CYP2C19 Reduced-function Allele Research Articles

Abstract 16710: CYP2C19 Polymorphisms and Clinical Outcomes Following Percutaneous Coronary Intervention (PCI) in the Million Veterans Program (MVP)

Introduction: CYP2C19 reduced function (RF) alleles (*2, *3) have been shown to impair clopidogrel effectiveness following percutaneous coronary intervention (PCI) in the setting of acute coronary syndromes (ACS); however, this association has not been explored in the Veterans Health Administration. Hypothesis: CYP2C19 RF alleles are associated with major adverse cardiac events (MACE) in patients treated with clopidogrel Methods: MACE and CYP2C19 genotype were determined in MVP participants who underwent PCI between 2009-2017 with 1 year follow-up. Age was restricted to <65 years of age to exclude Veterans likely receiving care outside VHA. DNA extracted from whole blood was genotyped using a customized array and imputed to the 1000 Genomes reference panel. MACE, encompassing all-cause mortality, myocardial infarction and ischemic stroke, was ascertained in VA electronic health records using ICD 9/10 codes. Time to first MACE was determined in the whole cohort and in the subgroup with ACS and stable coronary disease using Kaplan-Meier estimators and Cox proportional hazard models adjusted for clinical covariates and clopidogrel exposure modeled as a time-varying covariate. Results: Among 4,490 Veterans (age 59.1 ± 5 years, 18% African American, 6% Hispanic, 44% ACS) who were prescribed clopidogrel following PCI, 1,261 (28%) had RF CYP2C19 alleles. The overall MACE rate was 7.0%. MACE was associated with ACS as initial presentation, diagnosis of diabetes, chronic kidney disease, peripheral vascular disease, congestive heart failure, history of stroke, prior MI. Among the subgroup presenting with ACS, the adjusted risk of MACE was greater in participants with RF alleles compared to those with wildtype alleles (HR 1.38, 95% CI 1.002-1.916). There was no impact of RF alleles on MACE risk in those in the non-ACS group (HR 1.00, 95% CI 0.702-1.429). Conclusions: These data from the largest integrated health system in the US demonstrate that in Veterans presenting with ACS undergoing PCI, there was a higher risk of MACE in CYP2C19 RF carriers prescribed clopidogrel vs. wildtype carriers. The impact of the CYP2C19-clopidogrel interaction was not observed in the non-ACS patients. Further studies should explore the role of pharmacogenetic testing in Veterans.

Aspirin plus clopidogrel may reduce the risk of early neurologic deterioration in ischemic stroke patients carrying CYP2C19*2 reduced-function alleles.

The mechanisms of early neurologic deterioration (END) and prevention strategies for END are not completely understood. The aim of this study was to investigate the association between CYP2C19*2 variants and END, and the effectiveness of antiplatelet therapy for prevention of END according to CYP2C19*2 genotypes in patients with ischemic stroke (IS). This was a two-center, randomized controlled study. Between August 2009 and December 2011, 570 IS patients were randomly assigned to clopidogrel plus aspirin group (n = 284) or aspirin alone group (n = 286). Platelet aggregation and platelet-leukocyte aggregates were measured before and after 7-10days of treatment. CYP2C19*2 (rs4244285) genotypes were examined using mass spectrometry. The primary outcome was END during the 10days of admission. Among the 570 patients, 121 (21.2%) patients suffered from END. Carriers of CYP2C19*2 reduced-function alleles were associated with higher incidence of END (26.8% in carriers vs. 16.6% in noncarriers, P = 0.004). The incidence of END was lower in the clopidogrel plus aspirin group than in the aspirin alone group (17.6 vs. 24.8%, P = 0.032). Stratified analyses revealed that clopidogrel plus aspirin could be more effective in reducing END than aspirin alone for carriers of CYP2C19*2 reduced-function alleles (18.8 vs. 34.9%, P = 0.006). However, there was no significant difference in incidence of END between dual therapy group and monotherapy group for noncarriers (16.7 vs. 16.6%, P = 0.998). Dual therapy with clopidogrel and aspirin may be adequate for prevention of END in carriers of CYP2C19 reduced-function alleles, but not for noncarriers. Our findings may be useful to guide precise antiplatelet therapy, and decrease the risk of END.

Tailored Adjunctive Cilostazol Therapy Based on CYP2C19 Genotyping in Patients With Acute Myocardial Infarction - The CALDERA-GENE Study.

Patients with reduced-function CYP2C19 genotypes on dual antiplatelet therapy (DAPT) with aspirin and clopidogrel show higher clinical risk for acute myocardial infarction (AMI). We investigated the effect of CYP2C19 genotype-tailored adjunctive cilostazol therapy on treatment of AMI.Methods and Results:The study group of 138 patients with suspected AMI were screened for CYP2C19 genotype immediately after percutaneous coronary intervention (PCI) using a SPARTAN RX point-of-care device. Carriers of the CYP2C19 reduced-function allele were randomized into DAPT (Carrier/DAPT) and DAPT plus 14-day cilostazol (Carrier/DAPT+Cilostazol) groups, while noncarriers were treated with DAPT (Noncarrier/DAPT). After exclusion of 10 patients, the remaining 128 patients were analyzed for P2Y12 reaction unit (PRU) using VerifyNow®P2Y12 system, and levels of biomarkers immediately after, and 1, 14, and 28 days after PCI. DAPT+Cilostazol reduced PRU levels in carriers (n=46) to those found in the Noncarrier/DAPT group (n=40), and significantly lower than those of the Carrier/DAPT group (n=42) at 14 days post-PCI. Discontinuation of cilostazol for 14 days was associated with a significant rise in PRU levels to those of the Carrier/DAPT group at 28 days post-PCI. Plasma B-type natriuretic peptide levels at 14 days post-PCI were lower in Carrier/DAPT+Cilostazol than in the other 2 groups, and the levels increased to those of the other groups at 28 days post-PCI after withdrawal of cilostazol. Adjunctive cilostazol therapy tailored to CYP2C19 genotype seemed useful in AMI patients with the CYP2C19 reduced-function allele.

The secondary prevention of stroke according to cytochrome P450 2C19 genotype in patients with acute large-artery atherosclerosis stroke.

PurposeTo investigated the effectiveness of antiplatelet agents for the secondary prevention of stroke according to CYP2C19 genotype in patients with ischemic stroke (IS).MethodsBetween August 2009 and December 2011, 570 acute IS patients with acute large-artery atherosclerosis were randomly assigned to receive either combined clopidogrel and aspirin for the first 30 day, and clopidogrel thereafter (clopidogrel group, n=284) or aspirin monotherapy (aspirin group, n=286). CYP2C19 genotypes were measured and masked until the end-of-study. The primary outcome was a composite of IS, transient ischemic attack (TIA), myocardial infarction (MI), and death.ResultsDuring the 5 years follow-up, the primary outcome occurred in 105 patients (18.4%) (71 had IS, 10 had TIA, 12 had MI, and 12 died). There were no significant differences in the primary outcome between clopidogrel group and aspirin group (16.5% vs. 20.3%) or between carriers of the CYP2C19 reduced-function alleles and noncarriers (21.8% vs.15.7%). In patients with aspirin therapy, CYP2C19 polymorphism was not associated with the primary outcome. However, in patients treated with clopidogrel, carriers of at least one CYP2C19 reduced-function allele had a 3-fold higher adjusted risk for primary outcome compared with noncarriers (95% confidence interval, 1.23 to 8.74).ConclusionsAmong IS patients treated with clopidogrel, carriers of a reduced-function CYP2C19 allele had a significantly higher rate of adverse vascular events than did noncarriers. It should avoid prescribing clopidogrel to these patients with known CYP2C19 polymorphisms.

High On-Treatment Platelet Reactivity to Adenosine Diphosphate Predicts Ischemic Events of Minor Stroke and Transient Ischemic Attack

This study aimed to evaluate the relationship between thromboelastography adenosine diphosphate maximum amplitude (TEG-ADPMA) and recurrent ischemic events in patients with minor ischemic stroke or high-risk transient ischemic attack (TIA). A total of 265 patients received dual antiplatelet therapy were consecutively enrolled. High on-treatment platelet reactivity (HTPR) to ADP was assessed by TEG-ADPMA and detected the CYP2C19 genotype; recurrent ischemic events were followed up for 90 days after onset. The difference of recurrent ischemic events was analyzed with or without HTPR to ADP by the Kaplan-Meier, and further to determine the difference of recurrent ischemic events in each group according to TEG-ADPMA-based tertile distribution. A total of 23 (8.6%) patients had recurrent ischemic events. TEG-ADPMA greater than or equal to 48 mm had good predictive value. Whether these patients were divided into 2 groups or 3 groups, the HTPR to ADP group had higher risk of recurrent ischemic events than the normal on-treatment platelet reactivity to ADP group by the Kaplan-Meier (all, P < .05). The tertile distribution map showed that the results of recurrent ischemic events were statistically significant in the third tertile group compared with the other two groups (all, P < .03); also, the third tertile group had a higher rate of carriers of at least 1 CYP2C19 reduced-function allele than the other two groups (P < .05). In patients with minor ischemic stroke and high-risk TIA, the TEG-ADPMA could predict recurrent ischemic events and has auxiliary effect on clinical decision-making.

Non-Carriers of Reduced-Function CYP2C19 Alleles are Most Susceptible to Impairment of the Anti-Platelet Effect of Clopidogrel by Proton-Pump Inhibitors: A Pilot Study.

The phenomenon of CYP2C19 polymorphism affects the metabolism of both clopidogrel and proton-pump inhibitors (PPI). However, concomitant use of both drugs may reduce the desired therapeutic effects. In this study, we evaluated whether individuals with different numbers of reduced-function CYP2C19 alleles were equally affected and whether PPIs with different dependencies on CYP2C19 metabolism were equally involved. Thirty healthy volunteers were recruited to a six-week regimen of clopidogrel. Three PPIs with different metabolic dependencies on CYP2C19 were included and separately administered in this order. Each PPI was given for a week, followed by a one-week washout period before the intervention of the next PPI. The anti-platelet effect was examined by Thromboelastography Platelet Mapping(TM) (TEG®) and vasodilator-stimulated phosphoprotein (VASP) assays. Both TEG® and VASP tests showed the same general qualitative trend, but TEG® detected a statistically significant fluctuation of platelet aggregation in response to different drug interventions. The TEG® results also demonstrated that non-carriers experienced the most significant impairment of anti-platelet effect of clopidogrel after concomitant use of PPIs. This impairment was closely related to the metabolic dependence on CYP2C19 of PPI. Our study indicated that non-carriers of reduced-function CYP2C19 alleles are most susceptible to impairment of the anti-platelet effect of clopidogrel after concomitant PPI use. Individual subjects are not equally affected, and PPIs are not equally involved. However, large-scale randomized clinical trials are needed to evaluate the clinical outcome. Clopidogrel • CYP2C19 polymorphism • Platelet aggregation • Proton pump inhibitors • TEG • VASP.

Hyper-Response to Clopidogrel in Japanese Patients Undergoing Transcatheter Aortic Valve Implantation.

Dual antiplatelet therapy is empirically recommended following transcatheter aortic valve implantation (TAVI). The aims of the present study were to analyze the effect of clopidogrel on platelet function and to determine the relative contribution of each CYP2C19 loss-of-function genotype undergoing TAVI.Thirty-two patients undergoing TAVI and with clopidogrel treatment were studied. All patients were treated with an Edwards SapienXT valve. Platelet reactivity was measured by the VerifyNow P2Y12 point-of-care assay at 7 days and 30 days after the procedure and a cutoff value of 95 PRU was used to identify a hyper-response of platelet reactivity. The Spartan RX(TM) sample-to-result point-of-care DNA testing system was used to identify CYP2C19 loss-of-function genotypes. Hyper-response of platelet reactivity was identified in 11 (34.3%) patients, although 24 (80%) were carriers of at least one CYP2C19 reduced-function allele. The PRU values did not change significantly from 7 days to 30 days after TAVI (136.7 ± 73.4 versus 150.4 ± 83.2, P = 0.13). The incidences of life-threatening bleeding, minor bleeding, and transfusion were significantly higher among the hyper-response of platelet reactivity group (27.3% versus 0%, P = 0.03, 36.4% versus 4.8%, P = 0.04, 81.8% versus 42.9%, P = 0.04, respectively).A hyper-response to clopidogrel was observed in one-third of patients undergoing TAVI and was related to bleeding events, even though 80% of the patients were carriers of the CYP2C19 reduced-function allele.

HM4 - How Much Evidence Do We Need Before Implementing Pharmacogenomic Testing In The Clinic?

Consensus on the evidence required to recommend clinical pharmacogenomic testing is unclear. A formal assessment of pharmacogenomic evidence levels in relation to other clinical interventions, such as avoiding drug-drug interactions (DDI), may be helpful for policymakers. The objective of this study was to quantitatively compare the evidence levels of two contested drug-attenuating interactions with clopidogrel antiplatelet therapy, and assess the value of obtaining additional evidence to inform clinical practice guidelines. We developed analogous value of information (VOI) decision models for: (1) avoidance of proton pump inhibitors (PPIs) in clopidogrel patients, and (2) pharmacogenomic-guided antiplatelet selection, both versus no intervention. Interaction-specific parameters and model structures were the only dissimilarities. We calculated the expected value of obtaining perfect information (EVPI) per patient, and the expected population value of obtaining additional information through future studies (EVSI). Current evidence for interaction-1 was slightly less uncertain (a 20% probability of making a non-optimal recommendation) than for interaction-2 (23%). The relative risk for cardiovascular death (conferred by concomitant PPI use in interaction-1, and reduced-function CYP2C19 alleles in interaction-2) was the greatest source of uncertainty in both models. The expected value of perfect information for interaction-1 was $139 per patient, compared to $242 per patient for interaction-2. In simulated 10,000-patient clinical trials, the expected population value of future research for interaction-1 was $2 million, versus $110 million for interaction-2. The evidence levels for clopidogrel DDI and pharmacogenomic effects appear to be fairly similar. However, the value of conducting future research on clopidogrel pharmacogenomics is higher because of greater uncertainty about the impact of pharmacogenomic testing on cardiovascular mortality. Our findings imply that evidence-based clinical guidelines for DDI and pharmacogenomic effects should be generally similar with regard to direction and strength of recommendation. This contrasts to some degree with current guidelines and drug labeling.

CYP2C19 polymorphism and clinical outcomes among patients of different races treated with clopidogrel: A systematic review and meta-analysis

Several studies have investigated the association between CYP2C19 polymorphism and clinical outcomes of patients treated with clopidogrel, but few have noticed the difference in association between Westerners and Asians. We searched MEDLINE, EMBASE and Cochrane Library database and conducted a systematic review and meta-analysis. Thirty-six studies involving 44 655 patients with coronary artery disease (CAD) treated with clopidogrel were included, of which more than 68% had undergone percutaneous coronary intervention (PCI). The primary outcome of our interest was the recurrence of major adverse cardiovascular events (MACE) in those CAD patients. Firstly, we found that the distribution of reduced-function CYP2C19 allele varied between Westerners and Asians. Among Asians, 1 and 2 reduced-function CYP2C19 mutant allele carriers accounted for 42.5% and 10%, respectively. While among Westerners, 1 and 2 reduced-function CYP2C19 mutant allele carriers accounted for 25.5% and 2.4%, respectively. Secondly, the impact of CYP2C19 polymorphism on clinical outcomes of patients treated with clopidogrel varied with races. Among Asians, only 2 reduced-function CYP2C19 mutant allele carriers had the reduced effect of clopidogrel. And the reduced effect was significant only after the 30th day of treatment. While among Westerners, both 1 and 2 reduced-function CYP2C19 allele carriers had the reduced effect, and it mainly occurred within the first 30 days. Thirdly, the safety of clopidogrel was almost the same among races. Reduced-function allele non-carriers had higher risk for total bleeding but did not have higher risk for major bleeding. It is suggested that CYP2C19 polymorphism affects the efficacy of clopidogrel differently among Westerners and Asians.

Optimal cutoff value of P2Y12 reaction units to prevent major adverse cardiovascular events in the acute periprocedural period: Post-hoc analysis of the randomized PRASFIT-ACS study

BackgroundFew studies have examined the effects of on-treatment platelet reactivity on the risk of major adverse cardiovascular events (MACE). We aimed to determine the optimal cutoff value of P2Y12 reaction units (PRUs) to prevent MACE occurring within 3days after percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). MethodsWe performed post-hoc analyses of 1363 patients enrolled in PRASFIT-ACS, which compared the effects of a prasugrel regimen adjusted for Japanese patients (loading dose/maintenance dose: 20mg/3.75mg) with those of clopidogrel (300mg/75mg) on MACE and bleeding events for 24–48weeks after PCI in ACS patients. PRU was serially measured using the VerifyNow® P2Y12 assay and we assessed the relationship between PRU and MACE. ResultsReceiver operating characteristic curve analysis showed that PRU ≤262 at 5–12h after ADP receptor antagonist loading was the optimal cutoff value for preventing MACE at up to 3days after PCI. The incidences of MACE were 5.2% and 10.8% in patients with PRU ≤262 or >262, respectively (odds ratio 0.50, 95% confidence interval 0.25–0.99, p<0.01). Significantly more prasugrel-treated patients had lower on-treatment platelet reactivity (defined as PRU ≤262) compared with clopidogrel-treated patients (79.9% vs. 30.4%, p<0.0001). Similar differences were observed between the prasugrel and clopidogrel groups for patients with normal or reduced-function CYP2C19 alleles. ConclusionsThe optimal PRU cutoff value for preventing MACE was 262 in Japanese ACS patients. Prasugrel rapidly reduced PRU with a large proportion of patients having low on-treatment platelet reactivity.

Lack of association between peri-procedural myocardial damage and CYP2C19 gene variant in elective percutaneous coronary intervention.

Peri-procedural myocardial damage (MD) is associated with increased risk of major in-hospital complications and adverse clinical events. The aim of this study was to evaluate the effects of on-clopidogrel platelet aggregation and CYP2C19-reduced-function gene variants on elective percutaneous coronary intervention (PCI)-related MD. We measured changes in serum high-sensitive troponin T (hs-TnT) levels, CYP2C19 genotype, and on-clopidogrel platelet aggregation (PA) using VerifyNow(®) P2Y12 system in 91 patients who received stent implantation (stent group). The control group comprised 30 patients who did not receive PCI. Blood samples were obtained before and 24h after PCI or coronary angiography (CAG). Patients of the stent group were divided into high and low MD groups based on the median value of hs-TnT level at 24h after PCI. Serum hs-TnT levels were significantly higher 24h after PCI (86.8±121.5pg/ml) compared with before PCI (9.4±5.3, p<0.001), whereas the levels were identical before and 24h after CAG in the control group. Simple logistic regression analysis demonstrated that MD correlated with age (p=0.014), estimated GFR (p=0.003), hemoglobin A1c (p=0.015), baseline serum hs-TnT (p=0.049), and stent length (p<0.001). Multiple logistic regression analysis identified old age, high hemoglobin A1c level, and long stent, but not CYP2C19 reduced-function allele or high on-clopidogrel PA, as independent predictors of elective PCI-related MD. The present study demonstrated no significant relation between peri-procedural MD and high on-clopidgrel PA associated with CYP2C19 reduced-function allele in patients undergoing elective PCI.

Evaluation of the INNOVANCE PFA P2Y assay and its association with CYP2C19 genotypes

The purpose of this study was to evaluate associations between INNOVANCE PFA P2Y (PFA P2Y) test results and CYP2C19 genotypes and provide baseline data for PFA P2Y testing to establish a therapeutic monitoring strategy for clopidogrel. A total of 75 new patients with acute coronary syndrome with planned percutaneous coronary intervention were enrolled between June 2012 and September 2012. All patients received clopidogrel at an initial loading dose of 600 mg followed by a 75-mg daily maintenance dose. Blood samples were obtained on the third morning after clopidogrel loading. PFA P2Y, VerifyNow P2Y12 and VASP assays were used to determine platelet inhibition due to clopidogrel, and the Verigene CYP2C19 test was used for CYP2C19 genotyping. The genotype frequency of 75 patients was as follows: CYP2C19 *1/*1 (wild type), 28 (37.3%); *1/*2, 31 (41.3%); *1/*3, 4 (5.3%); *2/*2, 5 (6.7%); *2/*3, 5 (6.7%); *1/*17, 1 (1.3%); and *2/*17, 1 (1.3%). Classified according to CYP2C19 genotypes, there were 29 (38.7%) extensive metabolizers (EM) or ultra rapid metabolizers (UM), 35 (46.7%) intermediate metabolizers (IM), and 10 (13.3%) poor metabolizers (PM). Median (interquartile range) PFA P2Y closure times (seconds) were 119 (101–260), 300 (130–300) and 300 (300–300) in the PM, IM and EM or UM groups, respectively (p < 0.05). Median (interquartile range) VerifyNow PRUs were 294 (213–297), 215 (165–320) and 189 (118–279); and the VASP platelet reactivity index (%) was 52.7 (33.3–91.9), 59.9 (41.4–72.8) and 38.9 (26.8–62.2) in the PM, IM and EM or UM groups, respectively (p > 0.05). Compared with non-carriers, carriers of reduced function CYP2C19 alleles tended to have higher platelet reactivity after clopidogrel treatment. The cut-off for PM versus other groups (IM and EM or UM) was ≤141 seconds (AUC 0.704, sensitivity 70%, specificity 76.6%) on the ROC curve. A statistically significant correlation between PFA P2Y (seconds) and VerifyNow (PRU) was found (ρ = −0.47, p < 0.0001). In conclusion, the PFA P2Y test showed a statistically significant association with CYP2C19 metabolizer phenotypes based on CYP2C19 genotyping and effectively determined the risk groups resistant to clopidogrel therapy, including PM.

Impact of CYP2C19 Polymorphism on Platelet Function Tests and Coagulation and Inflammatory Biomarkers in Patients Undergoing Percutaneous Coronary Intervention

Carriers of the reduced-function CYP2C19 allele receiving dual antiplatelet therapy (DAPT) with aspirin and clopidogrel exhibit diminished platelet inhibition and an increased risk of events. The purpose of this study was to investigate the effects of CYP2C19 gene variants on platelet function tests and coagulation and inflammatory biomarkers in patients undergoing elective percutaneous coronary intervention (PCI). This prospective, observational, multicenter study enrolled 104 consecutive Japanese patients undergoing elective PCI. We examined the CYP2C19 genotype, platelet function tests, the levels of coagulation and inflammatory biomarkers and the serum levels of high-sensitivity troponin T (hs-TnT) before, immediately after and one, two and 28 days after PCI. A total of 68 (65%) of the 104 enrolled patients were carriers of the CYP2C19 reducedfunction allele. On-clopidogrel platelet aggregation (PA), measured using light transmittance aggregometry and the VerifyNow(®) P2Y12 system, and the platelet reactivity index (PRI) were significantly higher at all time points in the carriers than in the noncarriers (p＜0.05), whereas there were no differences in the levels of the coagulation and inflammatory biomarkers or serum hs-TnT. Simple and multiple logistic regression analyses identified on-clopidogrel PA and PRI as being significant predictors of carriers of the CYP2C19 reduced-function allele. The present study suggests that platelet function tests, but not coagulation, inflammatory or cardiac biomarkers, are useful for identifying carriers of CYP2C19 reduced-function gene variants and monitoring the efficacy of DAPT in patients undergoing elective PCI.

Effects of CYP2C19 genotype on vascular function in patients with coronary artery disease receiving clopidogrel

Purpose: The role of CYP2C19*2 polymorphism in plasma clopidogrel active drug metabolite concentrations, in platelet inhibition and in cardiovascular prognosis has come under question in recent studies. We examined the impact of functional genetic polymorphism CYP2C19*2 on endothelial function and arterial stiffness in patients with CAD treated with clopidogrel regimen. Methods: We consecutively enrolled 408 patients with stable CAD receiving clopidogrel regimen (75mg/d), one month after percutaneous coronary intervention. Endothelial function was evaluated by flow-mediated dilation (FMD) of the brachial artery. Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) as an index of arterial wave reflections. CYP2C19*2 genotyping was performed by real-time polymerase chain reaction. High on treatment platelet reactivity was evaluated using VerifyNow Assay. VerifyNow reports its results in P2Y12 reaction units (PRU) and the diagnostic cut-off value is 230 PRU. Results: From the study population 150 patients (36.8%) were carriers of at least one CYP2C19*2 reduced-function allele and 258 patients (63.2%) were non carriers. There was no statistically significant difference between carriers and non carriers in age, male sex and the presence of hyperlipidemia, diabetes mellitus, arterial hypertension, in smoking habits, in anticoagulant and statin treatment. Importantly, there was no difference in FMD (4.88±2.34% vs. 4.83±2.21%, p=0.83), PWV (8.53±2.54m/sec vs. 8.85±2.33m/sec, p=0.19) and AIx values (22.87±10.04% vs. 23.82±8.43%, p=0.31) between carriers and non carriers respectively. Finally, carriers of two CYP2C19*2 reduced-function allele had significantly increased PRU (292±53 vs. 198±83, p=0.007). Conclusions: The presence of CYP2C19*2 loss of action polymorphism displays no impact on arterial wall properties in patients with CAD treated with clopidogrel regimen. Moreover, carriers of two CYP2C19 reduced-function alleles had significantly increased platelet reactivity.

Influence of Genetic Polymorphisms on the Effect of High- and Standard-Dose Clopidogrel After Percutaneous Coronary Intervention: The GIFT (Genotype Information and Functional Testing) Study

This study sought to evaluate the influence of single nucleotide polymorphisms (SNPs) on the pharmacodynamic effect of high- or standard-dose clopidogrel after percutaneous coronary intervention (PCI). There is a lack of prospective, multicenter data regarding the effect of different genetic variants on clopidogrel pharmacodynamics over time in patients undergoing PCI. The GRAVITAS (Gauging Responsiveness with A VerifyNow assay-Impact on Thrombosis And Safety) trial screened patients with platelet function testing after PCI and randomly assigned those with high on-treatment reactivity (OTR) to either high- or standard-dose clopidogrel; a cohort of patients without high OTR were also followed. DNA samples obtained from 1,028 patients were genotyped for 41 SNPs in 17 genes related to platelet reactivity. After adjusting for clinical characteristics, the associations between the SNPs and OTR using linear regression were evaluated. CYP2C19*2 was significantly associated with OTR at 12 to 24 h (R(2) = 0.07, p = 2.2 × 10(-15)), 30 days (R(2) = 0.10, p = 1.3 × 10(-7)), and 6 months after PCI (R(2) = 0.07, p = 1.9 × 10(-11)), whereas PON1, ABCB1 3435 C→T, and other candidate SNPs were not. Carriers of 1 and 2 reduced-function CYP2C19 alleles were significantly more likely to display persistently high OTR at 30 days and 6 months, irrespective of treatment assignment. The portion of the risk of persistently high OTR at 30 days attributable to reduced-function CYP2C19 allele carriage was 5.2% in the patients randomly assigned to high-dose clopidogrel. CYP2C19, but not PON1 or ABCB1, is a significant determinant of the pharmacodynamic effects of clopidogrel, both early and late after PCI. In patients with high OTR identified by platelet function testing, the CYP2C19 genotype provides limited incremental information regarding the risk of persistently high reactivity with clopidogrel 150-mg maintenance dosing. (Genotype Information and Functional Testing Study [GIFT]; NCT00992420).

Antiplatelet Therapy and Proton Pump Inhibition

A 77-year-old man with history of diabetes mellitus and coronary artery disease presented with angina and evidence of ischemia despite maximal medical therapy. He underwent a percutaneous coronary intervention with a drug-eluting stent and was started on long-term dual antiplatelet therapy with aspirin and clopidogrel. His medical history was significant for an episode of gastrointestinal (GI) bleeding in the setting of using nonsteroidal antiinflammatory drugs. Dual antiplatelet therapy, typically the addition of an ADP receptor antagonist to aspirin, has become the cornerstone of management of patients with acute coronary syndromes and after percutaneous coronary intervention. However, along with the reduction of thrombotic outcomes, this therapeutic strategy has the untoward effect of increasing the risk of bleeding events, including GI bleeding.1 The use of gastroprotective strategies, most notably proton pump inhibitors (PPIs), has become a widely adopted and recommended practice in this patient population.2 Currently, the most commonly prescribed ADP receptor antagonist is clopidogrel, a prodrug that undergoes activation by the cytochrome P450 system, in particular CYP2C19. The importance of this reaction on the overall platelet inhibitory effects of clopidogrel is highlighted by the fact that patients with reduced-function CYP2C19 alleles exhibit a reduced response to clopidogrel compared with those with the wild-type alleles. This finding might translate into increased risk of adverse events after acute coronary syndromes and percutaneous coronary intervention. Given that PPIs are inhibitors of CYP2C19, coupled with reports suggesting a clinically significant interaction,3 regulatory agencies issued a cautionary statement advising against the combined use of PPIs (specifically omeprazole and esomeprazole) and clopidogrel.4 Aspirin causes direct damage to the gastric epithelium and inhibits prostaglandin production by the gastric mucosa, leading to ulcerations and an estimated 2-fold increased risk of GI bleeding with low-dose aspirin alone.1 The risk increases with the additional use of …

Determination of cut-off levels for on-clopidogrel platelet aggregation based on functional CYP2C19 gene variants in patients undergoing elective percutaneous coronary intervention

Introduction Carriers of reduced-function CYP2C19 allele on antiplatelet therapy show diminished platelet inhibition and higher rate of clinical risk. The purpose of this study was to determine cut-off levels of VerifyNow P2Y12 system associated with effective inhibition of on-clopidogrel platelet aggregation to predict carriers of CYP2C19 reduced-function allele among patients undergoing percutaneous coronary intervention (PCI). Materials and Methods We enrolled 202 consecutive patients with stable coronary artery disease (CAD) undergoing PCI and treated with clopidogrel. All patients underwent CYP2C19 genotyping and measurement of residual platelet aggregation by VerifyNow system. Results Carriers of CYP2C19 reduced-function allele constituted 131 (65%) of 202 CAD patients. Platelet inhibition measured by P2Y12 reaction units (PRU) and %inhibition was diminished in carriers compared with noncarriers (PRU: 290.0 ± 81.2 vs 217.6 ± 82.4, p < 0.001, %inhibition: 17.9 ± 17.8 vs 35.5 ± 22.8, p < 0.001, respectively). Multiple logistic regression analysis identified PRU and %inhibition as significant predictors of carrier state [odds ratio (OR) 4.95; 95% confidence interval (95%CI): 2.49 to 9.85; p < 0.001, OR 5.55; 95%CI: 2.80 to 10.99; p < 0.001, respectively]. Receiver-operating characteristic analysis showed that PRU and %inhibition were significant predictors of carrier state [area under the curve (AUC) 0.736 (95%CI: 0.664 to 0.808; p < 0.001), AUC 0.727 (95%CI: 0.651 to 0.803; p < 0.001), respectively]. The cut-off levels of PRU and %inhibition were 256 and 26.5% for the identification of carriers. Conclusions Our results suggested that the cut-off levels of PRU and %inhibition to discriminate carriers of CYP2C19 reduced-function allele from noncarriers are potentially useful clinically to provide optimal clopidogrel therapy in patients with stable CAD undergoing PCI.

Carriage of Reduced-Function CYP2C19 Allele Among Patients Treated With Clopidogrel

Carriage of Reduced-Function <i>CYP2C19</i> Allele Among Patients Treated With Clopidogrel

Top Advances in Functional Genomics and Translational Biology for 2010

In recent years, major advances have been made in transcriptomics, metabolomics, proteomics, and particularly population genetics. More than 850 genome-wide association studies (GWAS) were published by the end of 2010, now covering a vast number of diseases and phenotypes and often incorporating tens of thousands of subjects or, in some cases, more than 100 000 subjects, increasing statistical power to identify and replicate contributing loci. Sequencing throughput advances and decreasing costs per sample have allowed the application of genome-wide genotyping and sequencing technology to larger DNA samples as well as transcriptome and epigenome features. This year was marked not only by continuing progress with GWAS, sequencing, and copy number variation studies but also by follow-up of GWAS and other findings with functional studies that uncover new molecular pathways contributing to disease and pave the way for future clinical applications. The American Heart Association Functional Genomics and Translational Biology Interdisciplinary Council (http://www.americanheart.org/presenter.jhtml?identifier=3016539) provides a forum for a multidisciplinary group of volunteers committed to making a substantial contribution to reduce the burden of heart disease and stroke through genetics, genomics, proteomics, and metabolomics research and translational science. With input from the Early Career Committee of the Council on Functional Genomics and Translational Biology, we considered many papers and selected 10 outstanding manuscript groups (15 articles) published in 2010 that reflect these advances, and we briefly summarize each below in chronological order.

ACCF/ACG/AHA 2010 Expert Consensus Document on the Concomitant Use of Proton Pump Inhibitors and Thienopyridines: A Focused Update of the ACCF/ACG/AHA 2008 Expert Consensus Document on Reducing the Gastrointestinal Risks of Antiplatelet Therapy and NSAID Use

This expert consensus document was developed by the American College of Cardiology Foundation (ACCF), the American College of Gastroenterology (ACG), and the American Heart Association (AHA). Expert consensus documents inform practitioners, payers, and other interested parties of the opinion of ACCF and document cosponsors concerning evolving areas of clinical practice or medical technologies. Expert consensus documents cover topics for which the evidence base, experience with technology, or clinical practice is not considered sufficiently well developed to be evaluated by the formal ACCF/AHA Practice Guidelines process. Often, the topic is the subject of considerable ongoing investigation. Thus, the reader should view the expert consensus document as the best attempt of the ACCF and document cosponsors to inform clinical practice in areas where rigorous evidence may not yet be available. To avoid actual, potential, or perceived conflicts of interest that may arise as a result of industry relationships or personal interests among the writing committee, all members of the writing committee, as well as peer reviewers of the document, are asked to disclose all current healthcare-related relationships and those existing 12 months before initiation of the writing effort. The ACCF Task Force on Clinical Expert Consensus Documents (CECD) reviews these disclosures to determine which companies make products (on market or in development) that pertain to the document under development. Based on this information, a writing committee is formed to include a majority of members with no relevant relationships with industry (RWI), led by a chair with no relevant RWI. Authors with relevant RWI are not permitted to draft or vote on text or recommendations pertaining to their RWI. RWI are reviewed on all conference calls and updated as changes occur. Author and peer reviewer RWI pertinent to this document are disclosed in Appendixes 1 and 2, respectively. Additionally, to ensure complete transparency, …