Loss-of-function Allele Carriers Research Articles

Development of a routine bedside CYP2C19 genotype assessment programfor antiplatelet therapy guidance in a community hospital catheterization laboratory.

Genotype based personalized antiplatelet therapy in the setting of percutaneous coronary intervention (PCI) has been studied in clinical trials. Despite the demonstrated risk associated with CYP2C19 loss-of-function (LoF) carriage in clopidogrel-treated PCI patients, real-world implementation of genotyping for PCI has been low. The goal of the current study was to provide CYP2C19 genotype information to the interventionalist prior to the completion of the catheterization to facilitate immediate personalized antiplatelet therapy. Routine personalization of P2Y12 inhibitor therapy for PCI in a community hospital cardiac catheterization laboratory by POC genotyping with the SpartanRx system was first offered in February 2017. A best practice advisory (BPA) based on the Clinical Pharmacogenetics Implementation Consortium Guideline for CYP2C19 genotype and clopidogrel therapy was placed in the electronic health record prescription medication ordering system. By December 2019, 1,052 patients had CYP2C19 genotype testing, 429 patients underwent PCI with genotype guided antiplatelet therapy, and 250 patients underwent PCI without genotype testing and received antiplatelet therapy at the discretion of the treating physician. BPA compliance was 93. 87% of LoF allele carriers were prescribed ticagrelor or prasugrel whereas 96% of non-LoF allele carriers were prescribed clopidogrel. The genotyping results were available within 1h and made immediately available for decision making by the interventional cardiologist. POC CYP2C19 genotyping is feasible in a community hospital catheterization laboratory and is associated with high rate of best practice compliance.Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03040622.

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.

Use of Tirofiban to Prevent Ischemic Events in Patients with CYP2C19 Loss-of-Function Alleles during Flow Diversion of Intracranial Aneurysm: A Multicenter Cohort Study.

To analyze the effect of tirofiban on ischemic events in CYP2C19 loss-of-function (LOF) allele carriers during pipeline embolization device (PED) implantation. Demographic information, imaging data, ischemic complications, CYP2C19 genotyping, and platelet function test results were collected from patients with PED-treated intracranial aneurysms at three centers. Multivariate logistic regression was used to analyze risk factors for ischemic events. Patients were grouped according to LOF alleles and antiplatelet drugs, the baseline information of LOF allele carriers and non-carriers were compared, and the efficacy of tirofiban was analyzed by comparing the incidence of ischemic events in each group. In total, 278 patients were included in the study, 24 of whom had an ischemic event. 157 (56.5%) patients carried the LOF allele and were more likely to develop resistance to clopidogrel (P < 0.001) and hypertension (P = 0.010). Multivariate logistic regression analysis revealed that the independent risk factors for ischemic events were age of > 55years (OR = 3.308, P = 0.028), LOF alleles (OR = 3.960, P = 0.036), and clopidogrel nonresponsiveness (OR = 3.301, P = 0.014). For LOF allele carriers, prophylactic use of tirofiban after PED implantation helped to reduce ischemic events (4.3% vs. 16.4%, P = 0.039). This study supports CYP2C19 genotyping before flow diversion because LOF alleles increase the risk of ischemic events. Prophylactic use of tirofiban may help reduce ischemic events in LOF allele carriers.

CYP2C9 Polymorphisms and the Risk of Cardiovascular Events in Patients Treated with Clopidogrel: Combined Data from the POPular Genetics and POPular AGE Trials.

The cytochrome P450 (CYP)2C9 enzyme plays a role in the metabolization of clopidogrel. Carriage of a CYP2C9 loss-of-function (LoF) allele has been associated with attenuated pharmacokinetics, leading to a diminished pharmacodynamic response and increased risk for developing stent thrombosis in patients treated with clopidogrel. In this study, we aimed to determine the effect of the CYP2C9*2 and *3 LoF alleles on thrombotic events. Therefore, a post hoc analysis was performed in 878 patients with available CYP2C9 genotype status included in the POPular Genetics and POPular Age trials, which enrolled patients with ST-elevation myocardial infarction and non-ST-elevation myocardial infarction, respectively. The primary thrombotic outcome was a composite of cardiovascular death, myocardial infarction or stroke. A total of 526 (60%) patients were CYP2C9 LoF allele noncarriers and 352 (40%) were CYP2C9 LoF allele (*2 or *3) carriers. After correction for differences in baseline characteristics, there were no significant differences between CYP2C9 LoF allele carriers and noncarriers for the combined thrombotic outcome (6.3% vs. 5.9%, hazard ratio 1.16 [0.67-2.0], p=0.60), or the individual thrombotic outcomes. Moreover, no differences were seen in the event rates for clinically relevant bleeding (Bleeding Academic Research Consortium [BARC] 2-5 bleeding) as well as major bleeding (BARC 3 or 5 bleeding). Carriers of a CYP2C9 *2 or *3 LoF allele presenting with acute coronary syndrome and treated with clopidogrel did not have an increased risk for thrombotic events compared with noncarriers. Given the limited number of poor metabolizers, no firm conclusions could be drawn with regard to the thrombotic risk for patients carrying two CYP2C9 LoF alleles.

Abstract WP173: Interaction Between CYP2C19 Allele Status And Outcome Following Ischemic Stroke In Patients Treated With Clopidogrel: A TARDIS Trial Substudy

Background: Clopidogrel is routinely prescribed following ischaemic stroke (IS), or transient ischaemic attack (TIA), as secondary prevention. Conversion of clopidogrel to its active form involves several hepatic cytochrome P450 enzymes (CYP450), including P450-2C19 (CYP2C19). Previous evidence suggests that CYP2C19 loss of function (LoF) carriers prescribed clopidogrel are at increased risk of vascular events in comparison with non-carriers. We sought to test for interaction between CYP2C19 LoF status and treatment effects in the TARDIS trial. Methods: TARDIS was an international, randomised trial recruiting participants with acute IS/TIA. Participants were assigned to receive intensive antiplatelet therapy (aspirin, clopidogrel, and dipyridamole) or guideline therapy (clopidogrel alone or aspirin and dipyridamole). Blood samples for genotyping were taken from consented participants at a 70 of the 106 recruiting centres. Results: Of 3096 participants, 1361 (44%) had samples available for genotyping. Median age was 69.0 years and 65.1% were male. Of the 1361 with samples, 1071 (78.7%) were randomised to clopidogrel and 290 (21.3%) to aspirin plus dipyridamole. 387 (28.4%) participants were CYP2C19 LoF allele carriers. At 35 days, 64 participants (4.7%) had a further IS/TIA and the rate of major adverse cardiovascular events was 6.8%. In participants randomised to clopidogrel (monotherapy or intensive) the rates of further IS/TIA were 4.9% in LoF allele carriers and 4.2% in non-carriers. As for those taking clopidogrel monotherapy, the rates of further IS/TIA were 7.4% in LoF allele carriers compared to 3.8% in non-carriers, though this difference was non-significant (p=0.14). There were no significant differences, in outcome or bleeding risk, by treatment group and LoF carrier status. Conclusions: No significant interaction was found between CYP2C19 genotype and outcome following IS/TIA when prescribed clopidogrel, either as monotherapy or in combination with aspirin and dipyridamole. There was no observed interaction between LoF status, clinical outcome, and bleeding rates. A caveat is that this analysis was undertaken on a subgroup of TARDIS participants and so was underpowered to detect a difference in the monotherapy group.

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.

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.

The role of CYP2C19 genotyping to guide antiplatelet therapy following ischemic stroke or transient ischemic attack

ABSTRACT Introduction Clopidogrel is an antiplatelet agent recommended for secondary prevention of ischemic stroke (IS) and transient ischemic attack (TIA). Conversion of clopidogrel to its active metabolite by hepatic cytochrome P450-2C19 (CYP2C19) is essential for the inhibition of the P2Y12 receptor and subsequent platelet aggregation to prevent thrombotic events. CYP2C19 is highly polymorphic, with over 30 loss of function (LoF) alleles. This review considers whether there is sufficient data to support genotype guided antiplatelet therapy after stroke. Areas covered A systematic literature review retrieved articles, which describe the interaction between CYP2C19 genotype and clinical outcomes following IS or TIA when treated with clopidogrel. The review documents efforts to identify optimal antiplatelet regimens and explores the value genotype guided antiplatelet therapy. The work outlines the contemporary understanding of clopidogrel metabolism and appraises evidence linking CYP2C19 LoF variants with attenuated platelet inhibition and poorer outcomes. Expert opinion There is good evidence that CYP2C19 LoF allele carriers of Han-Chinese ancestry have increased risk for further vascular events following TIA or IS when treated with clopidogrel. The evidence base is less certain in other populations. The expansion of pharmacogenetics into routine clinical practice will facilitate further research and help tailor other aspects of secondary prevention.

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.

Implementation and clinical outcomes of pharmacogenetic CYP2C19 testing for clopidogrel therapy in real-world clinical practice.

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUNDCYP2C19 loss-of-function (LOF) polymorphisms are associated with adverse ischaemic events after PCI. The use of a point-of-care assay (POC) to routinely genotype patients immediately post PCI could rapidly identify patients at risk of adverse cardiac outcomes. PURPOSE To investigate the incidence of CYP2C19 polymorphisms (*2, *17) and 30-day MACE in patients presenting to catheter laboratory for PCI (See table 1).METHODS We performed a single centre prospective analysis of patients presenting to a cardiac catheterisation laboratory for percutaneous coronary intervention. Participants underwent prospective rapid point-of-care genotyping of CYP2C19 major alleles (2*,17*), using the SpartanRx PCR device via buccal swab sample. All patients provided written consent. RESULTS:A total of 120 tests were performed, 51 patients were normal allele carriers (*1), 31 patients were carriers of LOF alleles (*2) and 38 patients were carriers of gain of function alleles (*17). All tests results returned in one hour. Rate of dyslipidaemia was significantly different between three groups (55% vs. 63% vs. 36%; p = 0.050). A numerically higher proportion of LOF allele carriers received clopidogrel prior to undergoing pharmacogenetic testing but this was not statistically significant (52% vs. 35% vs. 34%; p = 0.09). Two cases of MACE at 30 day follow up occurred in the loss-of-function group. Both cases received clopidogrel.CONCLUSIONSWe have demonstrated that a rapid POC of CYP2C19 testing can take place in a real-world setting. Our incidence rate of LOF carriers is concordant with international published literature. We found 52% of LOF carriers were commenced on clopidogrel therapy prior to genetic analysis. Comparison of CPY2C19 Metabolisers genotype Loss of function normal Gain of function p values baseline characteristics age in years, median (range) 65 (43-82) 64 (43-85) 65 (42-89) 0.717 Male, N (%) 21 (68%) 43 (64%) 27 (71%) 0.198 Hypertensive, N (%) 16 (52%) 29 (57%) 24 (50%) 0.623 Dyslipidaemia. N (%) 17 (55%) 32 (63%) 14 (36%) 0.050 Indication, N (%) St-Elevation MI 12 (39%) 18 (35%) 11 (29%) 0.558 NSTEMI 5 (16%) 15 (29%) 14 (37%) 0.142 Unstable Angina 5 (16%) 7 (14%) 3 (8%) 0.518 Stable CAD 9 (29%) 11 (22%) 10 (26%) 0.731 Antiplatelet, N (%) Ticagrelor 15 (48%) 33 (65%) 25 (66%) 0.09 Clopidogrel 16 (52%) 18 (35%) 13 (34%) Complication, N (%) 30-day MACE 2 (6.5%) 0 0 0.01

Routine CYP2C19 Genotyping to Adjust Thienopyridine Treatment After Primary PCI for STEMI: Results of the GIANT Study

ObjectivesThe aim of this study was to evaluate prospectively the clinical impact of routine transmission of CYP2C19 genotype in the management of acute ST-segment elevation myocardial infarction with primary percutaneous coronary intervention. BackgroundResponse to clopidogrel differs widely among patients, notably because of CYP2C19 genetic polymorphisms. MethodsCYP2C19 genotype (6 alleles) was determined centrally and communicated within 4.1 ± 1.9 days of primary percutaneous coronary intervention in 1,445 patients with ST-segment elevation myocardial infarction recruited at 57 centers in France. CYP2C19 metabolic status was predicted from genotype and served to adjust thienopyridine treatment. The primary endpoint was differences in 12-month outcomes (death, myocardial infarction, and stent thrombosis) between patients with the wild-type genotype or gain-of-function allele (class 1, n = 1,118) and those with loss-of-function (LOF) alleles (class 2, n = 272) who received optimized thienopyridine treatment. ResultsDetection of LOF alleles resulted in adjustment of P2Y12 inhibition in 85% of patients, with significantly higher use of prasugrel or double-dose clopidogrel. The primary endpoint did not differ between class 1 and class 2 patients (3.31% vs. 3.04%, respectively; p = 0.82). In contrast, carriers of LOF alleles without treatment adjustment had significantly worse outcomes (15.6%; p < 0.05). Bleeding rates were not different between groups. ConclusionsIn a real-world setting, a complete CYPC2C19 genotype can be mostly determined in <7 days using analysis of saliva deoxyribonucleic acid collected during the in-hospital phase among patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention. Genotype information led to stronger platelet inhibition treatment in the vast majority of LOF allele carriers and to similar clinical outcomes as in patients carrying the wild-type genotype or gain-of-function allele. (Genotyping Infarct Patients to Adjust and Normalize Thienopyridine Treatment [GIANT]; NCT01134380)

Impacts of CYP2C19 Polymorphism and Clopidogrel Dosing on in-Stent Restenosis: A Retrospective Cohort Study in Chinese Patients.

ObjectiveThis retrospective cohort study is to analyze the impacts of CYP2C19 polymorphism and clopidogrel dosing on in-stent restenosis (ISR) after coronary stenting.MethodsTotally, 111 patients were included, who underwent percutaneous coronary intervention (PCI) with drug-eluting stent. Patients received clopidogrel treatment after the intervention on the background treatment with aspirin, based on the genotypes: 75 mg clopidogrel once each day for subjects without CYP2C19 loss-of-function (LOF) alleles (n=51; EM), 75 mg clopidogrel once each day (n=27; IM75) or twice each day (n=33; IM150) for subjects with one CYP2C19 LOF allele. ISR at 3–18 months after coronary stenting was assessed.ResultsISR rate was significantly higher in the IM75 group (40.7%) than the EM group (11.8%). ISR rate in the IM150 group was lower than the IM75 group (6.1% vs 40.7%), and comparable to that in the EM group. Multivariate logistic regression showed that both CYP2C19 genotype and clopidogrel dosing were associated with the risk of ISR after adjusting the relevant confounding factors. ISR risk was higher in the IM patients than the EM patients. Patients with clopidogrel dose of 75 mg once each day had significantly higher risk of ISR than those with the dose of 75 mg twice each day.ConclusionIncreased dose of clopidogrel may reduce the risk of ISR after PCI in CYP2C19 LOF allele(s) carriers. The presence of CYP2C19 LOF allele(s) increases the risk of ISR after stenting, which could be counteracted by the increased dose of clopidogrel.

Cost-effectiveness of CYP2C19 LOF-guided antiplatelet therapy in Chinese patients with acute coronary syndrome.

Aim: This study aimed to evaluate the cost-effectiveness of CYP2C19 loss-of-function(LOF)allele-guided antiplatelet therapy compared with the universal use of clopidogrel or ticagrelor among Chinese patients with acute coronary syndrome undergoing percutaneous coronary intervention. Methods: A two-part cost-effectiveness model comprising of a 1-year decision tree and a long-term Markov model was utilized to simulate outcomes of three treatment strategies: universal use of clopidogrel (75mg daily) or universal use of ticagrelor 90mg twice daily for all patients and CYP2C19 LOF-guided therapy (LOF allele carriers receiving ticagrelor, LOF allele noncarriers receiving clopidogrel). Model outcomes included quality-adjusted life years (QALYs) gained, direct medical costs and incremental cost-effectiveness ratios (ICERs). ICERs less than one-time gross domestic product per capita in China 59,660yuan/QALY were considered cost-effective. Results: Base-case analysis showed 'universal ticagrelor use' was cost-effective for an ICER of 33,875yuan per QALY gained compared with 'universal clopidogrel use' of which gained a 1.6932QALYs at lowest life-long cost of 2450yuan. CYP2C19 LOF-guided therapy had an effectiveness of 1.6975QALYs at a cost of 2812yuan, for an ICER of 84,118yuan per QALY gained relative to 'universal clopidogrel use'. Sensitivity analysis demonstrated that base-case results were significantly affected by five factors: the risk ratio of 'non-fatal myocardial infarction', 'non-fatal stroke' and 'cardiovascular death' in ticagrelor versus clopidogrel and the annual costs of clopidogrel and ticagrelor. According to the results of Monte Carlo simulation, when willing to pay is about 32,000yuan, patients willing to receive clopidogrel or ticagrelor are approximately equal. Conclusion: Optimal antiplatelet treatment is affected by lots of factors. The results of our study demonstrated that 'universal ticagrelor use' was cost-effective compared with 'universal clopidogrel use' for Chinese acute coronary syndrome patients with percutaneous coronary intervention.

P1934Platelet inhibitory profiles of prasugrel versus ticagrelor in patients with CYP2C19 loss-of-function genotypes undergoing percutaneous coronary intervention: results of a randomized feasibility study

Abstract Background Although clopidogrel is the most widely used P2Y12 inhibitor, loss-of-function (LOF) allelic variants located within the hepatic cytochrome P450 (CYP) 2C19 gene lead to attenuated bioactivation, increased rates of high platelet reactivity (HPR), and worse outcomes in patients undergoing percutaneous coronary intervention (PCI). Drug regulating authorities have suggested using alternative P2Y12 inhibitors (i.e., prasugrel or ticagrelor) in these patients. However, tailoring antiplatelet therapy in clinical practice according to results of genetic testing has been limited due to lack of access to promptly available results. Moreover, there are no head-to-head pharmacodynamic (PD) comparisons of prasugrel vs ticagrelor among patients with CYP2C19 LOF alleles. Purpose The aim of this study was to evaluate the feasibility of using rapid genetic testing in clinical practice and to compare the PD effects of prasugrel vs ticagrelor in patients undergoing PCI with CYP2C19 LOF alleles. Methods This was a prospective, randomized study conducted in patients with stable coronary artery disease and non-ST elevation acute coronary syndrome scheduled for left heart catheterization (LHC) with the intent to undergo PCI. Patients underwent rapid genetic testing using the Spartan RX assay, which defines CYP2C19 genetic status within 1 hour, allowing patients to be genotyped the same day of their LHC. Patients who were carriers of at least one LOF (*2 or *3) allele were randomized to receive either prasugrel [60mg loading dose (LD) - 10mg/day maintenance dose (MD)] or ticagrelor (180mg LD - 90mg b.i.d MD). Blood samples for PD analysis by VerifyNow were collected at 5 time points: baseline (prior to PCI), 30 minutes, 2 hours, 24 hours (or at hospital discharge whichever came first), and 1–4 weeks post-LD. All patients were treated with aspirin. The primary endpoint of our study was the non-inferiority in platelet reactivity, measured as PRU, at 24 hours of prasugrel vs ticagrelor in LOF allele carriers. Results A total of 781 consecutive patients scheduled for LHC were genotyped, of whom 223 (28.5%) were carriers of at least one LOF. Of these, 65 patients underwent PCI and randomized to prasugrel (n=32) vs ticagrelor (n=33). PRU levels at 24 hours were 33 vs 36 (prasugrel vs ticagrelor; mean difference = −3; 95% CI: −28 to 22; p=0.814) meeting the primary endpoint of non-inferiority. Both prasugrel and ticagrelor significantly reduced PRU to a similar extent with no differences between groups at all other time points (Figure). Accordingly, HPR rates were low and similar between groups. PRU by VerifyNow Conclusion Rapid genetic testing using the Spartan assay is feasible providing results in a timely fashion in a real-world clinical practice of patients undergoing PCI. Among patients with CYP2C19 LOF carrier status, prasugrel and ticagrelor are associated with similar levels of platelet inhibition. Acknowledgement/Funding Genetic testing was provided by Spartan RX

Efficacy of clopidogrel for stroke depends on CYP2C19 genotype and risk profile.

Dual antiplatelet therapy (DAT) with clopidogrel plus aspirin has been suggested by American Heart Association/American Stroke Association guidelines for minor stroke (MS) and transient ischemic attack (TIA) patients. The purpose of this study was to find the potential subgroups that benefit from DAT. We aimed to compare the efficacy of clopidogrel-aspirin therapy with that of aspirin therapy in MS/TIA patients stratified by CYP2C19 genotype and risk profiles. CYP2C19 loss-of-function allele (LoFA) carriers were defined as patients with LoFA of either *2 or *3. Low- and high-risk profile was defined as Essen Stroke Risk Score (ESRS) <3 and ≥3, respectively. Stroke recurrence at 1 year was considered primary outcome. Of a total 2,933 MS/TIA patients, there were 1,726 (58.8%) LoFA carriers and 1,068 (36.4%) patients at high risk (ESRS ≥3). No significant difference for stroke recurrence between the clopidogrel-aspirin group and aspirin alone group was found in LoFA carriers (11.2% vs 13.3%, hazard ratio [HR] = 0.83, 95% confidence interval [CI] = 0.64~1.09). In stratified analyses by CYP2C19 genotype and ESRS, HRs (95% CIs) of the clopidogrel-aspirin therapy for stroke recurrence were 1.00 (0.70~1.42), 0.63 (0.41~0.97), 0.62 (0.40~0.96), and 0.52 (0.31~0.88) among subgroups of LoFA carriers at low risk, LoFA carriers at high risk, LoFA noncarriers at low risk, and LoFA noncarriers at high risk, respectively, with p = 0.021 for interaction. Overall, LoFA carriers do not benefit from DAT, but there is significant benefit for LoFA carriers who are at high risk. The benefit of clopidogrel in Chinese MS/TIA patients depends on CYP2C19 genotype and risk profile. ANN NEUROL 2019;86:419-426.

Highlights From the Circulation Family of Journals.

Highlights From the Circulation Family of Journals.

CYP2C19 genotype and adverse cardiovascular outcomes after stent implantation in clopidogrel-treated Asian populations: A systematic review and meta-analysis

The effect of CYP2C19 gene polymorphism on clinical outcomes of patients with coronary artery disease (CAD) treated with clopidogrel remains controversial. Ethnicity has been proposed to influence clopidogrel response following stent implantation in CAD patients with different CYP2C19 genotypes. Furthermore, Asian populations are reported to have a relatively greater prevalence of CYP2C19 loss-of-function (LOF) alleles. We aimed to evaluate the impact of CYP2C19 gene polymorphism on clinical outcomes in Asian populations who underwent percutaneous coronary interventions (PCI) and received clopidogrel therapy. We conducted a comprehensive search in PubMed, EMBASE, and Cochrane Library from their inceptions to January 20, 2017. Studies that reported clopidogrel therapy information, clinically relevant outcomes (adverse cardiovascular events, stent thrombosis and bleeding), and CYP2C19 genotypes among Asian populations were included. The primary endpoint was major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death and myocardial infarction. The safety endpoint was any kind of bleeding. We retrieved 20 studies of 15056 patients reporting 1301 cardiovascular events. The primary analysis showed at least one CYP2C19 LOF allele (*2 and/or *3) carriers were at an increased risk of MACE compared with non-carriers (10.58% vs. 6.07%, OR: 1.99, 95% CI: 1.64 to 2.42, p < .001). Stent thrombosis (ST) was also more frequent in LOF allele carriers (2.22% vs. 0.44%, OR: 4.77, 95% CI: 2.84 to 8.01, p < .001). Inversely, the risk of bleeding was lower in LOF allele carriers (OR: 0.66, 95% CI: 0.46 to 0.96, p < .001). Subgroup analysis was performed to assess differences by high (600 mg) or routine (300 mg) loading dose of clopidogrel and by different nationalities. The risk of MACE in LOF allele carriers remained significantly higher even in high loading dose group (high loading dose: OR 1.72, 95% CI: 1.37 to 2.16, and routine loading dose: OR 2.22, 95% CI: 1.68 to 2.94, p for subgroup heterogeneity = 0.16). Subgroup analysis between three nationalities of China, Korea, and Japan demonstrated that the risk of MACE among Chinese LOF allele carriers was the greatest (OR: 2.28; 95% CI:1.91 to 2.73). In conclusion, among Asian populations with CAD undergoing stent implantation, CYP2C19 LOF allele carriers are at greater risk of adverse cardiovascular events and lower risk of bleeding compared with non-carriers. Genetic testing may be helpful for clinicians to personalize antiplatelet therapy especially in Asian population.

Association between platelet function and recurrent ischemic vascular events after TIAand minor stroke .

Platelet activation and aggregation play an important role in the pathological and physiological processes of recurrent ischemic vascular events in stroke patients. The purpose of this study is to determine the association between platelet function measured in the acute period and recurrent ischemic vascular events in patients with transient ischemic attack (TIA) or minor stroke. A total of 417 patients who were within the 24-hour period of clopidogrel-aspirin therapy after onset of a minor stroke or high-risk transient ischemic attack according to the Clopidogrel in High-risk patients with Acute Nondisabling Cerebrovascular Events (CHANCE) trial were included in this study. The platelet aggregation ratio was detected using a method of continuous platelet counting; patients underwent CYP2C19 genotyping, and the baseline data were recorded. The patients underwent a 6-month follow-up period during which the recurrent ischemic vascular events were observed. Logistic regression analysis was performed to obtain the risk factors for recurrent ischemic vascular events. The number of patients with recurrent ischemic events who had an arachidonic acid-induced maximum platelet aggregation ratio (MAR-AA) (aspirin 100 mg) (31.85 ± 12.86 vs. 26.71 ± 12.44, p=0.007) and adenosine diphosphate-induced maximum platelet aggregation ratio (MAR-ADP) after the administration of 75 mg clopidogrel for 12 ± 2 days (65.82 ± 10.72 vs. 53.10 ± 12.98, p<0.001) was significantly higher compared with the no ischemic vascular event group. Multivariate logistic regression analyses showed that being a carrier of the CYP2C19 loss-of-function (LOF) allele (OR=2.308, 95% CI: 1.087~4.901, p=0.029) as well as the MAR-AA (aspirin 100 mg) (OR=1.028, 95%CI: 1.006 ~ 1.052, p=0.014) and MAR-ADP after the administration of 75 mg clopidogrel (OR=1.067, 95% CI: 1.037~1.095, p<0.001) were risk factors for ischemic vascular events. The MAR-ADP after the administration of 75mg clopidogrel was significantly higher in patients who were carriers of the CYP2C19 (LOF) allele compared with non-carriers (57.53 ± 13.32 vs. 50.86 ± 12.55, p<0.001), and no significant differences between the CYP2C19 LOF allele carriers and non-carriers in the MAR-ADP were detected after the administration of 300 mg clopidogrel (37.18 ± 11.36 vs. 35.86 ± 12.49, p=0.264). Being a carrier of the CYP2C19 LOF allele has a significant influence on clopidogrel response. Platelet function is closely related to recurrent ischemic vascular events in acute minor stroke or TIA patients. .

CYP2C19 genotype plus platelet reactivity-guided antiplatelet therapy in acute coronary syndrome patients: a decision analysis.

We examined the cost-effectiveness of CYP2C19 genotype plus platelet reactivity-guided antiplatelet therapy (PG-PRT) from the perspective of US healthcare providers. A decision-analytic model was used to simulate life-long medical costs and quality-adjusted life-years (QALYs) of three antiplatelet strategies in a hypothetical cohort of 60-year-old patients with acute coronary syndrome after a percutaneous coronary intervention: (a) universal clopidogrel (75 mg daily), (b) universal alternative antiplatelet therapy (prasugrel or ticagrelor), and (c) all PG-PRT patients were genotyped. Noncarriers of the CYP2C19 loss-of-function (LOF) allele received clopidogrel 75 mg daily. CYP2C19 LOF allele(s) carriers who were poor metabolizers received prasugrel or ticagrelor. CYP2C19 LOF allele(s) carriers who were intermediate metabolizers (IM) received high-dose clopidogrel (225 mg daily) and were tested for high on-treatment platelet reactivity (HTPR). IM patients with HTPR were switched to prasugrel or ticagrelor. Model inputs were derived from the literature. In base-case analysis, PG-PRT was the least costly (USD 71,887) strategy with highest QALYs gained (7.886 QALYs). Sensitivity analyses found universal clopidogrel to be the preferred strategy if the prevalence of the CYP2C19 LOF allele was less than 2.6% or the incidence of HTPR in IM patients was greater than 82.8%. In 10,000 Monte Carlo simulations, PG-PRT was less costly than universal clopidogrel by USD 91 [95% confidence interval (CI) 83-99; P=0.0499], with higher QALYs by 0.0257 (95% CI: 0.0256-0.0258; P<0.001). Compared with universal alternative antiplatelet therapy, PG-PRT was less costly by USD 2208 (95% CI: 2195-2221; P<0.001) and gained 0.0085 QALYs (95% CI: 0.0083-0.0087; P=0.0260). PG-PRT seems to be cost-saving and effective for guiding selection of antiplatelet therapy in acute coronary syndrome patients undergoing percutaneous coronary intervention.