Cytochrome 2C19*17 allelic variant, platelet aggregation, bleeding events, and stent thrombosis in clopidogrel-treated patients with coronary stent placement

Is CYP2C Haplotype Relevant for Efficacy and Bleeding Risk in Clopidogrel-Treated Patients?

A recently discovered haplotype-CYP2C:TG-determines the ultrarapid metabolism of several CYP2C19 substrates. The platelet inhibitor clopidogrel requires CYP2C19-mediated activation: the risk of ischemic events is increased in patients with a poor (PM) or intermediate (IM) CYP2C19 metabolizer phenotype (vs. normal, NM; rapid, RM; or ultrarapid, UM). We investigated whether the CYP2C:TG haplotype affected efficacy/bleeding risk in clopidogrel-treated patients. Adults (n = 283) treated with clopidogrel over 3-6 months were classified by CYP2C19 phenotype based on the CYP2C19*2*17 genotype, and based on the CYP2C19/CYP2C cluster genotype, and regarding carriage of the CYP2:TG haplotype, and were balanced on a number of covariates across the levels of phenotypes/haplotype carriage. Overall, 45 (15.9%) patients experienced ischemic events, and 49 (17.3%) experienced bleedings. By either classification, the incidence of ischemic events was similarly numerically higher in PM/IM patients (21.6%, 21.8%, respectively) than in mutually similar NM, RM, and UM patients (13.2-14.8%), whereas the incidence of bleeding events was numerically lower (13.1% vs. 16.6-20.5%). The incidence of ischemic events was similar in CYP2C:TG carries and non-carries (14.1% vs. 16.1%), whereas the incidence of bleedings appeared mildly lower in the former (14.9% vs. 20.1%). We observed no signal to suggest a major effect of the CYP2C19/CYP2C cluster genotype or CYP2C:TG haplotype on the clinical efficacy/safety of clopidogrel.

Pharmacogenetic considerations in therapy with novel antiplatelet and anticoagulant agents

Antiplatelets and anticoagulants are extensively used in cardiovascular medicine for the prevention and treatment of thrombosis in the venous and arterial circulations. Wide inter-individual variability has been observed in response to antiplatelets and anticoagulants, which triggered researchers to investigate the genetic basis of this variability. Data from extensive pharmacogenetic studies pointed to strong evidence of association between polymorphisms in candidate genes and the pharmacokinetics and pharmacodynamic action and clinical response of the antiplatelets clopidogrel and the anticoagulant warfarin. In this review, we conducted an extensive search on Medline for the time period of 2009-2023. We also searched the PharmGKB website for levels of evidence of variant-drug combinations and for drug labels and clinical guidelines. We focus on the pharmacogenetics of novel antiplatelets and anticoagulants while excluding acetylsalicylic acid, warfarin and heparins, and discuss the current knowledge with emphasis on the level of evidence.

Pharmacogenomic evaluation of CYP2C19 alleles linking low clopidogrel response and the risk of acute coronary syndrome in Indians

BACKGROUND

Clopidogrel is an antiplatelet drug widely prescribed to prevent atherothrombotic events in coronary artery disease patients. However, there is evidence to suggest that the effectiveness of clopidogrel varies owing to genetic diversity in CYP2C19. This heterogeneity in South Asians, who are also known to have high risk of cardiac events than other population groups, highlights the importance of investigating CYP2C19 variants to estimate the risk proportion in the groups.

METHODS

Given the high prevalence and genetic heterogeneity, the population-based case control was conducted in a cohort of 1191 subjects comprising 645 acute coronary syndrome (ACS) cases (unstable angina, ST-elevation myocardial infarction, and non-ST-elevation myocardial infarction) and 546 healthy controls of South Asian Indian origin. The metabolization status of CYP2C19 was assessed using *2, *3 and *17 variants in the stated cohorts to determine the prevalence of metabolization and its association with phenotypes.

RESULTS

The results suggest a possible genetic association between studied CYP2C19 polymorphisms and ACS, since there was a higher proportion of intermediate and poor metabolizers present in the studied cohorts. The association analyses revealed that the *2 allele of CYP2C19 confers a significant risk for ACS, while the *17 allele provides protection.

CONCLUSIONS

These findings contribute to the understanding of CYP2C19 genetic variants and their impact on clopidogrel response in South Asian Indians. Additionally, they underline the significance of assessing CYP2C19 variations in patients receiving clopidogrel therapy in order to improve therapeutic outcomes.

Genetics in Ischemic Stroke: Current Perspectives and Future Directions

Ischemic stroke is a heterogeneous condition influenced by a combination of genetic and environmental factors. Recent advancements have explored genetics in relation to various aspects of ischemic stroke, including the alteration of individual stroke occurrence risk, modulation of treatment response, and effectiveness of post-stroke functional recovery. This article aims to review the recent findings from genetic studies related to various clinical and molecular aspects of ischemic stroke. The potential clinical applications of these genetic insights in stratifying stroke risk, guiding personalized therapy, and identifying new therapeutic targets are discussed herein.

Impact of Pharmacogenomics in Clinical Practice

Polymorphisms of genes encoding drug metabolizing enzymes and transporters can significantly modify pharmacokinetics, and this can be associated with significant differences in drug efficacy, safety, and tolerability. Moreover, genetic variants of some components of the immune system can explain clinically relevant drug-related adverse events. However, the implementation of drug dose individualization based on pharmacogenomics remains scarce. In this narrative review, the impact of genetic variations on the disposition, safety, and tolerability of the most commonly prescribed drugs is reported. Moreover, reasons for poor implementation of pharmacogenomics in everyday clinical settings are discussed. The literature analysis showed that knowledge of how genetic variations can modify the effectiveness, safety, and tolerability of a drug can lead to the adjustment of usually recommended drug dosages, improve effectiveness, and reduce drug-related adverse events. Despite some efforts to introduce pharmacogenomics in clinical practice, presently very few centers routinely use genetic tests as a guide for drug prescription. The education of health care professionals seems critical to keep pace with the rapidly evolving field of pharmacogenomics. Moreover, multimodal algorithms that incorporate both clinical and genetic factors in drug prescribing could significantly help in this regard. Obviously, further studies which definitively establish which genetic variations play a role in conditioning drug effectiveness and safety are needed. Many problems must be solved, but the advantages for human health fully justify all the efforts.

Pharmacogenomics of Cardiovascular Drugs for Atherothrombotic, Thromboembolic and Atherosclerotic Risk

PURPOSE OF REVIEW

Advances in pharmacogenomics have paved the way for personalized medicine. Cardiovascular diseases still represent the leading cause of mortality in the world. The aim of this review is to summarize the background, rationale, and evidence of pharmacogenomics in cardiovascular medicine, in particular, the use of antiplatelet drugs, anticoagulants, and drugs used for the treatment of dyslipidemia.

RECENT FINDINGS

Randomized clinical trials have supported the role of a genotype-guided approach for antiplatelet therapy in patients with coronary heart disease undergoing percutaneous coronary interventions. Numerous studies demonstrate how the risk of ineffectiveness of new oral anticoagulants and vitamin K anticoagulants is linked to various genetic polymorphisms. Furthermore, there is growing evidence to support the association of some genetic variants and poor adherence to statin therapy, for example, due to the appearance of muscular symptoms. There is evidence for resistance to some drugs for the treatment of dyslipidemia, such as anti-PCSK9.

SUMMARY

Pharmacogenomics has the potential to improve patient care by providing the right drug to the right patient and could guide the identification of new drug therapies for cardiovascular disease. This is very important in cardiovascular diseases, which have high morbidity and mortality. The improvement in therapy could be reflected in the reduction of healthcare costs and patient mortality.

Platelets and the Atherosclerotic Process: An Overview of New Markers of Platelet Activation and Reactivity, and Their Implications in Primary and Secondary Prevention

The key role played by platelets in the atherosclerosis physiopathology, especially in the acute setting, is ascertained: they are the main actors during thrombus formation and, thus, one of the major investigated elements related to atherothrombotic process involving coronary arteries. Platelets have been studied from different points of view, according with the technology advances and the improvement in the hemostasis knowledge achieved in the last years. Morphology and reactivity constitute the first aspects investigated related to platelets with a significant body of evidence published linking a number of their values and markers to coronary artery disease and cardiovascular events. Recently, the impact of genetics on platelet activation has been explored with promising findings as additional instrument for patient risk stratification; however, this deserves further confirmations. Moreover, the interplay between immune system and platelets has been partially elucidated in the last years, providing intriguing elements that will be basic components for future research to better understand platelet regulation and improve cardiovascular outcome of patients.

Pharmacokinetic and Pharmacogenetic Predictors of Major Bleeding Events in Patients with an Acute Coronary Syndrome and Atrial Fibrillation Receiving Combined Antithrombotic Therapy

Objective: This study's objective was to evaluate the effects of pharmacokinetic and pharmacogenetic factors on major bleeding in patients with ACS and non-valvular AF receiving combined antithrombotic therapy consisting of rivaroxaban, clopidogrel, and aspirin as part of dual or triple therapy. Methods: A prospective observational study was conducted in two PCI centers in Moscow, the Russian Federation, from 2017 to 2018. One hundred patients with ACS and AF were enrolled. Prospective follow-ups continued for 12 months. Results: A total of 36 patients experienced bleeding events, with 10 experiencing major bleeding based on the BARC scale and 17 experiencing major bleeding based on the ISTH scale. The following predictors associated with an increased number of major bleeding events were identified: for the ISTH scale, a Css min. of rivaroxaban of >137 pg/mL (5.94 OR, (95% CI, 3.13-12.99; p < 0.004)) and carriage of the T allelic variant polymorphism ABCB1 rs4148738 (8.97 OR (95% CI, 1.48-14.49; p < 0.017)), as well as for the BARC scale (5.76 OR (95% CI, 2.36-9.87; p < 0.018)). Conclusions: Measuring residual steady-state rivaroxaban concentrations and determining the carriage of the T allelic variant polymorphism ABCB1 rs4148738 may be applicable to high-risk patients for subsequent antithrombotic therapy modification.

CYP2C19 Genotype Prevalence and Association With Recurrent Myocardial Infarction in British-South Asians Treated With Clopidogrel

Background

Cytochrome P450 family 2 subfamily C member 19 (CYP2C19) is a hepatic enzyme involved in the metabolism of clopidogrel from a prodrug to its active metabolite. Prior studies of genetic polymorphisms in CYP2C19 and their relationship with clinical efficacy have not included South Asian populations.

Objectives

The objective of this study was to assess prevalence of common CYP2C19 genotype polymorphisms in a British-South Asian population and correlate these with recurrent myocardial infarction risk in participants prescribed clopidogrel.

Methods

The Genes & Health cohort of British Bangladeshi and Pakistani ancestry participants were studied. CYP2C19 diplotypes were assessed using array data. Multivariable logistic regression was used to test for association between genetically inferred CYP2C19 metabolizer status and recurrent myocardial infarction, controlling for known cardiovascular disease risk factors, percutaneous coronary intervention, age, sex, and population stratification.

Results

Genes & Health cohort participants (N = 44,396) have a high prevalence (57%) of intermediate or poor CYP2C19 metabolizers, with at least 1 loss-of-function CYP2C19 allele. The prevalence of poor metabolizers carrying 2 CYP2C19 loss-of-function alleles is 13%, which is higher than that in previously studied European (2.4%) and Central/South Asian populations (8.2%). Sixty-nine percent of the cohort who were diagnosed with an acute myocardial infarction were prescribed clopidogrel. Poor metabolizers were significantly more likely to have a recurrent myocardial infarction (OR: 3.1; P = 0.019).

Conclusions

A pharmacogenomic-driven approach to clopidogrel prescribing has the potential to impact significantly on clinical management and outcomes in individuals of Bangladeshi and Pakistani ancestry.

Post-percutaneous coronary intervention CYP2C19 genotyping in an Irish population: The potential role in identifying clopidogrel therapy-related bleeding risks

AIMS

Dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) remains the standard of care. CYP2C19 genetic polymorphisms cause variable clopidogrel bioactivation. Increased function (CYP2C19*17) allele carriers (rapid metabolizers [RM] or ultrarapid metabolizers [UM]) are clopidogrel hyper-responders, hence are more susceptible to clopidogrel-related bleeding. Since current guidelines recommend against routine genotyping following PCI, data on the clinical utility of CYP2C19*17 genotype guided strategy are sparce. Our study provides real-world data on the 12-month follow-up of CYP2C19 genotyping in patients post-PCI.

METHODS

This is a cohort study within an Irish population receiving 12-month DAPT following PCI. It identifies the prevalence of CYP2C19 polymorphisms within an Irish population and describes the ischaemic and bleeding outcomes after 12 months of DAPT.

RESULTS

A total of 129 patients were included with the following CYP2C19 polymorphism prevalence: 30.2% hyper-responders (26.4% RM [1*/17*], 3.9% UM [17*/17*]) and 28.7% poor-responders (22.5% IM [1*/2*], 3.9% IM [2*/17*], 2.3% PM [2*/2*]). A total of 53 and 76 patients received clopidogrel and ticagrelor, respectively. At 12 months, total bleeding incidence within the clopidogrel group was positively correlated with CYP2C19 activity: IM/PM (0.0%), NM (15.0%) and RM/UM (25.0%). The positive relationship showed a moderate association that was statistically significant: rτ  = 0.28, P = 0.035.

CONCLUSIONS

The prevalence of CYP2C19 polymorphisms in Ireland is 58.9% (30.2% CYP2C19*17, 28.7% CYP2C19*2) with an approximately one in three chance of being a clopidogrel hyper-responder. Positive correlation between bleeding and increasing CYP2C19 activity within the clopidogrel group (n = 53) suggests possible clinical utility of a genotype-guided strategy identifying high bleeding risk with clopidogrel in CYP2C19*17 carriers, but further studies are required.

Implications of Pharmacogenetic Testing for Clopidogrel Therapy in a Tertiary Healthcare Hospital in North India

Background Clopidogrel hyporesponsiveness with decreased antiplatelet activity is prevalent in percutaneous coronary intervention (PCI) patients due to reduced function polymorphism in the CYP2C19 enzyme gene which results in poor conversion of this prodrug to an active metabolite. However, pharmacogenetic testing is not part of routine clinical practice in India. Methodology In this retrospective observational study, we observed the prevalence of loss of function (LOF) gene variants of CYP2C19 (*2, *3) in 60 patients undergoing PCI with complex anatomies in a tertiary healthcare hospital in North India. We do not have follow-up data for a few patients. However, the treatment regimen was recorded, and the occurrence of any clinical event was monitored for the remaining 52 patients for six months. Results The mean age of the patients was 61.76 ± 10.14 years. We found that 52% of patients carried these LOF mutations, of which 37% were intermediate metabolizers, while 15% were poor metabolizers of clopidogrel. However, out of 52 patients for whom follow-up data were available, 22 (42.3%) were intermediate metabolizers, while six (11.54%) showed genotypes associated with poor metabolism of clopidogrel. Clopidogrel (75 mg BD) was the primary replacement drug in place of ticagrelor (90 mg BD) during follow-up after four weeks (based on the clinician's discretion). Conclusions No major ischemic event was reported during the follow-up of these 52 patients. The intermediate metabolizers' LOF in one copy of the CYP2C19 gene seems to overcome genetic deficiency with the clopidogrel 75 mg BD regime, which is comparable to maintenance with ticagrelor 90 mg BD. This study can be extrapolated to a larger cohort to observe statistically significant differences among various groups.

Pharmacogenetics of P2Y12 receptor inhibitors

Oral P2Y12 inhibitors are commonly prescribed for cardiovascular disease and include clopidogrel, prasugrel, and ticagrelor. Each of these drugs has its strengths and weaknesses. Prasugrel and ticagrelor are more potent inhibitors of platelet aggregation and were shown to be superior to clopidogrel in preventing major adverse cardiovascular events after an acute coronary syndrome and percutaneous coronary intervention (PCI) in the absence of genotyping. However, both are associated with an increased risk for non-coronary artery bypass-related bleeding. Clopidogrel is a prodrug requiring bioactivation, primarily via the CYP2C19 enzyme. Approximately 30% of individuals have a CYP2C19 no function allele and decreased or no CYP2C19 enzyme activity. Clopidogrel-treated carriers of a CYP2C19 no function allele have decreased exposure to the clopidogrel active metabolite and lesser inhibition of platelet aggregation, which likely contributed to reduced clopidogrel efficacy in clinical trials. The pharmacogenetic data for clopidogrel are most robust in the setting of PCI, but evidence is accumulating for other indications. Guidance is available from expert consensus groups and regulatory agencies to assist with integrating genetic information into P2Y12 inhibitor prescribing decisions, and CYP2C19 genotype-guided antiplatelet therapy after PCI is one of the most common examples of clinical pharmacogenetic implementation. Herein, we review the evidence for pharmacogenetic associations with clopidogrel response and outcomes with genotype-guided P2Y12 inhibitor selection and describe guidance to assist with pharmacogenetic implementation. We also describe processes for applying genotype data for P2Y12 inhibitor therapy selection and remaining gaps in the field. Ultimately, consideration of both clinical and genetic factors may guide selection of P2Y12 inhibitor therapy that optimally balances the atherothrombotic and bleeding risks.

Pharmacogenomics in Stroke and Cardiovascular Disease: State of the Art

There is considerable interindividual variability in the response to antiplatelet and anticoagulant therapies, and this variation may be attributable to genetic variants. There has been an increased understanding of the genetic architecture of stroke and cardiovascular disease, which has been driven by advancements in genomic technologies and this has raised the possibility of more targeted pharmaceutical treatments. Pharmacogenetics promises to use a patient's genetic profile to treat those who are more likely to benefit from a particular intervention by selecting the best possible therapy. Although there are numerous studies indicating strong evidence for the effect of specific genotypes on the outcomes of vascular drugs, the adoption of pharmacogenetic testing in clinical practice has been slow. This resistance may stem from sometimes conflicting findings among pharmacogenetic studies, a lack of stroke-specific randomized controlled trials to test the effectiveness of genetically-guided therapies, and the practical and cost-effective implementation of genetic testing within the clinic. Thus, this review provides an overview of the genetic variants that influence the individual responses to aspirin, clopidogrel, warfarin and statins and the different methods for pharmacogenetic testing and guidelines for clinical implementation for stroke patients.

Clinical Pharmacogenetics Implementation Consortium Guideline for CYP2C19 Genotype and Clopidogrel Therapy: 2022 Update

CYP2C19 catalyzes the bioactivation of the antiplatelet prodrug clopidogrel, and CYP2C19 genotype impacts clopidogrel active metabolite formation. CYP2C19 intermediate and poor metabolizers who receive clopidogrel experience reduced platelet inhibition and increased risk for major adverse cardiovascular and cerebrovascular events. This guideline is an update to the 2013 Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for the use of clopidogrel based on CYP2C19 genotype and includes expanded indications for CYP2C19 genotype-guided antiplatelet therapy, increased strength of recommendation for CYP2C19 intermediate metabolizers, updated CYP2C19 genotype to phenotype translation, and evidence from an expanded literature review (updates at www.cpicpgx.org).

Integrating pharmacogenomics into clinical trials of hearing disorders

In 2019, the U.S. Food and Drug Administration issued guidance to increase the efficiency of drug development and support precision medicine, including tailoring treatments to those patients who will benefit based on genetic variation even in the absence of a documented mechanism of action. Although multiple advancements have been made in the field of pharmacogenetics (PGx) for other disease conditions, there are no approved PGx guidelines in the treatment of hearing disorders. In studies of noise-induced hearing loss (NIHL), some progress has been made in the last several years associating genomic loci with susceptibility to noise damage. However, the power of such studies is limited as the underlying physiological responses may vary considerably among the patient populations. Here, we have summarized previous animal studies to argue that NIHL subtyping is a promising strategy to increase the granularity of audiological assessments. By coupling this enhanced phenotyping capability with genetic association studies, we suggest that drug efficacy will be better predicted, increasing the likelihood of success in clinical trials when populations are stratified based on genetic variation or designed with multidrug combinations to reach a broader segment of individuals suffering or at risk from NIHL.

Relationship between CYP2C19 Polymorphism and Clopidogrel Resistance in Patients with Coronary Heart Disease and Ischemic Stroke in China

Objective

Clopidogrel is widely used for preventing ischemic complications related to cardiovascular diseases. However, many patients experience clopidogrel resistance (CR). The polymorphisms of CYP2C19 have been implicated in CR, but CYP2C19 polymorphism considerably varies with both ethnic group and geographical location. This study aimed to investigate the association between CYP2C19 polymorphisms and clopidogrel resistance (CR) in patients with coronary heart disease and ischemic stroke among Han and Tibetan populations in Qinghai Province, China.

Methods

From June 2019 to January 2020, patients who were diagnosed with coronary heart disease or cerebral infarction in internal medicine of Qinghai Provincial People's Hospital and had taken dual antiplatelet drugs were included in this study. Blood was collected and routine items were completed. Whole exome sequencing was performed for CYP2C19 genetic polymorphisms of CYP2C19∗2 (rs4244285), CYP2C19∗3 (rs4986893), and CYP2C19∗17 (rs12248560).

Results

A total of 91 patients with coronary heart disease or cerebral infarction (67 Han people (65.99 ± 12.25 years old) and 24 Tibetan (63.6324 Tib years old)) including 52 cases with CR and 39 cases with non-CR were enrolled in this study. For the Han population, the differences in age, glycosylated hemoglobin, activated partial thromboplastin time (APTT), gender, aspirin resistance, and diabetes were significant between the CR and non-CR groups. For the Tibetan population, the two groups showed no significant difference in all indicators. There was no significant difference between CR and non-CR groups for all genotypes (CYP2C19 ∗2, ∗3, and ∗17) in either Han or Tibetan populations. For the Han populations, age, APTT, and aspirin resistance were significantly correlated with CR.

Conclusion

The present study indicated that CYP2C19∗2, CYP2C19∗3, and CYP2C19∗17 alleles were not correlated with CR for both Han and Tibetan populations in Qinghai Province, while age, APTT, and aspirin resistance were independent risk factors of CR in this region.

Evaluation of race and ethnicity disparities in outcome studies of CYP2C19 genotype-guided antiplatelet therapy

Dual antiplatelet therapy with a P2Y₁₂ inhibitor (clopidogrel, prasugrel, or ticagrelor) and aspirin remains the standard of care for all patients undergoing percutaneous coronary intervention (PCI). It is well-established that patients carrying CYP2C19 no function alleles have impaired capacity to convert clopidogrel into its active metabolite and thus, are at higher risk of major adverse cardiovascular events (MACE). The metabolism and clinical effectiveness of prasugrel and ticagrelor are not affected by CYP2C19 genotype, and accumulating evidence from multiple randomized and observational studies demonstrates that CYP2C19 genotype-guided antiplatelet therapy following PCI improves clinical outcomes. However, most antiplatelet pharmacogenomic outcome studies to date have lacked racial and ethnic diversity. In this review, we will (1) summarize current guideline recommendations and clinical outcome evidence related to CYP2C19 genotype-guided antiplatelet therapy, (2) evaluate the presence of potential racial and ethnic disparities in the major outcome studies supporting current genotype-guided antiplatelet therapy recommendations, and (3) identify remaining knowledge gaps and future research directions necessary to advance implementation of this precision medicine strategy for dual antiplatelet therapy in diverse, real-world clinical settings.

CYP2C19 polymorphisms and lipoproteins associated with clopidogrel resistance in children with Kawasaki disease in China: A prospective study

Background

CYP2C19 genetic variation and clinical factors have been proved to be related with clopidogrel resistance (CR) in adults, while the presence of CR in children with Kawasaki disease (KD) was seldom reported. Our objective was to evaluate KD patients’ response to clopidogrel treatment and determine whether CYP2C19 gene polymorphisms and laboratory indicators are associated with CR in this population.

Methods

This was a prospective and single-center study. We recruited children with KD hospitalized in the cardiology department at the Children’s Hospital Capital Institute of Pediatrics between January 2019 and October 2021, and the distribution of the CYP2C19 gene polymorphisms was assessed. According to the light transmission aggregometry (LTA) test results, KD patients who were treated with clopidogrel were divided into CR group and non-CR (NCR) group. We also analyzed the influence of CYP2C19 gene polymorphisms and laboratory indicators on CR in children with KD.

Results

(1) A total of 346 children with KD were evaluated for the genotypic and phenotypic distributions of CYP2C19. Loss-of-function (LOF) mutated allele was included in 56.9% of CYP2C19 genotypes, and their corresponding phenotypes were intermediate metabolizers (46.2%) and poor metabolizers (10.7%). (2) The incidence of CR in this study population was 31.4%. The multivariate logistic regression showed that carrying CYP2C19 LOF allele (OR, 3.922; 95%CI, 1.504–10.282; P = 0.005) and high levels of low-density lipoprotein (OR, 1.675; 95%CI, 1.069–2.623; P = 0.024) were independent risk factor for CR, while low levels of high-density lipoprotein (OR, 0.120; 95%CI, 0.020, 0.734; P = 0.022) was an independent protective factor for CR. The area under the receiver operator characteristic curve of the multivariate logistic regression model (including high-density lipoprotein, low-density lipoprotein, and CYP2C19 LOF allele carriers) for predicting CR was 0.769 (95% CI, 0.674–0.863; P < 0.001). The sensitivity and specificity were 70.3 and 74.0%, respectively.

Conclusion

Carrying CYP2C19 LOF allele, low levels of high-density lipoprotein, and high levels of low-density lipoprotein were independent risk factors for CR in children with KD in China. This may benefit pediatricians in choosing appropriate individualized antiplatelet therapy.

Effect of CYP2C19 genetic variants on bleeding and major adverse cardiovascular events in a cohort of Arab patients undergoing percutaneous coronary intervention and stent implantation

INTRODUCTION

One-third of patients have clopidogrel resistance that may lead to major adverse cardiac events (MACEs). By contrast, it was found that some clopidogrel-treated patients have hyperresponsive platelets that are associated with higher bleeding risk. Several studies have shown that polymorphisms in the gene encoding the CYP2C19 contribute to the variability in response to clopidogrel. Data on genetic and nongenetic factors affecting clopidogrel response in the Arab population are scarce. In this prospective cohort study, we sought to assess the association between the increased function allele (CYP2C19*17) and bleeding events, and validate the effect of the CYP2C19 genetic variants and nongenetic factors on the incidence of MACEs.

METHODS

Blood samples were collected from patients that were undergoing percutaneous coronary intervention and receiving clopidogrel at the Heart Hospital, a specialist tertiary hospital in Doha, Qatar. Patients were followed for 12 months. Genotyping was performed for CYP2C19*2, *3, and *17 using TaqMan assays.

RESULTS

In 254 patients, the minor allele frequencies were 0.13, 0.004, and 0.21 for *2, *3, and *17, respectively. Over a 12-month follow-up period, there were 21 bleeding events (8.5 events/100 patient-year). CYP2C19*17 carriers were found to be associated with increased risk of bleeding (OR, 21.6; 95% CI, 4.8-96.8; P < 0.0001). CYP2C19*2 or *3 carriers were found to be associated with increased risk of baseline and incident MACE combined (OR, 8.4; 95% CI, 3.2-23.9; P < 0.0001).

CONCLUSION

This study showed a significant association between CYP2C19*17 allele and the increased risk of bleeding, and CYP2C19*2 or *3 with MACE outcomes.

Quantitative Proteomics in Translational Absorption, Distribution, Metabolism, and Excretion and Precision Medicine

A reliable translation of in vitro and preclinical data on drug absorption, distribution, metabolism, and excretion (ADME) to humans is important for safe and effective drug development. Precision medicine that is expected to provide the right clinical dose for the right patient at the right time requires a comprehensive understanding of population factors affecting drug disposition and response. Characterization of drug-metabolizing enzymes and transporters for the protein abundance and their interindividual as well as differential tissue and cross-species variabilities is important for translational ADME and precision medicine. This review first provides a brief overview of quantitative proteomics principles including liquid chromatography-tandem mass spectrometry tools, data acquisition approaches, proteomics sample preparation techniques, and quality controls for ensuring rigor and reproducibility in protein quantification data. Then, potential applications of quantitative proteomics in the translation of in vitro and preclinical data as well as prediction of interindividual variability are discussed in detail with tabulated examples. The applications of quantitative proteomics data in physiologically based pharmacokinetic modeling for ADME prediction are discussed with representative case examples. Finally, various considerations for reliable quantitative proteomics analysis for translational ADME and precision medicine and the future directions are discussed. SIGNIFICANCE STATEMENT: Quantitative proteomics analysis of drug-metabolizing enzymes and transporters in humans and preclinical species provides key physiological information that assists in the translation of in vitro and preclinical data to humans. This review provides the principles and applications of quantitative proteomics in characterizing in vitro, ex vivo, and preclinical models for translational research and interindividual variability prediction. Integration of these data into physiologically based pharmacokinetic modeling is proving to be critical for safe, effective, timely, and cost-effective drug development.

Population genetic polymorphisms of pharmacogenes in Zimbabwe, a potential guide for the safe and efficacious use of medicines in people of African ancestry

OBJECTIVE

Pharmacogenomics (PGx) is a clinically significant factor in the safe and efficacious use of medicines. While PGx knowledge is abundant for other populations, there are scarce PGx data on African populations and is little knowledge on drug-gene interactions for medicines used to treat diseases common in Africa. The aim of this study was to use a custom-designed open array to genotype clinically actionable variants in a Zimbabwean population. This study also identified some of the commonly used drugs in Zimbabwe and the associated genes involved in their metabolism.

METHODS

A custom-designed open array that covers 120 genetic variants was used to genotype 522 black Zimbabwean healthy volunteers using TaqMan-based single nucleotide polymorphism genotyping. Data were also accessed from Essential Drugs' List in Zimbabwe (EDLIZ), and the medicines were grouped into the associated biomarker groups based on their metabolism. We also estimated the national drug procurement levels for medicines that could benefit from PGx-guided use based on the data obtained from the national authorities in Zimbabwe.

RESULTS

The results demonstrate the applicability of an open-array chip in simultaneously determining multiple genetic variants in an individual, thus significantly reducing cost and time to generate PGx data. There were significantly high frequencies of African-specific variants, such as the CYP2D6*17 and *29 variants and the CYP2B6*18 variant. The data obtained showed that the Zimbabwean population exhibits PGx variations in genes important for the safe and efficacious use of drugs approved by the EDLIZ and are procured at significantly large amounts annually. The study has established a cohort of genotyped healthy volunteers that can be accessed and used in the conduct of clinical pharmacogenetic studies for drugs entering a market of people of predominantly African ancestry.

CONCLUSION

Our study demonstrated the potential benefit of integrating PGx in Zimbabwe for the safe and efficacious use of drugs that are commonly used.

Clinical non-effectiveness of clopidogrel use for peripheral artery disease in patients with CYP2C19 polymorphisms: a systematic review

PURPOSE

To conduct a systematic review to identify studies that assessed the association between CYP2C19 polymorphisms and clinical outcomes in peripheral artery disease (PAD) patients who took clopidogrel.

METHODS

We systematically searched Ovid EMBASE, PubMed, and Web of Science from November 1997 (inception) to September 2020. We included observational studies evaluating how CYP2C19 polymorphism is associated with clopidogrel's effectiveness and safety among patients with PAD. We extracted relevant information details from eligible studies (e.g., study type, patient population, study outcomes). We used the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) Tool to assess the risk of bias for included observational studies.

RESULTS

The outcomes of interest were the effectiveness and safety of clopidogrel. The effectiveness outcomes included clinical ineffectiveness (e.g., restenosis). The safety outcomes included bleeding and death related to the use of clopidogrel. We identified four observational studies with a sample size ranging from 50 to 278. Outcomes and comparison groups of the studies varied. Three studies (75%) had an overall low risk of bias. All included studies demonstrated that carrying CYP2C19 loss of function (LOF) alleles was significantly associated with reduced clinical effectiveness and safety of clopidogrel.

CONCLUSIONS

Our systematic review showed an association between CYP2C19 LOF alleles and reduced functions of clopidogrel. The use of CYP2C19 testing in PAD patients prescribed clopidogrel may help improve the clinical outcomes. However, based on the limited evidence, there is a need for randomized clinical trials in PAD patients to test both the effectiveness and safety outcomes of clopidogrel.

De-escalation from Prasugrel or Ticagrelor to Clopidogrel in Patients with Acute Coronary Syndrome Managed with Percutaneous Coronary Intervention: An Updated Meta-analysis of Randomized Clinical Trials

INTRODUCTION

We aimed to evaluate the clinical benefits of a de-escalation strategy from prasugrel or ticagrelor to clopidogrel versus continuation of prasugrel or ticagrelor along with aspirin in both strategies for patients presenting with acute coronary syndrome (ACS) and treated with percutaneous coronary intervention (PCI), and to analyze the effect of the recently published randomized clinical trial (RCT) by Park et al., which included the largest sample size ever and the largest switched number of patients, on current guidelines and practices.

DATA SOURCES

The PubMed, EMBASE, Scopus, Web of Science, Cochrane Central, and Google Scholar databases were searched systematically from inception to May 2021 by using the search terms ('de-escalation' OR 'switching') AND ('antiplatelet' OR 'clopidogrel' OR 'ticagrelor' OR 'prasugrel') AND ('percutaneous coronary intervention' OR 'PCI'' OR 'Acute coronary syndrome' OR 'ACS').

STUDY SELECTION AND DATA EXTRACTION

We included RCTs that reported the primary outcomes, i.e. net clinical benefits and Bleeding Academic Research Consortium (BARC) type 2 or higher bleeding. A combination of both ischemic and bleeding events was defined as a net clinical benefit.

DATA SYNTHESIS

A total of four RCTs were included, with 5952 patients. A random-effects meta-analysis revealed that a de-escalation strategy was associated with lower ischemic and bleeding events (net clinical benefits; risk ratio [RR] 0.63, 95% confidence interval [CI] 0.47-0.85; p = 0.003), and lower BARC type 2 or higher bleeding (RR 0.51, 95% CI 0.29-0.91; p = 0.02) when compared with a continuation strategy.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

The current guidelines recommend potent P2Y12 prasugrel or ticagrelor for 12 months despite their association with a high risk of bleeding. Our meta-analysis updates cardiologists, providing them with the best available evidence in managing patients with ACS who underwent PCI.

CONCLUSION

Among patients with ACS treated with PCI, a de-escalation strategy (prasugrel or ticagrelor to clopidogrel) is associated with lower ischemic and bleeding events (net clinical benefits) and lower BARC type 2 or higher bleeding; however, due to the limited number of included studies, further high-quality studies are needed to establish the clinical efficacy of the de-escalation strategy.

Risk factors for adverse drug reactions associated with clopidogrel therapy

This study aimed to investigate the possible influence of genetic and non-genetic factors on the incidence of clopidogrel adverse drug reactions (ADRs) in cardiology patients, including the most important CYP2C19 alleles, namely *2 and *17, as well as compliance, dose, drug interactions, and clinical factors. A total of 102 clopidogrel-treated adult Caucasian patients hospitalized at the Cardiology Department of the Clinical Center of Montenegro were enrolled in the study. Data on clinical outcomes of interest were obtained by intensive monitoring ADRs during hospitalization and one year after hospital discharge. Genotyping for CYP2C19*2 and *17 was conducted using the real-time polymerase chain reaction method. ADRs were characterized using the Rawlins and Thompson classification and the World Health Organization criteria. Causality was assessed using the Naranjo probability scale. ADRs to clopidogrel were observed in 9 of 102 patients (8.8%). The observed frequencies of CYP2C19*2 and *17 were 13.2 and 25.5%, respectively. Our study, which is the first to report the frequency of CYP2C19 polymorphism in the Montenegrin population, as well as to link the pharmacovigilance of clopidogrel with CYP2C19 gene variability, shows that the incidence of ADRs of clopidogrel in cardiac patients is high and depends on CYP2C19 polymorphisms, comedication/drug interactions, and gastrointestinal comorbidity.

Genotype-Guided Use of P2Y12 Inhibitors: A Review of Current State of the Art

The pharmacodynamics of the purinergic receptor type Y, subtype 12 (P2Y12) inhibitors has evolved. Our understanding of the metabolism of P2Y12 inhibitors has revealed polymorphisms that impact drug metabolism and antiplatelet efficacy, leading to genetic testing guided therapy. In addition, assays of platelet function and biochemistry have provided insight into our understanding of the efficacy of "antiplatelet" therapy, identifying patients with high or low platelet reactivity on P2Y12 therapy. Despite the data, the implementation of these testing modalities has not gained mainstream adoption across hospital systems. Given differences in potency between the three clinically available P2Y12 inhibitors, the balance between thrombotic and bleeding complications must be carefully considered, especially for the large proportion of patients at higher risk for bleeding. Here we review the current data for genetic and functional testing, risk assessment strategies, and guidelines for P2Y12 inhibitors guided therapy.

Antiplatelet Therapy for Atherothrombotic Disease in 2022—From Population to Patient-Centered Approaches

Antiplatelet agents, with aspirin and P2Y₁₂ receptor antagonists as major key molecules, are currently the cornerstone of pharmacological treatment of atherothrombotic events including a variety of cardio- and cerebro-vascular as well as peripheral artery diseases. Over the last decades, significant changes have been made to antiplatelet therapeutic and prophylactic strategies. The shift from a population-based approach to patient-centered precision medicine requires greater awareness of individual risks and benefits associated with the different antiplatelet strategies, so that the right patient gets the right therapy at the right time. In this review, we present the currently available antiplatelet agents, outline different management strategies, particularly in case of bleeding or in perioperative setting, and develop the concept of high on-treatment platelet reactivity and the steps toward person-centered precision medicine aiming to optimize patient care.

Warfarin Pharmacogenomics for Precision Medicine in Real-Life Clinical Practice in Southern Africa: Harnessing 73 Variants in 29 Pharmacogenes

Pharmacogenomics is universally relevant for worldwide modern therapeutics and yet needs further development in resource-limited countries. While there is an abundance of genetic association studies in controlled medical settings, there is a paucity of studies with a naturalistic design in real-life clinical practice in patients with comorbidities and under multiple drug treatment regimens. African patients are often burdened with communicable and noncommunicable comorbidities, yet the application of pharmacogenomics in African clinical settings remains limited. Using warfarin as a model, this study aims at minimizing gaps in precision/personalized medicine research in African clinical practice. We present, therefore, pharmacogenomic profiles of a cohort of 503 black Africans (n = 252) and Mixed Ancestry (n = 251) patients from Southern Africa, on warfarin and co-prescribed drugs in a naturalized noncontrolled environment. Seventy-three (n = 73) single nucleotide polymorphisms (SNPs) in 29 pharmacogenes were characterized using a combination of allelic discrimination, Sanger sequencing, restriction fragment length polymorphism, and Sequenom Mass Array. The common comorbidities were hypertension (43-46%), heart failure (39-45%), diabetes mellitus (18%), arrhythmia (25%), and HIV infection (15%). Accordingly, the most common co-prescribed drugs were antihypertensives, antiarrhythmic drugs, antidiabetics, and antiretroviral therapy. We observed marked variation in major pharmacogenes both at interethnic levels and within African subpopulations. The Mixed Ancestry group presented a profile of genetic variants reflecting their European, Asian, and African admixture. Precision medicine requires that African populations begin to capture their own pharmacogenetic SNPs as they cannot always infer with absolute certainty from Asian and European populations. In the current historical moment of the COVID-19 pandemic, we also underscore that the spectrum of drugs interacting with warfarin will likely increase, given the systemic and cardiovascular effects of COVID-19, and the anticipated influx of COVID-19 medicines in the near future. This observational clinical pharmacogenomics study of warfarin, together with past precision medicine research, collectively, lends strong support for incorporation of pharmacogenetic profiling in clinical settings in African patients for effective and safe administration of therapeutics.

Personalizing treatments for patients based on cardiovascular phenotyping

Introduction

Cardiovascular disease persists as the leading cause of death worldwide despite continued advances in diagnostics and therapeutics. Our current approach to patients with cardiovascular disease is rooted in reductionism, which presupposes that all patients share a similar phenotype and will respond the same to therapy; however, this is unlikely as cardiovascular diseases exhibit complex heterogeneous phenotypes.

Areas covered

With the advent of high-throughput platforms for omics testing, phenotyping cardiovascular diseases has advanced to incorporate large-scale molecular data with classical history, physical examination, and laboratory results. Findings from genomics, proteomics, and metabolomics profiling have been used to define more precise cardiovascular phenotypes and predict adverse outcomes in population-based and disease-specific patient cohorts. These molecular data have also been utilized to inform drug efficacy based on a patient's unique phenotype.

Expert opinion

Multiscale phenotyping of cardiovascular disease has revealed diversity among patients that can be used to personalize pharmacotherapies and predict outcomes. Nonetheless, precision phenotyping for cardiovascular disease remains a nascent field that has not yet translated into widespread clinical practice despite its many potential advantages for patient care. Future endeavors that demonstrate improved pharmacotherapeutic responses and associated reduction in adverse events will facilitate mainstream adoption of precision cardiovascular phenotyping.

CYP2C19 polymorphisms are associated with severity of depression at initial evaluation and after the treatment independently of the prescribed medications: 4 weeks prospective study

BACKGROUND

The cytochrome P-450 2C19 (CYP2C19) enzyme is involved in the metabolism of numerous antidepressants. It also metabolises some endogenous substrates, which could also confer to vulnerability. We aimed to establish whether the severity of depression and treatment response are associated with the genetically predicted CYP2C19 phenotype.

METHODS

We assessed the CYP2C19 genotype-predicted metabolic phenotypes (normal, intermediate or ultrarapid, there were no poor metabolisers) in patients with moderate or severe depression. We used the self-rated Beck Depression Inventory-II (BDI-II) scale and the clinician-rated Montgomery-Åsberg Depression Rating Scale (MADRS) at baseline, after 2 and 4 weeks of an empirical treatment trial. Patients and clinicians were blind to the genetic testing results.

RESULTS

Seventy-six patients participated in the present study. At baseline, impaired CYP2C19 metabolisers, compared to normal metabolisers, had higher BDI-II (P = 0.046; ηp2 = 0.08) but not MADRS score. Intermediate metabolisers more often had a diagnosis of severe depression than normal metabolisers (P = 0.003). After 4 weeks of empirical treatment, intermediate metabolisers had significantly higher MADRS and BDI-II scores than normal metabolisers (P = 0.006; ηp2  = 0.131 and P = 0.030; ηp2 = 0.091). These differences were independent of the use of CYP2C19-metabolised medications in the treatment trial, as well as the treatment discrepancy status.

CONCLUSIONS

Intermediate CYP2C19 polymorphism-predicted activity was associated with more severe depression after an empirical treatment trial. The lack of association between the prescription of CYP2C19-metabolised drugs and treatment response calls for a further look into the role of endogenous substrates of CYP2C19.

Differential Impact of Cytochrome 2C19 Allelic Variants on Three Different Platelet Function Tests in Clopidogrel-Treated Patients

On-treatment platelet reactivity in clopidogrel-treated patients can be measured with several platelet function tests (PFTs). However, the agreement between different PFTs is only slight to moderate. Polymorphisms of the CYP2C19 gene have an impact on the metabolization of clopidogrel and, thereby, have an impact on on-treatment platelet reactivity. The aim of the current study is to evaluate the differential effects of the CYP2C19 genotype on three different PFTs. Methods: From a prospective cohort study, we included patients treated with clopidogrel following percutaneous coronary intervention (PCI). One month after PCI, we simultaneously performed three different PFTs; light transmission aggregometry (LTA), VerifyNow P2Y12, and Multiplate. In whole EDTA blood, genotyping of the CYP2C19 polymorphisms was performed. Results: We included 308 patients treated with clopidogrel in combination with aspirin (69.5%) and/or anticoagulants (33.8%) and, based on CYP2C19 genotyping, classified them as either extensive (36.4%), rapid (34.7%), intermediate (26.0%), or poor metabolizers (2.9%). On-treatment platelet reactivity as measured by LTA and VerifyNow is significantly affected by CYP2C19 metabolizer status (p < 0.01); as metabolizer status changes from rapid, via extensive and intermediate, to poor, the mean platelet reactivity increases accordingly (p < 0.01). On the contrary, for Multiplate, no such ordering of metabolizer groups was found (p = 0.10). Conclusions: For VerifyNow and LTA, the on-treatment platelet reactivity in clopidogrel-treated patients correlates well with the underlying CYP2C19 polymorphism. For Multiplate, no major effect of genetic background could be shown, and effects of other (patient-related) variables prevail. Thus, besides differences in test principles and the influence of patient-related factors, the disagreement between PFTs is partly explained by differential effects of the CYP2C19 genotype.

Pharmacogenetics to guide cardiovascular drug therapy

Over the past decade, pharmacogenetic testing has emerged in clinical practice to guide selected cardiovascular therapies. The most common implementation in practice is CYP2C19 genotyping to predict clopidogrel response and assist in selecting antiplatelet therapy after percutaneous coronary intervention. Additional examples include genotyping to guide warfarin dosing and statin prescribing. Increasing evidence exists on outcomes with genotype-guided cardiovascular therapies from multiple randomized controlled trials and observational studies. Pharmacogenetic evidence is accumulating for additional cardiovascular medications. However, data for many of these medications are not yet sufficient to support the use of genotyping for drug prescribing. Ultimately, pharmacogenetics might provide a means to individualize drug regimens for complex diseases such as heart failure, in which the treatment armamentarium includes a growing list of medications shown to reduce morbidity and mortality. However, sophisticated analytical approaches are likely to be necessary to dissect the genetic underpinnings of responses to drug combinations. In this Review, we examine the evidence supporting pharmacogenetic testing in cardiovascular medicine, including that available from several clinical trials. In addition, we describe guidelines that support the use of cardiovascular pharmacogenetics, provide examples of clinical implementation of genotype-guided cardiovascular therapies and discuss opportunities for future growth of the field.

Association between cytochrome P450 2C19 polymorphism and clinical outcomes in clopidogrel-treated Uygur population with acute coronary syndrome: a retrospective study

Background

Acute coronary syndrome (ACS) has become a vital disease with high mortality in the Uygur populations. Clopidogrel plays an important role in reducing the risk of recurrent cardiovascular events after ACS; however, it is a prodrug that requires biotransformation by cytochrome P450 (CYP450).

Objectives

To determine the effect of genetic polymorphisms in CYP2C19*2, *3, and *17, and along with clinical, demographic factors, on variation in response to clinical outcomes in Uygur patients.

Methods

A total of 351 patients with ACS were treated with clopidogrel and aspirin for at least 12 months; we recorded major adverse cardiovascular events (MACE) or bleeding within 1 year. Multivariable logistic regression analyses were carried out to identify factors associated with MACE or bleeding.

Results

We analyze risk factors include age, BMI (body mass index), smoking, alcohol intake, NSTEMI (non-ST-segment elevation myocardial infarction), hypertension, dyslipidemia, concomitant medication, CYP2C19*2 carriers, CYP2C19*17 carriers and metabolizer phenotype. CYP2C19*2 carriers had an odds of having MACE of 2.51 (95% CI: 1.534–4.09) compared with noncarriers (P < .001). However, no factors were significantly associated with bleeding (P > 0.05).

Conclusion

The CYP2C19*2 gene polymorphism contributes to the risk of MACE in dual clopidogrel—treated Uygur population with ACS with or without PCI (percutaneous coronary intervention). These data may provide valuable insights into the genetic polymorphisms affecting clopidogrel metabolism among minority groups in China.

PON1 Q192R is associated with high platelet reactivity with clopidogrel in patients undergoing elective neurointervention: A prospective single-center cohort study

Background and purpose

The impact of the paraoxonase-1 (PON1) polymorphism, Q192R, on platelet inhibition in response to clopidogrel remains controversial. We aimed to investigate the association between carrier status of PON1 Q192R and high platelet reactivity (HPR) with clopidogrel in patients undergoing elective neurointervention.

Methods

Post-clopidogrel platelet reactivity was measured using a VerifyNow^® P2Y12 assay in P2Y12 reaction units (PRU) for consecutive patients before the treatment. Genotype testing was performed for PON1 Q192R and CYP2C19*2 and *3 (no function alleles), and *17. PRU was corrected on the basis of hematocrit. We investigated associations between factors including carrying ≥1 PON1 192R allele and HPR defined as original and corrected PRU ≥208.

Results

Of 475 patients (232 men, median age, 68 years), HPR by original and corrected PRU was observed in 259 and 199 patients (54.5% and 41.9%), respectively. Carriers of ≥1 PON1 192R allele more frequently had HPR by original and corrected PRU compared with non-carriers (91.5% vs 85.2%, P = 0.031 and 92.5% vs 85.9%, P = 0.026, respectively). In multivariate analyses, carrying ≥1 PON1 192R allele was associated with HPR by original (odds ratio [OR] 1.96, 95% confidence interval [CI] 1.03–3.76) and corrected PRU (OR 2.34, 95% CI 1.21–4.74) after adjustment for age, sex, treatment with antihypertensive medications, hematocrit, platelet count, total cholesterol, and carrying ≥1 CYP2C19 no function allele.

Conclusions

Carrying ≥1 PON1 192R allele is associated with HPR by original and corrected PRU with clopidogrel in patients undergoing elective neurointervention, although alternative results related to other genetic polymorphisms cannot be excluded.

The effects of polymorphisms in CYP2C19, ATP-binding cassette transporter B1, and paraoxonase-1 on clopidogrel treatment of Uygur patients following percutaneous coronary intervention

BACKGROUND

Acute coronary syndrome (ACS) carries a high mortality in Uygur populations. Percutaneous coronary intervention (PCI) is a safe treatment for patients with ACS. Clopidogrel reduces the risk for recurrent cardiovascular events after PCI; however, its activity is influenced by cytochrome P450 (CYP450), ATP-binding cassette transporter B1 (ABCB1), and paraoxonase-1 (PON1).

OBJECTIVES

To assess the effects of genetic polymorphisms CYP2C19*2, *3, *17, ABCB1 C3435T, and PON1 Q192R along with clinical and demographic factors on variations in responses in Uygur patients following PCI.

METHODS

We enrolled 281 patients with PCI who were treated with clopidogrel and aspirin for at least 12 months and recorded major adverse cardiovascular events (MACE) or bleeding within 1 year. Approximately, 2 mL of peripheral venous blood samples were used for genotype detection. Binary logistic regression with likelihood ratio forward stepwise analysis and redundancy analysis were carried out to identify factors associated with MACE. We analyzed risk factors including age, body mass index, smoking, hypertension, dyslipidemia, gender, alcohol consumption, diabetes mellitus, carriers of ABCB1 C3435T T allele, carriers of PON1 Q192R A allele, metabolizer phenotype of CYP2C19, number of targeted vessels, and number of stents.

RESULTS

The CYP2C19 IMs (OR 3.546, 95% CI 1.972-6.375, P = 0.001), CYP2C19 PMs (OR 7.038, 95% CI 1.658-29.880, P = 0.008), and number of targeted vessels (OR 2.033, 95% CI 1.078-3.648, P = 0.026) were significantly associated with MACE.

CONCLUSION

The CYP2C19 IMs, PMs, and the number of targeted vessels are essential factors associated with MACE risk in dual clopidogrel-treated Uygur population with ACS following PCI. These data provide valuable insights into the genetic polymorphisms affecting clopidogrel response among minority groups in China.

Is monitoring of antiplatelet therapy by light transmission aggregometry dependent on instrument and reagent used?

INTRODUCTION

Light transmission aggregometry (LTA), used to detect clopidogrel resistance in patients under antiplatelet therapy, is prone to multiple variables potentially influencing results and interpretation. Currently, no attention is given to type of aggregometer or reagent used. The aim of this study was to evaluate the interassay variability between two aggregometers (Chronolog700 and TA-8V), using two different ADP reagents (Chrono-Par^® and Agro-Bio ADP) in patients under clopidogrel therapy. Additionally, LTA results were correlated to CYP2C19-polymorphism.

METHODS

Light transmission aggregometry was performed in 20 healthy individuals and 30 patients using both aggregometers, and applying two different reagents (2.5 and 5 µmol/L). The maximum platelet aggregation (ADP_max ), the platelet aggregation at 6 minutes (ADP_6min ), and the percentage of disaggregation at 6 min (ADP_%disaggr ) were compared between four applied combinations. Additionally, 23 clopidogrel-resistant patients according to Chronolog700-Chrono-par^® ADP reagent analysis were tested for CYP2C19*2 polymorphism.

RESULTS

Comparison of the LTA of healthy individuals revealed a significant lower ADP_max , lower ADP_6min , and higher ADP_%disaggr with the TA-8V aggregometer compared to Chronolog700, regardless of the reagent. In contrast, LTA results in patients are depending on the reagent, with significant higher ADP_max and ADP_6min and lower ADP_%disaggr using Chrono-Par^® compared to Agro-Bio ADP reagent. All intermediate clopidogrel metabolizers (CYP2C19*2 carriers) were correctly classified as clopidogrel resistant using Chrono-Par^® , in contrast to the Agro-Bio ADP reagent.

CONCLUSION

Light transmission aggregometry in clopidogrel-treated patients is mainly depending on the type of ADP reagent. Comparison of LTA with genotype reveals that the choice of instrument seems less influencing. In contrast, in the healthy individuals, differences could be attributed to the instrument.

Effect of CYP2C19 Genotype on Ischemic Outcomes During Oral P2Y12 Inhibitor Therapy: A Meta-Analysis

OBJECTIVES

The aim of this study was to examine the effect of CYP2C19 genotype on clinical outcomes in patients with coronary artery disease (CAD) who predominantly underwent percutaneous coronary intervention (PCI), comparing those treated with ticagrelor or prasugrel versus clopidogrel.

BACKGROUND

The effect of CYP2C19 genotype on treatment outcomes with ticagrelor or prasugrel compared with clopidogrel is unclear.

METHODS

Databases through February 19, 2020, were searched for studies reporting the effect of CYP2C19 genotype on ischemic outcomes during ticagrelor or prasugrel versus clopidogrel treatment. Study eligibility required outcomes reported for CYP2C19 genotype status and clopidogrel and alternative P2Y₁₂ inhibitors in patients with CAD with at least 50% undergoing PCI. The primary analysis consisted of randomized controlled trials (RCTs). A secondary analysis was conducted by adding non-RCTs to the primary analysis. The primary outcome was a composite of cardiovascular death, myocardial infarction, stroke, stent thrombosis, and severe recurrent ischemia. Meta-analysis was conducted to compare the 2 drug regimens and test interaction with CYP2C19 genotype.

RESULTS

Of 1,335 studies identified, 7 RCTs were included (15,949 patients, mean age 62 years; 77% had PCI, 98% had acute coronary syndromes). Statistical heterogeneity was minimal, and risk for bias was low. Ticagrelor and prasugrel compared with clopidogrel resulted in a significant reduction in ischemic events (relative risk: 0.70; 95% confidence interval: 0.59 to 0.83) in CYP2C19 loss-of-function carriers but not in noncarriers (relative risk: 1.0; 95% confidence interval: 0.80 to 1.25). The test of interaction on the basis of CYP2C19 genotype status was statistically significant (p = 0.013), suggesting that CYP2C19 genotype modified the effect. An additional 4 observational studies were found, and adding them to the analysis provided the same conclusions (p value of the test of interaction <0.001).

CONCLUSIONS

The effect of ticagrelor or prasugrel compared with clopidogrel in reducing ischemic events in patients with CAD who predominantly undergo PCI is based primarily on the presence of CYP2C19 loss-of-function carrier status. These results support genetic testing prior to prescribing P2Y₁₂ inhibitor therapy.

Clopidogrel Versus Ticagrelor or Prasugrel After Primary Percutaneous Coronary Intervention According to CYP2C19 Genotype: A POPular Genetics Subanalysis

[Figure: see text].

A Study on the Correlation Between MDR1 Polymorphism and Clopidogrel Resistance in Hui Patients Treated with Percutaneous Coronary Intervention

OBJECTIVE

This study assesses the correlation between MDR1 gene polymorphism and clopidogrel resistance (CR) in Hui patients with coronary heart disease (CHD) who were treated with percutaneous coronary intervention (PCI).

METHODS

The study includes 204 Ningxia Hui patients with CHD who were treated with PCI. These patients were divided into two groups: those who with CR and others were non-clopidogrel resistant (NCR), according to the results of the patients' platelet aggregation rate, which was tested by adenosine diphosphate-induced turbidimetry on the second postoperative day. C3435T and C1236T genotypes and alleles were tested by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

The CR rate was 24.0%, and there were 3 genotypes of C3435T and C1236T. For C3435T, the distribution frequency of the 3435TT genotype and T allele was significantly higher in the CR group than in the NCR group. For C1236T, no significant difference was found between the two groups.

CONCLUSION

Hui patients who had CHD were treated with PCI. CR was most likely to occur in those who had the T allele of MDR1 in gene C3435T.

P2Y12 inhibitors in neuroendovascular surgery: An opportunity for precision medicine

INTRODUCTION

Dual antiplatelet therapy (DAPT), primarily the combination of aspirin with a P2Y12 inhibitor, in patients undergoing intravascular stent or flow diverter placement remains the primary strategy to reduce device-related thromboembolic complications. However, selection, timing, and dosing of DAPT is critical and can be challenging given the existing significant inter- and intraindividual response variations to P2Y12 inhibitors.

METHODS

Assessment of indexed, peer-reviewed literature from 2000 to 2020 in interventional cardiology and neuroendovascular therapeutics with critical, peer-reviewed appraisal and extraction of evidence and strategies to utilize DAPT in cardio- and neurovascular patients with endoluminal devices.

RESULTS

Both geno- and phenotyping for DAPT are rapidly and conveniently available as point-of-care testing at a favorable cost-benefit ratio. Furthermore, systematic inclusion of a quantifying clinical risk score combined with an operator-linked, technical risk assessment for potential adverse events allows a more precise and individualized approach to new P2Y12 inhibitor therapy.

CONCLUSIONS

The latest evidence, primarily obtained from cardiovascular intervention trials, supports that combining patient pharmacogenetics with drug response monitoring, as part of an individually tailored, precision medicine approach, is both predictive and cost-effective in achieving and maintaining individual target platelet inhibition levels. Indirect evidence supports that this gain in optimizing drug responses translates to reducing main adverse events and overall treatment costs in patients undergoing DAPT after intracranial stent or flow diverting treatment.

Impact of genetic variants on major bleeding after percutaneous coronary intervention based on a prospective multicenter registry

Although dual antiplatelet therapy is essential for patients who undergo percutaneous coronary interventions, the risk of bleeding remains an unsolved problem, and there is limited information on the potential relationship between genetic variants and major bleeding. We analyzed the correlations between four major single nucleotide polymorphisms (CYP2C19, ABCB1, PON1, and P2Y12 G52T polymorphisms) and clinical outcomes in 4489 patients from a prospective multicenter registry. The primary endpoint was major bleeding, defined as a Bleeding Academic Research Consortium ≥ 3 bleeding event. The allelic frequencies of ABCB1, PON1, and both individual and combined CYP2C19 variants did not differ significantly between patient groups with and without major bleeding. However, the allelic frequency of the P2Y12 variant differed significantly between the two groups. Focusing on the P2Y12 G52T variant, patients in the TT group had a significantly higher rate of major bleeding (6.4%; adjusted hazard ratio [HR] 2.51; 95% confidence interval [CI] 1.08-5.84; p = 0.033) than patients in the other groups (GG [2.9%] or GT [1.9%]). Therefore, the TT variant of the P2Y12 G52T polymorphism may be an independent predictor of major bleeding.Trial registration: NCT02707445 ( https://clinicaltrials.gov/ct2/show/NCT02707445?term=02707445&draw=2&rank=1 ).

Genotype-guided antiplatelet treatment versus conventional therapy: A systematic review and meta-analysis

AIM

This meta-analysis was carried out to explore if a personalized antiplatelet strategy based on genotyping is superior to conventional therapy.

METHODS

PubMed, Web of Science, EMBASE and the Cochrane Library were searched from the inception of each database to 5 May 2020. Studies reporting endpoints in genotype-guided treatment group and conventional treatment group were included. The endpoint results were presented as the risk ratio (RR), with 95% confidence interval (CI).

RESULTS

A total of 10 561 patients from 16 studies (eight randomized controlled trials [RCT] and eight cohort studies) were included in the meta-analysis. The rates of major adverse cardiovascular events (MACE), stent thrombosis and myocardial infarction (MI) were significantly lower in the genotype-guided group than in the conventional treatment group (RR 0.56, 95% CI 0.44-0.73, P < .0001; RR 0.40, 95% CI 0.24-0.67, P = .0005; RR 0.45, 95% CI 0.35-0.58, P < .00001, respectively). A significant difference was found between the two groups in major bleeding (RR 0.73, 95% CI 0.55-0.98, P = .04), which was not robust after sensitivity analysis.

CONCLUSION

Genotype-guided antiplatelet treatment could decrease the risk of MACE, stent thrombosis and MI in patients with coronary artery disease or undergoing percutaneous coronary intervention, without increasing the risk of bleeding over a long follow-up period. The decreased risk of efficacy outcomes was more obvious in cohort studies. Well-organized RCTs and clinical trials are required to verify the benefit of genotype-guided therapy.

Impact of selected genetic factors on clopidogrel inactive metabolite level and antiplatelet response in patients after percutaneous coronary intervention

Background and objective

Clopidogrel is frequently used as part of optimal dual antiplatelet therapy in high-bleeding risk patients with the acute coronary syndrome. The concentration of the inactive carboxylic acid metabolite of clopidogrel might be useful to evaluate the response to clopidogrel therapy. Therefore, we sought to correlate the inhibition of platelet aggregation with the plasma level of the inactive metabolite of clopidogrel in patients after percutaneous coronary interventions (PCI) and their associations with the most frequently studied genetic polymorphisms. For this purpose, the fast and simple HPLC method for determining the concentration of the inactive metabolite was developed.

Methods

The effect of CYP2C19, CYP3A4/5, ABCB1 and PON1 genes on the plasma inactive metabolite concentration of clopidogrel and the platelet aggregation was investigated in 155 patients before and after PCI.

Results

The concentration of the inactive metabolite of clopidogrel was not significantly different in the intermediate metabolizers (IM) of CYP2C19 compared with extensive metabolizers (EM) both before and after PCI, while inhibition of platelet aggregation was found to be significantly better in EM than in IM. The presence of the A allele at position 2677 in the ABCB1 gene was associated with a significantly lower concentration of inactive metabolite of clopidogrel before PCI.

Conclusion

The CYP2C19*2 allele was associated with decreased platelet reactivity during clopidogrel therapy before and after PCI. Simultaneous determination of platelet aggregation and concentration of the inactive clopidogrel metabolite may be useful in clinical practice to find the cause of adverse effects or insufficient treatment effect in patients chronically treated with clopidogrel.

Implementation and management outcomes of pharmacogenetic CYP2C19 testing for clopidogrel therapy in clinical practice

Purpose

The antiplatelet prodrug clopidogrel is bioactivated by the polymorphic enzyme CYP2C19. Prospective clinical studies demonstrated an association between CYP2C19 loss of function (LoF) variants and an increased risk of thrombotic events under clopidogrel, but pharmacogenetic (PGx) testing is not frequently implemented in clinical practice. We report our experience with PGx-guided clopidogrel therapy with particular regard to clinically relevant patient management changes.

Methods

We conducted an observational study analyzing patients that underwent PGx testing for clopidogrel therapy at two Swiss hospitals. Primary outcome was the proportion of patients with clinically relevant PGx-based management recommendations and their implementation. The association of recurrent ischemic events under clopidogrel with CYP2C19 LoF variants and other factors was explored in a multivariate case-control analysis.

Results

Among 56 patients undergoing PGx testing, 18 (32.1%) were classified as CYP2C19 intermediate or poor metabolizers. This resulted in 17 recommendations for a change of antiplatelet therapy, which were implemented in 12 patients (70.1%). In the remaining five patients, specific reasons for non-implementation could be identified. Recurrent ischemic events under clopidogrel were associated with LoF variants (OR 2.2, 95% CI 0.3–14.4) and several cardiovascular risk factors. Associations were not statistically significant in our small study, but plausible and in line with estimates from large prospective studies.

Conclusion

PGx-guided clopidogrel therapy can identify patients with an elevated risk of ischemic events and offer evidence-based alternative treatments. Successful implementation in clinical practice requires a personalized interdisciplinary service that evaluates indications and additional risk factors, provides specific recommendations, and proactively follows their implementation.

Predictors of Clopidogrel Hyper-Responsiveness in Neuro-Interventional Procedures

BACKGROUND

Hyper-responsiveness to clopidogrel abnormally inhibits platelet aggregation and increases hemorrhagic complications. The present study investigated clinical factors related to clopidogrel hyper-responsiveness in neuro-interventional procedures.

METHODS

Two hundred twenty-four patients receiving clopidogrel for coil embolization to treat unruptured cerebral aneurysm or carotid artery stenting to treat carotid artery stenosis at the internal carotid artery origin were retrospectively reviewed for their P2Y12 reactivity unit (PRU) values and clinical characteristics. Hyper-responsiveness to clopidogrel was defined as a PRU of <95.

RESULTS

The mean PRU was 218.2 ± 77.8. Hyper-responsiveness to clopidogrel was observed in 12 patients (5.4%). Hyper-responsiveness was observed in younger patients, patients with a lower concentration of hemoglobin A1c, and patients with a higher low-density lipoprotein cholesterol (LDL-C) concentration compared with non-hyper-responsive patients (P = 0.01, P < 0.01, P < 0.01, respectively). On analysis of concomitant drugs, the patients in the hyper-responsive group were less frequently administered calcium channel blockers (CCBs) compared with the non-hyper-responsive group (P = 0.01). No significant differences in the usage of proton pump inhibitors or statins were observed. A LDL-C concentration of >120 mg/dL and no usage of CCBs were significant independent predictors of hyper-responsiveness to clopidogrel with a multivariate analysis (OR; 6.16, 95% CI, 1.57-26.64, P = 0.01, OR; 0.09, 95% CI, 0.01-0.82, P = 0.03, respectively).

CONCLUSION

The present study shows that a higher LDL-C concentration and no usage of CCBs are independent predictors of clopidogrel hyper-responsiveness. These results are useful to predict perioperative hemorrhagic complications. Considering dose reduction of clopidogrel or alternative drugs in high risk cases is necessary to prevent perioperative hemorrhagic complications.

Genetic Polymorphisms and Perioperative Bleeding in Off-Pump Coronary Artery Bypass Grafting Surgery

BACKGROUND

Clopidogrel use before coronary artery bypass graft surgery may increase risk for perioperative hemorrhage. The effect of genetic polymorphisms related to clopidogrel responses on bleeding during or after off-pump coronary artery bypass graft surgery is unknown.

METHODS

This prospective study included 206 coronary artery disease patients scheduled for off-pump coronary artery bypass graft surgery. Genotypes were determined using Sequenom MassARRAY system. Severe bleeding was defined by the universal definition of perioperative bleeding in cardiac surgery.

RESULTS

Patients carrying the ABCB1 3435 wild-type genotype (CC) had a higher risk of severe perioperative bleeding compared with patients carrying the variant genotype (CT or TT; 33.9% vs 16.5%, P = .009). Low baseline hemoglobin level (odds ratio 0.944; 95% confidence interval, 0.917 to 0.972; P < .001), low baseline estimated glomerular filtration rate (odds ratio 0.977; 95% confidence interval, 0.956 to 0.999; P = .041), discontinuing clopidogrel 5 days or less before surgery (odds ratio 2.458; 95% confidence interval, 1.044 to 5.786; P = .039), and the ABCB1 wild-type genotype (CC; odds ratio 2.941; 95% confidence interval, 1.250 to 6.944; P = .014) were independent risk factors for severe perioperative bleeding.

CONCLUSIONS

Patients carrying the ABCB1 wild-type genotype (CC) had a higher rate of severe perioperative bleeding compared with patients carrying the variant genotype (CT or TT). Discontinuation of clopidogrel 5 days or less before surgery and the ABCB1 wild-type genotype (CC) were independent risk factors for severe perioperative bleeding.

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.