Proton pump inhibitors: from CYP2C19 pharmacogenetics to precision medicine

Drug-Drug Interactions in Vestibular Diseases, Clinical Problems, and Medico-Legal Implications

Peripheral vestibular disease can be treated with several approaches (e.g., maneuvers, surgery, or medical approach). Comorbidity is common in elderly patients, so polytherapy is used, but it can generate the development of drug-drug interactions (DDIs) that play a role in both adverse drug reactions and reduced adherence. For this reason, they need a complex kind of approach, considering all their individual characteristics. Physicians must be able to prescribe and deprescribe drugs based on a solid knowledge of pharmacokinetics, pharmacodynamics, and clinical indications. Moreover, full information is required to reach a real therapeutic alliance, to improve the safety of care and reduce possible malpractice claims related to drug-drug interactions. In this review, using PubMed, Embase, and Cochrane library, we searched articles published until 30 August 2021, and described both pharmacokinetic and pharmacodynamic DDIs in patients with vestibular disorders, focusing the interest on their clinical implications and on risk management strategies.

Use of Pharmacogenomics to Guide Proton Pump Inhibitor Therapy in Clinical Practice

Prescribing the right medication, at the right dose, to the right patient is the goal of every physician. Pharmacogenomic information is an emerging tool that can be used to deliver precision medicine. In this review, we discuss the pharmacogenomics of available PPIs, racial differences of CYP2C19 and how PPI pharmacogenomics affects the treatment of common gastrointestinal diseases. We also provide practical guidance on when to order pharmacogenomic testing, which test to order, and how to modify treatment based on published guidelines.

Frequency and impact of DHODH, ABCG2 and CYP2C19 SNPs on the therapeutic efficacy, tolerability and toxicity of leflunomide

Introduction: Leflunomide is one of the commonly used drugs in treatment of rheumatoid arthritis (RA), which on administration is converted into its active metabolite teriflunomide. Aim: Our aim is to evaluate the frequencies of dihydrooroate dehydrogenase (DHODH) (rs3213422), ABCG2 (rs2231142) and CYP2C19 (rs4244285) allele distribution among patients receiving leflunomide for RA and their possible impact on leflunomide performance in disease control. Patients & methods: Patients (>18 years) who fulfilled the 2010 ACR classification criteria for RA receiving leflunomide (20 mg/day) were included in the study. Disease activity score 28 was used to assess patients disease activity. Blood samples were collected for full blood count and blood chemistry. Genomic DNA was extracted from peripheral blood. The selection of SNPs was based on the criteria of minor allele frequency among Caucasians. Results: A significant association between the therapeutic outcome of leflunomide and DHODH genotyping was observed but not with CYP2C19 and ABCG2. Importantly, there is a significant association between DHODH (rs3213422) CC genotype and the number of patients with controlled disease. Conclusion: We strongly suggest that polymorphisms in the DHODH are the major factor affecting leflunomide pharmacogenetics and therapeutic efficacy.

Host Genetic Determinants Associated With Helicobacter pylori Eradication Treatment Failure: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Helicobacter pylori infects approximately 50% of individuals worldwide. Successful H pylori eradication is associated with reduced risk of gastric cancer and peptic ulcer disease, among other conditions. We hypothesized that host genetic determinants, especially those affecting gastric pH, might contribute to eradication therapy failure, particularly when treatment adherence and antibiotic susceptibility are confirmed. We aimed to conduct a meta-analysis of host genetic variants associated with H pylori eradication failure.

METHODS

We searched the literature for studies comparing posttreatment H pylori eradication failure vs success (outcome) according to host genetic polymorphisms (exposure). Reference groups were defined according to genotypes (or corresponding phenotypes) hypothesized to be associated with successful eradication. We pooled estimates using a random-effects model and performed comprehensive sensitivity analyses.

RESULTS

We analyzed 57 studies from 11 countries; the vast majority analyzed CYP2C19 polymorphisms. Among individuals prescribed eradication regimens with proton pump inhibitors predominantly CYP2C19 metabolized, enhanced vs poor metabolizer phenotypes were associated with a 2.52-fold significantly higher likelihood of eradication failure and 4.44-fold significantly higher likelihood when treatment adherence and H pylori clarithromycin susceptibility (if relevant) were confirmed. There was no association between CYP2C19 variants and eradication failure if proton pump inhibitors less metabolized by or that bypass CYP2C19 metabolism were used. IL1B polymorphisms that are vs are not associated with less gastric acid suppression were associated with 1.72-fold significantly higher likelihood of eradication failure. There was no association between MDR1 polymorphisms and H pylori eradication failure. The certainty of evidence was moderate.

CONCLUSION

Based on meta-analysis, we identified host genetic polymorphisms significantly associated with H pylori eradication failure; host genetics might underlie eradication failure among treatment-adherent individuals with confirmed H pylori antibiotic susceptibility.

Pediatric Therapeutic Drug Monitoring for Selective Serotonin Reuptake Inhibitors

Therapeutic drug monitoring (TDM) is uncommon in child and adolescent psychiatry, particularly for selective serotonin reuptake inhibitors (SSRIs)—the first-line pharmacologic treatments for depressive and anxiety disorders. However, TDM in children and adolescents offers the opportunity to leverage individual variability of antidepressant pharmacokinetics to shed light on non-response and partial response, understand drug-drug interactions, evaluate adherence, and characterize the impact of genetic and developmental variation in pharmacokinetic genes. This perspective aims to educate clinicians about TDM principles and examines evolving uses of TDM in SSRI-treated youths and their early applications in clinical practice, as well as barriers to TDM in pediatric patients. First, the impact of pharmacokinetic genes on SSRI pharmacokinetics in youths could be used to predict tolerability and response for some SSRIs (e.g., escitalopram). Second, plasma concentrations are significantly influenced by adherence, which may relate to decreased efficacy. Third, pharmacometric analyses reveal interactions with proton pump inhibitors, oral contraceptives, cannabinoids, and SSRIs in youths. Rapid developments in TDM and associated modeling have enhanced the understanding of variation in SSRI pharmacokinetics, although the treatment of anxiety and depressive disorders with SSRIs in youths often remains a trial-and-error process.

Association between migraine prevalence, treatment with proton-pump inhibitors and CYP2C19 phenotypes in UK Biobank

Proton-pump inhibitors (PPIs) are used to suppress gastric acid secretion in several gastrointestinal conditions. While these drugs are generally well tolerated, their long-term use may be associated with different adverse effects, including migraine. We analyzed the association between treatment with PPIs (omeprazole, esomeprazole, lansoprazole, pantoprazole and rabeprazole) and migraine prevalence in the UK Biobank cohort through a cross-sectional analysis (using baseline data for 468,280 participants, 16,390 of whom had migraine) and a longitudinal analysis (including 145,007 participants with no migraine at baseline, of whom 3786 had probable migraine without aura [MWOA] and 9981 probable migraine with aura [MWA] or both MWOA and MWA at an average follow-up time of 10.06 years). We also evaluated the modulating role of the metabolizer phenotype of CYP2C19, the major enzyme involved in PPI clearance. Treatment with PPIs was associated with higher migraine prevalence at baseline (odds ratio [OR] = 1.25, p < 0.0001). CYP2C19 rapid metabolizer phenotype was associated with lower prevalence of migraine exclusively in participants treated with PPIs (OR = 0.89, p = 0.029). In addition, treatment with PPIs was associated with higher incidence of both probable MWOA (OR = 1.24, p = 0.002) and MWA (OR = 1.43, p < 0.0001) at follow-up. Treatment with PPIs and CYP2C19 poor metabolizer status were associated with higher incidence of probable chronic migraine exclusively in men. Our results suggest a significant association between treatment with PPIs and migraine in this large population-based cohort and support a potential relevant role of gender and CYP2C19 phenotype.

Specifically Targeted Transport of Plasma Membrane Transporters: From Potential Mechanisms for Regulating Cell Health or Disease to Applications

Normal substrate transport and signal transmission are the premise to ensure the health of biological somatic cells. Therefore, a comprehensive understanding of the molecular mechanism of intercellular substrate transport is of great significance for clinical treatment. In order to better understand the membrane protein through its interaction with receptors, to help maintain a healthy cell and the molecular mechanisms of disease, in this paper, we seek to clarify, first of all, the recognition mechanism for different types of membrane protein receptors; pathogen invasion using the transport pathway involved in the membrane; and the latest specific target sites of various kinds of membrane transport carriers; to provide an explanation and summary of the system. Secondly, the downstream receptor proteins and specific substrates of different membrane transporters were classified systematically; the functional differences of different subclasses and their relationship with intracellular transport disorders were analyzed to further explore the potential relationship between cell transport disorders and diseases. Finally, the paper summarizes the use of membrane transporter-specific targets for drug design and development from the latest research results; it points out the transporter-related results in disease treatment; the application prospects and the direction for drug development and disease treatment providing a new train of thought; also for disease-specific targeted therapy, it provides a certain reference value.

Inhibition of Aspirin-Induced Gastrointestinal Injury: Systematic Review and Network Meta-Analysis

Background: Administration of aspirin has the potential for significant side effects of gastrointestinal (GI) injury mainly caused by gastric acid stimulation, especially in long-term users or users with original gastrointestinal diseases. The debate on the optimal treatment of aspirin-induced gastrointestinal injury is ongoing. We aimed to compare and rank the different treatments for aspirin-induced gastrointestinal injury based on current evidence.

Methods: We searched PubMed, EMBASE, Cochrane Library (Cochrane Central Register of Controlled Trials), and Chinese databases for published randomized controlled trials (RCTs) of different treatments for aspirin-induced gastrointestinal injury from inception to 1 May 2021. All of the direct and indirect evidence included was rated by network meta-analysis under a Bayesian framework.

Results: A total of 10 RCTs, which comprised 503 participants, were included in the analysis. The overall quality of evidence was rated as moderate to high. Eleven different treatments, including omeprazole, lansoprazole, rabeprazole, famotidine, geranylgeranylacetone, misoprostol, ranitidine bismuth citrate, chili, phosphatidylcholine complex, omeprazole plus rebamipide, and placebo, were evaluated in terms of preventing gastrointestinal injury. It was suggested that omeprazole plus rebamipide outperformed other treatments, whereas geranylgeranylacetone and placebo were among the least treatments.

Conclusion: This is the first systematic review and network meta-analysis of different treatments for aspirin-induced gastrointestinal injury. Our study suggested that omeprazole plus rebamipide might be considered the best option to treat aspirin-induced gastrointestinal injury. More multicenter, high quality, large sample size randomized controlled trials will confirm the advantages of these medicines in the treatment of aspirin-induced gastrointestinal injury in the future.

The effect of CYP2C19 gene polymorphism on the eradication rate of Helicobacter pylori by proton pump inhibitors-containing regimens in Asian populations: a meta-analysis

Premise: The effects of proton pump inhibitors (PPI) depend on metabolic enzyme CYP2C19 that has different activity due to gene polymorphism. The purpose of this meta-analysis is to determine the potential effects of CYP2C19 polymorphism on the efficiency of PPI-based treatment. Materials & methods: The PubMed, EMBASE, Cochrane Library, etc. were searched for relevant articles published in English or Chinese from inception to 31 May 2020. Finally, 26 randomized controlled trials and 15 cohort studies met the inclusion criteria and used for the meta-analysis via STATA version 15. Results: Poor metabolizer (PM) genotype Helicobacter pylori eradication rates were highest for Asian individuals receiving triple or quadruple first-line therapy based on PPIs (p < 0.05). CYP2C19 polymorphism could influence H. pylori eradication rate only in Mainland China and Japan (p < 0.05). Conclusion: PM genotype facilitates the elimination of H. pylori in Asian populations. Rabeprazole-, esomeprazole- and pantoprazole-based eradication program was less affected by the CYP2C19 polymorphism.

The impact of catha edulis (vahl) forssk. ex endl. (celestraceae) (khat) on pharmacokinetics of clinically used drugs

INTRODUCTION

Catha edulis (Vahl) Forssk. ex Endl. (Celestraceae) is used as a recreational drug on daily basis for its euphoric and psychostimulant effects. It is also chewed by individuals who are on medications, raising the possibility of drug-khat interaction. However, limited data are available in the literature, although clinically significant interactions are expected, as khat contains a complex mixture of pharmacologically active constituents.

AREAS COVERED

It provides an overview of the phytochemistry, pharmacokinetics, pharmacodynamics, and pharmacogenetics of khat based on the literature mined from PubMed, Google Scholar, and Cochrane databases. It also presents a detailed account of drug-khat interactions with specific examples and their clinical significance. The interactions mainly occur at the pharmacokinetics level and particular attention is paid for the phases of absorption and cytochrome P450 enzyme-mediated metabolism.

EXPERT OPINION

Despite the increasing trend of khat chewing with medications among the populace and the potential risk for the occurrence of clinically significant interactions, there is paucity of data in the literature demonstrating the magnitude of the risk. The available data, however, clearly demonstrate that the consequence of drug-khat interaction is dependent on genotype. Genotyping, where feasible, could be used to improve clinical outcome and minimize adverse reactions.

Pharmacological Management of Peptic Ulcer: A Century of Expert Opinions in Cecil Textbook of Medicine

BACKGROUND

Advances in drug therapy for peptic ulcer have had a significant impact on quality of life and work potential of many millions of affected persons and have contributed to a remarkable decrease in the prevalence of the disease, frequency and severity of complications, hospitalizations, and mortality.

STUDY QUESTION

What are the milestones of the changes in the expert approach to the pharmacological management of peptic ulcer in the past century?

STUDY DESIGN

To determine the changes in the experts' approach to the management of peptic ulcer, as presented in a widely used textbook in the United States.

DATA SOURCES

The chapters presenting the management of peptic ulcer in the 26 editions of Cecil Textbook of Medicine published from 1927 through 2020.

RESULTS

Acid neutralization with alkalies was the only pharmacological intervention recommended in the textbooks published from 1927 to 1975. Atropine and other antimuscarinic agents were mainly used to relieve pain and acid secretion according to the paradigm "no acid no ulcer." The shift to the acid suppression paradigm started with the introduction of the histamine-2 receptor antagonist cimetidine in 1979, the proton-pump inhibitor omeprazole in 1988, and the prostaglandin agonist misoprostol in 1992. Finally, the eradication of Helicobacter pylori was codified in 1996.

CONCLUSIONS

The pharmacological management of peptic ulcer has remained archaic well into the 20th century. Fundamental progress occurred in a very short period (1979-1996) and was due to paradigm shifts from acid neutralization to acid suppression and later the recognition of the role of H. pylori infection.

Prevalence of five pharmacologically most important CYP2C9 and CYP2C19 allelic variants in the population from the Republic of Srpska in Bosnia and Herzegovina

The enzymes of the cytochrome P450 superfamily play a critical role in phase I drug metabolism. Among them, CYP2C9 and CYP2C19 are clinically important, as they can mediate severe toxicity, therapy failure, and increased susceptibility to cancer and other diseases caused by chemicals. The aim of this study was to determine the prevalence of pharmacologically most important allelic variants of the CYP2C9 and CYP2C19 genes in the general population of the Republic of Srpska (Bosnia and Herzegovina) and to compare them with other populations. For this purpose we determined the genotype profile and allele frequency of 216 randomly selected healthy volunteers using real-time polymerase chain reaction (RT-PCR). The prevalence of the CYP2C9 *2 and *3 alleles was 13.6 and 7.4 %, respectively. Based on these frequencies, of the 216 participants four (1.86 %) were predicted to be poor metabolisers, 78 (36.11 %) intermediate, and the remaining 134 (62.03 %) normal metabolisers. Based on the prevalence of CYP2C19 *2 and *17 variants – 16.2 and 20.4 %, respectively – nine (4.17 %) were predicted to be poor, 57 (26.39 %) rapid, and nine (4.17 %) ultra-rapid metabolisers. We found no significant differences in allele frequencies in our population and populations from other European countries. These findings suggest that genetically determined phenotypes of CYP2C9 and CYP2C19 should be taken into consideration to minimise individual risk and improve benefits of drug therapy in the Republic of Srpska.

CYP2C19 genotype variability in patients with refractory gastroesophageal reflux after per-oral endoscopic myotomy (POEM)

Background and study aims  Symptomatic gastroesophageal reflux is a recognized potential adverse event following peroral endoscopic myotomy (POEM). Proton pump inhibitors (PPIs) are an effective first-line therapy; although their efficacy can be affected by genotype cytochrome P450 2C19 (CYP2C19) variability leading to enhanced clearance of PPIs. The aim of our study was to evaluate the incidence of CYP2C19 genotype variability in POEM patients with refractory gastroesophageal reflux symptoms. Patients and methods  This was a single-center, prospective, cohort study of consecutive POEM cases during a 7-year study period (2013-2020). Reflux symptoms were assessed with the validated gastroesophageal reflux disease questionnaire (GerdQ) and objective pH testing after POEM. CYP2C19 genotype testing was obtained in all patients with refractory gastroesophageal reflux disease (GERD) symptoms, defined as an abnormal pH study and GerdQ score ≥ 8 while on PPIs twice daily. Results  POEM was performed in 325 consecutive patients (48.3 % female; mean age 57 years) during the study period. Twenty patients (6.8 %) had PPI-refractory, post-POEM gastroesophageal reflux based on their GerdQ score (median 9, range 8-11) and abnormal pH studies. CYP2C19 genotype testing identified 55 % (11/20) of these patients as being rapid metabolizers. Out of these, 9 (82 %) had improvement in clinical GERD symptoms after changing to a PPI less affected by CYP2C19 pharmacogenetics. Conclusions  Post-POEM, PPI-refractory GERD is rare. As shown in this study, rapid metabolizers commonly respond by changing to a PPI less affected by CYP2C19 pharmacogenetics, thereby reducing the risk of long-term consequences from GERD and unnecessary anti-reflux surgery.

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2C19 and Proton Pump Inhibitor Dosing

Proton pump inhibitors (PPIs) are widely used for acid suppression in the treatment and prevention of many conditions, including gastroesophageal reflux disease, gastric and duodenal ulcers, erosive esophagitis, Helicobacter pylori infection, and pathological hypersecretory conditions. Most PPIs are metabolized primarily by cytochrome P450 2C19 (CYP2C19) into inactive metabolites, and CYP2C19 genotype has been linked to PPI exposure, efficacy, and adverse effects. We summarize the evidence from the literature and provide therapeutic recommendations for PPI prescribing based on CYP2C19 genotype (updates at www.cpicpgx.org). The potential benefits of using CYP2C19 genotype data to guide PPI therapy include (i) identifying patients with genotypes predictive of lower plasma exposure and prescribing them a higher dose that will increase the likelihood of efficacy, and (ii) identifying patients on chronic therapy with genotypes predictive of higher plasma exposure and prescribing them a decreased dose to minimize the risk of toxicity that is associated with long-term PPI use, particularly at higher plasma concentrations.

Assessment of the Implementation of Pharmacogenomic Testing in a Pediatric Tertiary Care Setting

IMPORTANCE

Pharmacogenomic (PGx) testing provides preemptive pharmacotherapeutic guidance regarding the lack of therapeutic benefit or adverse drug reactions of PGx targeted drugs. Pharmacogenomic information is of particular value among children with complex medical conditions who receive multiple medications and are at higher risk of developing adverse drug reactions.

OBJECTIVES

To assess the implementation outcomes of a PGx testing program comprising both a point-of-care model that examined targeted drugs and a preemptive model informed by whole-genome sequencing that evaluated a broad range of drugs for potential therapy among children in a pediatric tertiary care setting.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study was conducted at The Hospital for Sick Children in Toronto, Ontario, from January 2017 to September 2020. Pharmacogenomic analyses were performed among 172 children who were categorized into 2 groups: a point-of-care cohort and a preemptive cohort. The point-of-care cohort comprised 57 patients referred to the consultation clinic for planned therapy with PGx targeted drugs and/or for adverse drug reactions, including lack of therapeutic benefit, after the receipt of current or past medications. The preemptive cohort comprised 115 patients who received exploratory whole-genome sequencing-guided PGx testing for their heart conditions from the cardiac genome clinic at the Ted Rogers Centre for Heart Research.

EXPOSURES

Patients received PGx analysis of whole-genome sequencing data and/or multiplex genotyping of 6 pharmacogenes (CYP2C19, CYP2C9, CYP2D6, CYP3A5, VKORC1, and TPMT) that have established PGx clinical guidelines.

MAIN OUTCOMES AND MEASURES

The number of patients for whom PGx test results warranted deviation from standard dosing regimens.

RESULTS

A total of 172 children (mean [SD] age, 8.5 [5.6] years; 108 boys [62.8%]) were enrolled in the study. In the point-of-care cohort, a median of 2 target genes (range, 1-5 genes) were investigated per individual, with CYP2C19 being the most frequently examined; genotypes in 21 of 57 children (36.8%) were incompatible with standard treatment regimens. As expected from population allelic frequencies, among the 115 children in the whole-genome sequencing-guided preemptive cohort, 92 children (80.0%) were recommended to receive nonstandard treatment regimens for potential drug therapies based on their 6-gene pharmacogenetic profile.

CONCLUSIONS AND RELEVANCE

In this cohort study, among both the point-of-care and preemptive cohorts, the multiplex PGx testing program provided dosing recommendations that deviated from standard regimens at an overall rate that was similar to the population frequencies of relevant variants.

New Guidance on Cytochrome P450 2C19 Phenotype-based Use of Proton Pump Inhibitors

Since the approval of the first proton pump inhibitor (PPI) in 1989, our knowledge regarding this class of medications has further developed. An increasing amount of data now supports the association between cytochrome P450 2C19 (CYP2C19) phenotype and PPI safety and efficacy. This includes pediatric studies, such as those published here and in other pediatric journals within the past year. Moreover, the most recent pediatric Helicobacter pylori guidelines stated that using the PPIs that are less dependent on CYP2C19 for inactivation may be preferred for H pylori eradication among populations that are more likely to have rapid clearance of CYP2C19-metabolized PPIs. Conversely, pantoprazole package insert recommends a dose reduction in known pediatric CYP2C19 poor metabolizers (PMs), citing a 6-fold increase in serum concentrations compared with normal metabolizers (NMs). The purpose of this communication is to introduce a recently published Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for CYP2C19 and PPI dosing.

Evaluation of CYP2C19 Gene Polymorphisms in Patients with Acid Peptic Disorders Treated with Esomeprazole

Background

CYP2C19 is a highly polymorphic gene that encodes an enzyme with the same name and whose function is associated with the metabolism of many important drugs, such as proton pump inhibitors (such as esomeprazole, which is used for the treatment of acid peptic disease). Genetic variants in CYP2C19 alter protein function and affect drug metabolism. This study aims to genotypically and phenotypically characterize the genetic variants in the CYP2C19 gene in 12 patients with acid peptic disorders and different therapeutic profiles to proton pump inhibitor (PPI) drugs. The patients were randomly selected from a controlled, randomized and blinded clinical pilot trial of 33 patients. We determined the presence and frequency of single nucleotide polymorphisms (SNPs) within exons 1–5 and 9, the intron-exon junctions, and a fragment in the 3ʹ UTR region of the CYP2C19 gene using Sanger sequencing. Undescribed polymorphisms were analyzed by free online bioinformatics tools to evaluate the potential molecular effects of these genetic variants.

Results

We identified nine polymorphisms, six of which had no reported functions. One of these genetic variants, with a functional impact, not yet reported (p.Arg132Trp) was predicted by bioinformatic tools as potentially pathogenic. This finding suggests that p.Arg132Trp could be related to poor metabolizers of drugs metabolized by CYP2C19.

Conclusion

We identified the genotype spectrum of variants in CYP2C19. The genotype spectrum of variants in CYP2C19 could predict the treatment response and could support to evaluate clinical efficacy in patients treated with esomeprazole.

A Novel CYP2C-Haplotype Associated With Ultrarapid Metabolism of Escitalopram

Escitalopram is one of the most commonly used antidepressant drugs but exhibits a substantial interindividual variation in clinical response. A key factor underlying response differences is the polymorphic nature of the CYP2C19 gene encoding the major enzyme responsible for escitalopram metabolism. Although pre-emptive CYP2C19 genotyping may improve escitalopram treatment outcome by dose individualization, much of the interindividual variability cannot be assigned to the currently known CYP2C19 gene variants. The aim of the present study was to search for novel CYP2C-haplotypes for better genetic prediction of escitalopram metabolism. First, the CYP2C18/CYP2C19 locus was sequenced from gDNA obtained from 24 patients previously genotyped as CYP2C19*1/*1 showing consistently low serum concentrations of escitalopram (< 25 nM/10 mg). Three new haplotypes of the CYP2C locus (CYP2C:TG, CYP2C:TA, and CYP2C:CG) were here identified, and their functional roles were evaluated using gDNA from 875 previously genotyped escitalopram-treated patients. The CYP2C:CG and CYP2C:TA haplotypes had no significant impact on escitalopram concentration. Based on the estimated effects of the novel CYP2C-haplotypes on escitalopram exposure, the predicted serum concentrations of escitalopram in homozygous CYP2C:TG and CYP2C19*17 carriers were 24.8% and 17.3% lower compared with the baseline (CYP2C:CG and CYP2C:TA), respectively. In conclusion, a novel CYP2C-haplotype defined by rs2860840T and rs11188059G associated with ultrarapid metabolism of escitalopram was identified. Further studies should clarify the genetic basis for the enhanced escitalopram metabolism and the impact of the CYP2C:TG haplotype on the metabolism of other CYP2C19 substrates like omeprazole, voriconazole, and clopidogrel.

AGA Clinical Practice Update on the Management of Refractory Helicobacter pylori Infection: Expert Review

The purpose of this CPU Expert Review is to provide clinicians with guidance on the management of Helicobacter pylori after an initial attempt at eradication therapy fails, including best practice advice on specific regimen selection, and consideration of patient and systems factors that contribute to treatment efficacy. This Expert Review is not a formal systematic review, but is based upon a review of the literature to provide practical advice. No formal rating of the strength or quality of the evidence was carried out. Accordingly, a combination of available evidence and consensus-based expert opinion were used to develop these best practice advice statements.

The Role of Genetic Polymorphism and Other Factors on Clopidogrel Resistance (CR) in an Asian Population with Coronary Heart Disease (CHD)

Clopidogrel is a widely-used antiplatelet drug. It is important for the treatment and prevention of coronary heart disease. Clopidogrel can effectively reduce platelet activity and therefore reduce stent thrombosis. However, some patients still have ischemic events despite taking the clopidogrel due to the alteration in clopidogrel metabolism attributable to various genetic and non-genetic factors. This review aims to summarise the mechanisms and causes of clopidogrel resistance (CR) and potential strategies to overcome it. This review summarised the possible effects of genetic polymorphism on CR among the Asian population, especially CYP2C19 *2 / *3 / *17, where the prevalence rate among Asians was 23.00%, 4.61%, 15.18%, respectively. The review also studied the effects of other factors and appropriate strategies used to overcome CR. Generally, CR among the Asian population was estimated at 17.2-81.6%. Therefore, our overview provides valuable insight into the causes of RC. In conclusion, understanding the prevalence of drug metabolism-related genetic polymorphism, especially CYP2C19 alleles, will enhance clinical understanding of racial differences in drug reactions, contributing to the development of personalised medicine in Asia.

Potential Utility of Pre-Emptive Germline Pharmacogenetics in Breast Cancer

Patients with breast cancer often receive many drugs to manage the cancer, side effects associated with cancer treatment, and co-morbidities (i.e., polypharmacy). Drug-drug and drug-gene interactions contribute to the risk of adverse events (AEs), which could lead to non-adherence and reduced efficacy. Here we investigated several well-characterized inherited (germline) pharmacogenetic (PGx) targets in 225 patients with breast cancer. All relevant clinical, pharmaceutical, and PGx diplotype data were aggregated into a single unifying informatics platform to enable an exploratory analysis of the cohort and to evaluate pharmacy ordering patterns. Of the drugs recorded, there were 38 for which high levels of evidence for clinical actionability with PGx was available from the US FDA and/or the Clinical Pharmacogenetics Implementation Consortium (CPIC). These data were associated with 10 pharmacogenes: DPYD, CYP2C9, CYP2C19, CYP2D6, CYP3A5, CYP4F2, G6PD, MT-RNR1, SLCO1B1, and VKORC1. All patients were taking at least one of the 38 drugs and had inherited at least one actionable PGx variant that would have informed prescribing decisions if this information had been available pre-emptively. The non-cancer drugs with PGx implications that were common (prescribed to at least one-third of patients) included anti-depressants, anti-infectives, non-steroidal anti-inflammatory drugs, opioids, and proton pump inhibitors. Based on these results, we conclude that pre-emptive PGx testing may benefit patients with breast cancer by informing drug and dose selection to maximize efficacy and minimize AEs.

Contribution of comorbidities to obesity-related asthma in children

Children with obesity are at increased risk for developing asthma that is difficult to control. A complicating factor to asthma management among these children is likely the commonplace co-morbidities that also result from obesity. We discuss three common obesity-related comorbidities which appear to complicate the effective management of asthma, including hypovitaminosis D, obstructive sleep apnea and gastro-esophageal reflux. Each conditions requires more research to understand their effects on asthma management.

Pharmacokinetics and Pharmacodynamics of Esomeprazole/Sodium Bicarbonate Immediate-Release Capsules in Healthy Chinese Volunteers: A Cross-Over, Randomized Controlled Trial

INTRODUCTION

Esomeprazole delayed release tablets (ESO) are one of the most effective treatments for acid-related disorders. The purpose of this study is to compare the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of an immediate-release capsule formulation containing esomeprazole 20 mg and sodium bicarbonate 1100 mg (IR-ESO) compared to those of the esomeprazole delayed release tablet 20 mg (ESO). In addition, the impact of CYP2C19 gene polymorphisms on PK and PD was evaluated.

METHODS

A single-center, open-label, randomized, 2-treatment, 2-sequence, and 2-period crossover study was conducted in 40 healthy Chinese subjects. Subjects received either IR-ESO or ESO for 5 days. After single- and multiple-dosing administration, blood samples were collected for PK analysis, and intragastric pH was assessed by 24-h pH monitoring. The CYP2C19 gene polymorphisms were analyzed by Sanger sequencing.

RESULTS

The geometric mean ratios (90% confidence interval) [GMR (95%CI)] of IR-ESO/ESO for AUC_inf [single dose: 103.60% (96.58%, 111.14%), multiple doses: 101.65% (97.88%, 105.57%)] were within the range of 80.00-125.00%. The AUC_inf showed an increasing trend between CYP2C19 extensive metabolizer (EM), intermediate metabolizer (IM), and poor metabolizer (PM) after single-dose and multiple-dose administration (p < 0.05). The GMR (95%CI) of IR-ESO/ESO for 24-h integrated gastric acidity from baseline [single dose: 101.07% (96.56%, 105.78%), multiple doses: 101.24% (97.74%, 104.86%)] were within the range of 80.00-125.00%. The percentage changes in 24-h integrated gastric acidity from baseline was significant difference between EM, IM, and PM after single-dose IR-ESO and ESO (p < 0.05). Drugs were all well tolerated, and there were no significant differences in adverse events between IR-ESO and ESO.

CONCLUSION

This study showed that IR-ESO can inhibit the secretion of gastric acid rapidly and continuously, and that the PK and PD of IR-ESO are affected by CYP2C19 genotypes. The GMR (95% CI) of IR-ESO/ESO for AUC_inf and the percentage changes in 24-h integrated gastric acidity from baseline were all within the range of 80.00-125.00%.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR1900024935.

Prevalence of CYP2C19 polymorphism in Bogotá, Colombia: The first report of allele *17

INTRODUCTION

Proton pump inhibitors (PPIs) are a group of drugs that are essential for the treatment of acid-related disorders, such as gastroesophageal reflux (GERD), dyspepsia, gastric ulcers and Helicobacter pylori (H. pylori) infection. PPIs such as omeprazole, esomeprazole, pantoprazole and lansoprazole are metabolized by the CYP2C19 enzyme, which is encoded by a polymorphic gene. Four polymorphisms have an impact on the speed of PPI metabolism: CYP2C19*1/*1 (extensive metabolizers), CYP2C19*2/*2 (intermediate metabolizers), CYP2C19*3/*3 (poor metabolizers) and CYP2C19*17/*17 (ultrarapid metabolizers). Extensive and ultrarapid metabolizers inactivate PPIs quickly, which consequently causes low plasma concentrations of PPIs, while intermediate or poor metabolizers have higher plasma concentrations of PPIs and, therefore, PPIs have greater therapeutic efficacy in individuals with these polymorphisms.

OBJECTIVE

To determine the frequency of genetic polymorphisms of the CPY2C19 enzyme in Bogotá, Colombia.

METHODS

This observational study was conducted in Bogotá between 2012 and 2015 and was part of a clinical trial (ID: NCT03650543). It included 239 subjects with dyspepsia, H. pylori infection, or GERD symptoms. CYP2C19 genotyping was performed on gastric biopsy samples. Polymorphisms *1, *2, and *3 were analyzed by real-time PCR (Roche®), and PCR-RFLP was used to determine the presence of polymorphism *17.

RESULTS

The distribution of different types of PPI metabolizers was as follows: extensive (70.7%), ultrarapid (12.9%), intermediate (8.8%) and poor (0.8%).

CONCLUSION

The population studied consisted mainly of extensive and ultrarapid PPI metabolizers. These findings show that it is necessary to increase PPI doses in this group of subjects or to use PPIs that are not metabolized by CYP2C19 (rabeprazole). This is the first Colombian work to identify ultrarapid metabolizers.

Sources of Interindividual Variability

The efficacy, safety, and tolerability of drugs are dependent on numerous factors that influence their disposition. A dose that is efficacious and safe for one individual may result in sub-therapeutic or toxic blood concentrations in others. A significant source of this variability in drug response is drug metabolism, where differences in presystemic and systemic biotransformation efficiency result in variable degrees of systemic exposure (e.g., AUC, C_max, and/or C_min) following administration of a fixed dose.Interindividual differences in drug biotransformation have been studied extensively. It is recognized that both intrinsic factors (e.g., genetics, age, sex, and disease states) and extrinsic factors (e.g., diet , chemical exposures from the environment, and the microbiome) play a significant role. For drug-metabolizing enzymes, genetic variation can result in the complete absence or enhanced expression of a functional enzyme. In addition, upregulation and downregulation of gene expression, in response to an altered cellular environment, can achieve the same range of metabolic function (phenotype), but often in a less predictable and time-dependent manner. Understanding the mechanistic basis for variability in drug disposition and response is essential if we are to move beyond the era of empirical, trial-and-error dose selection and into an age of personalized medicine that will improve outcomes in maintaining health and treating disease.

The Use and Misuse of Proton Pump Inhibitors: An Opportunity for Deprescribing

Proton pump inhibitors (PPIs) are proven medications of choice for gastroesophageal reflux disease (GERD), acid-related disorders, erosive esophagitis, Barrett esophagus, prevention of gastrointestinal bleeding while on nonsteroidal anti-inflammatory drugs, eosinophilic esophagitis, peptic ulcer disease, stress ulcer prophylaxis in critically ill patients, and other indications. Best practice guidelines from several sources on the appropriate indications and duration of PPI therapy have been summarized for easy assimilation. Individualized decision with regard to PPI use is illustrated by case vignettes; best approaches are provided. The significant increase in use of PPIs for ill-defined indications over the years, associated adverse outcomes with long-term use, and consequent increase in health care costs have drawn much attention. Adverse outcomes due to PPI therapy may be categorized as unrelated or related to gastric acid inhibition. Examples of outcomes unrelated to acid inhibition include allergic reactions, acute interstitial nephritis, chronic kidney disease, poor cardiovascular outcomes, dementia, and drug interactions; consequences of acid inhibition include gastrointestinal infections, pneumonia, nutrient deficiencies, fractures, spontaneous bacterial peritonitis, and small intestinal bacterial overgrowth. Provider awareness regarding best practice guidelines on PPI use and imparting pertinent education to patients may be the rational approach to safe and effective PPI therapy. In individuals in whom the drug is not indicated, efforts at deprescribing the PPI may be attempted following discussion with the patient. Approaches include stopping the drug, reducing the dose or using "on-demand" therapy after completing the course of treatment for the specific indication. Barriers to successful deprescribing exist. Follow-up is recommended for recurrence of manifestations; in the event of recurrence, the PPI may need to be re-instituted. PPIs are valuable, irreplaceable drugs in the prevention and treatment of certain disorders for specific durations of time. Evidence nevertheless suggests that excessive and inappropriately prolonged use of PPIs is associated with a broad range of adverse effects. Education of provider and patient, stewardship, and motivation are key to appropriate use of PPIs for the right indications. Key implications for practice are offered.

Investigation of the interaction between proton pump inhibitors and clopidogrel using VerifyNow P2Y12 assay

BACKGROUND

Randomized trials and observation studies have revealed conflicting results regarding the interaction between clopidogrel and proton pump inhibitors (PPIs). The aim of our study was to provide laboratory evidence regarding whether PPIs blunt the antiplatelet reactivity of clopidogrel.

METHODS

We included records of Asian patients who received clopidogrel treatment for cardiovascular or cerebrovascular events and the VerifyNow P2Y12 assay for platelet reactivity monitoring. The responsiveness of antiplatelet effect to clopidogrel was analyzed according to 3 criteria:Results: Patients treated without PPIs did not differ significantly from those concomitantly treated with PPIs in terms of levels of PI (25.7% ± 24.3% vs 23.0 ± 25.3%, P = .4315), PRU (187.3 ± 74.0 vs 197.4 ± 77.3, P = .3373), or responsiveness to antiplatelet (adjusted absolute risk, 3.5%; 95% confidence interval, - 10.7 to 17.7%; P = .6297). Patients treated with lansoprazole, esomeprazole, pantoprazole, and rabeprazole exhibited no significant differences in PRU or PI levels compared with those treated without PPIs. By contrast, patients treated with dexlansoprazole exhibited a significantly decreased level of PI (25.7% ± 24.3% vs 14.0% ± 21.6%, P = .0297) and responsiveness to clopidogrel under the criterion PI > 20% (adjusted absolute risk: 10.5%; 95% confidence interval: 2.6% to 43.6%; P = .0274).

CONCLUSION

No robust interaction between clopidogrel and PPIs was found, but caution should be exercised in the concomitant use of dexlansoprazole and clopidogrel in Asians.

CYP2C19 Loss-of-Function is Associated with Increased Risk of Ischemic Stroke after Transient Ischemic Attack in Intracranial Atherosclerotic Disease

OBJECTIVES

Intracranial atherosclerotic disease (ICAD) is responsible for 8-10% of acute ischemic strokes, and resistance to antiplatelet therapy is prevalent. CYP2C19 gene loss-of-function (up to 45% of patients) causes clopidogrel resistance. For patients with asymptomatic ICAD and ICAD characterized by transient ischemic attack (TIA), this study measures the effect of CYP2C19 loss-of-function on ischemic stroke risk during clopidogrel therapy.

MATERIALS AND METHODS

From a deidentified database of medical records, patients were selected with ICD-9/10 code for ICAD, availability of CYP2C19 genotype, clopidogrel exposure, and established patient care. Dual-antiplatelet therapy patients were included. Patients with prior ischemic stroke, other neurovascular condition, intracranial angioplasty/stenting, or observation time <1 month were excluded. Time-to-event analysis using Cox regression was conducted to model first-time ischemic stroke events based on CYP2C19 loss-of-function allele and adjusted for age, gender, race, length of aspirin, length of concurrent antiplatelet/anticoagulant treatment, diabetes, coagulopathy, hypertension, heart disease, atrial fibrillation, and lipid disorder. Subset analyses were performed for asymptomatic and post-TIA subtypes of ICAD.

RESULTS

A total of 337 patients were included (median age 68, 58% male, 88% Caucasian, 26% CYP2C19 loss-of-function). A total of 161 (47.8%) patients had TIA at time of ICAD diagnosis, while 176 (52.2%) were asymptomatic. First-time ischemic stroke was observed among 20 (12.4%) post-TIA ICAD patients and 17 (9.7%) asymptomatic ICAD patients. Median observation time was 2.82 [IQR 1.13-5.17] years. CYP2C19 loss-of-function allele was associated with ischemic stroke event (HR 2.2, 95% CI 1.1-4.3, p=0.020) after adjustment. Post-TIA ICAD patients had a higher risk of ischemic stroke from CYP2C19 loss-of-function (HR 3.4, 95% CI 1.4-8.2, p=0.006).

CONCLUSIONS

CYP2C19 loss-of-function was associated with 3-fold increased risk of first-time ischemic stroke for ICAD patients treated with clopidogrel after TIA. This effect was not observed for asymptomatic ICAD. CYP2C19-guided antiplatelet selection may improve stroke prevention in ICAD after TIA.

An update on current and advancing pharmacotherapy options for the treatment of H. pylori infection

Introduction: Eradication of Helicobacter pylori (H. pylori) becomes more challenging due to increasing antimicrobial resistance. Consequently, the performance of clarithromycin-containing triple therapies is now declining to unacceptable levels and should be abandoned unless a prior susceptibility test precludes clarithromycin resistance.Areas covered: This review summarizes updated evidence concerning new and advancing pharmacotherapy options for H. pylori eradication.Expert opinion: Due to the declining efficacy of legacy triple therapies, most guidelines recommend bismuth quadruple therapy as the best initial empiric treatment. Concomitant, sequential and hybrid therapies are remarkable bismuth-free quadruple options, provided that dual clarithromycin-metronidazole resistance is low. Levofloxacin-, rifabutin-, furazolidone- and sitafloxacin-containing regimens remain useful, particularly as salvage options. To eradicate H. pylori in line with the rules of antibiotic stewardship, susceptibility-guided treatment appears as the ideal approach. However, the feasibility and cost-effectiveness of universal pre-treatment susceptibility testing warrants further evaluation. Molecular testing methods promise convenient characterization of H. pylori antibiotic susceptibility. High-dose dual therapy (proton-pump-inhibitor plus amoxicillin) and vonoprazan, a more potent acid inhibitor that likely enhances the activity of amoxicillin, are promising alternatives that could decrease misuse of antibiotics. Addition of certain probiotics could somewhat increase the performance of H. pylori eradication regimens, while improving tolerability.

Generalized exfoliative skin rash as an early predictor of supratherapeutic voriconazole trough levels in a leukemic child: A case report

Background and Purpose:

Skin rashes, mostly seen in children and adolescents, are considered among the most common side effects of azole antifungals. Although therapeutic concentrations of voriconazole (VCZ) have been documented for infected skin, there is no evidence specifying whether specific dermatologic side effects could predict high VCZ serum concentration, especially in high-risk leukemic children.

Case report:

Herein, we report a unique skin side effect of VCZ in a 5-year-old boy with T-cell acute lymphoblastic leukemia (ALL) referred to Amir Medical Oncology Center in Shiraz, Iran. The patient experienced erythroderma and macular rashes shortly after VCZ consumption, leading to generalized exfoliative skin rashes. Concurrent to these skin manifestations, VCZ serum concentration reached the supratherapeutic levels despite the recommended VCZ doses. As a result, VCZ was withheld, and the patient was treated with caspofungin. The lesions were resolved gradually within 2 weeks, and the patient successfully completed his treatment course with caspofungin.

Conclusion:

The unique case presented in this study emphasizes the need for a high index of suspicion for VCZ toxicity in any patient with atypical dermatologic manifestations, especially generalized exfoliative skin rashes. Based on this report, VCZ supratherapeutic concentration could be predicted early in the course of treatment. Additional therapeutic dose monitoring should be considered to establish a confirmatory diagnosis. It is required to further investigate the toxic effect of high VCZ concentration on the skin epithelium.

Impact of the CYP2C19*17 Allele on Outcomes in Patients Receiving Genotype-Guided Antiplatelet Therapy After Percutaneous Coronary Intervention

Genotyping for CYP2C19 no function alleles to guide antiplatelet therapy after percutaneous coronary intervention (PCI) improves clinical outcomes. Although results for the increased function CYP2C19*17 allele are also reported, its clinical relevance in this setting remains unclear. A collaboration across nine sites examined antiplatelet therapy prescribing and clinical outcomes in 3,342 patients after implementation of CYP2C19-guided antiplatelet therapy. Risk of major atherothrombotic and bleeding events over 12 months after PCI were compared across cytochrome P450 2C19 isozyme (CYP2C19) metabolizer phenotype and antiplatelet therapy groups by proportional hazards regression. Clopidogrel was prescribed to a similar proportion of CYP2C19 normal (84.5%), rapid (82.9%), and ultrarapid metabolizers (80.6%) (P = 0.360). Clopidogrel-treated normal metabolizers (20.4 events/100 patient-years; adjusted hazard ratio (HR) 1.00, 95% confidence interval (CI), 0.75-1.33, P = 0.993) and clopidogrel-treated rapid or ultrarapid metabolizers (19.1 events/100 patient-years; adjusted HR 0.95, 95% CI, 0.69-1.30, P = 0.734) exhibited no difference in major atherothrombotic events compared with patients treated with prasugrel or ticagrelor (17.6 events/100 patient-years). In contrast, clopidogrel-treated intermediate and poor metabolizers exhibited significantly higher atherothrombotic event risk compared with prasugrel/ticagrelor-treated patients (adjusted HR 1.56, 95% CI, 1.12-2.16, P = 0.008). When comparing clopidogrel-treated rapid or ultrarapid metabolizers to normal metabolizers, no difference in atherothrombotic (adjusted HR 0.97, 95% CI, 0.73-1.29, P = 0.808) or bleeding events (adjusted HR 1.34, 95% CI, 0.83-2.17, P = 0.224) were observed. In a real-world setting of genotype-guided antiplatelet therapy, the CYP2C19*17 allele did not significantly impact post-PCI prescribing decisions or clinical outcomes. These results suggest the CYP2C19 *1/*17 and *17/*17 genotypes have limited clinical utility to guide antiplatelet therapy after PCI.

The prolongation effect of ilaprazole-based standard triple therapy for Helicobacter pylori

BACKGROUND

Helicobacter pylori (HP) infection causes many diseases, such as peptic ulcers, gastritis and gastric cancer, and MALToma. It has been gradually accepted that all HP-infected patients should be treated because HP is regarded as an infection. Therefore, the importance of selecting the optimal treatment regimen has increased. Although the 14-day standard triple therapy (STT) is recommended in the current guidelines, prolonging treatment duration is controversial in real practice because of inconsistent results from previous data and the risk of adverse effects. Additionally, the effect of STT using ilaprazole has not been reported until now. We aimed to compare the eradication rate between 7 and 10 days STT using ilaprazole.

METHODS

A prospective randomized controlled trial was conducted, which was divided into 2 treatment groups: the control group was 7 days of STT, and the test group was 10 days of STT. The eradication regimen was 10 mg ilaprazole, 500 mg clarithromycin, and 1000 mg amoxicillin twice daily. We included patients who were diagnosed with positive results of H pylori examination. We compared the HP eradication rate according to treatment duration, CYP2C19 subtype and endoscopic diagnosis.

RESULTS

We enrolled a total of 254 patients consisting of 127 patients in each treatment arm. The eradication rates of the control and test groups were 65.4% (82/127) and 74.8% (95/127), respectively, in the intention-to-treat analysis (P = .1). In the per-protocol analysis, 70.3% (83/118) and 82.6% (94/115) were eradicated in each group, which was statistically significant (P = .027). The CYP2C19 subtype was examined in 230 patients. The eradication rate was 79.2% (57/72), 75.4% (92/122), and 72.2% (26/36) in each group, which was not significantly different (P = .704).

CONCLUSION

Ten-day STT was more effective than 7-day STT for HP eradication. The eradication rate was not affected by the CYP2C19 genotype.

Design and Early Implementation Successes and Challenges of a Pharmacogenetics Consult Clinic

Pharmacogenetic testing (PGT) is increasingly being used as a tool to guide clinical decisions. This article describes the development of an outpatient, pharmacist-led, pharmacogenetics consult clinic within internal medicine, its workflow, and early results, along with successes and challenges. A pharmacogenetics-trained pharmacist encouraged primary care physicians (PCPs) to refer patients who were experiencing side effects/ineffectiveness from certain antidepressants, opioids, and/or proton pump inhibitors. In clinic, the pharmacist confirmed the need for and ordered CYP2C19 and/or CYP2D6 testing, provided evidence-based pharmacogenetic recommendations to PCPs, and educated PCPs and patients on the results. Operational and clinical metrics were analyzed. In two years, 91 referred patients were seen in clinic (mean age 57, 67% women, 91% European-American). Of patients who received PGT, 77% had at least one CYP2C19 and/or CYP2D6 phenotype that would make conventional prescribing unfavorable. Recommendations suggested that physicians change a medication/dose for 59% of patients; excluding two patients lost to follow-up, 87% of recommendations were accepted. Challenges included PGT reimbursement and referral maintenance. High frequency of actionable results suggests physician education on who to refer was successful and illustrates the potential to reduce trial-and-error prescribing. High recommendation acceptance rate demonstrates the pharmacist's effectiveness in providing genotype-guided recommendations, emphasizing a successful pharmacist-physician collaboration.

How to Transition from Single-Gene Pharmacogenetic Testing to Preemptive Panel-Based Testing: A Tutorial

There have been significant advancements in precision medicine and approaches to medication selection based on pharmacogenetic results. With the availability of direct-to-consumer genetic testing and growing awareness of genetic interindividual variability, patient demand for more precise, individually tailored drug regimens is increasing. The University of Florida (UF) Health Precision Medicine Program (PMP) was established in 2011 to improve integration of genomic data into clinical practice. In the ensuing years, the UF Health PMP has successfully implemented several single-gene tests to optimize the precision of medication prescribing across a variety of clinical settings. Most recently, the UF Health PMP launched a custom-designed pharmacogenetic panel, including pharmacogenes relevant to supportive care medications commonly prescribed to patients undergoing chemotherapy treatment, referred to as "GatorPGx." This tutorial provides guidance and information to institutions on how to transition from the implementation of single-gene pharmacogenetic testing to a preemptive panel-based testing approach. Here, we demonstrate application of the preemptive panel in the setting of an adult solid tumor oncology clinic. Importantly, the information included herein can be applied to other clinical practice settings.

Primary Care Prescription Drug Use and Related Actionable Drug-Gene Interactions in the Danish Population

Pharmacogenetics (PGx) aims to improve drug therapy using the individual patients' genetic make-up. Little is known about the potential impact of PGx on the population level, possibly hindering implementation of PGx in clinical care. Therefore, we investigated how many patients use actionable PGx drugs, have actionable genotypes or phenotypes and which patients could benefit the most of PGx testing. We included PGx recommendations from two international PGx consortia (Clinical Pharmacogenetics Implementation Consortium (CPIC) and Dutch Pharmacogenetics Working Group (DPWG)). Using data from publically accessible sales information drawn from the Danish Register of Medicinal Product Statistics (MEDSTAT), we identified the number of users of actionable prescription PGx drugs among the total Danish population in 2017. We estimated actionable genotypes or phenotypes based on reported frequencies from literature. We identified 49 drug-gene interactions related to 41 unique prescription drugs. The estimated median frequency of actionable genotypes or phenotypes among prescription drug users was 25% (interquartile range 7-26%). Six of 41 drugs were used more than twice as much in women. Actionable PGx drugs were most frequently used by 45-79 year old patients (62%), followed by 25-44 year old patients (18%). Almost half of the actionable PGx drugs (19/41) were psychotropics (i.e., antidepressants, antipsychotics, or psychostimulants). PGx testing can have a substantial impact on the population, as one in four prescription drug users has an actionable genotype or phenotype and could thus benefit from PGx testing. We advocate for prospective panel-based PGx testing at the time of the first PGx drug prescription ("as needed"), with PGx results ready prior to start of the first, and all future, therapies.

Effects of Voriconazole on the Pharmacokinetics of Vonoprazan in Rats

Purpose

The purpose of this study was to examine the effects of voriconazole on the pharmacokinetics of vonoprazan.

Methods

Fifteen Sprague-Dawley rats were randomly divided into three groups: five rats in each group, including control group, single-dose group (a single dose of 30 mg/kg of voriconazole), and multiple-dose group (multiple doses of 30 mg/(kg•day) per dose of voriconazole). Each group of rats was given an oral dose of 10 mg/kg vonoprazan 30 min after the administration of voriconazole or vehicle. After the oral administration of vonoprazan, 50 µL of blood was collected into 1.5-mL heparinized tubes via the caudal vein. The concentration of vonoprazan in plasma was quantified by ultra-performance liquid chromatography/tandem mass spectrometry. Both in vitro effects of voriconazole on vonoprazan and the mechanism of the observed inhibition were studied in rat liver microsomes.

Results

When orally administered, voriconazole increased the area under the plasma concentration-time curve (AUC), prolonged the elimination half-life (t_1/2), and decreased the clearance (CL) of vonoprazan; there was no significant difference between the single-dose and multiple-dose groups. Voriconazole inhibited the metabolism of vonoprazan at an IC50 of 2.93 μM and showed mixed inhibition. The results of the in vivo experiments were consistent with those of the in vitro experiments.

Conclusion

Our findings provide the evidence of drug-drug interactions between voriconazole and vonoprazan that could occur with pre-administration of voriconazole. Thus, clinicians should pay attention to the resulting changes in pharmacokinetic parameters and accordingly, adjust the dose of vonoprazan in clinical settings.

Projected impact of pharmacogenomic testing on medications beyond antiplatelet therapy in percutaneous coronary intervention patients

Aim: CYP2C19 genotyping is used to guide antiplatelet therapy after percutaneous coronary intervention (PCI). This study evaluated the potential impact of CYP2C19 and multigene pharmacogenomics (PGx) testing on medications beyond antiplatelet therapy in a real-world cohort of PCI patients that underwent CYP2C19 testing. Methodology & results: Multiple medications with actionable PGx recommendations, including proton pump inhibitors, antidepressants and opioids, were commonly prescribed. Approximately 50% received a CYP2C19 metabolized medication beyond clopidogrel and 7% met criteria for a CYP2C19 genotype-guided intervention. A simulation analysis projected that 17.5 PGx-guided medication interventions per 100 PCI patients could have been made if multigene PGx results were available. Conclusion: This suggests that CYP2C19 and multigene PGx results could be used to optimize medication prescribing beyond antiplatelet therapy in PCI patients.

Treatment of Refractory Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a common disorder that is treated with lifestyle modification, weight loss, and medications, such as proton pump inhibitors (PPIs). An empiric course of PPI therapy is an effective and cost-effective strategy for the management of GERD. However, in some patients, PPI therapy and lifestyle changes are inadequate to control symptoms. When there is persistence of symptoms despite empiric therapy, patients are labeled as having refractory GERD. This label underestimates the wide differential diagnosis of foregut pathology that can mimic symptoms of GERD. A careful history of symptoms, response to PPI therapy, adherence, compliance, and timing helps elucidate if medication has been helping. When patients are refractory, alternative etiologies of GERD must be considered. Many of these alternatives can be determined on an upper endoscopy or with complementary testing, such as high-resolution esophageal manometry or gastric emptying testing as symptoms dictate. When an alternative cause is not found and index endoscopy is normal, additional testing with either traditional pH or impedance testing can be completed based on prior examination results and response to therapy. Further therapy, including medical, endoscopic, or surgical, can then be targeted at the etiology.

Pharmacogenomics at the center of precision medicine: challenges and perspective in an era of Big Data

Pharmacogenomics (PGx) is one of the core elements of personalized medicine. PGx information reduces the likelihood of adverse drug reactions and optimizes therapeutic efficacy. St Catherine Specialty Hospital in Zagreb/Zabok, Croatia has implemented a personalized patient approach using the RightMed^® Comprehensive PGx panel of 25 pharmacogenes plus Facor V Leiden, Factor II and MTHFR genes, which is interpreted by a special counseling team to offer the best quality of care. With the advent of significant technological advances comes another challenge: how can we harness the data to inform clinically actionable measures and how can we use it to develop better predictive risk models? We propose to apply the principles artificial intelligence to develop a medication optimization platform to prevent, manage and treat different diseases.

Role of Genetic Polymorphisms of Cytochrome P450 2C19 in Pantoprazole Metabolism and Pantoprazole-based Helicobacter pylori Eradication Regimens

BACKGROUND

Cytochrome P450 (CYP450) enzymes play an important role in the metabolism of 70-80% of the currently used medications, including proton pump inhibitors. There are some data analyzing the impact of gene polymorphisms of CYP450 enzymes on most widely used PPIs, such as omeprazole, however, the data on pantoprazole are highly lacking.

OBJECTIVE

To summarize the most recent publications and studies on the role of polymorphisms of the genes encoding CYP450 enzyme 2C19 in the metabolism of pantoprazole and pantoprazole based Helicobacter pylori eradication regimens.

METHODS

We performed a non-systematic search of the available literature on the selected topic.

RESULTS AND CONCLUSION

The data on cytochrome P450 gene polymorphisms and their role in pantoprazole metabolism and pantoprazole based Helicobacter pylori eradication remain conflicting. Individual differences in pantoprazole metabolism might be partly related to genetic polymorphisms of CYP450 enzymes. Most of the studies support the observation that cytochrome 2C19 polymorphisms have an impact on the pharmacokinetics of pantoprazole and its therapeutic effects: poor metabolizers of PPIs are more likely to have a better response to pantoprazole therapy and achieve better H. pylori eradication rates compared to rapid metabolizers. The determination of alleles that are associated with decreased (e.g., *2, *3 alleles) or increased (e.g., *17 allele) cytochrome 2C19 enzyme activity might be used as predictive factors for the potential of acid suppression and the success of Helicobacter pylori eradication. Overall, currently available data do not provide robust evidence, therefore, the application of genetic polymorphisms of cytochrome enzymes in clinical practice still cannot be recommended as routine practice for personalized pantoprazole prescription strategies.

Pharmacokinetic/Pharmacodynamic Evaluation of Dexlansoprazole Infusion Injection Compared with Lansoprazole in Healthy Chinese Adults

BACKGROUND AND OBJECTIVE

This study was performed in healthy Chinese subjects to evaluate the safety and pharmacokinetic/pharmacodynamic characteristics of a novel injection formulation of dexlansoprazole in the context of single and multiple administration, compared with the original lansoprazole injection.

METHODS

Helicobacter pylori-negative healthy volunteers were recruited, and 70 participants were enrolled into five dosing groups (seven males and seven females in each group), including 15 mg once daily (qd), 15 mg every 12 h (q12h), 30 mg qd and 30 mg q12h of dexlansoprazole treatment for 5 days, as well as 30 mg q12h of lansoprazole treatment for 5 days. Blood samples were collected at scheduled time spots postdose on day 1 (first dose) and day 5 (last dose). Twenty-four-hour intragastric pH was continuously monitored on day 0 (baseline) and days 1 and 5. Dexlansoprazole and S-lansoprazole in human plasma were determined by validated chiral liquid chromatography with tandem mass spectrometry, and the pharmacokinetic parameters were determined by a non-compartmental method using Phoenix WinNonlin software. Safety assessment included changes in vital signs and laboratory tests, physical examination findings, and incidence or reports of adverse events.

RESULTS

The half-life (t_½) and clearance (CL) of dexlansoprazole were 1.76-2.06 h and 4.52-5.40 L/h, respectively, while the t_½ and CL of S-lansoprazole were 0.87-1.02 h and 34.66-35.98 L/h, respectively. No drug accumulation after repeated administration was noted. Administration of lansoprazole 30 mg resulted in higher area under the concentration-time curve from time zero to the last measurable concentration (AUC_t) of dexlansoprazole than that of dexlansoprazole 15 mg (p = 0.026). Zero to 24 h after q12h multiple dosing, median and mean intragastric pH, percentage of time with the intragastric pH above 4.0 [TpH ≥ 4.0(%)] and percentage of time with the intragastric pH above 6.0 [TpH ≥ 6.0(%)] in the dexlansoprazole 15 mg q12h group were 6.07 ± 0.61, 5.70 ± 0.76, 83.58 ± 12.34, and 53.70 ± 17.06, respectively, which was similar to the lansoprazole 30 mg q12h group, i.e. 6.15 ± 0.62, 5.88 ± 0.67, 87.26 ± 12.08 and 57.00 ± 16.35, respectively. A weak positive correlation between dexlansoprazole AUC_t and baseline-adjusted TpH ≥ 4.0(%) over 0-24 h was observed, with Pearson correlation coefficients of 0.437 (p = 0.029), while no correlation was observed between AUC_t and baseline-adjusted TpH ≥ 6.0(%) over 0-24 h.

CONCLUSION

Every 12 h intravenous dosing of dexlansoprazole up to 30 mg for 5 days was safe and well-tolerated in healthy Chinese subjects. Every 12 h dosing of dexlansoprazole 15 mg has a comparable effect of gastric acid inhibition as lansoprazole 30 mg q12h.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT03120273.

Changes of gastric ulcer bleeding in the metropolitan area of Japan

BACKGROUND

The two main causes of gastric ulcer bleeding are Helicobacter pylori (H. pylori) infection and ulcerogenic medicines, although the number of cases caused by each may vary with age. In Japan, the rate of H. pylori infection has fallen over the last decade and the number of prescriptions for non-steroidal anti-inflammatory drugs (NSAIDs) and antithrombotic drugs is increasing as the population ages. Methods of treatment for gastric ulcer bleeding have advanced with the advent of hemostatic forceps and potassium-competitive acid blocker (P-CAB). Thus, causes and treatments for gastric ulcer bleeding have changed over the last decade.

AIM

To examine the trends of gastric ulcer bleeding over 10 years in the metropolitan area of Japan.

METHODS

This is a single-center retrospective study. A total of 564 patients were enrolled from inpatients admitted to our hospital with gastric ulcer bleeding between 2006 and 2016. Age, medication history, H. pylori infection, method of treatment, rate of rebleeding, and the length of hospitalization were analyzed. Factors associated with gastric ulcer bleeding were evaluated using Fisher's exact test, Pearson's Chi-squared test or Student's t-test as appropriate. The Jonckheere-Terpstra test was used to evaluate trends. A per-protocol analysis was used to examine the rate of H. pylori infection.

RESULTS

There was a significant increase in the mean age over time (P < 0.01). The rate of H. pylori infection tended to decrease over the study period (P = 0.10), whereas the proportion of patients taking antithrombotic agents or NSAIDs tended to increase (P = 0.07). Over time, the use of NSAIDs and antithrombotic drugs increased with age. By contrast, the rate of H. pylori infection during the study period fell with age. H. pylori-induced ulcers accounted for the majority of cases in younger patients (< 70 years old); however, the rate decreased with age (P < 0.01). The method of treatment trend has changed significantly over time. The main method of endoscopic hemostasis has changed from clipping and injection to forceps coagulation (P < 0.01), and frequently prescribed medicines have changed from proton pump inhibitor to P-CAB (P < 0.01). The rate of rebleeding during the latter half of the study was significantly lower than that in the first half.

CONCLUSION

These trends, gastric ulcers caused by ulcerogenic drugs were increasing with age and H. pylori-induced ulcers were more common in younger patients, were observed.

In search of the grail: A race for acid suppression

Proton pump inhibitors are the reference standards for the treatment of acid-related diseases. Acid suppression in gastroesophageal reflux disease is associated with a high rate of mucosal cicatrization, but symptom response differs among endoscopic phenotypes. Extraesophageal manifestations have a good clinical response in patients that present with abnormal acid exposure (diagnostic test) in the esophagus. Proton pump inhibitors have shown their effectiveness for reducing symptom intensity in nighttime reflux and sleep disorders, improving quality of life and work productivity. That can sometimes be achieved through dose modifications by splitting or increasing the dose, or through galenic formulation. Proton pump inhibitors are not exempt from controversial aspects related to associated adverse events. Technological development is directed at improving proton pump inhibitor performance through increasing the half-life, maximum concentration, and area under the curve of the plasma concentrations through galenic formulation, as well as creating safer and more tolerable drugs. The present review is focused on the mechanisms of action, pharmacokinetic properties, and technological advances for increasing the pharmacologic performance of a proton pump inhibitor.

Personalized therapy for Helicobacter pylori: CYP2C19 genotype effect on first-line triple therapy

BACKGROUND

Triple therapy efficacy against Helicobacter pylori is low worldwide, and thus, alternatives must be sought to improve eradication. The aim of the present study was to determine CYP2C19 genetic polymorphism effect on H pylori eradication.

METHODS

A randomized, single-blinded clinical trial including 133 participants was carried out. H pylori infection was confirmed by histologic and microbiologic test. Antibiotic susceptibility to amoxicillin and clarithromycin was performed. CYP2C19 polymorphisms *1, *2, and *3 were analyzed by real-time PCR (Roche ®), and nested PCR for CYP2C19*17 polymorphisms. Participants were randomized into two groups for different H pylori therapies, one with standard omeprazole doses and another with omeprazole doses depending on CYP2C19 polymorphism. H pylori eradication was verified by stool antigen tests (Meridian ®).

RESULTS

The most common CYP2C19 polymorphism was *1/*1 in 54.9% of the participants followed by *17/*17 in 21.1%. Triple therapy efficacy with standard omeprazole doses versus personalized therapy based on CYP2C19 polymorphism by ITT analysis was 84% (95% CI: 0.73-0.91) vs 92.2% (95% CI: 0.82-0.97) (P = 0. 14), respectively. The efficacy by PP analysis was 92.1% (95% CI: 0.82-0.97) vs 100% (95% CI: 0.92-0.01) (P = 0.027), respectively.

CONCLUSIONS

The most frequent polymorphism was extensive PPI metabolizers (62.4%). Effectiveness of guided therapies by susceptibility test was good, yet they can be further improved by customized therapy based on CYP genotype. Therefore, high PPI (80 mg/d) doses are recommended for H pylori eradication therapies in Colombia. ClinicalTrials.gov ID: NCT03650543.