Jessica L Mega

Harvard University, Boston, MA, USA

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Publications (29)584.88 Total impact

  • Article: Rivaroxaban in Patients Stabilized after a ST-Elevation Myocardial Infarction: Results from the ATLAS ACS 2-TIMI 51 Trial.
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    ABSTRACT: OBJECTIVES AND BACKGROUND: In ATLAS ACS 2-TIMI 51, rivaroxaban reduced cardiovascular events across the spectrum of ACS. The present analysis reports on the pre-specified subgroup of STEMI patients, in whom anticoagulant therapy has been of particular interest. METHODS: 7,817 patients in ATLAS ACS 2-TIMI 51 presented with a STEMI. After being stabilized (1-7 days), they underwent randomization to twice daily rivaroxaban 2.5 mg, rivaroxaban 5 mg, or placebo. Data are presented as 2-year Kaplan-Meier rates, and for ITT and modified ITT (mITT) analyses. RESULTS: Among STEMI patients, rivaroxaban reduced the primary efficacy endpoint of cardiovascular death, MI, or stroke, as compared with placebo (ITT: 8.4% vs. 10.6%, HR 0.81, 95% CI 0.67-0.97, P=0.019; mITT: 8.3% vs. 9.7%, HR 0.85, 95% CI 0.70-1.03, P=0.09). This reduction emerged by 30 days (ITT and mITT: 1.7% vs. 2.3%, P=0.042) and was evident in analyses that included events while on background antiplatelet therapies (ITT: 7.9% vs. 11.8%, P=0.010; mITT: 7.7% vs. 10.1%, P=0.061). In terms of the individual doses, rivaroxaban 2.5 mg reduced cardiovascular death (ITT: 2.5% vs. 4.2%, P=0.006; mITT: 2.2% vs. 3.9%, P=0.006), which was not seen with 5 mg. Rivaroxaban vs. placebo increased non-CABG TIMI major bleeding (2.2% vs. 0.6%, P<0.001) and intracranial hemorrhage (0.6% vs. 0.1%, P=0.015), without a significant increase in fatal bleeding (0.2% vs. 0.1%, P=0.51). CONCLUSION: In patients with a recent STEMI, rivaroxaban reduced cardiovascular events. This benefit emerged early and persisted during continued treatment with background antiplatelet therapies. Rivaroxaban as compared with placebo increased the rate of major bleeding, but there was no significant increase in fatal bleeding.
    Journal of the American College of Cardiology 03/2013; · 14.16 Impact Factor
  • Article: CYP2C19 genotype and cardiovascular events.
    Jessica L Mega, Eric J Topol, Marc S Sabatine
    JAMA The Journal of the American Medical Association 04/2012; 307(14):1482-3; author reply 1484-5. · 30.03 Impact Factor
  • Article: Large-scale gene-centric meta-analysis across 39 studies identifies type 2 diabetes loci.
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    ABSTRACT: To identify genetic factors contributing to type 2 diabetes (T2D), we performed large-scale meta-analyses by using a custom ∼50,000 SNP genotyping array (the ITMAT-Broad-CARe array) with ∼2000 candidate genes in 39 multiethnic population-based studies, case-control studies, and clinical trials totaling 17,418 cases and 70,298 controls. First, meta-analysis of 25 studies comprising 14,073 cases and 57,489 controls of European descent confirmed eight established T2D loci at genome-wide significance. In silico follow-up analysis of putative association signals found in independent genome-wide association studies (including 8,130 cases and 38,987 controls) performed by the DIAGRAM consortium identified a T2D locus at genome-wide significance (GATAD2A/CILP2/PBX4; p = 5.7 × 10(-9)) and two loci exceeding study-wide significance (SREBF1, and TH/INS; p < 2.4 × 10(-6)). Second, meta-analyses of 1,986 cases and 7,695 controls from eight African-American studies identified study-wide-significant (p = 2.4 × 10(-7)) variants in HMGA2 and replicated variants in TCF7L2 (p = 5.1 × 10(-15)). Third, conditional analysis revealed multiple known and novel independent signals within five T2D-associated genes in samples of European ancestry and within HMGA2 in African-American samples. Fourth, a multiethnic meta-analysis of all 39 studies identified T2D-associated variants in BCL2 (p = 2.1 × 10(-8)). Finally, a composite genetic score of SNPs from new and established T2D signals was significantly associated with increased risk of diabetes in African-American, Hispanic, and Asian populations. In summary, large-scale meta-analysis involving a dense gene-centric approach has uncovered additional loci and variants that contribute to T2D risk and suggests substantial overlap of T2D association signals across multiple ethnic groups.
    The American Journal of Human Genetics 02/2012; 90(3):410-25. · 10.60 Impact Factor
  • Article: Dosing clopidogrel based on CYP2C19 genotype and the effect on platelet reactivity in patients with stable cardiovascular disease.
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    ABSTRACT: Variants in the CYP2C19 gene influence the pharmacologic and clinical response to the standard 75-mg daily maintenance dose of the antiplatelet drug clopidogrel. To test whether higher doses (up to 300 mg daily) improve the response to clopidogrel in the setting of loss-of-function CYP2C19 genotypes. ELEVATE-TIMI 56 was a multicenter, randomized, double-blind trial that enrolled and genotyped 333 patients with cardiovascular disease across 32 sites from October 2010 until September 2011. Maintenance doses of clopidogrel for 4 treatment periods, each lasting approximately 14 days, based on genotype. In total, 247 noncarriers of a CYP2C19*2 loss-of-function allele were to receive 75 and 150 mg daily of clopidogrel (2 periods each), whereas 86 carriers (80 heterozygotes, 6 homozygotes) were to receive 75, 150, 225, and 300 mg daily. Platelet function test results (vasodilator-stimulated phosphoprotein [VASP] phosphorylation and VerifyNow P2Y(12) assays) and adverse events. With 75 mg daily, CYP2C19*2 heterozygotes had significantly higher on-treatment platelet reactivity than did noncarriers (VASP platelet reactivity index [PRI]: mean, 70.0%; 95% CI, 66.0%-74.0%, vs 57.5%; 95% CI, 55.1%-59.9%, and VerifyNow P2Y(12) reaction units [PRU]: mean, 225.6; 95% CI, 207.7-243.4, vs 163.6; 95% CI, 154.4-173.9; P < .001 for both comparisons). Among CYP2C19*2 heterozygotes, doses up to 300 mg daily significantly reduced platelet reactivity, with VASP PRI decreasing to 48.9% (95% CI, 44.6%-53.2%) and PRU to 127.5 (95% CI, 109.9-145.2) (P < .001 for trend across doses for both). Whereas 52% of CYP2C19*2 heterozygotes were nonresponders (≥230 PRU) with 75 mg of clopidogrel, only 10% were nonresponders with 225 or 300 mg (P < .001 for both). Clopidogrel, 225 mg daily, reduced platelet reactivity in CYP2C19*2 heterozygotes to levels achieved with standard clopidogrel, 75 mg, in noncarriers (mean ratios of platelet reactivity, VASP PRI, 0.92; 90% CI, 0.85-0.99, and PRU, 0.94; 90% CI, 0.84-1.04). In CYP2C19*2 homozygotes, even with 300 mg daily of clopidogrel, mean VASP PRI was 68.3% (95% CI, 44.9%-91.6%) and mean PRU, 287.0 (95% CI, 170.2-403.8). Among patients with stable cardiovascular disease, tripling the maintenance dose of clopidogrel to 225 mg daily in CYP2C19*2 heterozygotes achieved levels of platelet reactivity similar to that seen with the standard 75-mg dose in noncarriers; in contrast, for CYP2C19*2 homozygotes, doses as high as 300 mg daily did not result in comparable degrees of platelet inhibition. clinicaltrials.gov Identifier: NCT01235351.
    JAMA The Journal of the American Medical Association 11/2011; 306(20):2221-8. · 30.03 Impact Factor
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    Article: Rivaroxaban in patients with a recent acute coronary syndrome.
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    ABSTRACT: Acute coronary syndromes arise from coronary atherosclerosis with superimposed thrombosis. Since factor Xa plays a central role in thrombosis, the inhibition of factor Xa with low-dose rivaroxaban might improve cardiovascular outcomes in patients with a recent acute coronary syndrome. In this double-blind, placebo-controlled trial, we randomly assigned 15,526 patients with a recent acute coronary syndrome to receive twice-daily doses of either 2.5 mg or 5 mg of rivaroxaban or placebo for a mean of 13 months and up to 31 months. The primary efficacy end point was a composite of death from cardiovascular causes, myocardial infarction, or stroke. Rivaroxaban significantly reduced the primary efficacy end point, as compared with placebo, with respective rates of 8.9% and 10.7% (hazard ratio in the rivaroxaban group, 0.84; 95% confidence interval [CI], 0.74 to 0.96; P=0.008), with significant improvement for both the twice-daily 2.5-mg dose (9.1% vs. 10.7%, P=0.02) and the twice-daily 5-mg dose (8.8% vs. 10.7%, P=0.03). The twice-daily 2.5-mg dose of rivaroxaban reduced the rates of death from cardiovascular causes (2.7% vs. 4.1%, P=0.002) and from any cause (2.9% vs. 4.5%, P=0.002), a survival benefit that was not seen with the twice-daily 5-mg dose. As compared with placebo, rivaroxaban increased the rates of major bleeding not related to coronary-artery bypass grafting (2.1% vs. 0.6%, P<0.001) and intracranial hemorrhage (0.6% vs. 0.2%, P=0.009), without a significant increase in fatal bleeding (0.3% vs. 0.2%, P=0.66) or other adverse events. The twice-daily 2.5-mg dose resulted in fewer fatal bleeding events than the twice-daily 5-mg dose (0.1% vs. 0.4%, P=0.04). In patients with a recent acute coronary syndrome, rivaroxaban reduced the risk of the composite end point of death from cardiovascular causes, myocardial infarction, or stroke. Rivaroxaban increased the risk of major bleeding and intracranial hemorrhage but not the risk of fatal bleeding. (Funded by Johnson & Johnson and Bayer Healthcare; ATLAS ACS 2-TIMI 51 ClinicalTrials.gov number, NCT00809965.).
    New England Journal of Medicine 11/2011; 366(1):9-19. · 53.30 Impact Factor
  • Article: Impact of smoking on antiplatelet effect of clopidogrel and prasugrel after loading dose and on maintenance therapy.
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    ABSTRACT: Pharmacodynamic studies reported an amplified on-clopidogrel platelet inhibition in smokers potentially caused by an increased metabolic drug activation via induction of cytochrome P450 1A2. The aims of this analysis were to evaluate the impact of smoking on the antiplatelet effect of clopidogrel and prasugrel and to test the potential interaction of smoking with the treatment effect of these drugs. A variety of platelet function results was analyzed from 2 large cohorts of patients undergoing coronary intervention after loading with clopidogrel 600 mg (n = 2,533 and n = 1,996), a cohort of patients undergoing dose adaptation from 75 to 150 mg according to response to clopidogrel (n = 117) and a crossover trial comparing clopidogrel 150 mg with prasugrel 10 mg (n = 87). Linear regression analyses were used to test the impact of smoking on platelet function and to identify independent predictors of on-treatment platelet reactivity. The potential interaction of smoking with the clinical effect of clopidogrel versus prasugrel was analyzed in the TRITON-TIMI 38 cohort (n = 13,608). No significant association of smoking with platelet reactivity on clopidogrel was seen in unadjusted and adjusted analyses. The variables most consistently associated with on-clopidogrel platelet function were age, sex, diabetes, and body mass index. There was no significant interaction of smoking status at presentation with the clinical efficacy of prasugrel versus clopidogrel (P for interaction = .39). Smoking does not impact on platelet reactivity in patients after loading or on different maintenance doses of clopidogrel. The clinical treatment effect of clopidogrel versus prasugrel is not affected by smoking status at presentation.
    American heart journal 09/2011; 162(3):518-26.e5. · 4.65 Impact Factor
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    Article: A new era for anticoagulation in atrial fibrillation.
    Jessica L Mega
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    ABSTRACT: For more than 50 years, warfarin has been the primary medication used to reduce the risk of thromboembolic events in patients with atrial fibrillation. Despite its clinical efficacy, warfarin has multiple, well-known limitations, including numerous interactions with other drugs and the need for regular blood monitoring and dose adjustments. Thus, clinicians and patients have been eager to embrace alternative oral anticoagulants that are equally efficacious but easier to administer. In this issue of the Journal, Granger and colleagues report the impressive primary results of the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial (ARISTOTLE; ClinicalTrials.gov . . .
    New England Journal of Medicine 08/2011; 365(11):1052-4. · 53.30 Impact Factor
  • Article: Rationale and design of the Anti-Xa therapy to lower cardiovascular events in addition to standard therapy in subjects with acute coronary syndrome-thrombolysis in myocardial infarction 51 (ATLAS-ACS 2 TIMI 51) trial: a randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of rivaroxaban in subjects with acute coronary syndrome.
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    ABSTRACT: Although therapy with aspirin or aspirin plus a thienopyridine reduces the incidence of long-term adverse cardiovascular events among patients with acute coronary syndrome (ACS), there remains a significant residual risk of cardiovascular death, recurrent myocardial infarction (MI), and stroke. In a phase 2 trial (ClinicalTrials.gov NCT00402597) in which the addition of the factor Xa inhibitor rivaroxaban was compared with placebo, among ACS patients receiving either aspirin alone or dual-antiplatelet therapy with aspirin and a thienopyridine, the end point of death, MI, or stroke compared with placebo was reduced (87/2331 [3.9%] vs 62/1160 [5.5%]; hazard ratio 0.69, [95% CI 0.50-0.96], P = .027). Two candidate doses of rivaroxaban were selected for further evaluation in a pivotal phase 3. The second ATLAS-ACS 2 TIMI 51 Trial is an international, randomized, double-blind, event-driven (n = 983) phase 3 trial involving more than 15,570 patients hospitalized with ACS (ClinicalTrials.gov NCT00809965). All patients are treated with a background of standard therapy including low-dose aspirin, and patients are stratified by the administration of a thienopyridine (clopidogrel or ticlopidine; stratum 2) or not (stratum 1). Within each stratum, patients are randomly assigned in a 1:1:1 ratio to receive rivaroxaban 2.5 mg twice daily, or rivaroxaban 5 mg twice daily, or placebo twice daily. The primary efficacy end point is the composite of cardiovascular death, MI, or stroke. The primary safety end point is thrombolysis in MI major bleeding not associated with coronary artery bypass graft surgery. The ATLAS-ACS 2 TIMI 51 is testing the hypothesis that anticoagulation with the oral factor Xa inhibitor rivaroxaban reduces cardiovascular death, MI, and stroke among patients with ACS treated with guideline-based therapies for ACS.
    American heart journal 05/2011; 161(5):815-821.e6. · 4.65 Impact Factor
  • Article: Carriage of Reduced-Function CYP2C19 Allele Among Patients Treated With Clopidogrel-Reply.
    Jessica L Mega, Marc S Sabatine
    JAMA The Journal of the American Medical Association 02/2011; 305(5):467-468. · 30.03 Impact Factor
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    Article: Meta-analysis of Dense Genecentric Association Studies Reveals Common and Uncommon Variants Associated with Height.
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    ABSTRACT: Height is a classic complex trait with common variants in a growing list of genes known to contribute to the phenotype. Using a genecentric genotyping array targeted toward cardiovascular-related loci, comprising 49,320 SNPs across approximately 2000 loci, we evaluated the association of common and uncommon SNPs with adult height in 114,223 individuals from 47 studies and six ethnicities. A total of 64 loci contained a SNP associated with height at array-wide significance (p < 2.4 × 10(-6)), with 42 loci surpassing the conventional genome-wide significance threshold (p < 5 × 10(-8)). Common variants with minor allele frequencies greater than 5% were observed to be associated with height in 37 previously reported loci. In individuals of European ancestry, uncommon SNPs in IL11 and SMAD3, which would not be genotyped with the use of standard genome-wide genotyping arrays, were strongly associated with height (p < 3 × 10(-11)). Conditional analysis within associated regions revealed five additional variants associated with height independent of lead SNPs within the locus, suggesting allelic heterogeneity. Although underpowered to replicate findings from individuals of European ancestry, the direction of effect of associated variants was largely consistent in African American, South Asian, and Hispanic populations. Overall, we show that dense coverage of genes for uncommon SNPs, coupled with large-scale meta-analysis, can successfully identify additional variants associated with a common complex trait.
    The American Journal of Human Genetics 01/2011; 88(1):6-18. · 10.60 Impact Factor
  • Article: Another step on the road to tailored antiplatelet therapy.
    Stephen D Wiviott, Jessica L Mega
    Journal of the American College of Cardiology 11/2010; 56(20):1637-8. · 14.16 Impact Factor
  • Article: Genetic variants in ABCB1 and CYP2C19 and cardiovascular outcomes after treatment with clopidogrel and prasugrel in the TRITON-TIMI 38 trial: a pharmacogenetic analysis.
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    ABSTRACT: Clopidogrel and prasugrel are subject to efflux via P-glycoprotein (encoded by ABCB1, also known as MDR1). ABCB1 polymorphisms, particularly 3435C→T, may affect drug transport and efficacy. We aimed to assess the effect of this polymorphism by itself and alongside variants in CYP2C19 on cardiovascular outcomes in patients treated with clopidogrel or prasugrel in TRITON-TIMI 38. We also assessed the effect of genotype on the pharmacodynamic and pharmacokinetic properties of these drugs in healthy individuals. We genotyped ABCB1 in 2932 patients with acute coronary syndromes undergoing percutaneous intervention who were treated with clopidogrel (n=1471) or prasugrel (n=1461) in the TRITON-TIMI 38 trial. We evaluated the association between ABCB1 3435C→T and rates of the primary efficacy endpoint (cardiovascular death, myocardial infarction, or stroke) until 15 months. We then assessed the combined effect of ABCB1 3435C→T genotype and reduced-function alleles of CYP2C19. 321 healthy individuals were also genotyped, and we tested the association of genetic variants with reduction in maximum platelet aggregation and plasma concentrations of active drug metabolites. In patients treated with clopidogrel, ABCB1 3435C→T genotype was significantly associated with the risk of cardiovascular death, myocardial infarction, or stroke (p=0·0064). TT homozygotes had a 72% increased risk of the primary endpoint compared with CT/CC individuals (Kaplan-Meier event rates 12·9% [52 of 414] vs 7·8% [80 of 1057 participants]; HR 1·72, 95% CI 1·22-2·44, p=0·002). ABCB1 3435C→T and CYP2C19 genotypes were significant, independent predictors of the primary endpoint, and 681 (47%) of the 1454 genotyped patients taking clopidogrel who were either CYP2C19 reduced-function allele carriers, ABCB1 3435 TT homozygotes, or both were at increased risk of the primary endpoint (HR 1·97, 95% CI 1·38-2·82, p=0·0002). In healthy participants, 3435 TT homozygotes had an absolute reduction in maximum platelet aggregation with clopidogrel that was 7·3 percentage points less than for CT/CC individuals (p=0·0127). ABCB1 genotypes were not significantly associated with clinical or pharmacological outcomes in patients with an acute coronary syndrome or healthy individuals treated with prasugrel, respectively. Individuals with the ABCB1 3435 TT genotype have reduced platelet inhibition and are at increased risk of recurrent ischaemic events during clopidogrel treatment. In patients with acute coronary syndromes who have undergone percutaneous intervention, when both ABCB1 and CYP2C19 are taken into account, nearly half of the population carries a genotype associated with increased risk of major adverse cardiovascular events while on standard doses of clopidogrel. Daiichi Sankyo Company Ltd and Eli Lilly and Company.
    The Lancet 10/2010; 376(9749):1312-9. · 38.28 Impact Factor
  • Article: Reduced-function CYP2C19 genotype and risk of adverse clinical outcomes among patients treated with clopidogrel predominantly for PCI: a meta-analysis.
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    ABSTRACT: Clopidogrel, one of the most commonly prescribed medications, is a prodrug requiring CYP450 biotransformation. Data suggest its pharmacologic effect varies based on CYP2C19 genotype, but there is uncertainty regarding the clinical risk imparted by specific genotypes. To define the risk of major adverse cardiovascular outcomes among carriers of 1 (≈ 26% prevalence in whites) and carriers of 2 (≈ 2% prevalence in whites) reduced-function CYP2C19 genetic variants in patients treated with clopidogrel. Data Sources and A literature search was conducted (January 2000-August 2010) in MEDLINE, Cochrane Database of Systematic Reviews, and EMBASE. Genetic studies were included in which clopidogrel was initiated in predominantly invasively managed patients in a manner consistent with the current guideline recommendations and in which clinical outcomes were ascertained. Investigators from 9 studies evaluating CYP2C19 genotype and clinical outcomes in patients treated with clopidogrel contributed the relevant hazard ratios (HRs) and 95% confidence intervals (CIs) for specific cardiovascular outcomes by genotype. Among 9685 patients (91.3% who underwent percutaneous coronary intervention and 54.5% who had an acute coronary syndrome), 863 experienced the composite end point of cardiovascular death, myocardial infarction, or stroke; and 84 patients had stent thrombosis among the 5894 evaluated for such. Overall, 71.5% were noncarriers, 26.3% had 1 reduced-function CYP2C19 allele, and 2.2% had 2 reduced-function CYP2C19 alleles. A significantly increased risk of the composite end point was evident in both carriers of 1 (HR, 1.55; 95% CI, 1.11-2.17; P = .01) and 2 (HR, 1.76; 95% CI, 1.24-2.50; P = .002) reduced-function CYP2C19 alleles, as compared with noncarriers. Similarly, there was a significantly increased risk of stent thrombosis in both carriers of 1 (HR, 2.67; 95% CI, 1.69-4.22; P < .0001) and 2 (HR, 3.97; 95% CI, 1.75-9.02; P = .001) CYP2C19 reduced-function alleles, as compared with noncarriers. Among patients treated with clopidogrel for percutaneous coronary intervention, carriage of even 1 reduced-function CYP2C19 allele appears to be associated with a significantly increased risk of major adverse cardiovascular events, particularly stent thrombosis.
    JAMA The Journal of the American Medical Association 10/2010; 304(16):1821-30. · 30.03 Impact Factor
  • Article: Clinical features and outcomes of women with unstable ischemic heart disease: observations from metabolic efficiency with ranolazine for less ischemia in non-ST-elevation acute coronary syndromes-thrombolysis in myocardial infarction 36 (MERLIN-TIMI 36).
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    ABSTRACT: The pathobiological basis of ischemic heart disease and thus the manifestations and response to therapy can differ between women and men. In prior studies, sex-based treatment differences have been observed with the antiischemic ranolazine, with a possibly diminished effect in women. We conducted a prospectively planned analysis of the clinical, biomarker, angiographic, and continuous ECG features and 1-year outcomes of women with unstable ischemic heart disease randomized to ranolazine or placebo in Metabolic Efficiency With Ranolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndromes-Thrombolysis in Myocardial Infarction 36 (MERLIN-TIMI 36). Compared with men (n=4269), women (n=2291) were older with more risk factors (P<0.001). On presentation, women were less likely than men to have significant epicardial coronary artery disease (no stenosis >or=50% on angiography, 19.4% versus 8.6%; P<0.001) or elevated troponin (57.1% versus 68.9%; P<0.001). Yet, women were more likely to have an elevated B-type natriuretic peptide (47.0% versus 40.2%; P<0.001), worse median angina frequency scores (80 versus 100; P<0.001), and an ischemic episode on continuous ECG administered during the first 7 days (22.5% versus 19.3%; P=0.0025). Women and men were at similar adjusted risk for the primary end point of cardiovascular death, myocardial infarction, or recurrent ischemia (adjusted hazard ratio, 1.11; 95% confidence interval, 0.96 to 1.29; P=0.15). Ranolazine was associated with a significant reduction in recurrent ischemia in women (13.0% versus 18.2%; hazard ratio, 0.71; 95% confidence interval, 0.57 to 0.88; P=0.002). Women with a clinical syndrome consistent with unstable ischemic heart disease, despite having less obstructive coronary artery disease, were more likely than men to report anginal episodes and had more recorded ischemic periods on continuous ECG. In this setting, ranolazine may be a particularly useful antiischemic agent in women. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00099788.
    Circulation 04/2010; 121(16):1809-17. · 14.74 Impact Factor
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    Article: Identification of genetic variants associated with response to statin therapy.
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    ABSTRACT: The purpose of this study was to test the association between polymorphisms in genes involved in either LDL cholesterol (LDL-C) metabolism or statin pharmacokinetics and LDL-C reduction with statins. 49 tagging and candidate polymorphisms in 9 genes were genotyped in 1507 post-ACS subjects randomized to atorvastatin or pravastatin. Two polymorphisms (rs7412, rs429358) that define the epsilon2, epsilon3, and epsilon4 isoforms of apolipoprotein E were significantly associated with percent reduction in LDL-C with atorvastatin (epsilon2 carriers 53.8%, epsilon3/epsilon3 48.1%, and epsilon4 carriers 46.4%, respectively, P=0.00039) and replicated in the pravastatin arm (epsilon2 carriers 22.1%, epsilon3/epsilon3 21.8%, and epsilon4 carriers 16.6%, respectively, P=0.00038). The proportion of subjects achieving an LDL-C < or =70 mg/dL at day 30 was higher for epsilon2 than epsilon4 carriers (P=1.3 x 10(-5)). In the pravastatin group, the triallelic rs2032582 variant (G2677T/A) in ABCB1 was associated with the percent reduction in LDL-C (GG 23.3%, non-G heterozygote 20.3%, and non-G homozygote 17.4%, P=0.042). Carriers of APOE epsilon2 versus epsilon4 had significantly greater LDL-C reduction with atorvastatin and with pravastatin, and more frequently achieved a guideline-recommended LDL-C < or =70 mg/dL. Polymorphisms in triallelic G2677T/A variant in ABCB1 were associated with the degree of LDL-C lowering with pravastatin.
    Arteriosclerosis Thrombosis and Vascular Biology 09/2009; 29(9):1310-5. · 6.37 Impact Factor
  • Article: Pharmacodynamic effect and clinical efficacy of clopidogrel and prasugrel with or without a proton-pump inhibitor: an analysis of two randomised trials.
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    ABSTRACT: Proton-pump inhibitors (PPIs) are often prescribed in combination with thienopyridines. Conflicting data exist as to whether PPIs diminish the efficacy of clopidogrel. We assessed the association between PPI use, measures of platelet function, and clinical outcomes for patients treated with clopidogrel or prasugrel. In the PRINCIPLE-TIMI 44 trial, the primary outcome was inhibition of platelet aggregation at 6 h assessed by light-transmission aggregometry. In the TRITON-TIMI 38 trial, the primary endpoint was the composite of cardiovascular death, myocardial infarction, or stroke. In both studies, PPI use was at physician's discretion. We used a multivariable Cox model with propensity score to assess the association of PPI use with clinical outcomes. In the PRINCIPLE-TIMI 44 trial, 201 patients undergoing elective percutaneous coronary intervention were randomly assigned to prasugrel (n=102) or high-dose clopidogrel (n=99). Mean inhibition of platelet aggregation was significantly lower for patients on a PPI than for those not on a PPI at 6 h after a 600 mg clopidogrel loading dose (23.2+/-19.5% vs 35.2+/-20.9%, p=0.02), whereas a more modest difference was seen with and without a PPI after a 60 mg loading dose of prasugrel (69.6+/-13.5% vs 76.7+/-12.4%, p=0.054). In the TRITON-TIMI 38 trial, 13,608 patients with an acute coronary syndrome were randomly assigned to prasugrel (n=6813) or clopidogrel (n=6795). In this study, 33% (n=4529) of patients were on a PPI at randomisation. No association existed between PPI use and risk of the primary endpoint for patients treated with clopidogrel (adjusted hazard ratio [HR] 0.94, 95% CI 0.80-1.11) or prasugrel (1.00, 0.84-1.20). The current findings do not support the need to avoid concomitant use of PPIs, when clinically indicated, in patients receiving clopidogrel or prasugrel. Daiichi Sankyo Company Limited and Eli Lilly and Company sponsored the trials. This analysis had no funding.
    The Lancet 09/2009; 374(9694):989-97. · 38.28 Impact Factor
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    Article: Cytochrome P450 genetic polymorphisms and the response to prasugrel: relationship to pharmacokinetic, pharmacodynamic, and clinical outcomes.
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    ABSTRACT: Both clopidogrel and prasugrel require biotransformation to active metabolites by cytochrome P450 (CYP) enzymes. Among persons treated with clopidogrel, carriers of reduced-function CYP2C19 alleles have significantly lower levels of active metabolite, diminished platelet inhibition, and higher rates of adverse cardiovascular events. The effect of CYP polymorphisms on the clinical outcomes in patients treated with prasugrel remains unknown. The associations between functional variants in CYP genes, plasma concentrations of active drug metabolite, and platelet inhibition in response to prasugrel were tested in 238 healthy subjects. We then examined the association of these genetic variants with cardiovascular outcomes in a cohort of 1466 patients with acute coronary syndromes allocated to treatment with prasugrel in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 38 trial. Among the healthy subjects, no significant attenuation of the pharmacokinetic or the pharmacodynamic response to prasugrel was observed in carriers versus noncarriers of at least 1 reduced-function allele for any of the CYP genes tested (CYP2C19, CYP2C9, CYP2B6, CYP3A5, and CYP1A2). Consistent with these findings, in subjects with acute coronary syndromes treated with prasugrel, no significant associations were found between any of the tested CYP genotypes and risk of cardiovascular death, myocardial infarction, or stroke. Common functional CYP genetic variants do not affect active drug metabolite levels, inhibition of platelet aggregation, or clinical cardiovascular event rates in persons treated with prasugrel. These pharmacogenetic findings are in contrast to observations with clopidogrel, which may explain, in part, the different pharmacological and clinical responses to the 2 medications.
    Circulation 06/2009; 119(19):2553-60. · 14.74 Impact Factor
  • Article: Interaction between cigarette smoking and clinical benefit of clopidogrel.
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    ABSTRACT: The aim of this study was to examine the interaction between cigarette smoking and the clinical efficacy of clopidogrel in ST-segment elevation myocardial infarction (STEMI). Cigarette smoking induces cytochrome P450 (CYP)1A2, which converts clopidogrel into its active metabolite, and prior studies suggest greater inhibition of platelet aggregation by clopidogrel in smokers of > or =10 cigarettes/day. The effect of clopidogrel compared with placebo on angiographic and clinical outcomes was examined in 3,429 STEMI patients in the CLARITY-TIMI 28 (Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis In Myocardial Infarction 28) randomized trial stratified by smoking intensity as follows: not current smokers (n = 1,732), and smokers of 1 to 9 (n = 206), 10 to 19 (n = 354), 20 to 29 (n = 715), and > or =30 cigarettes/day (n = 422). Logistic regression was used to adjust for other baseline characteristics and interaction terms to test for effect modification. Although clopidogrel reduced the rate of the primary end point of a closed infarct-related artery or death/myocardial infarction before angiography in the CLARITY-TIMI 28 trial, the benefit was especially marked among those who smoked > or =10 cigarettes/day (adjusted odds ratio [OR]: 0.49, 95% confidence interval [CI]: 0.37 to 0.66; p < 0.0001) compared with those who did not (adjusted OR: 0.72, 95% CI: 0.57 to 0.91; p = 0.006; p(interaction) = 0.04). Similarly, clopidogrel was significantly more effective at reducing the rate of cardiovascular death, myocardial infarction, or urgent revascularization through 30 days among those who smoked > or =10 cigarettes/day (adjusted OR: 0.54, 95% CI: 0.38 to 0.76; p = 0.0004) compared with those who did not (adjusted OR: 0.98; 95% CI: 0.75 to 1.28; p = 0.87; p(interaction) = 0.006). Cigarette smoking seems to positively modify the beneficial effect of clopidogrel on angiographic and clinical outcomes. This study demonstrates that common clinical factors that influence the metabolism of clopidogrel might impact its clinical effectiveness.
    Journal of the American College of Cardiology 05/2009; 53(15):1273-8. · 14.16 Impact Factor
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    Article: Cytochrome p-450 polymorphisms and response to clopidogrel.
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    ABSTRACT: Clopidogrel requires transformation into an active metabolite by cytochrome P-450 (CYP) enzymes for its antiplatelet effect. The genes encoding CYP enzymes are polymorphic, with common alleles conferring reduced function. We tested the association between functional genetic variants in CYP genes, plasma concentrations of active drug metabolite, and platelet inhibition in response to clopidogrel in 162 healthy subjects. We then examined the association between these genetic variants and cardiovascular outcomes in a separate cohort of 1477 subjects with acute coronary syndromes who were treated with clopidogrel in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis in Myocardial Infarction (TRITON-TIMI) 38. In healthy subjects who were treated with clopidogrel, carriers of at least one CYP2C19 reduced-function allele (approximately 30% of the study population) had a relative reduction of 32.4% in plasma exposure to the active metabolite of clopidogrel, as compared with noncarriers (P<0.001). Carriers also had an absolute reduction in maximal platelet aggregation in response to clopidogrel that was 9 percentage points less than that seen in noncarriers (P<0.001). Among clopidogrel-treated subjects in TRITON-TIMI 38, carriers had a relative increase of 53% in the composite primary efficacy outcome of the risk of death from cardiovascular causes, myocardial infarction, or stroke, as compared with noncarriers (12.1% vs. 8.0%; hazard ratio for carriers, 1.53; 95% confidence interval [CI], 1.07 to 2.19; P=0.01) and an increase by a factor of 3 in the risk of stent thrombosis (2.6% vs. 0.8%; hazard ratio, 3.09; 95% CI, 1.19 to 8.00; P=0.02). Among persons treated with clopidogrel, carriers of a reduced-function CYP2C19 allele had significantly lower levels of the active metabolite of clopidogrel, diminished platelet inhibition, and a higher rate of major adverse cardiovascular events, including stent thrombosis, than did noncarriers.
    New England Journal of Medicine 12/2008; 360(4):354-62. · 53.30 Impact Factor
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    Article: Thrombus precursor protein and clinical outcomes in patients with acute coronary syndromes.
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    ABSTRACT: We sought to test the prognostic performance of thrombus precursor protein (TpP) in patients presenting with an acute coronary syndrome (ACS). Because thrombus formation is a critical step in the development of ACS, a measurement of activated coagulation could yield important information. Thrombus precursor protein is a biomarker that is used to measure soluble fibrin polymers, which are the penultimate products in fibrin formation. We measured the levels of TpP in 284 healthy volunteers and in 2,349 patients with ACS. Median TpP concentrations were 3.6 mug/ml (interquartile range 2.6 to 5.5) in the volunteers and 8.9 mug/ml (interquartile range 4.9 to 15.9) in the ACS patients (p < 0.001). Patients with ACS who had elevated TpP were older, more likely to be women, and more likely to have diabetes and pre-existing CAD (p < 0.02 for each). Thrombus precursor protein levels greater than the median were associated with a significantly increased risk for the composite of death, myocardial infarction (MI), or recurrent ischemia leading to rehospitalization or urgent revascularization through 10 months (hazard ratio [HR] 1.45, p < 0.001), as well as death or MI (HR 1.42, p = 0.02). We found that TpP correlated only weakly with cardiac troponin I, B-type natriuretic peptide, and high-sensitivity C-reactive protein (|r| <0.15 for each). After adjusting for clinical characteristics, cardiac troponin I, high-sensitivity C-reactive protein, and B-type natriuretic peptide, we found that patients with TpP levels greater than the median remained at significantly increased risk for the composite outcome (adjusted HR 1.51, p = 0.001) and death or MI (adjusted HR 1.58, p = 0.02). In patients with ACS, increased levels of TpP are associated with an increased risk of death or ischemic complications. The incorporation of a marker of activated coagulation, such as TpP, with established cardiovascular risk factors may offer valuable complementary insight into risk assessment in ACS.
    Journal of the American College of Cardiology 06/2008; 51(25):2422-9. · 14.16 Impact Factor