rs762551 (G/A + A/A genotypes) disclosing a substantial association with a decreased risk of epileptic seizures among drug-resistant patients compared to drug-responsive patients (OR = 0.07, p-value < 0.001). Conversely, the ABCB1*rs2032582 (G allele) and the CYP2B6*rs3745274 (T allele) did not attain a significant difference with the epilepsy risk compared to healthy controls (p-value > 0.05).

CONCLUSIONS

The findings of our study emphasize the importance of pharmacogenetic screening in epilepsy research, particularly regarding to drug-resistant patients. The ABCC2*rs717620 variant conferred a significant correlation with elevated risk of epileptic seizures, while the ABCC2*rs2273697 and CYP1A2*rs762551 variants confirmed their contributions as protective markers against epilepsy development. Conversely, the ABCB1*rs2032582 and CYP2B6*rs3745274 alleles were not considered as independent risk factors with the course of epilepsy disease.

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.

Association between Genetic Polymorphism of SCN1A, GABRA1 and ABCB1 and Drug Responsiveness in Vietnamese Epileptic Children

Background and Objectives: Drug resistant epilepsy (DRE) is a major hurdle in epilepsy, which hinders clinical care, patients' management and treatment outcomes. DRE may partially result from genetic variants that alter proteins responsible for drug targets and drug transporters in the brain. We aimed to examine the relationship between SCN1A, GABRA1 and ABCB1 polymorphism and drug response in epilepsy children in Vietnam. Materials and Methods: In total, 213 children diagnosed with epilepsy were recruited in this study (101 were drug responsive and 112 were drug resistant). Sanger sequencing had been performed in order to detect six single nucleotide polymorphisms (SNPs) belonging to SCN1A (rs2298771, rs3812718, rs10188577), GABRA1 (rs2279020) and ABCB1 (rs1128503, rs1045642) in study group. The link between SNPs and drug response status was examined by the Chi-squared test or the Fisher's exact test. Results: Among six investigated SNPs, two SNPs showed significant difference between the responsive and the resistant group. Among those, heterozygous genotype of SCN1A rs2298771 (AG) were at higher frequency in the resistant patients compared with responsive patients, playing as risk factor of refractory epilepsy. Conversely, the heterozygous genotype of SCN1A rs3812718 (CT) was significantly lower in the resistant compared with the responsive group. No significant association was found between the remaining four SNPs and drug response. Conclusions: Our study demonstrated a significant association between the SCN1A genetic polymorphism which increased risk of drug-resistant epilepsy in Vietnamese epileptic children. This important finding further supports the underlying molecular mechanisms of SCN1A genetic variants in the pathogenesis of drug-resistant epilepsy in children.

How to handle a missed or delayed dose of lacosamide in pediatric patients with epilepsy? a mode-informed individual dosing

This study aims to investigate the effects on the pharmacokinetic (PK) of lacosamide (LCM), and to guide the individual dosing regimens for children and ones with poor medication adherence. Population PK research was performed based on 164 plasma samples of 113 pediatric patients aged from 1.75 to 14.42 years old. The PK characteristic of LCM was developed by a one-compartment model with first-order elimination. The typical value of apparent clearance (CL) and apparent volume of distribution (Vd) was 1.91 L·h-1 and 56.53 L respectively. In the final model, the variability of CL was significantly associated with the body surface area (BSA) and elevated uric acid (UA) level. In contrast, the impact of some prevalent anti-seizure medicines, such as valproic acid, levetiracetam, oxcarbazepine, lamotrigine, and perampanel, and gene polymorphisms of Cytochrome P450 (CYP)2C19, ATP-binding cassette (ABC)B1, and ABCC2 had no clinical significance on the PK parameters of LCM. BSA-based dosing regimen of LCM was provided according to Monte Carlo simulation approach; while the dosage should reduce half in patients with an UA level of more than 400 μmol·L-1 comparing with an UA level of 100 μmol·L-1. Individualize remedial doses of about 0.5- to 1.5-fold of regular doses were recommended in six common scenarios of missed or delayed doses, that depended on the delayed time. In current study, the population PK model of LCM in children with epilepsy was developed successfully. The BSA-based dosing regimen and individualized remedial strategy were recommended to guarantee the precise administration of LCM.

Integrative analysis of rs717620 polymorphism in therapeutic response to anti-seizure medications

Background

Previous studies have shown that the rs717620 polymorphism in ABCC2, the gene encoding multidrug resistance protein 2, influences the therapeutic response to anti-seizure medications (ASMs). However, this result is not consistent, and the mechanism by which rs717620 influences ASM responses is unclear.

Aims

The present study evaluated the association between rs717620 genotype and ASM efficacy, and examined the potential mechanisms.

Main

methods: We conducted a literature search of five electronic databases, Embase, Medline, Web of Science, China National Knowledge Infrastructure, and Wanfang, to identify relevant studies on response to ASM therapy among rs717620 genotypes. Expression quantitative trait loci analysis and drug-gene interaction analysis were also performed to assess the underlying mechanisms.

Key findings

The pooled results for 18 studies revealed a significant association between rs717620 genotype and ASM resistance under the recessive model (TT vs. CT + CC: OR = 1.68, 95 % CI = 1.27-2.21, I2 = 3.1 %). A significant association was also found in the Asian population under the recessive model (TT vs. CT + CC: OR = 1.70, 95 % CI = 1.26-2.29, I2 = 29.3 %). Further analysis revealed that rs717620 regulates the expression of ABCC2 in human brain, while drug-gene interaction analysis suggested that ABCC2 interacts with oxcarbazepine and carbamazepine.

Significance

The rs717620 polymorphism influences ASM therapeutic responses by altering brain expression levels of ABCC2.

Polymorphisms Affecting the Response to Novel Antiepileptic Drugs

Epilepsy is one of the most frequent chronic neurologic disorders that affects nearly 1% of the population worldwide, especially in developing countries. Currently, several antiepileptic drugs (AEDs) are available for its therapy, and although the prognosis is good for most patients, 20%-30% amongst them do not reach seizure freedom. Numerous factors may explain AED-resistance such as sex, age, ethnicity, type of seizure, early epilepsy onset, suboptimal dosing, poor drug compliance, alcohol abuse, and in particular, genetic factors. Specifically, the interindividual differences in drug response can be caused by single nucleotide polymorphisms (SNPs) in genes encoding for drug efflux transporters, for the brain targets of AEDs, and for enzymes involved in drug metabolism. In this review, we used the PubMed database to retrieve studies that assessed the influence of SNPs on the pharmacokinetic (PK), pharmacodynamic (PD), and efficacy of new antiepileptic drugs. Our results showed that polymorphisms in the ABCB1, ABCC2, UGT1A4, UGT2B7, UGT2B15, CYP2C9, and CYP2C19 genes have an influence on the PK and efficacy of AEDs, suggesting that a genetic pre-evaluation of epileptic patients could help clinicians in prescribing a personalized treatment to improve the efficacy and the safety of the therapy.

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

BACKGROUND

Lacosamide (LCM) is a newer anti-seizure medication (ASM) that was approved in China in 2018, but its real-world clinical data and plasma concentrations in Chinese children with epilepsy are very limited. Of note, the reference range for routine LCM therapeutic drug monitoring is still unknown. The purpose of this study was to investigate the efficacy and safety of LCM as a monotherapy or an adjunctive treatment with other ASMs and to evaluate the potential factors affecting its efficacy and variable LCM plasma concentrations in Chinese children with epilepsy.

METHODS

Children with epilepsy (<18 years) with routine plasma LCM monitoring from March 2019 to December 2021 at the Department of Pharmacy, Children's Hospital of Nanjing Medical University were retrospectively collected. Clinical data were obtained from the hospital information system.

RESULTS

76 pediatric patients (52 males) were finally enrolled. Mean age was 7.9 years (1.3-17.3 years) with a mean dose of LCM 6.3 mg/kg/day (2.0-11.3 mg/kg/day). The TDM data as a whole showed that the median plasma trough concentration (C ₀) was 3.42 μg/mL (1.25-8.31 μg/mL). A 6-month LCM add-on therapy produced 70% of patients achieving ≥50% seizure frequency reductions, and the number was 81% for the one-year follow-up findings. Interestingly, more patients who took LCM monotherapy achieved seizure freedom over the same periods of follow-up observations. Under maintenance dosages, approximately 92.1% of the C ₀ values were 2.0-7.0 μg/mL. The plasma-C ₀-to-daily dose (C ₀/Dose) ratio was significantly associated with age and body weight (BW). The C ₀/Dose ratio in patients aged 1- ≤ 6 and 6- ≤ 12 years was significantly higher by 81% and 29% than those aged 12- ≤ 18 years, respectively. The C ₀/Dose ratio in patients with a BW of ≥40 kg was 1.7-fold lower than in patients with a BW of ≤ 20 kg. In addition, complex LCM-ASMs interactions were observed. Oxcarbazepine significantly decreased the C ₀/Dose ratio of LCM by 28%.

CONCLUSION

This retrospective study confirmed the effectiveness and tolerability of the LCM treatment used alone or with other ASMs in children with focal epilepsy. Children with higher BW and older age have lower C ₀/Dose ratio. Complex drug interactions between LCM and other concomitant ASMs were revealed. Notably, based on the data in our hands, the reference range, i.e., 2.0-7.0 μg/mL, for routine LCM monitoring may be feasible. The real-world evidence of this study supports LCM as a promising option in children with focal epilepsy.