Association between HLA-DRB1*0405, -DQB1*0401 and -DQA1*0303 alleles and lamotrigine-induced cutaneous adverse drug reactions. A pilot case-control study from Japan

HLA alleles and antiseizure medication-induced cutaneous reactions in Brazil: A case-control study

In this observational case-control study, 107 cutaneous adverse reaction (CAR) cases (CAR+) manifesting up to 12 weeks after the start of treatment with antiseizure medication (ASM) were identified. Control groups consisted of 98 epilepsy patients without a history of CAR (CAR-) and 3965 healthy individuals in the Brazilian National Registry of Bone Marrow Donors. All participants were HLA typed by high-resolution Next Generation Sequencing for HLA-A, B, C, DQB1 and DRB1; HLA-DPA1, DPB1, DQA1, DRB3, DRB4 and DRB5 were also sequenced in samples from CAR+ and CAR- individuals. The relationship between the carrier frequency of each allele, CAR type and ASM for all participants was investigated. The ASMs most frequently associated with CAR were carbamazepine (48% of CAR+ subjects), lamotrigine (23%), phenytoin (18%), phenobarbital (13%) and oxcarbazepine (5%). The main alleles associated with a risk of CAR were HLA-A*02:05 (OR = 6.28; p = 0.019, carbamazepine or oxcarbazepine); HLA-DPA1*02:02 (OR = 4.16, p = 0.003, carbamazepine); HLA-B*53:01 (OR = 47.9, p = 0.014, oxcarbazepine), HLA-DPA1*03:01/DPB1*105:01 (OR = 25.7, p = 0.005, phenobarbital); HLA-C*02:10 (OR = 25.7, p = 0.005, phenobarbital) and HLA-DRB1*04:02 (OR = 17.22, p = 0.007, phenytoin). HLA-A*03:01 increased the risk for phenytoin-induced maculopapular exanthema 4.71-fold (p = 0.009), and HLA-B*35:02 was associated with a 25.6-fold increase in the risk of carbamazepine-induced Stevens-Johnson syndrome (p = 0.005). None of the 4170 subjects carried the HLA-B*15:02 allele, and HLA-A*31:01 was not associated with CAR. Hence, HLA-A*31:01 and HLA-B*15:02 were not associated with CAR in this population. Although other HLA class I and II alleles tested were associated with a risk of CAR, none of these associations were strong enough to warrant HLA testing before prescribing ASM.

Genetics and antiepileptic mood stabilizer treatment response in bipolar disorder: what do we know?

Antiepileptic mood stabilizers (AED-MS) are often used to treat bipolar disorder (BD). Similar to other mood disorder medications, AED-MS treatment response varies between patients. Identification of biomarkers associated with treatment response may ultimately help with the delivery of individualized treatment and lead to improved treatment efficacy. Here, we conducted a narrative review of the current knowledge of the pharmacogenomics of AED-MS (valproic acid, lamotrigine and carbamazepine) treatment response in BD, including genetic contributions to AED-MS pharmacokinetics. Genes involved in neurotransmitter systems and drug transport have been shown to be associated with AED-MS treatment response. As more studies are conducted, and experimental and analytical methods advance, knowledge of AED-MS pharmacogenomics is expected to grow and contribute to precision medicine in BD.

Severe cutaneous adverse reactions in Asians: Trends observed in culprit anti-seizure medicines using VigiBase®

PURPOSE

Diverse ethnic genetic populations display variability in the risk regarding anti-seizure medicine (ASM)-induced severe cutaneous adverse reactions (SCARs). However, clinical and epidemiological data on ASM-induced SCARs in Asians is limited.

METHODS

We conducted a retrospective, post-market study until April 30, 2020 using VigiBase® for demographic characteristics, causative ASMs, complications and mortality. The study included adverse events as classified by Standardized Medical Dictionary for Regulatory Activities (MedDRA) queries of SCARs, mainly Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms (DRESS), and SJS/TEN overlap reported for ASMs.

RESULTS

A total of 694,811 adverse events were reported across the world while using ASMs. Of this, skin and subcutaneous tissue adverse events were 122,885 (17.6%). Among ASM-induced skin and subcutaneous tissue adverse events, SJS, TEN, DRESS and SJS/TEN overlap represented 11,181 (9.1%), 3,645 (3.0%), 5,106 (4.1%) and 6 (0.004%) cases, respectively. Female SJS/TEN/DRESS patients were 54.1%, and 75% of them were adults (>18Y). Nearly 64% of the ASM-induced SCARs were serious and culminated in death (3.5%), life-threatening conditions (11.5%), and hospitalization/prolonged hospitalization (43.5%) of patients on ASM therapy. Carbamazepine (31.6%), phenytoin (29.6%), lamotrigine (24.3%), valproic acid (6.4%) and phenobarbital (5.7%) are the most commonly used ASMs linked with SCARs. ASMs associated with significantly higher risk of SCARs in Asians were carbamazepine [n = 3265, ROR 3.55 (95% CI 3.38-3.72, P < 0.0001)], lamotrigine [n = 1253, ROR 3.90 (95% CI 3.63-4.18, P < 0.0001)], gabapentin [n = 85, ROR 3.58 (95% CI 2.79-4.60, P < 0.0001)], pregabalin [n = 68, ROR 3.16 (95% CI 2.40-4.16, P < 0.0001)], clonazepam [n = 53, ROR 3.19 (95% CI 2.31-4.41, P < 0.0001)], lorazepam [n = 31, ROR 3.07 (95% CI 2.06-4.59, P < 0.0001)] and acetazolamide [n = 28, ROR 3.90 (95% CI 2.45-6.21, P < 0.0001)].

CONCLUSION

Based on our study, carbamazepine, lamotrigine, gabapentin, pregabalin, clonazepam, lorazepam, and acetazolamide are the most common causative ASMs for SCARs in the Asian population.

Therapeutic Drug Monitoring of Antiepileptic Drugs in Epilepsy: A 2018 Update

BACKGROUND

Antiepileptic drugs (AEDs) are the mainstay of epilepsy treatment. Since 1989, 18 new AEDs have been licensed for clinical use and there are now 27 licensed AEDs in total for the treatment of patients with epilepsy. Furthermore, several AEDs are also used for the management of other medical conditions, for example, pain and bipolar disorder. This has led to an increasingly widespread application of therapeutic drug monitoring (TDM) of AEDs, making AEDs among the most common medications for which TDM is performed. The aim of this review is to provide an overview of the indications for AED TDM, to provide key information for each individual AED in terms of the drug's prescribing indications, key pharmacokinetic characteristics, associated drug-drug pharmacokinetic interactions, and the value and the intricacies of TDM for each AED. The concept of the reference range is discussed as well as practical issues such as choice of sample types (total versus free concentrations in blood versus saliva) and sample collection and processing.

METHODS

The present review is based on published articles and searches in PubMed and Google Scholar, last searched in March 2018, in addition to references from relevant articles.

RESULTS

In total, 171 relevant references were identified and used to prepare this review.

CONCLUSIONS

TDM provides a pragmatic approach to epilepsy care, in that bespoke dose adjustments are undertaken based on drug concentrations so as to optimize clinical outcome. For the older first-generation AEDs (carbamazepine, ethosuximide, phenobarbital, phenytoin, primidone, and valproic acid), much data have accumulated in this regard. However, this is occurring increasingly for the new AEDs (brivaracetam, eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, perampanel, piracetam, pregabalin, rufinamide, stiripentol, sulthiame, tiagabine, topiramate, vigabatrin, and zonisamide).

Long-term efficacy and safety of lamotrigine monotherapy in Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures: An open-label extension study

PURPOSE

To investigate the efficacy and safety of long-term lamotrigine (LTG) monotherapy in Japanese and South Korean pediatric patients with newly diagnosed typical absence seizures.

METHODS

Six Japanese patients and one South Korean patient were enrolled in the extension phase of the study after completing the 12-week maintenance phase of an open-label clinical study of LTG monotherapy. During the extension phase, patients underwent efficacy and safety evaluation every 12 weeks.

RESULTS

Of the seven patients, six patients completed the extension phase. The seizure-free rate confirmed by hyperventilation (HV)-electroencephalography ranged from 71.4% to 100.0% at each visit up to Week 168 of the extension phase. Similar effects were confirmed by HV-clinical signs and seizure diaries. Although no unexpected adverse events were observed, one Japanese patient was withdrawn from the extension phase due to mild drug-related rash developed 842 days after the start of LTG.

CONCLUSION

Although the number of patients is limited, long-term LTG monotherapy appeared to be effective and generally well tolerated in Japanese and South Korean pediatric patients with typical absence seizures.

The Medication Risk of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis in Asians: The Major Drug Causality and Comparison With the US FDA Label

Specific ethnic genetic backgrounds are associated with the risk of Stevens-Johnson syndrome / toxic epidermal necrolysis (SJS/TEN) especially in Asians. However, there have been no large cohort, multiple-country epidemiological studies of medication risk related to SJS/TEN in Asian populations. Thus, we analyzed the registration databases from multiple Asian countries who were treated during 1998-2017. A total 1,028 SJS/TEN cases were identified with the algorithm of drug causality for epidermal necrolysis. Furthermore, those medications labeled by the US Food and Drug Administration (FDA) as carrying a risk of SJS/TEN were also compared with the common causes of SJS/TEN in Asian countries. Oxcarbazepine, sulfasalazine, COX-II inhibitors, and strontium ranelate were identified as new potential causes. In addition to sulfa drugs and beta-lactam antibiotics, quinolones were also a common cause. Only one acetaminophen-induced SJS was identified, while several medications (e.g., oseltamivir, terbinafine, isotretinoin, and sorafenib) labeled as carrying a risk of SJS/TEN by the FDA were not found to have caused any of the cases in the Asian countries investigated in this study.

Association of HLA-A and HLA-B Alleles with Lamotrigine-Induced Cutaneous Adverse Drug Reactions in the Thai Population

Background: Lamotrigine (LTG) is commonly used for treatment of epilepsy and bipolar disorder. It is one of the common cause of cutaneous adverse drug reactions (CADR). Clinical symptoms of LTG-induced CADR range from maculopapular exanthema (MPE) to severe cutaneous adverse reactions (SCAR). This study aimed to determine the association of the LTG-induced CADR with human leukocyte antigen (HLA) alleles in Thai patients.

Methods: Fifteen patients with LTG-induced CADR [10 MPE; 4 Stevens–Johnson syndrome; and 1 drug reaction with eosinophilia and systemic symptoms] and 50 LTG-tolerant controls were included in the study. HLA-A and HLA-B genotyping was performed using polymerase chain reaction-sequence-specific oligonucleotides probes.

Results: The proportion of HLA-A^∗02:07 and HLA-B^∗15:02 allele carriers were significantly higher in the LTG-induced CADR group than in the tolerant controls [odds ratio (OR): 7.83; 95% confidence interval (CI): 1.60–38.25; P = 0.013, and OR: 4.89; 95% CI: 1.28–18.67; P = 0.014]. In addition, subjects with HLA-A^∗33:03, HLA-B^∗15:02, and HLA-B^∗44:03 were significantly higher in the LTG-induced MPE group than in the tolerant controls (OR: 8.27; 95% CI: 1.83–37.41; P = 0.005, OR: 7.33; 95% CI: 1.63–33.02; P = 0.005; and OR: 10.29; 95% CI: 1.45–72.81; P = 0.029). In contrast to the LTG-induced MPE group, there were no significant differences between HLA alleles and LTG-induced SCAR group.

Conclusion:HLA-A^∗02:07 and HLA-B^∗15:02 were associated with LTG-induced CADR in Thai patients. We also identified an association between HLA-A^∗33:03, HLA-B^∗15:02, and HLA-B^∗44:03 and LTG-induced MPE in this population. These results suggest that these alleles could be useful screening markers for preventing CADR before LTG treatment in Thai patients, but further replication studies with larger sample sizes are needed.

An update on HLA alleles associated with adverse drug reactions

Adverse drug reactions (ADRs) are considered as an important cause of morbidity and mortality. The hypersensitivity reactions are immune-mediated ADRs, which are dose-independent, unpredictable and have been associated with several HLA alleles. The present review aimed to describe HLA alleles that have been associated with different ADRs in populations worldwide, the recommendations of regulatory agencies and pharmacoeconomic information and databases for the study of HLA alleles in pharmacogenetics. A systematic search was performed in June 2016 of articles relevant to this issue in indexed journals and in scientific databases (PubMed and PharmGKB). The information of 95 association studies found was summarized. Several HLA alleles and haplotypes have been associated with ADRs induced mainly by carbamazepine, allopurinol, abacavir and nevirapine, among other drugs. Years with the highest numbers of publications were 2013 and 2014. The majority of the reports have been performed on Asians and Caucasians, and carbamazepine was the most studied ADR drug inducer. Two HLA alleles' databases are described, as well as the recommendations of the U.S. Food and Drug Administration, the European Medicine Agency and the Clinical Pharmacogenetics Implementation Consortium. Pharmacoeconomic studies on this issue are also mentioned. The strongest associations remain for HLA-B*58:01, HLA-B*57:01, HLA-B*15:02 and HLA-A*31:01 but only in certain populations; therefore, studies on different ethnic groups would be useful. Due to the improvement of drug therapy and the economic benefit that HLA screening represents, investigations on HLA alleles associated with ADR should continue.

Lamotrigine induced DIHS/DRESS: Manifestations, treatment, and outcome in 57 patients

OBJECTIVE

To evaluate the clinical features, course, response to treatment, and outcome of lamotrigine induced drug-induced hypersensitivity syndrome (DIHS) or drug reaction with eosinophilia and systemic symptoms (DRESS).

METHODS

A comprehensive PubMed and Scopus search (covering the period from January 1999 through April 2014) of the English and non-English literature (with English abstract) was conducted to identify published reports of severe cutaneous adverse reactions (SCARs) associated with lamotrigine therapy.

RESULTS

This study population included 57 patients, of whom 38 (66.67%) were female and 19 (33.33%) were male. The latency period varied from 9 days to 120 days, with a mean of 27.58 ± 20.65 days. Multisystem involvement was present in 97.37% (37/38) patients. Systemic corticosteroids were administered to (61.29%) 19/31 patients. 35/38 (92.11%) patients recovered completely, one patient developed liver failure and needed liver transplant, one died from septic shock and one died from multiple organ failure.

CONCLUSIONS

We found a greater predominance of women with LTG-DIHS/DRESS, and 68.42% patients were >18 years of age. The presenting symptoms in most of patients were fever, skin rash, liver involvement, hypereosinophilia, and lymphadenopathy. Lamotrigine is associated to a rather high risk of severe cutaneous adverse reactions and to the risk of dying from such reactions, likes many other anticonvulsants. Early recognition and withdrawal of the suspected agent may avoid irreversible damage to the organs will be life saving.