Kenneth J Winters

Eli Lilly, Indianapolis, Indiana, United States

Are you Kenneth J Winters?

Claim your profile

Publications (81)584.89 Total impact

  • American Heart Journal 06/2015; DOI:10.1016/j.ahj.2015.05.017 · 4.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Little is known regarding consequences of frailty in patients with acute coronary syndrome (ACS). We assessed the associations of frailty and outcomes in ACS patients who were participating in a clinical trial. The TaRgeted platelet Inhibition to cLarify the Optimal strateGy to medicallY manage Acute Coronary Syndromes (TRILOGY ACS) trial randomized 9326 patients planned for medical management to prasugrel or clopidogrel. The primary endpoint was a composite of cardiovascular death, myocardial infarction (MI), or stroke over a period of 30 months. A frailty score based upon the Fried score was self-reported at baseline in patients aged ⩾65 years. Five frailty questions were recorded for 4996/5102 (97.9%) patients: 72.3% were classified as not-frail (0 items), 23.0% as pre-frail (1-2 items), and 4.7% as frail (⩾3 items). Increasing frailty score was associated with older age, diabetes, and higher Global Registry of Acute Coronary Events (GRACE) scores. Frailty was associated with a higher unadjusted incidence of the primary endpoint (pre-frail vs not-frail: 29.2% vs 23.1%; hazard ratio [HR]: 1.39; 95% confidence interval [CI]: 1.19-1.61; p<0.001; frail vs not-frail: 39.7% vs 23.1%; HR: 1.76; 95% CI: 1.36-2.28; p<0.001), and all-cause mortality (pre-frail vs not-frail: 21.7% vs 15.0%; HR: 1.45; 95% CI: 1.22-1.73; p<0.001; frail vs not-frail: 30.2% vs 15.0%; HR: 1.98; 95% CI: 1.47-2.68; p<0.001). After adjustment for baseline characteristics and GRACE covariates, frailty remained independently associated with the primary endpoint: pre-frail vs not-frail, HR: 1.33; 95% CI: 1.15-1.54; p<0.001; frail vs not-frail, HR: 1.52; 95% CI: 1.18-1.98; p=0.002. There was no association of frailty with bleeding. Frailty is associated with the composite of cardiovascular death, MI, or stroke. Frailty assessment contributes to risk prediction and adds to the GRACE score. © The European Society of Cardiology 2015.
    04/2015; DOI:10.1177/2048872615581502
  • [Show abstract] [Hide abstract]
    ABSTRACT: This phase 2 study was designed to characterize the relationship among prasugrel dose, prasugrel's active metabolite (Pras-AM), and platelet inhibition while evaluating safety in children with sickle cell disease. It was open-label, multicenter, adaptive design, dose ranging, and conducted in 2 parts. Part A: Patients received escalating single doses leading to corresponding increases in Pras-AM exposure and VerifyNow®P2Y12 (VN) platelet inhibition and decreases in VNP2Y12 reaction units and vasodilator-stimulated phosphoprotein platelet reactivity index. Part B: Patients were assigned daily doses (0.06, 0.08, and 0.12 mg/kg) based on VN pharmacodynamic measurements at the start of 2 dosing periods, each 14±4 days. Platelet inhibition was significantly higher at 0.12 mg/kg (56.3%±7.4%; least squares mean±SE) compared with 0.06 mg/kg (33.8%±7.4%) or 0.08 mg/kg (37.9%±5.6%). Patients receiving 0.12 mg/kg achieved ≥30% platelet inhibition; only 1 patient receiving 0.06 mg/kg exceeded 60% platelet inhibition. High interpatient variability in response to prasugrel and the small range of exposures precluded rigorous characterization of the relationship among dose, Pras-AM, and platelet inhibition. No hemorrhagic events occurred in Part A; 3 occurred in Part B, all mild and self-limited. Most children with sickle cell disease may achieve clinically relevant platelet inhibition with titration of daily-dose prasugrel.
    American Journal of Hematology 12/2014; 88(12). DOI:10.1097/MPH.0000000000000291 · 3.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background-The TAXUS Liberté Post Approval Study (TL-PAS) contributed patients treated with TAXUS Liberté paclitaxel-eluting stent and prasugrel to the Dual Antiplatelet Therapy Study (DAPT) that compared 12 and 30 months thienopyridine plus aspirin therapy after drug-eluting stents. Methods and Results-Outcomes for 2191 TL-PAS patients enrolled into DAPT were assessed. The DAPT coprimary composite end point (death, myocardial infarction [MI], or stroke) was lower with 30 compared with 12 months prasugrel treatment (3.7% versus 8.8%; hazard ratio [HR], 0.407; P<0.001). Rates of death and stroke were similar between groups, but MI was significantly reduced with prolonged prasugrel treatment (1.9% versus 7.1%; HR, 0.255; P<0.001). The DAPT coprimary end point, stent thrombosis, was also lower with longer therapy (0.2% versus 2.9%; HR, 0.063; P<0.001). MI related to stent thrombosis (0% versus 2.6%; P<0.001) and occurring spontaneously (1.9% versus 4.5%; HR, 0.407; P=0.007) were both reduced with prolonged prasugrel. MI rates increased within 90 days of prasugrel cessation after both 12 and 30 months treatment. Composite Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) moderate or severe bleeds were modestly increased (2.4% versus 1.7%; HR, 1.438; P=0.234) but severe bleeds were not more frequent (0.3% versus 0.5%; HR, 0.549; P=0.471) in the prolonged treatment group. Conclusions-Prasugrel and aspirin continued for 30 months reduced ischemic events for the TAXUS Liberté paclitaxeleluting stent patient subset from DAPT through reductions in MI and stent thrombosis. Withdrawal of prasugrel was followed by an increase in MI after both 12 and 30 months therapy. The optimal duration of dual antiplatelet therapy with prasugrel after TAXUS Liberté paclitaxel-eluting stent remains unknown, but appears to be >30 months.
    Circulation 11/2014; 131(1). DOI:10.1161/CIRCULATIONAHA.114.013570 · 14.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction Patients treated with clopidogrel who have higher body size exhibit greater platelet reactivity than patients with lower body size. In a retrospective analysis of the FEATHER trial, we examined the relationship between platelet response to thienopyridines clopidogrel 75 mg (Clop-75), prasugrel 5 mg (Pras-5), and prasugrel 10 mg (Pras-10) using 3 body size indices: body weight (BW), body mass index (BMI), and body surface area (BSA). Relationships are assessed as continuous variables and as 4 incremental body size groups. Materials and Methods Aspirin-treated patients with stable coronary artery disease (N = 72) and a BW range of 45-134 kg received Clop-75, Pras-5, and Pras-10 in a 3-period, blinded, cross-over study. Platelet assays included maximum platelet aggregation (MPA) to 20 μM ADP by light transmission aggregometry, VerifyNow-P2Y12 reaction units (PRU), and vasodilator-associated stimulated phosphoprotein (VASP) phosphorylation platelet reactivity index (PRI). Exposure to active metabolites (AMs) was also assessed. Results Body size was a determinant of AM exposure and residual platelet reactivity regardless of type and dose of thienopyridine. BW and BSA demonstrated marginally stronger correlations with platelet reactivity; VASP-PRI demonstrated a stronger correlation with the body size than the other tests. Correlation coefficients ranged from a high of 0.64 (BW vs. PRI on Pras-5) to a low of 0.34 (BMI vs. MPA on Pras-10), but all were statistically significant (p < 0.01). Conclusions Using a comprehensive selection of body size indices, AM exposures, platelet function tests, and thienopyridine doses, we demonstrated a consistent inverse relationship between body size and response to clopidogrel and prasugrel.
    Thrombosis Research 09/2014; 134(3). DOI:10.1016/j.thromres.2014.05.019 · 2.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Platelets of patients with sickle cell disease (SCD) show evidence of mild activation in the non-crisis steady state and greater activation during vaso-occlusive crises (VOC). Prasugrel, a potent inhibitor of ADP-mediated platelet activation and aggregation, may be useful in attenuating VOC. We compared platelet responses to ADP stimulation in patients with SCD and healthy subjects before and after treatment with prasugrel. In a phase 1 study, platelet biomarker levels were assessed in 12 adult patients with SCD and 13 healthy subjects before and after 12 ± 2 days of 5.0 or 7.5 mg/day prasugrel. The following were determined in whole blood samples stimulated with 20 µM ADP: (i) percentages of monocytes and neutrophils with adherent platelets (cell-platelet aggregates); (ii) the relative number (mass) of platelets associated with each monocyte and neutrophil as reported by CD61 mean fluorescence intensity (MFI) of the monocyte-platelet and neutrophil-platelet aggregates; (iii) the percentages of platelets positive for surface expression of CD40 ligand (CD40L), P-selectin (CD62p) and activated glycoprotein IIb-IIIa (GPIIb-IIIa); and (iv) the percentages of platelets and monocyte-platelet aggregates positive for surface tissue factor (TF) expression. At baseline, there were no significant differences between cohorts in the percentages of platelets expressing activation biomarkers. Following 12 days of prasugrel administration, the percentages of platelets expressing activation biomarkers following ADP stimulation were reduced in both cohorts, and there were no significant differences between groups. Both patients with SCD and healthy subjects had significant reductions in the monocyte-platelet and neutrophil-platelet aggregate MFI and the percentage of platelets expressing P-selectin and activated GPIIb-IIIa (all p < 0.05). Healthy subjects also had significant reductions in monocyte-platelet aggregate percentages (p = 0.004), neutrophil-platelet aggregate percentages (p = 0.011) and the percentage of CD40L-positive platelets (p = 0.044) that were not observed in patients with SCD. Prasugrel administration to SCD patients attenuates ex vivo ADP-stimulated platelet activation as measured by the percentage of platelets positive for P-selectin and GPIIb-IIIa, thus reducing the proportion of platelets that may participate in aggregates. Furthermore, prasugrel decreases ex vivo ADP-stimulated platelet aggregation with monocytes and neutrophils as measured by the monocyte-platelet and neutrophil-platelet aggregate MFI. This implies that in the presence of prasugrel, fewer platelets adhere to monocytes and neutrophils, which may result in reducing cell-platelet aggregate size. Therefore, reduced platelet reactivity and decreased size of leukocyte-platelet aggregates suggest additional mechanisms by which prasugrel may provide benefit to patients with SCD and support further investigation of possible therapeutic benefits of prasugrel in this population.
    Platelets 08/2014; DOI:10.3109/09537104.2014.940887 · 2.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: CYP2C19 genotype has been shown to impact response to clopidogrel 75-mg but not prasugrel 10-mg. Here, we assessed effects of CYP2C19 metaboliser status on pharmacokinetics (PK) and pharmacodynamic (PD) responses to prasugrel 5-mg and 10-mg and clopidogrel 75-mg using data from two PK/PD studies in stable coronary artery disease (CAD) patients (GENERATIONS and FEATHER). Active metabolite concentrations (area under the curve, AUC[0-tlast]), maximum platelet aggregation (MPA) measured by light transmission aggregometry, vasodilator-stimulated phosphoprotein platelet reactivity index, and VerifyNow P2Y12-platelet reaction units (VN-PRU) were analysed by CYP2C19-predicted phenotype (extensive metaboliser [EM; N=154], *2-*8 non-carriers, vs reduced metaboliser [RM; N=41],*2-*8 carriers/*17 non-carriers). AUC(0-tlast) was unaffected by metaboliser status for prasugrel 5-mg and 10-mg (geometric mean EM/RM ratios 1.00, 95% confidence interval [CI]: 0.86,1.17, p>0.99; and 0.97, 95% CI:0.85,1.12, p=0.71, respectively), but was lower among RMs receiving clopidogrel 75-mg (1.37, 95% CI:1.14,1.65, p<0.001). Platelet reactivity was not significantly affected by CYP2C19 metaboliser status for prasugrel 5-mg, or for prasugrel 10-mg by MPA and VN-PRU, but for clopidogrel 75-mg was significantly higher in reduced metabolisers (all measures p<0.01). Prasugrel 10-mg showed greater antiplatelet effects vs clopidogrel 75-mg (all comparisons p<0.001). Prasugrel 5-mg showed greater antiplatelet effects vs clopidogrel 75-mg in RMs (all p<0.001), and comparable effects in EMs (all p≥0.37). In contrast to clopidogrel, prasugrel active metabolite PK was not influenced by CYP2C19 genotype. Antiplatelet effect for prasugrel 10-mg was greater irrespective of metaboliser status and for prasugrel 5-mg was greater for RMs and comparable for EMs as compared to clopidogrel 75-mg.
    Thrombosis and Haemostasis 07/2014; 112(3). DOI:10.1160/TH13-10-0891 · 5.76 Impact Factor
  • Journal of the American College of Cardiology 04/2014; 63(12):A104. DOI:10.1016/S0735-1097(14)60104-2 · 15.34 Impact Factor
  • Journal of the American College of Cardiology 04/2014; 63(12):A103. DOI:10.1016/S0735-1097(14)60103-0 · 15.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We compared results obtained with the Nanosphere Verigene® System, a novel point-of-care (POC) genetic test capable of analysing 11 CYP2C19 variants within 3 hours, to an established, validated genotyping method (Affymetrix™ DMET+; reference assay) for identifying extensive and reduced metabolisers of clopidogrel. Based on genotyping, patients (N=82) with stable coronary artery disease on clopidogrel 75 mg daily were defined as extensive metabolisers (*1/*1, *1/*17, *17/*17), reduced metabolisers (*1/*2, *1/*8, *2/*2, *2/*3), or of indeterminate metaboliser status (*2/*17). Pharmacokinetic exposure to clopidogrel's active metabolite and pharmacodynamic measures with protein reaction units (PRU) (VerifyNow® P2Y12 assay) and VASP PRI (PRI) were also assessed. There was a 99.9% overall concordance of marker-level data between the Nanosphere Verigene and DMET+ systems in identifying the CYP2C19 variants and 100% agreement in classifying the patients as extensive (n=59) or reduced metabolisers (n=15). Extensive metabolisers had significantly higher active metabolite exposure than reduced metabolisers (LS means 12.6 ng*h/ml vs 7.7 ng*h/ml; p<0.001). Extensive metabolisers also had lower PRU (LS means 158 vs 212; p=0.003) and VASP PRI (LS means 48% vs 63%, p=0.01) compared to reduced metabolisers. Rates of high on-treatment platelet reactivity were higher in reduced metabolisers compared to extensive metabolisers (VASP PRI ≥50%: 79% vs 47%; PRU ≥ 235: 33% vs 16%). The Nanosphere Verigene CBS system identified 11 CYP2C19 alleles in less than 3 hours with a high degree of accuracy when compared to a conventional method, and was further validated against pharmacokinetic and pharmacodynamic phenotypes.
    Thrombosis and Haemostasis 01/2014; 111(5). DOI:10.1160/TH13-09-0767 · 5.76 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Prasugrel, a P2Y12 adenosine diphosphate (ADP) receptor antagonist effectively inhibits ADP-mediated platelet activation and aggregation, and may be useful in reducing vaso-occlusive crises in sickle cell disease (SCD). In this study, we assess the effect of prasugrel on biomarkers of platelet activation and coagulation in patients with SCD. Twelve adult patients with SCD and 13 healthy subjects were examined before and after 12±2days of 5.0 or 7.5mg/day oral prasugrel. Assessed cellular biomarkers included monocyte- and neutrophil-platelet aggregates, activated glycoprotein IIb-IIIa (GPIIbIIIa), P-selectin, CD40 ligand (CD40L), tissue factor (TF) expression on circulating platelets and on monocyte-platelet aggregates, and platelet-erythrocyte aggregates. Soluble biomarkers included CD40L, prothrombin fragment 1.2 (F1.2), thromboxane B2 (TXB2), P-selectin, and TF. Patients with SCD had increased platelet baseline activation compared to healthy subjects, as measured by percentages of monocyte-platelet aggregates, neutrophil-platelet aggregates, and platelets expressing CD40L. Likewise, baseline levels of soluble F1.2 and TXB2 were elevated in patients with SCD compared to healthy subjects. After 12days of prasugrel, patients with SCD had a significant reduction in platelet-monocyte aggregates that was not observed in healthy subjects. Following prasugrel administration, those with SCD maintained higher levels of monocyte-platelet aggregates and soluble F1.2, but had lower levels of platelet-erythrocyte aggregates and soluble TF compared to healthy subjects. These results provide evidence for chronic platelet activation in the SCD steady state, activation that was in part attenuated by prasugrel, thereby suggesting that ADP may mediate platelet activation in SCD.
    Thrombosis Research 12/2013; DOI:10.1016/j.thromres.2013.12.008 · 2.43 Impact Factor
  • Source
    Journal of the American College of Cardiology 10/2013; 62(18). DOI:10.1016/j.jacc.2013.08.875 · 15.34 Impact Factor
  • Source
    Journal of the American College of Cardiology 10/2013; 62(18). DOI:10.1016/j.jacc.2013.08.881 · 15.34 Impact Factor
  • Source
    Journal of the American College of Cardiology 10/2013; 62(18). DOI:10.1016/j.jacc.2013.08.901 · 15.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Body weight is a predictor of clopidogrel response. However, no prospective studies have compared pharmacodynamic (PD) and pharmacokinetic (PK) data based on body weight. We compared PD and PK effects of clopidogrel 75 mg in low body weight (LBW, <60 kg) and higher body weight (HBW, ≥60 kg) patients with stable coronary artery disease. LBW (n = 34, 56.4 ± 3.7 kg) and HBW (n = 38, 84.7 ± 14.9 kg) aspirin-treated patients received clopidogrel 75 mg for 10-14 days. The area under the concentration-time curve of active metabolite (Clop-AM) calculated through the last quantifiable concentration up to 4 h postdose, AUC(0-tlast), was calculated by noncompartmental methods. Light transmission aggregometry (LTA) (maximum platelet aggregation and inhibition of platelet aggregation to 20 μM adenosine diphosphate (ADP), and residual platelet aggregation to 5 μM ADP), VerifyNow(®) P2Y12 reaction units (PRU), and vasodilator-associated stimulated phosphoprotein phosphorylation platelet reactivity index (VASP-PRI) were performed. Mean AUC(0-tlast) was lower in HBW than LBW patients: 12.8 versus 17.9 ng h/mL. HBW patients had higher platelet reactivity as measured by LTA (all p ≤ 0.01), PRU (207 ± 68 vs. 152 ± 57, p < 0.001), and VASP-PRI (56 ± 18 vs. 39 ± 17, p < 0.001). More HBW patients exhibited high on-treatment platelet reactivity (HPR) using PRU (35 vs. 9 %) and VASP-PRI (65 vs. 27 %). Body weight correlated with PRU and VASP-PRI (both p < 0.001), and inversely with log transformed AUC(0-tlast) (p < 0.001). In conclusion, HBW patients had lower levels of Clop-AM, and higher platelet reactivity and rates of HPR than LBW subjects, contributing to their suboptimal response to clopidogrel.
    Journal of Thrombosis and Thrombolysis 09/2013; 38(2). DOI:10.1007/s11239-013-0987-8 · 2.17 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Clopidogrel response varies according to the presence of genetic polymorphisms. The CYP2C19*2 allele has been associated with impaired response; conflicting results have been reported for CYP2C19*17, ABCB1, and PON1 genotypes. We assessed the impact of CYP2C19, PON1, and ABCB1 polymorphisms on clopidogrel and prasugrel pharmacodynamic (PD) and pharmacokinetic (PK) parameters. Aspirin-treated patients (N=194) with coronary artery disease from two independent, prospective, randomised, multi-centre studies comparing clopidogrel (75 mg) and prasugrel (10 mg) were genotyped and classified by predicted CYP2C19 metaboliser phenotype (ultra metabolisers [UM] = *17 carriers; extensive metabolisers [EM] = *1/1 homozygotes; reduced metabolisers [RM] = *2 carriers). ABCB1 T/T and C/T polymorphisms and PON1 A/A, A/G and G/G polymorphisms were also genotyped. PD was assessed using VerifyNow® P2Y12 and vasodilator stimulated phosphoprotein (VASP) expressed as platelet reactivity index (PRI) after 14 days of maintenance dosing. Clopidogrel and prasugrel active metabolite (AM) exposure was calculated in a cohort of 96 patients. For clopidogrel, genetic variants in CYP2C19, but not ABCB1 or PON1, affected PK and PD. For prasugrel, none of the measured genetic variants affected PK or PD. Compared with clopidogrel, platelet inhibition with prasugrel was greater even in CYP2C19 UM phenotype. Prasugrel generated more AM and achieved greater platelet inhibition than clopidogrel irrespective of CYP2C19, ABCB1, and PON1 polymorphisms. The lack of effect from genetic variants on prasugrel AM generation or antiplatelet activity is consistent with previous studies in healthy volunteers and is consistent with improved efficacy in acute coronary syndrome patients managed with percutaneous coronary intervention.
    Thrombosis and Haemostasis 09/2013; 110(20130905). DOI:10.1160/TH13-03-0263 · 5.76 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Treatment with prasugrel and aspirin improves outcomes compared with clopidogrel and aspirin for patients with acute coronary syndrome who have had angiography and percutaneous coronary intervention; however, no clear benefit has been shown for patients managed first with drugs only. We assessed outcomes from the TRILOGY ACS trial based on whether or not patients had coronary angiography before treatment was chosen. TRILOGY ACS ( number NCT00699998) was a randomised controlled trial, done at more than 800 sites worldwide. Patients with non-ST-elevation acute coronary syndrome who were selected for management with revascularisation were randomly assigned to clopidogrel or prasugrel. The primary endpoint was cardiovascular death, myocardial infarction, or stroke at 30 months. In the present analysis we assessed differences in the primary endpoint by angiography status and whether the effects of treatment on the primary endpoint differed between patients who had angiography before enrolment and those who had not. 7243 patients younger than 75 years were included in the TRILOGY ACS primary analysis. 3085 (43%) had angiography at baseline, 4158 (57%) had not. Fewer patients who had angiography reached the primary endpoint at 30 months compared with those who did not have angiography, according to Kaplan-Meier analysis (281/3085 [12·8%] vs 480/4158 [16·5%], adjusted hazard ratio [HR] 0·63, 95% CI 0·53-0·75; p<0·0001). The proportion of patients who reached the primary endpoint was lower in the prasugrel group than in the clopidogrel group for those who had angiography (122/1524 [10·7%] vs 159/1561 [14·9%], HR 0·77, 95% CI 0·61-0·98; p=0·032) but did not differ between groups in patients who did not have angiography (242/2096 [16·3%] vs 238/2062 [16·7%], HR 1·01, 0·84-1·20; p=0·94; pinteraction=0·08). Overall, TIMI major bleeding and GUSTO severe bleeding were rare. Bleeding outcomes tended to be higher with prasugrel but did not differ significantly between treatment groups in either angiography cohort. Among patients who had angiography who took prasugrel there were fewer cardiovascular deaths, myocardial infarctions, or strokes than in those who took clopidogrel. This result needs to be corroborated, but it is consistent with previous trials of more versus less intensive antiplatelet treatment. When angiography is done for acute coronary syndrome and anatomic coronary disease confirmed, the benefits and risks of intensive antiplatelet treatment exist whether the patient is treated with drugs or percutaneous coronary intervention. Daiichi Sankyo, Eli Lilly.
    The Lancet 08/2013; 382(9892):605-13. DOI:10.1016/S0140-6736(13)61451-8 · 45.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dual antiplatelet therapy in older vs. younger patients with acute coronary syndromes (ACS) is under-studied. Low-dose prasugrel (5mg/d) is recommended for younger, lower-body-weight ACS patients and elderly ACS patients to mitigate bleeding risk of standard-dose prasugrel (10mg/d). 9326 medically managed ACS patients from the TRILOGY trial (7243 <75y; 2083 ≥75y) were randomized to prasugrel (10mg/d; 5mg/d for those ≥75y or <75y and <60kg) or clopidogrel (75mg/d), plus aspirin, for ≤30 months. A total of 515 participants ≥75y (25% of total elderly population) had serial platelet reactivity unit (PRU) measurements in a platelet-function substudy (PFS). Cumulative risks of the primary endpoint (cardiovascular death/myocardial infarction/stroke) and TIMI major bleeding increased progressively with age and were ≥twofold higher in older participants. Among those ≥75y, TIMI-major bleeding (4.1% vs. 3.4%, HR=1.09, 95%CI: 0.57-2.08) and primary endpoint rates were similar with reduced-dose prasugrel vs. clopidogrel. Despite a correlation between lower 30-day on-treatment PRU values and lower weight only in the prasugrel group, there was a nonsignificant treatment-by-weight interaction for PRU values among participants ≥75y in the PFS (P=0.06). No differences in weight were seen in all participants ≥75y with vs. without TIMI-major/minor bleeding in both treatment groups. Older age is associated with substantially increased long-term cardiovascular risk and bleeding among medically managed ACS patients, with no differences in ischemic or bleeding outcomes with reduced-dose prasugrel vs. clopidogrel in elderly patients. No significant interaction among weight, pharmacodynamic response, and bleeding risk was observed between reduced-dose prasugrel vs. clopidogrel in elderly patients. Identifier: NCT0069999.
    Circulation 07/2013; 128(8). DOI:10.1161/CIRCULATIONAHA.113.002303 · 14.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVES: We assessed pharmacodynamic (PD) response for the reduced prasugrel 5-mg maintenance dose in very elderly (≥75y; VE) patients. BACKGROUND: In TRITON-TIMI 38, prasugrel 10-mg reduced ischemic events versus clopidogrel 75-mg, but increased bleeding in VE patients. METHODS: We examined PD and active-metabolite pharmacokinetics with prasugrel 5-mg and 10-mg and clopidogrel 75-mg in a three-period (12 days each), blinded, cross-over study in VE (n=73, mean 79±3y) or non-elderly (≥45-<65y, NE) (n=82, 56±5y) stable coronary artery disease (CAD) patients on background aspirin. Assays included light transmission aggregometry (LTA), VerifyNow(®) P2Y12 (VN-P2Y12), and VASP. The primary comparison was non-inferiority of maximum platelet aggregation (MPA) comparing the median for prasugrel 5-mg in VE versus the 75th percentile for prasugrel 10-mg in NE, using a prespecified one-sided 97.5% confidence interval for the difference <15%. RESULTS: Prasugrel 5-mg in VE met the primary pharmacodynamic non-inferiority criterion versus prasugrel 10-mg in NE. For prasugrel 5-mg, MPA was significantly lower (mean±SD, 57±14%) than clopidogrel (63±14%) (p<0.001) in VE, but higher than prasugrel 10-mg in NE (46±12%) (p<0.001). PD response by LTA, VN-P2Y12, and VASP during all treatments appeared similar between age cohorts. Prasugrel 5-mg resulted in fewer VE poor responders versus clopidogrel. Rates of mild bleeding were higher with prasugrel 10-mg, but similar for prasugrel 5-mg versus clopidogrel 75-mg. CONCLUSIONS: In aspirin-treated stable CAD patients, prasugrel 5-mg in VE attenuated platelet inhibition while meeting prespecified non-inferiority criterion versus prasugrel 10-mg in NE, with significantly better PD response and fewer poor responders compared to clopidogrel 75-mg in VE.
    Journal of the American College of Cardiology 06/2013; 62(7). DOI:10.1016/j.jacc.2013.05.023 · 15.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Platelet activation has been implicated in the pathogenesis of sickle cell disease (SCD) suggesting antiplatelet agents may be therapeutic. To evaluate the safety of prasugrel, a thienopyridine antiplatelet agent, in adult patients with SCD, we conducted a double-blind, randomized, placebo-controlled study. The primary endpoint, safety, was measured by hemorrhagic events requiring medical intervention. Patients were randomized to prasugrel 5 mg daily (n = 41) or placebo (n = 21) for 30 days. Platelet function by VerifyNow® P2Y12 and vasodilator-stimulated phosphoprotein assays at days 10 and 30 were significantly inhibited in prasugrel- compared with placebo-treated SCD patients. There were no hemorrhagic events requiring medical intervention in either study arm. Mean pain rate (percentage of days with pain) and intensity in the prasugrel arm were decreased compared with placebo. However, these decreases did not reach statistical significance. Platelet surface P-selectin and plasma soluble P-selectin, biomarkers of in vivo platelet activation, were significantly reduced in SCD patients receiving prasugrel compared with placebo. In sum, prasugrel was well tolerated and not associated with serious hemorrhagic events. Despite the small size and short duration of this study, there was a decrease in platelet activation biomarkers and a trend toward decreased pain.
    Journal of Hematology & Oncology 02/2013; 6(1):17. DOI:10.1186/1756-8722-6-17 · 4.93 Impact Factor

Publication Stats

4k Citations
584.89 Total Impact Points


  • 2006–2015
    • Eli Lilly
      • Lilly Research Laboratories
      Indianapolis, Indiana, United States
  • 2013
    • Lund University
      • Department of Cardiology
      Lund, Skane, Sweden
  • 2012
    • Technische Universität München
      München, Bavaria, Germany
  • 2008
    • Uppsala Monitoring Centre
      Uppsala, Uppsala, Sweden