CYP2C19 Loss-of-function Alleles Research Articles

Comparative effects of different antiplatelet strategies in carriers of CYP2C19 loss-of-function alleles: a network meta-analysis.

Carriers of cytochrome 2C19 (CYP2C19) loss of function (LoF) alleles treated with clopidogrel have impaired drug metabolism resulting in reduced active metabolite levels, high platelet reactivity (HPR), and an increased risk of thrombotic events. Several alternative antiplatelet therapies have been proposed to overcome HPR in these patients, but their comparative effects remain poorly explored. Randomized controlled trials (RCTs) comparing different oral antiplatelet therapies in carriers of CYP2C19 LoF alleles undergoing percutaneous coronary interventions (PCI) were included. A frequentist network meta-analysis was conducted to estimate mean difference (MD) or odds ratios (OR) and 95% confidence intervals (CI). The primary outcome was platelet reactivity assessed by VerifyNow and reported as P2Y12 reaction unit (PRU). The secondary outcome was the rate of HPR. Standard-dose of clopidogrel (75 mg daily) was used as reference treatment. A total of 12 RCTs testing 6 alternative strategies (i.e., clopidogrel 150 mg, prasugrel 3.75 mg, 5 mg, and 10 mg, ticagrelor 90 mg bid, and adjunctive cilostazol 100 mg bid) were included in the network. Compared with standard-dose clopidogrel, the greatest reduction in PRU was observed with prasugrel 10 mg (MD -127.91; 95% CI -141.04; -114.78) and ticagrelor 90 mg bid (MD -124.91; 95% CI -161.78; -88.04), followed by prasugrel 5 mg (MD -76.33; 95% CI -98.01; -54.65) and prasugrel 3.75 mg (MD -73.00; 95% CI -100.28; -45.72). Among other strategies, adjunctive cilostazol (MD-42.64; 95% CI -64.72; -20.57) and high-dose clopidogrel (MD -32.11; 95% CI -51.33; -12.90) were associated with a modest reduction in PRU compared with standard-dose clopidogrel. Among carriers of CYP2C19 LoF alleles undergoing PCI, standard-dose prasugrel or ticagrelor are most effective in reducing platelet reactivity, while double-dose clopidogrel and additional cilostazol showed modest effects. Reduced-dose of prasugrel may represent a balanced strategy to overcome HPR without a significant increase in bleeding. The clinical implications of these pharmacodynamic findings warrant further investigation.

Impact of CYP2C19 Genotype on Efficacy and Safety of Clopidogrel-based Antiplatelet Therapy in Stroke or Transient Ischemic Attack Patients: An Updated Systematic Review and Meta-analysis of Non-East Asian Studies.

Inconclusive and limited results have been reported on the clinical utility of CYP2C19 genotyping in stroke/TIA patients of non-East Asian ancestries. We herein performed an updated systematic review and meta-analysis to quantitatively estimate the association of CYP2C19 loss-of function (LOF) status with efficacy and safety of clopidogrel-based antiplatelet therapy in non-East Asian patients affected by stroke or TIA. A comprehensive search was performed up to July 2023 using PubMed, Web of Knowledge, and Cochrane Library databases. The clinical outcomes investigated were stroke, composite vascular events and bleeding. Pooled estimates were calculated as risk ratios (RR) with 95% CI using the Mantel- Haenszel random-effects model. The quality of evidence was assessed using the GRADEpro tool. A total number of 1673 stroke/TIA patients from 8 non-East Asian studies, published between 2014 and 2022, were included in the systematic review. Clopidogrel-treated carriers of CYP2C19 LOF alleles were found at increased risk of stroke compared to non-carriers (RR: 1.68, 95%CI: 1.04-2.71, P = 0.03). However, no significant association was observed with the risk of composite vascular events (RR: 1.15, 95%CI: 0.58-2.28, P = 0.69) or bleeding (RR: 0.84, 95%CI: 0.38-1.86, P = 0.67). Similarly, European ancestry patients carrying CYP2C19 LOF alleles displayed a higher risk of stroke (RR: 2.69 (1.11-6.51, P = 0.03), but not of composite vascular events or bleeding. The present updated meta-analysis provides moderate quality evidence of association between CYP2C19 LOF alleles and an increased risk of stroke in non-East Asian patients with stroke/TIA after receiving clopidogrel therapy. Further large pharmacogenetic studies are still warranted to corroborate these findings.

CYP2C19 genotype prevalence and association with recurrent myocardial infarction in British-South Asians treated with clopidogrel

Abstract Background Pharmacogenomics examines how genes and drugs interact to explain some of the inter-individual variability in response to medications. CYP2C19 is a hepatic enzyme involved in the metabolism of clopidogrel from a prodrug to its active metabolite. Although the European Society of Cardiology and National Institute for Care Excellence recommend ticagrelor (a non CYP2C19 dependent P2Y12 antagonist) as the antiplatelet agent of choice, clopidogrel remains widely prescribed for acute coronary syndrome and myocardial infarction. CYP2C19 poor metabolizers are known to be more common in Asian ancestry but very few studies have looked specifically at South Asian populations or linked metabolizer diplotypes with clinical efficacy data in this population. The outcome studies on which clopidogrel was licensed for efficacy and safety did not include significant South Asian representation. Furthermore, South Asians are known to have a higher prevalence of cardio-metabolic disease compared with European ancestry populations. Methods We studied the Genes & Health cohort of British Bangladeshi and Pakistani ancestry participants to look at prevalence of CYP2C19 metabolizer genotypes and correlate these with recurrent myocardial infarction risk for those who had been prescribed clopidogrel in primary care. Multivariable regression was used to test for association between known CYP2C19 diptotypes and recurrent myocardial infarction in those prescribed clopidogrel, controlling for known CVD risk factors, percutaneous coronary intervention, age, and gender. 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 allele. The prevalence of poor metabolizers carrying 2 CYP2C19 loss of function alleles is 13%, which is higher than in previously studied European (2.4%) and Central/South Asian populations (8.2%). This is primarily due to the *2 LOF allele present in 56% of the population. 69% of the cohort who were diagnosed with an acute MI were prescribed clopidogrel. The presence of the poor metabolizer diplotype is significantly associated with higher risk of recurrent MI, or failed secondary prevention on clopidogrel in this population, OR 3.1 (p = 0.02), with some subsequent ischemic events already described in this young cohort (Acute MI prescribed clopidogrel N = 697, Recurrent MI in this group N=39). 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. In absence of genotype guided prescribing, maximal adherence to guidelines recommending non CYP2C19 dependent P2Y12 anti-platelet therapy is likely to be disproportionately beneficial in this ethnic cohort.Risk of recurrent MICentral illustration

CYP2C19 loss-of-function alleles and use of omeprazole or esomeprazole increase the risk of cardiovascular outcomes in patients using clopidogrel.

Our aim was to investigate in a real-life prospective patient cohort how CYP2C19 loss-of-function (LOF) variants and CYP2C19 inhibitor omeprazole or esomeprazole influence the incidence of cardiovascular events in patients using clopidogrel. Data based simultaneously on these factors are conflicting and sparse. A cohort of prospective patients (n = 1972) with acute coronary syndrome (n = 1302) or symptomatic chronic coronary disease (n = 656) was followed for 365 days after hospitalization with information on purchased prescription drugs, hospital discharge, death, and genotype for CYP2C19*2, CYP2C19*3, and CYP2C19*8 LOF variants. The primary study outcome measurement was cardiovascular death or recurring myocardial infarction or stroke. Altogether, 608 patients (30.8%) carried CYP2C19 LOF alleles. During the 365-day follow-up 252 patients (12.8%) had an ischemic vascular event. Cardiovascular events were significantly more frequent in carriers of CYP2C19 LOF alleles (14.8%, 95% confidence interval [CI], 11.7-17.8) than in non-carriers (10.8%, 95% CI, 9.0-12.6, p = 0.0159). Omeprazole or esomeprazole use was similar among LOF allele carriers (n = 131, 21.5%) and non-carriers (n = 250, 18.3%, p = 0.185). Cardiovascular events were significantly more common in a composite group consisting of all CYP2C19 LOF carriers regardless of proton pump inhibitor use status and non-carriers using omeprazole or esomeprazole than in non-carriers not using omeprazole or esomeprazole (14.8%, 95% CI, 12.2-17.3 vs. 9.9%, 95% CI, 8.0-11.9, p = 0.00173). We observed significantly more cardiovascular events in carriers of CYP2C19 LOF variants and in non-carriers using omeprazole or esomeprazole. For optimal patient care, both genetics and concomitant medication should be considered.

Influence of CYP2C19 genetic variants and smoking on dual antiplatelet efficacy in patients with coronary artery disease.

This study aimed to investigate the effects of smoking and CYP2C19 gene polymorphism on antiplatelet therapy to specify the most optimized and accurate antiplatelet therapy for different populations. This study included 6,353 patients with coronary artery disease (CAD). In total, 2,256 (35.5%) were smokers and 4,097 (64.5%) were non-smokers. Patients carrying a CYP2C19*2 or *3 allele were considered loss-of-function (LOF) allele carriers. The medical history of patients who had undergone percutaneous coronary intervention (PCI) at Beijing Anzhen Hospital was recorded. The primary endpoint was major adverse cardiovascular or cerebrovascular events (MACCE) during the 6-month follow-up period. A Cox regression model was used to assess the interactions between antiplatelet efficacy and CYP2C19 LOF allele carrier status, stratified by smoking status. Compared to clopidogrel plus aspirin, ticagrelor plus aspirin reduced the MACCE recurrence risk in non-smokers (carrier: 6.0 vs. 2.0%, hazard ratio 0.298, 95% confidence interval 0.204-0.635, P < 0.0001; non-carrier: 5.8 vs. 2.1%, hazard ratio 0.358, 95% confidence interval 0.189-0.678, P = 0.002), and not in smokers. Similar results were discovered regarding the recurrence rate for hospitalization for ischemic cardiac events in non-smokers. No apparent difference was discovered in the bleeding events in either group. There were no significant associations between antiplatelet medication and CYP2C19 LOF allele carrier status for the MACCE recurrence risk among smokers (P = 0.943, respectively) or non-smokers (P = 0.774, respectively). In patients with CAD after PCI, ticagrelor plus aspirin lowered the MACCE recurrence risk in CYP2C19 LOF allele carriers and non-carriers compared with clopidogrel plus aspirin alone among non-smokers. The efficacy of antiplatelet therapy varies between CYP2C19 LOF allele carrier status. No significant interaction between CYP2C19 LOF allele carrier status and antiplatelet effectiveness was observed. However, caution should be used to interpret our results considering the many limitations of our investigation.

Neurointerventional Advances in 2022

Neurointerventional Advances in 2022

Derivation of a Novel Scoring System Predicting High Platelet Reactivity on Prasugrel in Patients with Coronary Artery Disease.

High platelet reactivity (HPR) has been associated with an increased risk of thrombotic events in patients undergoing percutaneous coronary intervention. HPR has been well examined in patients treated with clopidogrel; however, HPR on prasugrel is poorly investigated. Four prospective studies were pooled, in which platelet reactivity on prasugrel was measured using VerifyNow assay; genotyping of CYP2C19 was also performed. Factors associated with HPR on prasugrel were identified using multivariable analysis to develop a risk prediction model. In total, 180 patients were examined in this study, of whom 51 (28%) had HPR on prasugrel. The multivariable analysis indicated that hypertension, diabetes, hemodialysis, and the number of CYP2C19 loss-of-function (LOF) alleles are significant factors for HPR on prasugrel. These four factors were then incorporated to develop the HHD-GENE score. The receiver operating characteristic curve analysis showed that the HHD-GENE score predicted HPR on prasugrel (area under the curve (AUC) 0.74, best cutoff value 5, p＜0.001). With the best cutoff value, patients with the HHD-GENE score ≥ 5 had a significantly increased risk of HPR on prasugrel than their counterpart (50% vs. 18%, p＜0.001). The HHD-GENE score consisting of hypertension, diabetes, hemodialysis, and CYP2C19 LOF alleles may be useful in identifying patients on prasugrel who are at high risk for HPR. External validation is needed to define the clinical utility of this novel scoring system.

CYP2C19 loss-of-function alleles and the use of omeprazole or esomeprazole increase the risk of cardiovascular outcomes in patients using clopidogrel – a real-world study

Abstract Background Patients carrying loss-of-function (LOF) variants of CYP2C19 or using the CYP2C19-inhibitors omeprazole or esomeprazole cannot fully bioactivate clopidogrel, and thus are lacking optimal thrombosis prevention. However, clopidogrel is a relevant alternative to ticagrelor due to its lower incidence of hemorrhagic events and lower cost. Purpose The purpose of this study was to investigate in a real-life prospective patient cohort how loss-of-function (LOF) CYP2C19 variants and omeprazole or esomeprazole influence the incidence of cardiovascular events (cardiovascular deaths, reinfarction and strokes) in patients using clopidogrel. Methods A cohort of prospective patients (N=1972) with acute coronary syndrome (ACS) (N=1302) or symptomatic chronic coronary disease (N=670) were followed for 365 days. Information of purchased prescription drugs, hospital discharge, and death registry was available for all patients. The patients were retrospectively genotyped for the CYP2C19*2, CYP2C19*3, and CYP2C19*8 LOF variants. Results A total of 608 (30.8%) patients carried CYP2C19 LOF alleles. During the 365 days follow-up, 252 patients had a recurring ischemic vascular event, either myocardial infarction (N=189), stroke (N=24) or cardiovascular death (N=39). Vascular events were significantly more frequent among carriers of CYP2C19 LOF alleles [14.8% (95% CI 11.7–17.8] than in non-carriers [10.8% (95% CI 9.0–12.6)], p=0.016. Omeprazole or esomeprazole use was similar among the LOF allele carriers and non-carriers, but inclusion of their use in the analysis strengthened the association. Vascular events were significantly more common in a composite group of carriers of CYP2C19 LOF alleles and non-carriers who were using omeprazole or esomeprazole than in non-carriers who were not using omeprazole or esomeprazole 14.8% (95% CI 12.2–17.3) vs 9.9% (95% CI 8.0–11.9) p=0.002. There was a tendency towards lower risk of hemorrhagic complications in carriers of LOF alleles than in non-carriers (p=0.07). Conclusions Patients with impaired clopidogrel bioactivation due to loss-of-function CYP2C19 variants or concomitant omeprazole or esomeprazole use are at increased risk of cardiovascular events. For relevant patient care both genetics and concomitant medication should be considered both in everyday patient care and further randomised studies. Funding Acknowledgement Type of funding sources: None.

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

BackgroundCYP2C19 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.MethodsThis 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.ConclusionCarrying 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.

CYP2C19 loss-of-function alleles predicts clinical outcomes in East Asian patients with acute myocardial infarction undergoing percutaneous coronary intervention and stenting receiving clopidogrel

BackgroundCYP2C19 loss-of-function (LOF) alleles reduce the effectiveness of clopidogrel and are associated with high rates of clinical events in patients undergoing percutaneous coronary intervention (PCI) and stenting in Northeast Asians. However, the prevalence and influence of CYP2C19 LOF alleles in Southeast Asians remain unclear.ObjectivesThis study aims to retrospectively investigate the prevalence of CYP2C19 LOF alleles and clinical outcomes in East Asian patients taking clopidogrel and undergoing PCI.MethodsBetween June 2019 and June 2020, volunteer participants in a single medical center were consecutively selected. The genetic data of CYP2C19 were derived from the Taiwan Precision Medicine Initiative (TPMI). Patients receiving clopidogrel while undergoing PCI with stenting were retrospectively analyzed.ResultsA total of 999 patients (62.4 ± 11.1 years old, 83.7% men) were enrolled; 39.3% without the CYP2C19 LOF allele (normal metabolizers + rapid metabolizers, NM + RM); 44.9% with one LOF allele (intermediate metabolizers, IM); 15.7% with two LOF alleles (poor metabolizers, PM). The incidence of stroke was higher in the PM subgroup compared to the NM + RM subgroup or IM subgroup in patients presenting with acute myocardial infarction (AMI). The 1-year major adverse cardiac and cerebrovascular events (MACCE)-free survival rates in all participants were similar among the three groups. However, in the AMI group, the 1-year MACCE-free survival rates were significantly lower in the PM subgroup compared to the NM + RM subgroup or IM subgroup.ConclusionIn East Asians presenting with AMI, CYP2C19 PM was associated with deleterious cardiovascular outcomes and stroke. Our results reinforce the crucial role of preemptive CYP2C19 genotyping in East Asian AMI patients receiving clopidogrel treatment.

Comparison of ticagrelor and clopidogrel in the treatment of patients with coronary heart disease carrying CYP2C19 loss of function allele

BackgroundClopidogrel is a traditional P2Y12 receptor inhibitor that is widely used in clinical practice, but there are significant individual differences in its therapeutic effect. Carriers of the CYP2C19 deletion allele have a higher risk of adverse cardiovascular events than non-carriers.MethodsIn this study, 170 patients diagnosed with coronary heart disease (CHD) and on regular oral clopidogrel or ticagrelor antiplatelet therapy in the Department of Cardiology of Wuxi Second People’s Hospital from August to December 2019 were screened. Baseline patient data were collected, percutaneous coronary angiography (CAG) or coronary computed tomography angiography (CTA) results were recorded, CYP2C19 gene type was detected, and prognosis/outcome was assessed by telephone/outpatient/inpatient follow-up for 12 months.Results(I) Of the 170 patients, 0.66% were the fast metabolic type, 41.45% were the normal metabolic type, 42.76% were the intermediate metabolic type, and 15.13% were the poor metabolic type. CYP2C19*2 mutation accounted for 89.29% of all mutations, CYP2C19*3 mutation accounted for 9.82%, and CYP2C19*17 mutation accounted for only 0.89%. (II) Among the patients with CHD who regularly took clopidogrel, the risk in the intermediate metabolic group was 5.208-fold higher than that of normal metabolic group, and that of the poor metabolic group was 3.75-fold higher than that of normal metabolic group; there was no significant difference between the intermediate and poor metabolic groups. (III) Prognosis was significantly associated with regular use of ticagrelor or clopidogrel by patients in the intermediate metabolic group. There was no significant correlation between poor metabolism (PM) and normal metabolism (NM). Prognosis was significantly associated with regular use of ticagrelor or clopidogrel in patients undergoing percutaneous coronary intervention (PCI), but not in patients who did not undergo PCI.ConclusionsCYP2C19 polymorphism was associated with the prognosis of patients with CHD administered antiplatelet therapy with oral clopidogrel. The incidence of poor prognosis was significantly increased with CYP2C19*2 and/or CYP2C19*3 mutations, and patients undergoing PCI or carrying a single CYP2C19 deletion allele had a better prognosis with ticagrelor as replacement therapy.

Time Course for Benefit and Risk With Ticagrelor and Aspirin in Individuals With Acute Ischemic Stroke or Transient Ischemic Attack Who Carry CYP2C19 Loss-of-Function Alleles

Dual antiplatelet therapy (DAPT) with ticagrelor and aspirin has been found to be effective for secondary prevention after minor ischemic stroke or transient ischemic attack (TIA) in individuals who carry CYP2C19 loss-of-function (LOF) alleles; however, uncertainties remain about the time course of benefit and risk with ticagrelor and aspirin in these patients. To obtain time-course estimates of efficacy and risk with ticagrelor and aspirin after minor stroke or TIA in individuals with CYP2C19 LOF alleles. The Ticagrelor or Clopidogrel With Aspirin in High-risk Patients With Acute Nondisabling Cerebrovascular Events II (CHANCE-2) randomized clinical trial enrolled patients 40 years and older from 202 hospitals in China with acute minor stroke or TIA who carried CYP2C19 LOF alleles between September 23, 2019, and March 22, 2021, and were followed up for 90 days. All 6412 patients enrolled in the CHANCE-2 trial were included in this secondary analysis. Data were analyzed in October 2021. Ticagrelor (180 mg on day 1 followed by 90 mg twice daily on days 2-90) or clopidogrel (300 mg on day 1 followed by 75 mg daily on days 2-90). All patients received aspirin (75-300 mg on day 1 followed by 75 mg daily for 21 days). The efficacy outcome was major ischemic event, defined as the composite of ischemic stroke or nonhemorrhagic death. Safety outcomes included moderate to severe bleeding and any bleeding. A total of 6412 patients were included (3205 in the ticagrelor and aspirin group and 3207 in the clopidogrel and aspirin group). The median (IQR) age was 65 (57-71) years, and 4242 patients (66%) were men. The reduction of major ischemic events with ticagrelor and aspirin predominately occurred in the first week (absolute risk reduction, 1.34%; 95% CI, 0.29 to 2.39) and attenuated but remained in the next 3 weeks (absolute risk reduction in the second week, 0.11%; 95% CI, -0.24 to 0.45; absolute risk reduction in the third week, 0.14%; 95% CI, -0.11 to 0.38; absolute risk reduction in the fourth week, 0.04%; 95% CI, -0.18 to 0.25). The risk of moderate to severe bleeding was consistently low in the ticagrelor and aspirin group. The absolute increase in any bleeding seen in the first week (0.87%; 95% CI, 0.25 to 1.50) remained in the next 3 weeks (absolute increase in the second week, 1.21%; 95% CI, 0.75 to 1.68; absolute increase in the third week, 0.33%; 95% CI, -0.05 to 0.72; absolute increase in the fourth week, 0.23%; 95% CI, -0.03 to 0.49). Among patients with minor stroke or TIA who carried CYP2C19 LOF alleles, benefit with ticagrelor and aspirin was present predominately in the first week, with additional small benefit accruing in the next 2 weeks.

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

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. 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. 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. 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.

High-Dose Clopidogrel versus Ticagrelor in CYP2C19 intermediate or poor metabolizers after percutaneous coronary intervention: A Meta-Analysis of Randomized Trials.

For patients after percutaneous coronary interventions (PCI), clopidogrel combined with aspirin is a conventional dual antiplatelet therapy (DAPT) method. Because the genetic polymorphism of CYP2C19gene leads to clopidogrel resistance, guidelines for antiplatelet recommendations in CYP2C19 of ultrarapid metabolizers (UM), extended metabolizers (EM) and poor metabolizers (PM) are clear. However, there is no clear recommendation as to whether ticagrelor or double dose clopidogrel is the best antiplatelet regimen for CYP2C19 of intermediate metabolizers (IM). To evaluate the efficacy and safety of ticagrelor (combined with aspirin) and high-dose clopidogrel (combined with aspirin) in patients after PCI with CYP2C19loss-of-function (LOF) alleles. We searched the following databases to select RCTs of comparing ticagrelor with high-dose clopidogrel in patients after PCI with CYP2C19 LOF alleles: CNKI, Wanfang Data, PubMed, Clinical trials, Cochrane, Web of Science and Embase. Major adverse cardiovascular events (MACEs), platelet function and TIMI bleeding event were defined as the outcomes. revman 5.3software was used to perform meta-analysis. A total of 14 RCTs with 2351 patients were enrolled. Meta-analysis showed that compared with high-dose clopidogrel, ticagrelor had reduced incidence of MACEs (OR=0.32, 95% Cl: 0.23-0.44, p<0.00001), stent thrombosis (OR: 0.24, 95%CI: 0.13-0.44, p<0.00001), myocardial infarction OR: 0.42, 95%CI: 0.22-0.80, p=0.008), revascularization (OR: 0.29, 95%CI: 0.10-0.82, p=0.02) and unstable angina (OR: 0.47, 95%CI: 0.29-0.77, p=0.003) in patients after PCI with CYP2C19 LOF alleles. A subgroup analysis showed that ticagrelor reduced the risk of MACEs compared with high-dose clopidogrel regardless of the type of metabolizer. Compared with high-dose clopidogrel, ticagrelor significantly reduced the risk of MACE with longer follow-up period (more than 3months) without increasing the risk of bleeding (OR: 0.89, 95%CI: 0.53-1.49, p=0.30), while elevated dyspnoea (OR: 5.62, 95%CI: 3.07-10.28, p<0.00001). For patients carrying CYP2C19 LOF alleles after PCI, ticagrelor may be better than high-dose clopidogrel in reducing the risk of MACEs, while dyspnoea incidents should be alerted.

Effect of CYP2C19 genetic polymorphism on the pharmacodynamics and clinical outcomes for patients treated with ticagrelor: a systematic review with qualitative and quantitative meta-analysis

BackgroundStudies show inconsistent results regarding the impact of CYP2C19 genotype on the pharmacodynamics (PD) and clinical outcomes of ticagrelor. With the implementation of genotype-guided individualized antiplatelet therapy, the association between CYP2C19 polymorphism and the efficacy and safety of ticagrelor for patients is still worthy of exploring and studying.MethodsThis systematic review protocol has been registered in the PROSPERO network (No. CRD 42020158920). Electronic databases of PubMed, EmBase, and the Cochrane Library were systematically searched from inception to January 6th, 2022 to select studies investigating the impact of CYP2C19 genotype on PD and clinical outcomes of ticagrelor. The results were presented as odds ratio (OR) or weight mean difference with its 95% confidence interval (CI) by using the random-effects model. Trial sequential analysis (TSA) was used to control risk of random errors and detect the robustness of outcomes.ResultsEight studies recruited a total of 6405 patients treated with ticagrelor. Mostly trials reported no significant effect of any or no CYP2C19 loss-of-function (LOF) allele (*2 or *3) on all the endpoints. Compared with no LOF allele carriers, subgroup analysis suggested any LOF allele in Asian patients was associated with a significant decreased risk of bleeding events (OR: 0.41; 95% CI: 0.22–0.75; P = 0.004). Furthermore, any LOF allele carriers didn’t yield any impact on the risk of MACEs (OR: 1.11; 95% CI: 0.76–1.64; P = 0.586), stroke (OR: 1.71; 95% CI: 0.99–2.96; P = 0.054), definite stent thrombosis (OR: 0.88; 95% CI: 0.17–4.60; P = 0.882), bleeding (OR: 0.63; 95% CI: 0.27–1.46; P = 0.281), myocardial infarction (OR: 0.81; 95% CI: 0.30–2.20; P = 0.682), and revascularization (OR: 0.81; 95% CI: 0.33–2.00; P = 0.649) in all patients. The results of TSA were indicated that more further trials would be required.ConclusionsThis qualitative and quantitative study suggested Asian patients carrying any CYP2C19 LOF allele might have a lower risk of bleeding events comparing with no LOF allele carriers when treated with ticagrelor. However, we did not prove an important role of CYP2C19 genotype on the risk of PD and clinical endpoints in the whole cohort. In future, more large-scale prospective studies and more different ethnic populations should be included.

Increased frequency of CYP2C19 loss-of-function alleles in clopidogrel-treated patients with recurrent cerebral ischemia.

Clopidogrel is used as secondary prevention after cerebral ischaemia. Previous, mainly Asian, studies have shown that genetic variations in CYP2C19 are associated with an increased risk of recurrent stroke in clopidogrel-treated patients. Evidence on the impact of this drug-gene interaction in European neurology patients is currently limited. The aim of this study is to compare the prevalence of CYP2C19 loss-of-function (LoF) alleles in a population with recurrent cerebral ischaemia to two reference groups from the same region. CYP2C19-genotyping (*2 and *3) was performed in clopidogrel-treated patients who presented with a recurrent ischaemic stroke/transient ischaemic attack (TIA). Genotype distributions were compared with two reference groups; a cohort of consecutive patients who underwent elective coronary stent implantation and a cohort of healthy Dutch volunteers. In total, 188 cases with a recurrent ischaemic event were identified, of whom 38 (20.2%) experienced an early recurrent event (24 hours to 90 days after the previous event). Among the total case group, 43.6% of the patients carried at least one CYP2C19 LoF allele, compared with 27.6% and 24.7% in respectively the cardiology and the healthy volunteers reference groups (P < .001 for both comparisons). Among the cases with an early recurrent event, 55.3% of patients were carriers of at least one CYP2C19 LoF allele (P < .0001). In this clopidogrel-treated population with recurrent cerebral ischaemia, the frequency of CYP2C19 LoF alleles was significantly higher than in reference groups, especially in early recurrent events. This study adds to the growing body of evidence that genotype-guided antiplatelet therapy could improve patient outcomes.

A study of microRNA-223 in evaluating platelet reactivity in patients with acute ischemic stroke.

To investigate the relationship between plasma microRNA-223 expression and platelet reactivity in patients with acute ischemic stroke (AIS) and to evaluate its predictive value in clopidogrel resistance or high on-treatment platelet reactivity (HTPR). A total of 120 patients with acute ischemic stroke were screened in this study, and 60 patients were included in the acute ischemic stroke group according to the inclusion criteria and platelet reactivity after clopidogrel treatment. control group was 60 non-ischemic stroke patients hospitalized. The levels of phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and adenosine diphosphate-induced platelet aggregation (ADP-PAg) in platelets were detected by flow cytometry. The expression level of plasma microRNA-223 was detected before and after clopidogrel treatment using quantitative real-time polymerase chain reaction (PcR). The AIS group was then divided into the clopidogrel non-HTPR and the clopidogrel HTPR groups based on the relative inhibition rate. We found that: 1) the VASP platelet reactivity index (PRI) was positively correlated with ADP-PAg; 2) before administration, the plasma microRNA-223 expression level and VASP-PRI were higher in the AIS group than in the control group; 3) after administration, the expression level of microRNA-223 was negatively correlated with VASP-PRI; 4) before and after treatment, the plasma microRNA-223 expression level in the clopidogrel HTPR group was lower than in the non-AIS patients; 5) before treatment, there was an interaction between the expression level of microRNA-223 in the plasma and the cYP2c19 loss-of-function (LOF) allele. The study showed that decreased plasma microRNA-223 expression levels in AIS patients indicate an increased risk of clopidogrel HTPR. carrying cYP2c19 LOF alleles may result in the microRNA-223 expression being more distinct. The combined detection of plasma microRNA-223 and cYP2c19 gene polymorphisms may be effective in predicting the occurrence of clopidogrel HTPR in patients with AIS.

Effects of the CYP2C19 LoF allele on major adverse cardiovascular events associated with clopidogrel in acute coronary syndrome patients undergoing percutaneous coronary intervention: a meta-analysis.

The aggregated risk of major adverse cardiovascular events (MACE) in acute coronary syndrome (ACS) patients inheriting CYP2C19 loss-of function (LoF) alleles who underwent percutaneous coronary intervention (PCI) and were treated with clopidogrel is controversial. In the current study, we searched the literature in different databases for eligible studies. The risk ratio (RR) was measured where p<0.05 was statistically significant. The ACS patients with either one or two CYP2C19 LoF alleles who underwent PCI, treated with clopidogrel were correlated with a significantly escalated risk of MACE compared with noncarriers (RR: 1.53, 95% CI: 1.39-1.69, p < 0.00001), driven by CV death (RR: 1.88, 95% CI: 1.18-3.01, p = 0.008), MI (RR: 1.67, 95% CI: 1.21-2.31, p = 0.002) and ST (RR: 1.90, 95% CI: 1.27-2.84, p = 0.002). Patients with two CYP2C19 LoF alleles were correlated with significantly greater risk of MACE compared with noncarriers (RR: 3.91, 95% CI: 2.78-5.50, p < 0.00001). Further analysis revealed that the risk of MACE was markedly significant in Asian patients (RR: 2.02, 95% CI: 1.67-2.44, p < 0.00001) and wascomparatively low significance in western patients (RR: 1.35, 95% CI: 1.20-1.52, p < 0.00001). There was no significantly different bleeding events in patients with CYP2C19 LoF alleles compared with noncarriers (RR: 0.99, 95% CI: 0.85-1.15, p = 0.87). The ACS patients inheriting CYP2C19 LoF alleles, who underwent PCI and were treated with clopidogrel were correlated with significantly increased risk of MACE compared with noncarriers.

Clinical Outcomes After Percutaneous Coronary Intervention Over Time on the Basis of CYP2C19 Polymorphisms.

The aim of this study was to investigate the association between CYP2C19 gene polymorphisms and the risk of cardiovascular events in the early stage and subsequent period after percutaneous coronary intervention (PCI) among patients who received clopidogrel. Between October 2015 and January 2017, CYP2C19 genotyped patients who were treated with clopidogrel after PCI were enrolled in this study. Included patients were categorized as non-loss-of-function metabolizers, intermediate metabolizers, and poor metabolizers based on CYP2C19 genotype. The primary outcome was a composite of any-cause mortality, nonfatal myocardial infarction, nonfatal ischemic stroke, and stent thrombosis occurring during exposure to clopidogrel. The rates of clinical outcome events were compared between CYP2C19 phenotypes. Landmark analyses were processed at 90 days and 1 year post-PCI. Of 1341 patients, 161 (12.0%) had 2 copies of loss-of-function (LOF) alleles, 621(46.3%) had one LOF allele, and 559 (41.7%) had no LOF allele. At the 3-month follow-up, the primary outcome events were more frequent in carriers of 2 LOF alleles (5.6%) than in noncarriers (1.8%) [adjusted hazard ratio (HR) 2.944, 95% confidence interval, 1.184-7.321, P = 0.020). A similar finding was observed among in patients with acute coronary syndrome indications at the index PCI (adjusted HR 3.046, 95% confidence interval, 1.237-7.501, P = 0.015). These differences did not persist within the subsequent 9 months of follow-up, among either all comers or subjects with acute coronary syndrome. In conclusion, these data demonstrate a higher risk for ischemic events in patients with 2 CYP2C19 LOF alleles who are prescribed clopidogrel, seen at 3 months after PCI, that is not sustained for 12 months.

Clopidogrel versus Ticagrelor in CYP2C19 Loss-of-Function Allele Noncarriers: A Real-World Study in China

This article compares the clinical outcomes of clopidogrel and ticagrelor in patients with acute coronary syndrome (ACS) without cytochrome P450 (CYP)2C19 loss-of-function (LOF) alleles and investigates whether clopidogrel could be an alternative P2Y12 inhibitor without increasing the risk of ischemic events. Patients were divided into the clopidogrel-treated group and the ticagrelor-treated group. Inverse probability of treatment weighting (IPTW) calculated by propensity scores was used to adjust confounding covariates. The primary outcome was major adverse cardiovascular or cerebrovascular events (MACCEs) within 12 months. The secondary outcomes were MACCEs plus unstable angina, and clinically significant bleeding events. Finally, 2,199 patients were included. Of them, 1,606 were treated with clopidogrel, and 593 were treated with ticagrelor. The mean age of the original cohort was 59.92 ± 9.81 years. During the 12-month follow-up period, MACCEs occurred in 89 patients (4.0%). No significant differences were observed in MACCEs (IPTW-adjusted hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.65-1.18), MACCEs plus unstable angina (IPTW-adjusted HR, 1.20; 95% CI, 0.91-1.59), or clinically significant bleeding events (IPTW-adjusted HR, 0.81; 95% CI, 0.53-1.23) between the clopidogrel- and ticagrelor-treated groups. In patients with ACS without CYP2C19 LOF alleles, clopidogrel was not associated with a higher risk of MACCEs when compared with ticagrelor. The main findings of this study support use of clopidogrel in CYP2C19 LOF noncarriers as an alternative P2Y12 inhibitor, which may reduce medical expenses and adverse reactions caused by more potent P2Y12 inhibitors in these patients.