Jean-Sébastien Hulot

Cytochrome P450 2C19 polymorphism in young patients treated with clopidogrel after myocardial infarction: a cohort study.

BACKGROUND Clopidogrel and low-dose aspirin have become the mainstay oral antiplatelet regimen to prevent recurrent ischaemic events after acute coronary syndromes or stent placement. The frequent genetic functional variant 681 G>A (*2) of cytochrome P450 2C19 (CYP2C19) is an important contributor to the wide variability between individuals of the antiplatelet effect of clopidogrel. We assessed whether the CYP2C19*2 polymorphism affected long-term prognosis of patients who were chronically treated with clopidogrel. METHODS Between April 1, 1996, and April 1, 2008, 259 young patients (aged <45 years) who survived a first myocardial infarction and were exposed to clopidogrel treatment for at least a month, were enrolled in a multicentre registry and underwent CYP2C19*2 determination. The primary endpoint was a composite of death, myocardial infarction, and urgent coronary revascularisation occurring during exposure to clopidogrel. Follow-up was every 6 months. The key secondary endpoint was stent thrombosis proven by angiography. FINDINGS Median clopidogrel exposure time was 1.07 years (IQR 0.28-3.0). Baseline characteristics were balanced between carriers (heterozygous *1/*2, n=64; homozygous *2/*2, n=9) and non-carriers (n=186) of CYP2C19*2 variant. The primary endpoint occurred more frequently in carriers than in non-carriers (15 vs 11 events; hazard ratio [HR] 3.69 [95% CI 1.69-8.05], p=0.0005), as did stent thrombosis (eight vs four events; HR 6.02 [1.81-20.04], p=0.0009). The detrimental effect of the CYP2C19*2 genetic variant persisted from 6 months after clopidogrel initiation up to the end of follow-up (HR 3.00 [1.27-7.10], p=0.009). After multivariable analysis, the CYP2C19*2 genetic variant was the only independent predictor of cardiovascular events (HR 4.04 [1.81-9.02], p=0.0006). INTERPRETATION The CYP2C19*2 genetic variant is a major determinant of prognosis in young patients who are receiving clopidogrel treatment after myocardial infarction.

Heart Rate and Cardiac Rhythm Relationships With Bisoprolol Benefit in Chronic Heart Failure in CIBIS II Trial

Background —&bgr;-Blockade–induced benefit in heart failure (HF) could be related to baseline heart rate and treatment-induced heart rate reduction, but no such relationships have been demonstrated. Methods and Results —In CIBIS II, we studied the relationships between baseline heart rate (BHR), heart rate changes at 2 months (HRC), nature of cardiac rhythm (sinus rhythm or atrial fibrillation), and outcomes (mortality and hospitalization for HF). Multivariate analysis of CIBIS II showed that in addition to &bgr;-blocker treatment, BHR and HRC were both significantly related to survival and hospitalization for worsening HF, the lowest BHR and the greatest HRC being associated with best survival and reduction of hospital admissions. No interaction between the 3 variables was observed, meaning that on one hand, HRC-related improvement in survival was similar at all levels of BHR, and on the other hand, bisoprolol-induced benefit over placebo for survival was observed to a similar extent at any level of both BHR and HRC. Bisoprolol reduced mortality in patients with sinus rhythm (relative risk 0.58, P <0.001) but not in patients with atrial fibrillation (relative risk 1.16, P =NS). A similar result was observed for cardiovascular mortality and hospitalization for HF worsening. Conclusions —BHR and HRC are significantly related to prognosis in heart failure. &bgr;-Blockade with bisoprolol further improves survival at any level of BHR and HRC and to a similar extent. The benefit of bisoprolol is questionable, however, in patients with atrial fibrillation.

Clinical Pharmacogenetics Implementation Consortium Guidelines for CYP2C19 Genotype and Clopidogrel Therapy: 2013 Update

Cytochrome P450 (CYP)2C19 catalyzes the bioactivation of the antiplatelet prodrug clopidogrel, and CYP2C19 loss‐of‐function alleles impair formation of active metabolites, resulting in reduced platelet inhibition. In addition, CYP2C19 loss‐of‐function alleles confer increased risks for serious adverse cardiovascular (CV) events among clopidogrel‐treated patients with acute coronary syndromes (ACSs) undergoing percutaneous coronary intervention (PCI). Guideline updates include emphasis on appropriate indication for CYP2C19 genotype–directed antiplatelet therapy, refined recommendations for specific CYP2C19 alleles, and additional evidence from an expanded literature review (updates at http://www.pharmgkb.org).

Natural History and Risk Stratification of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Background—Management of patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is complicated by the incomplete information on the natural history of the disease and by the lack of risk stratification for cardiovascular death. The aim of the study was the identification of risk factors related to long-term prognosis. Methods and Results—Data were collected from 130 patients (100 men; age at onset of symptoms, 31.8±14.4 years) from a tertiary center between 1977 and 2000 who fulfilled the international standardized diagnostic criteria for ARVD/C. Risk factors for cardiovascular death were determined by a logistic regression model. After a mean follow-up of 8.1±7.8 years, 24 deaths were recorded, with a mean age at death of 54±19 years (annual mortality rate, 2.3%). There were 21 deaths with a cardiovascular origin (progressive heart failure for 14 patients and sudden death for the remaining 7 patients). All patients who died had a history of ventricular tachycardia. Multivariate analysis showed that after adjustment for sex, history of syncope, chest pain, inaugural ventricular tachycardia, recurrence of ventricular tachycardia, and QRS dispersion, clinical signs of right ventricular failure and left ventricular dysfunction both remained independently associated with cardiovascular mortality. The combined presence of one of these risk factors and ventricular tachycardia identifies high-risk subjects for cardiovascular mortality, whereas patients without ventricular tachycardia displayed the best prognosis. Conclusions—The information on the natural history of patients with ARVD allowed us to identify risks factors for cardiovascular mortality. An analysis of a large international registry is needed to refine these results.

Cardiovascular risk in clopidogrel-treated patients according to cytochrome P450 2C19*2 loss-of-function allele or proton pump inhibitor coadministration: a systematic meta-analysis.

OBJECTIVES The aim of this study was to assess the association between the loss-of-function cytochrome P450 2C19 (CYP2C19)*2 variant (10 studies, 11,959 patients) or the use of proton pump inhibitors (PPIs) (13 studies, 48,674 patients) and ischemic outcomes (major adverse cardiovascular events [MACE]) in patients treated with clopidogrel. BACKGROUND In clopidogrel-treated patients, increased cardiovascular risk has been identified with the loss-of-function CYP2C19*2 allele or the use of PPIs, some of them CYP2C19 inhibitors. To further estimate the effect of a reduction in activity of this enzyme, the authors performed a meta-analysis of the studies available. METHODS The meta-analysis was performed on 23 studies using the odds ratio (OR) as the parameter of efficacy, with a fixed-effect model. The end points were MACE, mortality, or stent thrombosis. RESULTS Of the 11,959 patients, carriers of the loss-of-function CYP2C19*2 allele (28% [n = 3,418]) displayed a 30% increase in the risk for MACE compared with noncarriers (9.7% vs. 7.8%; OR: 1.29; 95% confidence interval [CI]: 1.12 to 1.49; p < 0.001). This single gene variant (CYP2C19*2) was also associated with an excess of mortality (1.8% vs. 1.0%; OR: 1.79; 95% CI: 1.10 to 2.91; p = 0.019; n = 6,225) and of stent thrombosis (2.9% vs. 0.9%; OR: 3.45; 95% CI: 2.14 to 5.57; p < 0.001; n = 4,905). This increased risk was apparent in both heterozygotes and homozygotes and was independent of the baseline cardiovascular risk. PPI users (42% [n = 19,614]) displayed increased risk for MACE (21.8% vs. 16.7%; OR: 1.41; 95% CI: 1.34 to 1.48; p < 0.001) and mortality (12.7% vs. 7.4%; OR: 1.18; 95% CI: 1.07 to 1.30; p < 0.001; n = 23,977) compared with nonusers. The impact of PPI use was, however, significantly influenced by baseline cardiovascular risk, being significant only in high-risk patients. CONCLUSIONS In this global meta-analysis, reduced CYP2C19 function appears to expose clopidogrel-treated patients to excess cardiovascular risk and mortality. Conflicting results among studies may be explained by differences in types and/or levels of risk of patients.

Clinical Pharmacogenetics Implementation Consortium Guidelines for Cytochrome P450-2C19 (CYP2C19) Genotype and Clopidogrel Therapy

CYP2C19 is one of the principal enzymes involved in the bioactivation of the antiplatelet prodrug clopidogrel. A common loss‐of‐function allele, CYP2C19*2 (c.681G>A; rs4244285), is associated with increased risk for serious adverse cardiovascular events in both heterozygous and homozygous patients (~25–50% of the population) with acute coronary syndromes (ACSs) who are receiving clopidogrel, particularly among those undergoing percutaneous coronary intervention (PCI). We provide evidence from published literature and guidelines for CYPC19 genotype–directed antiplatelet therapy (periodically updated at http://www.pharmgkb.org).

Clinical ResearchAntiplatelet TherapyCardiovascular Risk in Clopidogrel-Treated Patients According to Cytochrome P450 2C19*2 Loss-of-Function Allele or Proton Pump Inhibitor Coadministration: A Systematic Meta-Analysis

OBJECTIVES The aim of this study was to assess the association between the loss-of-function cytochrome P450 2C19 (CYP2C19)*2 variant (10 studies, 11,959 patients) or the use of proton pump inhibitors (PPIs) (13 studies, 48,674 patients) and ischemic outcomes (major adverse cardiovascular events [MACE]) in patients treated with clopidogrel. BACKGROUND In clopidogrel-treated patients, increased cardiovascular risk has been identified with the loss-of-function CYP2C19*2 allele or the use of PPIs, some of them CYP2C19 inhibitors. To further estimate the effect of a reduction in activity of this enzyme, the authors performed a meta-analysis of the studies available. METHODS The meta-analysis was performed on 23 studies using the odds ratio (OR) as the parameter of efficacy, with a fixed-effect model. The end points were MACE, mortality, or stent thrombosis. RESULTS Of the 11,959 patients, carriers of the loss-of-function CYP2C19*2 allele (28% [n = 3,418]) displayed a 30% increase in the risk for MACE compared with noncarriers (9.7% vs. 7.8%; OR: 1.29; 95% confidence interval [CI]: 1.12 to 1.49; p < 0.001). This single gene variant (CYP2C19*2) was also associated with an excess of mortality (1.8% vs. 1.0%; OR: 1.79; 95% CI: 1.10 to 2.91; p = 0.019; n = 6,225) and of stent thrombosis (2.9% vs. 0.9%; OR: 3.45; 95% CI: 2.14 to 5.57; p < 0.001; n = 4,905). This increased risk was apparent in both heterozygotes and homozygotes and was independent of the baseline cardiovascular risk. PPI users (42% [n = 19,614]) displayed increased risk for MACE (21.8% vs. 16.7%; OR: 1.41; 95% CI: 1.34 to 1.48; p < 0.001) and mortality (12.7% vs. 7.4%; OR: 1.18; 95% CI: 1.07 to 1.30; p < 0.001; n = 23,977) compared with nonusers. The impact of PPI use was, however, significantly influenced by baseline cardiovascular risk, being significant only in high-risk patients. CONCLUSIONS In this global meta-analysis, reduced CYP2C19 function appears to expose clopidogrel-treated patients to excess cardiovascular risk and mortality. Conflicting results among studies may be explained by differences in types and/or levels of risk of patients.

Association between ABCC2 Gene Haplotypes and Tenofovir-Induced Proximal Tubulopathy

BACKGROUND Tenofovir disoproxil fumarate (TDF) may induce renal proximal tubulopathy (rPT). There are no data on pharmacogenomic predictors of rPT in the genes encoding the multidrug-resistance protein (MRP) 2 and MRP4 transporters. METHODS Mutational screening of the genes for MRP2 (ABCC2) and MRP4 (ABCC4) was performed using genomic DNA from 13 human immunodeficiency virus type 1 (HIV-1)-infected patients (group 1) presenting with TDF-induced rPT. Concomitantly, 17 unrelated HIV-1-infected patients who had received TDF therapy and who did not have rPT (group 2) were included in a case-control analysis, to assess the influence of single-nucleotide polymorphisms (SNPs) identified in ABCC2 and ABCC4. RESULTS Six SNPs were identified in ABCC2. A significant allelic association between the 1249 G-->A SNP and TDF-induced rPT was observed (odds ratio, 6.11 [95% confidence interval, 1.19-31.15]; P<.02). ABCC2 haplotypes were significantly associated with the onset of TDF-induced rPT--CATC appeared to be a predisposing haplotype, as it was found in 40.9% of the group 1 case patients and in 13.7% of the group 2 control subjects (P<.01), whereas CGAC appeared to be a protective haplotype, as it was not observed in the group 1 case patients but was present in 20.2% of the group 2 control subjects (P<.01). No association was observed between ABCC4 polymorphism and TDF-induced rPT in the present study. CONCLUSION ABCC2 haplotypes are associated with rPT induced by TDF in HIV-1-infected patients.

Influence of CYP2C19 and CYP3A4 gene polymorphisms on clopidogrel responsiveness in healthy subjects

P . FONTANA,* J . S . HULOT , P . DE MOERLOOS E* and P . GAUSSEM *Division of Angiology and Haemostasis, Department of Internal Medicine, Faculty of Medicine and University Hospitals of Geneva, Geneva, Switzerland; AP-HP, Hôpital Pitié-Salpêtrière, Service de Pharmacologie, Unité de Pharmacogénétique, Université Pierre et Marie Curie-Paris6, UMR S 621 (INSERM), Paris; and AP-HP, Hôpital Européen Georges Pompidou, Service d Hématologie Biologique, INSERM Unité 765, Université Paris-Descartes, Paris, France

Can We Override Clopidogrel Resistance

Clopidogrel, a thienopyridine antiplatelet agent, has been used alone or in association with aspirin to prevent vascular complications in atherothrombotic patients. It is also, in combination with aspirin, the key treatment to prevent stent thrombosis in patients who have undergone percutaneous coronary intervention. It is estimated that >40 million patients worldwide receive clopidogrel. Recent investigations into genetic mechanisms that influence clopidogrel efficacy suggest that a common variant present in ≈30% of whites has the potential to identify patients with a deficient clopidogrel metabolic activation who are consequently at risk of recurrent cardiovascular events, including stent thrombosis.1–3 Stent thrombosis is the most serious complication of coronary stent implantation, often leading to empiric modifications of antiplatelet treatments, although stent thrombosis pathogenesis is complex and the weight of the various factors involved is not known.4 We report 7 recent cases of stent thrombosis with demonstrated platelet resistance to clopidogrel, and we describe a novel clinical approach using pharmacodynamic and genetic information to override clopidogrel resistance. ### Patient Selection and Characteristics The clinical characteristics of 7 patients who presented with stent thrombosis on clopidogrel treatment (75 mg maintenance dose [MD]) are presented in the Table. Stent thrombosis was angiographically proven in all patients and occurred on days 1, 3, 5, 6 (2 patients), 11, and 70, with a median time from stent implantation to stent occlusion of 6 days (interquartile range, 4 to 8.5 days). Clinical presentation was ST-elevation myocardial infarction in all cases, and 4 of 7 patients had a history of myocardial infarction. Stent thrombosis occurred in 6 patients with a bare metal stent and 1 patient with a drug-eluting stent. Primary percutaneous coronary intervention revascularization of stent thrombosis was performed with a new bare metal stent in 6 patients; in the remaining patient, a drug-eluting stent was implanted. View this table: Table. Baseline Characteristics of the …