Biomarkers for antiepileptic drug response

Effect of S-1 on blood levels of phenobarbital and phenytoin: A case report

Drug-drug interaction of fluorinated pyrimidine anticancer agents with phenytoin is well known, but interaction with phenobarbital is limited. We describe a case showing increases in plasma phenobarbital as well as phenytoin concentrations during preoperative S-1 (tegafur/gimeracil/oteracil) and radiation therapy for rectal cancer.

Molecular network-selected pharmacogenomics in a case of bipolar spectrum disorder

Personal genomic analysis was used for molecular diagnosis and pharmacogenomics in a 53-year-old female suffering from alternating depressive and dysphoric episodes. A total of 52 genes and 108 SNPs were analyzed in the whole genome. Results from the pharmacogenomic analysis were consistent with the pharmacological history and indicate mutations associated with low monoaminergic tone, but also a hyperactive 5HT2A receptor, a feature that associates to a high probability of developing a bipolar condition, especially under 5-hydroxytryptamine potentiating pharmacology. This aligns with the patient developing dysphoria with high clomipramine. The pharmacokinetic genomics pointed out to some absorption, distribution, metabolism, and excretion (ADME) alterations that can lower or nullify drug's activity. A personalized regimen was proposed, with a positive outcome after 1 year.

Pharmacotherapy in pediatric epilepsy: from trial and error to rational drug and dose selection - a long way to go

INTRODUCTION

Whereas ongoing efforts in epilepsy research focus on the underlying disease processes, the lack of a physiologically based rationale for drug and dose selection contributes to inadequate treatment response in children. In fact, limited information on the interindividual variation in pharmacokinetics and pharmacodynamics of anti-epileptic drugs (AEDs) in children drive prescription practice, which relies primarily on dose regimens according to a mg/kg basis. Such practice has evolved despite advancements in pediatric pharmacology showing that growth and maturation processes do not correlate linearly with changes in body size.

AREAS COVERED

In this review we aim to provide 1) a comprehensive overview of the sources of variability in the response to AEDs, 2) insight into novel methodologies to characterise such variation and 3) recommendations for treatment personalisation.

EXPERT OPINION

The use of pharmacokinetic-pharmacodynamic principles in clinical practice is hindered by the lack of biomarkers and by practical constraints in the evaluation of polytherapy. The identification of biomarkers and their validation as tools for drug development and therapeutics will require some time. Meanwhile, one should not miss the opportunity to integrate the available pharmacokinetic data with modeling and simulation concepts to prevent further delays in the development of personalised treatments for pediatric patients.

Tag SNPs for HLA-B alleles that are associated with drug response and disease risk in the Chinese Han population

Multiple HLA-B alleles (haplotypes) are associated with drug-induced adverse responses and disease risks but are difficult to be directly genotyped. The goal of this study is to identify single nucleotide polymorphisms (SNPs) that are able to tag HLA-B alleles in the Chinese Han population. Twelve HLA-B alleles that are associated with drug adverse responses and disease risks were identified. They were sequenced initially in 880 Chinese Han subjects where high-density SNPs within the HLA-B gene were available. Performances of these SNPs to tag the HLA-B alleles were assessed primarily by sensitivity and specificity. Two HLA-B alleles can be reliably tagged by SNPs at 100% sensitivity and >95% specificity. For example, HLA-B*15:02 can be tagged by the 'C' allele of rs10484555, and HLA-B*58:01 can be tagged by the 'T' allele of rs9262570. These results were confirmed in 500 additional Chinese Han subjects. If confirmed in independent studies, these tag SNPs could be used as a reliable, simple and cost-effective alternative for genotyping a subset of HLA-B alleles.

Diagnosis and management of childhood epilepsy

Epilepsy is a relatively common neurologic disorder in children that has important implications for development, parents, and society. Making the correct diagnosis starts with an accurate and complete history that consequently leads to a directed diagnostic workup. This article outlines a diagnostic and management approach to pediatric seizures and epilepsy syndromes. Making the correct diagnosis of epilepsy or nonepileptic imitators allows the practitioner to prescribe appropriate therapy. Initial management for typical epileptic syndromes and seizures and potential adverse effects are discussed. Alternative treatment options for pharmacologically resistant patients such as ketogenic diet, vagal nerve stimulation, and surgery are also discussed. While most children favorably respond to antiepileptic medications, early identification of medication failure is important to ensure optimal neurodevelopment.

The search for circulating epilepsy biomarkers

Few would experience greater benefit from the development of biomarkers than those who suffer from epilepsy. Both the timing of individual seizures and the overall course of the disease are highly unpredictable, and the associated morbidity is considerable. Thus, there is an urgent need to develop biomarkers that can predict the progression of epilepsy and treatment response. Doing so may also shed light on the mechanisms of epileptogenesis and pharmacoresistance, which remain elusive despite decades of study. However, recent advances suggest the possible identification of circulating epilepsy biomarkers – accessible in blood, cerebrospinal fluid or urine. In this review, we focus on advances in several areas: neuroimmunology and inflammation; neurological viral infection; exemplary pediatric syndromes; and the genetics of pharmacoresistance, as relevant to epilepsy. These are fertile areas of study with great potential to yield accessible epilepsy biomarkers.

Management of childhood epilepsy

PURPOSE OF REVIEW

This article outlines a diagnostic and management approach to pediatric seizures and epilepsy syndromes, and delineates pharmacologic and nonpharmacologic treatment options.

RECENT FINDINGS

Progress in tracking of seizures, identifying and addressing medication nonadherence, treatment with novel devices, and clinical decision support algorithms will provide additional management options in the future.

SUMMARY

The management of pediatric seizures and epilepsies presents multiple challenges to the clinician because of nonepileptic imitators, evolving classification approaches, clinical presentations, limited clinical trial data for medications, and the toxicities of therapies. While certain pediatric seizures and epilepsy syndromes respond best to certain medications, early identification of pharmacologically resistant patients who may be candidates for epilepsy surgery is important. Alternative treatment options may include ketogenic diet or vagus nerve stimulation.