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Objective: Patients with diabetes mellitus (DM) presenting with acute coronary syndrome (ACS) and undergoing percutaneous coronary intervention (PCI) derived enhanced benefit with dual antiplatelet therapy (DAPT) with prasugrel vs. clopidogrel. The risk profile and treatment response to DAPT for medically managed ACS patients with DM remains uncertain., Methods: The TRILOGY ACS trial compared aspirin + prasugrel vs. aspirin + clopidogrel for up to 30months in non-ST-segment elevation (NSTE) ACS patients managed medically without revascularization. We compared treatment-related outcomes among 3539 patients with DM vs. 5767 patients without DM. The primary endpoint was a composite of cardiovascular death, myocardial infarction, or stroke., Results: Patients with vs. without DM were younger, more commonly female, heavier, and more often had revascularization prior to the index ACS event. The frequency of the primary endpoint through 30months was higher among patients with vs. without DM (24.8% vs. 16.3%), with a higher risk for those patients with DM treated with insulin vs. those treated without insulin (35.3% vs. 19.9%). There was no significant difference in the frequency of the primary endpoint by treatment with prasugrel vs. clopiodgrel in those with or without DM (P int =0.82) and with or without insulin treatment among those with DM (P int =0.304)., Conclusions: Among NSTE ACS patients managed medically without revascularization, patients with DM had a higher risk of ischemic events that was amplified among those treated with insulin. There was no differential treatment effect with a more potent DAPT regimen of aspirin + prasugrel vs. aspirin + clopidogrel., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Both diabetes mellitus (DM) and carriage of the CYP2C19*2 allele are associated with a reduced response to clopidogrel. The relative contributions of these factors and whether higher clopidogrel doses can overcome both factors remain unknown. The objective of this study was to test the ability of clopidogrel doses up to 300 mg daily to decrease platelet reactivity in patients with DM and/or CYP2C19*2. ELEVATE-TIMI 56 randomised 333 patients with coronary artery disease to different maintenance doses of clopidogrel in four treatment periods, each lasting approximately 14 days. On-treatment platelet reactivity was compared between patients stratified by DM, CYP2C19*2 status and clopidogrel dose. Both DM and CYP2C19*2 were independently associated with elevated on-treatment platelet reactivity with clopidogrel 75 mg daily (p<0.0001 for each). With 75 mg, mean on-treatment PRU was progressively higher (p trend <0.001) when evaluating patients: with neither DM nor CYP2C19*2 (150.7; 95 % CI 140.5-162.6), with only DM (187.2; 95 % CI, 171.3-206.9), with only CYP2C19*2 (227.9; 95 % CI, 205.1-250.8), and with both DM and CYP2C19*2 (239.9; 95 % CI, 209.7-270.1). Notably, with 75 mg, patients with only CYP2C19*2 had higher on-treatment platelet reactivity than those with only DM (p=0.0068). To achieve on-treatment platelet reactivity similar to that seen with clopidogrel 75 mg in patients with neither DM nor CYP2C19*2, the following doses were required: 150 mg with only DM, 225 mg with only CYP2C19*2, and 300 mg with both DM and CYP2C19*2. Patients with both DM and CYP2C19*2 required a four-fold increase in clopidogrel maintenance dose as compared to patients without these factors to achieve a similar antiplatelet response.

Background: Ticagrelor reduced cardiovascular events compared with clopidogrel in PLATO without increasing overall major bleeding. We evaluated whether the use of glycoprotein IIb/IIIa inhibitor (GPI) impacts the relative efficacy and safety of ticagrelor compared with clopidogrel., Methods: PLATO randomized 18,624 subjects with acute coronary syndrome to ticagrelor versus clopidogrel. The primary efficacy end point was cardiovascular death/myocardial infarction/stroke, and the primary safety end point was major bleeding. The use of GPI was at the physician's discretion and open-label. We evaluated outcomes at 30 days stratified by GPI use in the subgroup of 9,983 patients who underwent percutaneous coronary intervention (PCI) within 72 hours., Results: A total of 4,020 (40%) received a GPI. Those receiving a GPI were more likely to be younger, be male, and undergo multivessel PCI. There was no interaction between treatment and GPI use for the primary efficacy and safety end points. Patients treated without GPI had a lower rate of definite stent thrombosis and higher rate of minor/major bleeding with ticagrelor compared with clopidogrel (P < .05), whereas there was no such difference with GPI (P interaction < .05)., Conclusions: In patients with acute coronary syndrome undergoing early PCI, the efficacy and safety of ticagrelor as compared with clopidogrel were not modified by GPI use according to the primary efficacy and safety end point of the trial, although there were indications of greater benefit on definite stent thrombosis and more major or minor bleeding with ticagrelor in patients without (vs with) GPI treatment., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Clopidogrel and prasugrel are antiplatelet therapies commonly used to treat patients with cardiovascular disease. They are both pro-drugs requiring biotransformation into active metabolites. It has been proposed that a genetic variant Q192R (rs662 A>G) in PON1 significantly alters the biotransformation of clopidogrel and affects clinical outcomes; however, this assertion has limited support. The relationship between this variant and clinical outcomes with prasugrel has not been studied. We genotyped PON1 Q192R in 275 healthy subjects treated with clopidogrel or prasugrel and 2922 patients with an ACS undergoing PCI randomized to treatment with clopidogrel or prasugrel in the TRITON-TIMI 38 trial. A meta-analysis was performed including 13 studies and 16,760 clopidogrel-treated patients. Among clopidogrel-treated subjects, there were no associations between Q192R and active drug metabolite levels (P = 0.62) or change in platelet aggregation (P = 0.51). Consistent with these results, in clopidogrel-treated patients in TRITON-TIMI 38, there was no association between Q192R and the rates of CV death, myocardial infarction, or stroke (RR 11.2 %, QR 8.6 %, and QQ 9.3 %; P = 0.66) or stent thrombosis (RR 2.4 %, QR 0.7 %, and QQ 1.6 %, P = 0.30), with patients with the putative at-risk Q variant having numerically lower event rates. Likewise, among prasugrel-treated subjects, there were no associations between Q192R and active drug metabolite levels (P = 0.88), change in platelet aggregation (P = 0.97), or clinical outcomes (P = 0.72). In a meta-analysis, the Q variant was not significantly associated with MACE (QQ vs. RR 1.22, 95 % CI 0.84-1.76) or stent thrombosis (QQ vs. RR OR 1.36, 95 % CI 0.77-2.38). Furthermore, when restricted to the validation studies, the OR (95 % CI) for MACE and stent thrombosis were 0.99 (0.77-1.27) and 1.23 (0.74-2.03), respectively. In the present study, the Q192R genetic variant in PON1 was not associated with the pharmacologic or clinical response to clopidogrel, nor was it associated with the response to prasugrel. The meta-analysis reinforced a lack of a significant association between Q192R and cardiovascular outcomes in clopidogrel-treated patients.

Aims: Studies have suggested increased cancer incidence associated with long-term dual antiplatelet therapy (DAPT) for acute coronary syndrome (ACS). We evaluated cancer incidence and treatment-related differences in an analysis of DAPT for ACS., Methods and Results: The Targeted Platelet Inhibition to Clarify the Optimal Strategy to Medically Manage Acute Coronary Syndromes trial enrolled 9326 participants with ACS, who received aspirin plus clopidogrel or prasugrel. Median treatment exposure was 15 months. Cancer history and screening procedures were collected. Suspected non-benign neoplasm events were reported and adjudicated. The primary outcome was detection of new, non-benign neoplasm. Factors associated with neoplasm events, the relationship of these events to cardiovascular and bleeding endpoints, and treatment-related differences in neoplasm detection were studied. Among 9240 participants who received ≥1 dose of study drug, 1.8% had a confirmed neoplasm event. The efficacy composite of cardiovascular death, myocardial infarction, or stroke occurred more frequently among those with a neoplasm event vs. those without (18.2 vs. 13.5%) as did Global Use of Strategies to Open Occluded Coronary Arteries severe/moderate bleeding (11.2 vs. 1.5%). Screening rates were substantially higher in North America and Western Europe/Scandinavia vs. other regions. Factors most strongly associated with detection of neoplasm events were older age, region, male sex, and current/recent smoking. Among the pre-specified population without a history of neoplasm or previous curative treatment for neoplasm (n = 9105), the incidence of neoplasm events was similar with prasugrel vs. clopidogrel (1.8 vs. 1.7%; HR = 1.04; 95% CI 0.77-1.42; P = 0.79)., Conclusions: Neoplasm events were infrequent during long-term DAPT after ACS, were associated with differential cancer-screening practices across regions, and the frequency of neoplasm detection was similar with prasugrel vs. clopidogrel., Trial Registration: ClinicalTrials.gov identifier: NCT00699998., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Background: Dual antiplatelet therapy is recommended after coronary stenting to prevent thrombotic complications, yet the benefits and risks of treatment beyond 1 year are uncertain., Methods: Patients were enrolled after they had undergone a coronary stent procedure in which a drug-eluting stent was placed. After 12 months of treatment with a thienopyridine drug (clopidogrel or prasugrel) and aspirin, patients were randomly assigned to continue receiving thienopyridine treatment or to receive placebo for another 18 months; all patients continued receiving aspirin. The coprimary efficacy end points were stent thrombosis and major adverse cardiovascular and cerebrovascular events (a composite of death, myocardial infarction, or stroke) during the period from 12 to 30 months. The primary safety end point was moderate or severe bleeding., Results: A total of 9961 patients were randomly assigned to continue thienopyridine treatment or to receive placebo. Continued treatment with thienopyridine, as compared with placebo, reduced the rates of stent thrombosis (0.4% vs. 1.4%; hazard ratio, 0.29 [95% confidence interval {CI}, 0.17 to 0.48]; P<0.001) and major adverse cardiovascular and cerebrovascular events (4.3% vs. 5.9%; hazard ratio, 0.71 [95% CI, 0.59 to 0.85]; P<0.001). The rate of myocardial infarction was lower with thienopyridine treatment than with placebo (2.1% vs. 4.1%; hazard ratio, 0.47; P<0.001). The rate of death from any cause was 2.0% in the group that continued thienopyridine therapy and 1.5% in the placebo group (hazard ratio, 1.36 [95% CI, 1.00 to 1.85]; P=0.05). The rate of moderate or severe bleeding was increased with continued thienopyridine treatment (2.5% vs. 1.6%, P=0.001). An elevated risk of stent thrombosis and myocardial infarction was observed in both groups during the 3 months after discontinuation of thienopyridine treatment., Conclusions: Dual antiplatelet therapy beyond 1 year after placement of a drug-eluting stent, as compared with aspirin therapy alone, significantly reduced the risks of stent thrombosis and major adverse cardiovascular and cerebrovascular events but was associated with an increased risk of bleeding. (Funded by a consortium of eight device and drug manufacturers and others; DAPT ClinicalTrials.gov number, NCT00977938.).

Objectives: This study sought to evaluate the efficacy of prasugrel versus clopidogrel in ST-segment elevation myocardial infarction (STEMI) by the timing of percutaneous coronary intervention (PCI)., Background: Treatment strategies and outcomes for patients with STEMI may differ when treated with primary compared with secondary PCI., Methods: STEMI patients in the TRITON-TIMI 38 (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis In Myocardial Infarction 38) were randomized to prasugrel or clopidogrel on presentation if primary PCI was intended or later during secondary PCI. Primary PCI was defined as within 12 h of symptom onset. The primary endpoint was cardiovascular death, myocardial infarction (MI), or stroke. Because periprocedural MI is difficult to assess in the setting of STEMI, we performed analyses excluding these events., Results: Reductions in the primary endpoint with prasugrel versus clopidogrel (hazard ratio [HR]: 0.79; 95% confidence interval [CI]: 0.65 to 0.97; p = 0.022) were consistent between primary and secondary PCI patients at 15 months (HR: 0.89; 95% CI: 0.69 to 1.13 vs. HR: 0.65; 95% CI: 0.46 to 0.93; p interaction = 0.15). However, a tendency toward a difference in treatment effect at 30 days (HR: 0.68; 95% CI: 0.54 to 0.87; p = 0.002) was observed between primary and secondary PCI patients (HR: 0.81; 95% CI: 0.60 to 1.09 vs. HR: 0.51; 95% CI: 0.34 to 0.76; p interaction = 0.06). When periprocedural MI was excluded, the efficacy of prasugrel remained consistent among primary and secondary PCI patients at 30 days (HR: 0.53; 95% CI: 0.34 to 0.81 vs. HR: 0.44; 95% CI: 0.22 to 0.88; p interaction = 0.68) and 15 months (HR: 0.76; 95% CI: 0.56 to 1.03 vs. HR: 0.75; 95% CI: 0.46 to 1.21; p interaction = 0.96)., Conclusions: The efficacy of prasugrel versus clopidogrel was consistent irrespective of the timing of PCI, particularly in preventing nonprocedural events. (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis in Myocardial Infarction 38; NCT00097591)., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: P2Y12 antagonist therapy improves outcomes in acute myocardial infarction (MI) patients. Novel agents in this class are now available in the US. We studied the introduction of prasugrel into contemporary MI practice to understand the appropriateness of its use and assess for changes in antiplatelet management practices., Methods and Results: Using ACTION Registry-GWTG (Get-with-the-Guidelines), we evaluated patterns of P2Y12 antagonist use within 24 hours of admission in 100 228 ST elevation myocardial infarction (STEMI) and 158 492 Non-ST elevation myocardial infarction (NSTEMI) patients at 548 hospitals between October 2009 and September 2012. Rates of early P2Y12 antagonist use were approximately 90% among STEMI and 57% among NSTEMI patients. From 2009 to 2012, prasugrel use increased significantly from 3% to 18% (5% to 30% in STEMI; 2% to 10% in NSTEMI; P for trend <0.001 for all). During the same period, we observed a decrease in use of early but not discharge P2Y12 antagonist among NSTEMI patients. Although contraindicated, 3.0% of patients with prior stroke received prasugrel. Prasugrel was used in 1.9% of patients ≥75 years and 4.5% of patients with weight <60 kg. In both STEMI and NSTEMI, prasugrel was most frequently used in patients at the lowest predicted risk for bleeding and mortality. Despite lack of supporting evidence, prasugrel was initiated before cardiac catheterization in 18% of NSTEMI patients., Conclusions: With prasugrel as an antiplatelet treatment option, contemporary practice shows low uptake of prasugrel and delays in P2Y12 antagonist initiation among NSTEMI patients. We also note concerning evidence of inappropriate use of prasugrel, and inadequate targeting of this more potent therapy to maximize the benefit/risk ratio.

Objectives: The goal of this study was to determine whether there is a relationship between aspirin dose and the potent antiplatelet agent prasugrel in the TRITON-TIMI 38 (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis In Myocardial Infarction 38) study., Background: Optimal aspirin dosing after acute coronary syndromes remains uncertain. Previous studies have raised questions regarding an interaction between high-dose aspirin and the potent antiplatelet agent ticagrelor., Methods: In TRITON-TIMI 38, we classified 12,674 patients into low-dose (<150 mg) or high-dose (≥150 mg) aspirin groups based on discharge dose. We identified independent correlates of dose selection and studied the impact of aspirin dose on the clinical effects of prasugrel., Results: There was significant geographical variation in aspirin dosing, with North American patients receiving high-dose aspirin more frequently than other countries (66% vs. 28%; p < 0.001). Clinical factors correlating with high-dose aspirin included previous percutaneous coronary intervention and use of aspirin before randomization. Characteristics associated with the use of low-dose aspirin included age ≥75 years, white race, and use of bivalirudin or a glycoprotein IIb/IIIa inhibitor during coronary intervention. Regardless of low- or high-dose aspirin use, prasugrel had lower rates of the primary efficacy endpoint (cardiovascular death, myocardial infarction, or stroke [CVD/MI/stroke]) (hazard ratio [HR]CVD/MI/stroke = 0.78 [95% confidence interval (CI) 0.64 to 0.95] and HRCVD/MI/stroke = 0.87 [95% CI 0.69 to 1.10], respectively; p value for interaction = 0.48) and higher rates of the primary safety endpoint (HR TIMI major bleeding = 1.40 [95% CI 0.81 to 2.42] and TIMImajor bleeding = 1.30 [95% CI 0.63 to 2.68], respectively; p value for interaction = 0.84) compared with clopidogrel., Conclusions: In TRITON-TIMI 38, the safety and efficacy outcomes of prasugrel compared with those of clopidogrel were directionally consistent regardless of aspirin dose, although only the primary efficacy endpoint achieved statistical significance. There was no clinically meaningful interaction of aspirin with prasugrel, suggesting that previous observations with potent antiplatelet agents indicating differential results are not universal. (A Comparison of Prasugrel [CS-747] and Clopidogrel in Acute Coronary Syndrome Subjects Who Are to Undergo Percutaneous Coronary Intervention; NCT00097591)., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to evaluate the clinical relevance of potential clopidogrel drug-drug interactions., Background: Some studies have demonstrated that statins and calcium-channel blockers (CCBs) may attenuate the pharmacodynamic effects of clopidogrel., Methods: The TRITON-TIMI 38 (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 38) enrolled 13,608 patients with an acute coronary syndrome (ACS) and planned percutaneous coronary intervention (PCI), and randomized them to clopidogrel or prasugrel. Use of a statin or CCB was left to the discretion of the treating physician. A multivariable Cox model with propensity score was employed to evaluate the association between statin or CCB use and clinical outcomes., Results: Of the 6,795 subjects assigned to clopidogrel, 4,794 (70.6%) were on a CYP3A4-metabolized statin, and 966 (14.2%) were on a CCB at randomization. The risk of cardiovascular (CV) death, myocardial infarction (MI), or stroke was similar regardless of baseline use of statins (adjusted hazard ratio [HR]: 1.02, 95% confidence interval [CI]: 0.85 to 1.22) or CCBs (adjusted HR: 1.16; 95% CI: 0.94 to 1.43) in clopidogrel-treated patients. Further, the combined use of a CCB and atorvastatin 80 mg daily (adjusted HR: 0.82; 95% CI: 0.37 to 1.84), or a CCB, statin, and proton pump inhibitor (adjusted HR: 1.04; 95% CI: 0.70 to 1.54) were not associated with an increased risk of CV death, MI, or stroke. The use of statins or CCBs did not modify the relative efficacy of prasugrel versus clopidogrel for the primary endpoint (p for interaction = 0.43, 0.55, respectively)., Conclusions: In patients with ACS undergoing PCI, the use of statins or CCBs was not associated with an increased risk of CV events in clopidogrel-treated patients. Consistent results were observed when the drugs were administered alone, together, or in combination with proton pump inhibitors., (Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: The well-described morning peak in the onset of acute coronary syndromes has been partly attributed to increased platelet activity upon arising. It has been suggested that stent thrombosis (ST) exhibits a similar pattern. We assessed whether a diurnal variation in ST occurs, and whether more robust antiplatelet therapy with prasugrel (vs clopidogrel) can attenuate a morning excess., Methods and Materials: Patients from the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis in Myocardial Infarction (TRITON-TIMI) 38 trial (N = 13 608) with adjudicated ST classified per the Academic Research Consortium definitions of definite (N = 135) and probable (N = 27) were grouped into prespecified 8-hour intervals by time of onset: early (6 am-2 pm), late-day (2 pm-10 pm), and overnight (10 pm-6 am). We compared the rates per 1000 patients of ST across time intervals and stratified by treatment and stent type., Results: A diurnal variation in definite/probable ST was observed with rates of 6.5, 3.7, and 2.1 for early, late-day, and overnight intervals, respectively (P < .001), per 1000 patients treated. A sensitivity analysis excluding periprocedural acute-ST (<24 hours after index percutaneous coronary intervention [PCI]) resulted in similar findings (5.2, 2.5, and 1.8 per 1000, P < .001). The circadian variation in ST was observed in patients on clopidogrel (9.7, 4.8, and 3.1 per 1000, P < .001) with the highest rate of ST early in the day. Patients on prasugrel also demonstrated a circadian variation with particularly low rates of overnight ST (3.4, 3.0, and 1.1 per 1000, P = .020)., Conclusions: In TRITON-TIMI 38 trial, the timing of ST exhibited a significant diurnal variation similar to that seen with onset of other acute coronary syndromes. ST occurred less frequently among patients randomized to prasugrel compared to clopidogrel with the greatest absolute reduction (6.2 per 1000 patients) in events earlier in the day when platelet activity is known to be highest.

Background: 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., Methods: TRILOGY ACS (ClinicalTrials.gov 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 without [corrected] 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., Findings: 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., Interpretation: 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., Funding: Daiichi Sankyo, Eli Lilly., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Clopidogrel prescription is a class I guideline recommendation for medically managed patients with non-ST-segment-elevation myocardial infarction (NSTEMI). However, clopidogrel has historically been underused in this population. We evaluated contemporary rates of its use and evaluated associated factors, with a particular focus on hospital quality of myocardial infarction (MI) care., Methods and Results: We examined clopidogrel prescription rates among 23 186 patients with NSTEMI discharged from 382 US hospitals between October 2009 and March 2011. Associations between clopidogrel prescription and various patient and hospital factors, including hospital quality of MI care, were determined with regression modeling. Of the sample, 54.9% of eligible patients with NSTEMI received clopidogrel prescription at hospital discharge. Variation in rate by hospital was large, ranging from 22% to 97%. A variety of patient and hospital factors were associated with clopidogrel prescription. Hospital quality of MI care demonstrated modest association with clopidogrel prescription (odds ratio, 0.68; 95% CI, 0.54-0.85) between the lowest and highest hospital quality quartile) and accounted for 5.7% of the variation in prescription rates., Conclusions: Clopidogrel prescription is significantly underused in the medically managed NSTEMI population and demonstrates wide variability by hospital. Although hospital quality of MI care is associated with its use, the findings suggest that it only has a modest effect. Therefore, efforts to improve clopidogrel use likely will require measures beyond improving the overall hospital quality of MI care.

Background: Among patients with acute coronary syndrome (ACS), demographics, procedural characteristics and adjunctive medications differ globally. We examined whether there were differential effects of prasugrel compared with clopidogrel in the multinational TRITON-TIMI 38 study., Methods: We divided the enrollment into 5 pre-specified geographic regions. Patients were randomized to prasugrel or clopidogrel without regard to country of enrollment. End points are expressed as Kaplan-Meier failure estimates through 15 months. Heterogeneity was evaluated using Cox proportional hazards model. Additional sensitivity analyses were performed by dividing countries into categories based on the Human Development Index (HDI), which is a composite measure of social and economic development., Results: 13,608 patients were enrolled. Clinical characteristics including age, comorbidities, ACS presentation, stent types, and adjunctive medications differed broadly among regions. Despite these differences, no regional heterogeneity was observed with prasugrel compared to clopidogrel in the reduction of ischemic events (HR range: 0.76-0.87, p(interaction)>0.10 for each) and stent thrombosis (HR range: 0.34-0.72, p(interaction)>0.10 for each) or in the increased rate of non-CABG TIMI major bleeding (HR range: 1.16-1.76, p(interaction)>0.10 for each). There was a consistent trend in net clinical benefit (all cause death/MI/stroke/non-CABG TIMI major bleeding) favoring prasugrel (HR range: 0.81-0.97, p(interaction)>0.10 for each). Consistent results were also observed regarding the safety and efficacy of prasugrel compared with clopidogrel in both developed and developing countries., Conclusions: Despite differences in patient demographics, procedural techniques and adjunctive medications, consistent reduction in ischemic events and increased bleeding were seen with prasugrel compared with clopidogrel throughout the world., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Background: The 2007 update of the ACC/AHA guidelines for STEMI patients recommended addition of clopidogrel to aspirin regardless of reperfusion strategy, with a bolus dose in patients <75 years of age., Methods and Results: We evaluated use and dose of early clopidogrel among 52,140 STEMI patients enrolled in 368 hospitals participating in NCDR's ACTION Registry®--Get with the Guidelines (GWTG™) from January 2007-September 2009. Patients were stratified by reperfusion strategy: primary percutaneous coronary intervention (PCI, n=37,108), fibrinolysis (n=5805), or no-reperfusion (n=9227), and by age (<75 or ≥75 years). Adjusted odds for in-hospital outcomes are reported by clopidogrel use across reperfusion strategies. Clopidogrel was administered early to 97% of primary PCI, 18% of fibrinolytic, and 6% of non-reperfused patients. Among patients receiving clopidogrel, a loading dose (≥300 mg) was often used in primary PCI (91%) but less frequently among fibrinolysis-treated (83%) and non-reperfused patients (74%). A positive time trend from Q1 2007-Q3 2009 in overall clopidogrel use was observed only in fibrinolytic patients (15-20%) Use of clopidogrel was associated with a significant increase in major bleeding only among older patients in the no-reperfusion group (21.9% vs. 13.2%; OR 2.19; 95% CI 1.47-3.27). A significantly lower risk of in-hospital death was associated with clopidogrel use across all reperfusion strategies (OR [95% CI], primary PCI: 0.15 [0.13-0.19]; fibrinolysis: 0.26 [0.12-0.57]; no reperfusion: 0.42 [0.27-0.65])., Conclusion: Early clopidogrel use has not yet extended to the routine care of STEMI patients treated with fibrinolysis or those not receiving reperfusion as recommended in the guideline update.

Background: 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., Methods: 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)., Results: 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)., Conclusions: 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., (Copyright © 2011 Mosby, Inc. All rights reserved.)

It was the objective of this study to determine whether the intrinsic platelet response to adenosine diphosphate (ADP) before thienopyridine exposure contributes to residual platelet reactivity to ADP despite high level P2Y12 blockade by prasugrel (60 mg loading dose [LD]), 10 mg daily maintenance dose [MD]) or high-dose clopidogrel (600 mg LD, 150 mg daily MD). High residual platelet function during clopidogrel therapy is associated with poor clinical outcomes. It remains unknown whether the relationship between platelet reactivity prior to treatment with clopidogrel (300 mg LD, 75 mg daily MD) and residual on-treatment platelet reactivity is maintained after more potent P2Y12 inhibition. PRINCIPLE-TIMI 44 was a randomised, double-blind, two-phase crossover study of prasugrel compared with high-dose clopidogrel in 201 patients undergoing cardiac catheterisation for planned percutaneous coronary intervention. ADP-stimulated platelet-monocyte aggregates, platelet surface P-selectin and platelet aggregation were measured pre-treatment, during LD (6 h and 18-24 h) and MD (15 d). Correlations of pre-treatment to on-treatment values were determined by Spearman rank order. Prasugrel resulted in greater platelet inhibition than high-dose clopidogrel for each measure. However, for both drugs, pre-treatment reactivity to ADP predicted 6 h, 18-24 h and 15 day reactivity to ADP (correlations 0.24-0.62 for platelet-monocyte aggregates and P-selectin). In conclusion, a patient's intrinsic platelet response to ADP before exposure to thienopyridines contributes to residual platelet reactivity to ADP despite high level P2Y12 blockade with high-dose clopidogrel or even higher level P2Y12 blockade with prasugrel. Patients who are hyper-responsive to ADP pre-treatment are more likely to be hyper-responsive to ADP on-treatment, which may be relevant to therapeutic strategies.

Background: A higher loading dose of clopidogrel achieves a more rapid and consistent degree of platelet inhibition than standard dosing, although the clinical benefit of higher doses has not been clearly established. The use of the different doses in clinical practice is not known. We evaluated the patient, procedural, and hospital characteristics associated clopidogrel loading doses given to patients with non-ST-segment elevation myocardial infarction (NSTEMI)., Methods: The National Cardiovascular Data Registry ACTION Get With the Guidelines Registry was queried for patients with NSTEMI admitted from 2007 to 2008. Demographic, clinical, and procedural information were collected on standardized data forms. Patients were categorized according to the clopidogrel loading dose received. Temporal trends in the use of different doses were evaluated in quarterly time intervals., Results: Between January 1, 2007, and December 31, 2008, the use of a 600-mg clopidogrel loading dose increased steadily from 36.4% to 45.5%, whereas the use of 300 mg decreased slightly from 40.1% to 37.1%. Patients loaded with clopidogrel before cardiac catheterization were more likely to receive 300 mg, whereas those receiving a loading dose at the time of catheterization more often received 600 mg. The temporal increase in the use of 600 mg clopidogrel loading doses was not explained by temporal changes in periprocedural loading, use of early invasive management of patients with NSTEMI, or use of antithrombotics or glycoprotein 2b/3a inhibitors., Conclusions: Higher loading dose clopidogrel increased between 2007 and 2008. Higher-dose clopidogrel was more frequently used in lower-risk patients undergoing an early invasive strategy and receiving periprocedural loading., (Copyright © 2011 Mosby, Inc. All rights reserved.)

Content: 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., Objective: 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 Study Selection: 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., Data Extraction: 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., Results: 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., Conclusion: 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.

Background: 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., Methods: 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., Findings: 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., Interpretation: 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., Funding: Daiichi Sankyo Company Ltd and Eli Lilly and Company., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Background: The TIMI risk score (TRS) for ST-segment elevation myocardial infarction (STEMI) is a convenient validated clinical risk score for predicting mortality. Although not part of the risk score, ST-segment resolution (STRes) may provide a simple method of risk stratification based on the response to reperfusion. We sought to determine whether STRes provides incremental risk stratification to the TIMI risk score., Methods: The Clopidogrel as Adjunctive Reperfusion Therapy--Thrombolysis in Myocardial Infraction (CLARITY-TIMI 28) trial randomized STEMI patients receiving fibrinolysis to clopidogrel or placebo. A total of 2,340 patients had electrocardiograms (ECGs) valid to calculate STRes at 90 minutes, which was defined as complete (>70%), partial (30%-70%), or no resolution (30%). TRS was defined as low (0-2), medium (3-4), and high (> or =5). Clinical follow-up was through 30 days. Results were validated in 2,743 patients from the ExTRACT-TIMI 25 study., Results: The degree of STRes at 90 minutes after fibrinolysis correlated in a stepwise fashion with death or heart failure (5.1% complete STRes, 8.9% partial STRes, 13.4% no STRes, P < .001). Furthermore, the degree of STRes provided a consistent and significant gradient of risk across all risk score categories (low, medium, or high) and significantly improved the discriminatory ability of TIMI risk score to predict death or heart failure (c-statistic 0.69 for TIMI risk score alone and 0.74 with STRes added to the model, P < .001). With the inclusion of STRes to the TIMI risk score, 913 patients (39%) were reclassified to higher or lower risk groups, and the net reclassification improvement (NRI) was highly significant (P < .001). In the ExTRACT-TIMI 25 trial, addition of the STRes improved also the c-statistic (P = .012) and NRI (P < .001)., Conclusions: The extent of STRes based on routinely obtained ECGs is an independent predictor of death and heart failure when used together with the TIMI risk score and significantly improves the ability to risk stratify patients after fibrinolysis., (Copyright 2010 Mosby, Inc. All rights reserved.)

Background: 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., Methods: 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., Findings: 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)., Interpretation: The current findings do not support the need to avoid concomitant use of PPIs, when clinically indicated, in patients receiving clopidogrel or prasugrel., Funding: Daiichi Sankyo Company Limited and Eli Lilly and Company sponsored the trials. This analysis had no funding.

Background: Prasugrel led to a significant reduction in ischemic cardiovascular events among patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) with stent implantation compared to clopidogrel. Whether this benefit extends to patients undergoing PCI without stent implantation is unknown., Methods: In TRial to assess Improvement in Therapeutic Outcomes by optimizing platelet inhibitioN with prasugrel (TRITON)-Thrombolysis in Myocardial Infarction (TIMI) 38, patients (n = 13 608) undergoing PCI for ACS were randomized to aspirin plus clopidogrel or prasugrel. This postrandomization analysis of a prespecified subgroup was restricted to patients who underwent PCI without stent implantation (n = 569)., Results: Patients who underwent PCI without stent implantation were older and had a higher incidence of hypertension, diabetes, prior myocardial infarction (MI), prior coronary artery bypass (CABG) surgery, and renal dysfunction than patients who underwent stent implantation. In the group that did not undergo stent implantation, baseline characteristics were similar between patients receiving clopidogrel and prasugrel. The composite of cardiovascular death, nonfatal MI, and nonfatal stroke occurred in 14.2% of patients receiving prasugrel and 17.1% of patients receiving clopidogrel (HR 0.82, P = .27). There were significant reductions favoring prasugrel in the rates of urgent target vessel revascularization (TVR; HR 0.46, P = .040) and any TVR (HR 0.40, P = .009) and a trend toward a reduction in the incidence of nonfatal MI (HR 0.65, P = .11). CABG-related TIMI major bleeding was more frequent among patients receiving prasugrel. There were no significant interactions between treatment and PCI type., Conclusion: Among ACS patients who underwent PCI without stent implantation, prasugrel therapy tended to reduce clinical ischemic events and to increase bleeding events to a similar magnitude as among patients who received stents.

Aims: To examine the extent of platelet inhibition by prasugrel vs. clopidogrel in a TRITON-TIMI 38 substudy., Methods and Results: TRITON-TIMI 38 randomized acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) to prasugrel or standard dose clopidogrel. Selected sites prospectively enrolled TRITON-TIMI 38 patients to evaluate adenosine diphosphate (ADP)-attenuated phosphorylation of platelet vasodilator-stimulated phosphoprotein (VASP) (n = 125 patients) and, in a subset (n = 31 patients), ADP-stimulated platelet aggregation. VASP platelet reactivity index (PRI) was lower in prasugrel-treated patients than in clopidogrel-treated patients at 1-2 h post-PCI (>or=1 h after loading dose) (P < 0.001) and at 30 days (P < 0.001). Maximal platelet aggregation to 20 microM ADP was lower in prasugrel-treated patients than in clopidogrel-treated patients at 1-2 h (P = 0.004) and 30 days (P = 0.03). Results were similar with 5 microM ADP. Thienopyridine hyporesponsiveness, prespecified as VASP PRI >50%, was more frequent in clopidogrel-treated patients than in prasugrel-treated patients at 1-2 h (P < 0.001) and 30 days (P = 0.03)., Conclusions: The TRITON-TIMI 38 platelet substudy shows that prasugrel results in greater inhibition of ADP-mediated platelet function in ACS patients than clopidogrel, supporting the hypothesis that greater platelet inhibition leads to a lower incidence of ischaemic events and more bleeding both early and late following PCI.

Background: Prasugrel is a novel thienopyridine that reduces new or recurrent myocardial infarctions (MIs) compared with clopidogrel in patients with acute coronary syndrome undergoing percutaneous coronary intervention. This effect must be balanced against an increased bleeding risk. We aimed to characterize the effect of prasugrel with respect to the type, size, and timing of MI using the universal classification of MI., Methods and Results: We studied 13 608 patients with acute coronary syndrome undergoing percutaneous coronary intervention randomized to prasugrel or clopidogrel and treated for 6 to 15 months in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction (TRITON-TIMI 38). Each MI underwent supplemental classification as spontaneous, secondary, or sudden cardiac death (types 1, 2, and 3) or procedure related (Types 4 and 5) and examined events occurring early and after 30 days. Prasugrel significantly reduced the overall risk of MI (7.4% versus 9.7%; hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.67 to 0.85; P<0.0001). This benefit was present for procedure-related MIs (4.9% versus 6.4%; HR, 0.76; 95% CI, 0.66 to 0.88; P=0.0002) and nonprocedural (type 1, 2, or 3) MIs (2.8% versus 3.7%; HR, 0.72; 95% CI, 0.59 to 0.88; P=0.0013) and consistently across MI size, including MIs with a biomarker peak > or =5 times the reference limit (HR. 0.74; 95% CI, 0.64 to 0.86; P=0.0001). In landmark analyses starting at 30 days, patients treated with prasugrel had a lower risk of any MI (2.9% versus 3.7%; HR, 0.77; P=0.014), including nonprocedural MI (2.3% versus 3.1%; HR, 0.74; 95% CI, 0.60 to 0.92; P=0.0069)., Conclusions: Treatment with prasugrel compared with clopidogrel for up to 15 months in patients with acute coronary syndrome undergoing percutaneous coronary intervention significantly reduces the risk of MIs that are procedure related and spontaneous and those that are small and large, including new MIs occurring during maintenance therapy.

Background: Mechanical reperfusion with stenting for ST-elevation myocardial infarction (STEMI) is supported by dual antiplatelet treatment with aspirin and clopidogrel. Prasugrel, a potent and rapid-acting thienopyridine, is a potential alternative to clopidogrel. We aimed to assess prasugrel versus clopidogrel in patients undergoing percutaneous coronary intervention (PCI) for STEMI., Methods: We undertook a double-blind, randomised controlled trial in 707 sites in 30 countries. 3534 participants presenting with STEMI were randomly assigned by interactive voice response system either prasugrel (60 mg loading, 10 mg maintenance [n=1769]) or clopidogrel (300 mg loading, 75 mg maintenance [n=1765]) and were unaware of the allocation. The primary endpoint was cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke. Efficacy analyses were by intention to treat. Follow-up was to 15 months, with secondary analyses at 30 days. This trial is registered with ClinicalTrials.gov, number NCT00097591., Findings: At 30 days, 115 (6.5%) individuals assigned prasugrel had met the primary endpoint compared with 166 (9.5%) allocated clopidogrel (hazard ratio 0.68 [95% CI 0.54-0.87]; p=0.0017). This effect continued to 15 months (174 [10.0%] vs 216 [12.4%]; 0.79 [0.65-0.97]; p=0.0221). The key secondary endpoint of cardiovascular death, myocardial infarction, or urgent target vessel revascularisation was also significantly reduced with prasugrel at 30 days (0.75 [0.59-0.96]; p=0.0205) and 15 months (0.79 [0.65-0.97]; p=0.0250), as was stent thrombosis. Treatments did not differ with respect to thrombolysis in myocardial infarction (TIMI) major bleeding unrelated to coronary-artery bypass graft (CABG) surgery at 30 days (p=0.3359) and 15 months (p=0.6451). TIMI life-threatening bleeding and TIMI major or minor bleeding were also similar with the two treatments, and only TIMI major bleeding after CABG surgery was significantly increased with prasugrel (p=0.0033)., Interpretation: In patients with STEMI undergoing PCI, prasugrel is more effective than clopidogrel for prevention of ischaemic events, without an apparent excess in bleeding.

Background: 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., Methods: 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., Results: 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)., Conclusions: 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., (2009 Massachusetts Medical Society)

Aims: In the TRITON-TIMI 38 trial, greater platelet inhibition with prasugrel reduced the first occurrence of the primary endpoint (cardiovascular death, MI, or stroke) compared with clopidogrel in patients with an acute coronary syndrome (ACS) undergoing planned percutaneous coronary intervention. We hypothesized that prasugrel would reduce not only first events but also recurrent primary endpoint events and therefore total events compared with clopidogrel., Methods and Results: Poisson regression analysis was performed to compare the number of occurrences of the primary endpoint between prasugrel and clopidogrel in TRITON-TIMI 38. Landmark analytic methods were used to evaluate the risk of a recurrent primary endpoint event following an initial non-fatal endpoint event. Among patients with an initial non-fatal event, second events were significantly reduced with prasugrel compared to clopidogrel (10.8 vs. 15.4%, HR 0.65, 95% CI 0.46-0.92; P = 0.016), as was CV death following the non-fatal event (3.7 vs. 7.1%, HR 0.46, 95% CI 0.25-0.82; P = 0.008). Overall there was a reduction of 195 total primary efficacy events with prasugrel vs. clopidogrel (rate ratio 0.79, 95% CI 0.71-0.87; P < 0.001). Recurrent bleeding events occurred infrequently (TIMI major non-CABG bleeds: four with prasugrel and two with clopidogrel). Study drug discontinuation was frequent following the initial major bleeding event (42% of patients discontinued study drug)., Conclusion: While standard statistical analytic techniques for clinical trials censor patients who experience a component of the primary composite endpoint, total cardiovascular events remain important to both patients and clinicians. Prasugrel, a more potent anti-platelet agent, reduced both first and subsequent cardiovascular events compared with clopidogrel in patients with ACS.

Background: Intracoronary stenting can improve procedural success and reduce restenosis compared with balloon angioplasty in patients with acute coronary syndromes, but can also increase the rate of thrombotic complications including stent thrombosis. The TRITON-TIMI 38 trial has shown that prasugrel-a novel, potent thienopyridine-can reduce ischaemic events compared with standard clopidogrel therapy. We assessed the rate, outcomes, and prevention of ischaemic events in patients treated with prasugrel or clopidogrel with stents in the TRITON-TIMI 38 study., Methods: Patients with moderate-risk to high-risk acute coronary syndromes were included in our analysis if they had received at least one coronary stent at the time of the index procedure following randomisation in TRITON-TIMI 38, and were further subdivided by type of stent received. Patients were randomly assigned in a 1 to 1 fashion to receive a loading dose of study drug (prasugrel 60 mg or clopidogrel 300 mg) as soon as possible after randomisation, followed by daily maintenance therapy (prasugrel 10 mg or clopidogrel 75 mg). All patients were to receive aspirin therapy. Treatment was to be continued for a minimum of 6 months and a maximum of 15 months. Randomisation was not stratified by stents used or stent type. The primary endpoint was the composite of cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke. Stent thrombosis was assessed using Academic Research Consortium definitions, and analysis was by intention to treat. TRITON-TIMI 38 is registered with ClinicalTrials.gov, number NCT00097591., Findings: 12,844 patients received at least one coronary stent; 5743 received only drug-eluting stents, and 6461 received only bare-metal stents. Prasugrel compared with clopidogrel reduced the primary endpoint (9.7 vs 11.9%, HR 0.81, p=0.0001) in the stented cohort, in patients with only drug-eluting stents (9.0 vs 11.1%, HR 0.82, p=0.019), and in patients with only bare-metal stents (10.0 vs 12.2%, HR 0.80, p=0.003). Stent thrombosis was associated with death or myocardial infarction in 89% (186/210) of patients. Stent thrombosis was reduced with prasugrel overall (1.13 vs 2.35%, HR 0.48, p<0.0001), in patients with drug-eluting stents only (0.84 vs 2.31%, HR 0.36, p<0.0001), and in those with bare-metal stents only (1.27 vs 2.41%, HR 0.52, p=0.0009)., Interpretation: Intensive antiplatelet therapy with prasugrel resulted in fewer ischaemic outcomes including stent thrombosis than with standard clopidogrel. These findings were statistically robust irrespective of stent type, and the data affirm the importance of intensive platelet inhibition in patients with intracoronary stents.

Background: The increasing use of higher-than-approved doses of clopidogrel in clinical practice is based in part on the desire for greater levels of inhibition of platelet aggregation (IPA). Prasugrel is a new thienopyridine that is more potent than standard-dose clopidogrel in healthy subjects and patients with stable coronary artery disease. The relative antiplatelet effects of prasugrel versus high-dose clopidogrel in percutaneous coronary intervention patients are unknown., Methods and Results: Prasugrel in Comparison to Clopidogrel for Inhibition of Platelet Activation and Aggregation-Thrombolysis in Myocardial Infarction 44 (PRINCIPLE-TIMI 44) was a randomized, double-blind, 2-phase crossover study of prasugrel compared with high-dose clopidogrel in patients undergoing cardiac catheterization for planned percutaneous coronary intervention. The primary end point of the loading-dose phase (prasugrel 60 mg versus clopidogrel 600 mg) was IPA with 20 mumol/L ADP at 6 hours. Patients with percutaneous coronary intervention entered the maintenance-dose phase, a 28-day crossover comparison of prasugrel 10 mg/d versus clopidogrel 150 mg/d with a primary end point of IPA after 14 days of either drug. In this study, 201 subjects were randomized. IPA at 6 hours was significantly higher in subjects receiving prasugrel (mean+/-SD, 74.8+/-13.0%) compared with clopidogrel (31.8+/-21.1%; P<0.0001). During the maintenance-dose phase, IPA with 20 mumol/L ADP was higher in subjects receiving prasugrel (61.3+/-17.8%) compared with clopidogrel (46.1+/-21.3%; P<0.0001). Results were consistent across all key secondary end points; significant differences emerged by 30 minutes and persisted across all time points., Conclusions: Among patients undergoing cardiac catheterization with planned percutaneous coronary intervention, loading with 60 mg prasugrel resulted in greater platelet inhibition than a 600-mg clopidogrel loading dose. Maintenance therapy with prasugrel 10 mg/d resulted in a greater antiplatelet effect than 150 mg/d clopidogrel.

Background: Dual-antiplatelet therapy with aspirin and a thienopyridine is a cornerstone of treatment to prevent thrombotic complications of acute coronary syndromes and percutaneous coronary intervention., Methods: To compare prasugrel, a new thienopyridine, with clopidogrel, we randomly assigned 13,608 patients with moderate-to-high-risk acute coronary syndromes with scheduled percutaneous coronary intervention to receive prasugrel (a 60-mg loading dose and a 10-mg daily maintenance dose) or clopidogrel (a 300-mg loading dose and a 75-mg daily maintenance dose), for 6 to 15 months. The primary efficacy end point was death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. The key safety end point was major bleeding., Results: The primary efficacy end point occurred in 12.1% of patients receiving clopidogrel and 9.9% of patients receiving prasugrel (hazard ratio for prasugrel vs. clopidogrel, 0.81; 95% confidence interval [CI], 0.73 to 0.90; P<0.001). We also found significant reductions in the prasugrel group in the rates of myocardial infarction (9.7% for clopidogrel vs. 7.4% for prasugrel; P<0.001), urgent target-vessel revascularization (3.7% vs. 2.5%; P<0.001), and stent thrombosis (2.4% vs. 1.1%; P<0.001). Major bleeding was observed in 2.4% of patients receiving prasugrel and in 1.8% of patients receiving clopidogrel (hazard ratio, 1.32; 95% CI, 1.03 to 1.68; P=0.03). Also greater in the prasugrel group was the rate of life-threatening bleeding (1.4% vs. 0.9%; P=0.01), including nonfatal bleeding (1.1% vs. 0.9%; hazard ratio, 1.25; P=0.23) and fatal bleeding (0.4% vs. 0.1%; P=0.002)., Conclusions: In patients with acute coronary syndromes with scheduled percutaneous coronary intervention, prasugrel therapy was associated with significantly reduced rates of ischemic events, including stent thrombosis, but with an increased risk of major bleeding, including fatal bleeding. Overall mortality did not differ significantly between treatment groups. (ClinicalTrials.gov number, NCT00097591 [ClinicalTrials.gov].), (Copyright 2007 Massachusetts Medical Society.)

Background: The aim of this study was to compare rate of onset, magnitude, and consistency of platelet inhibition after administration of prasugrel or clopidogrel and to relate platelet inhibition to systemic exposure to each active metabolite. Thienopyridines are prodrugs, metabolized in vivo to active metabolites that inhibit the platelet P2Y12 adenosine diphosphate (ADP) receptor., Methods: This was an open-label, 2-way, crossover study that randomized healthy subjects (n = 68) to an oral loading dose (LD) of prasugrel 60 mg or clopidogrel 300 mg. Platelet aggregation response to 5 and 20 micromol/L of ADP was measured by turbidometric aggregometry. Plasma concentrations of the active metabolites of prasugrel and clopidogrel were quantified by liquid chromatography with tandem mass spectrometry detection methods., Results: Inhibition of platelet aggregation (IPA) after prasugrel was significantly higher (P < .01) than that after clopidogrel from 15 minutes through 24 hours (5 micromol/L ADP) and from 30 minutes through 24 hours (20 micromol/L ADP). For 20 micromol/L ADP, the median time to reach > or = 20% IPA was 30 minutes for prasugrel and 1.5 hours for clopidogrel (P < .001). The maximum IPA was 84.1% +/- 9.5% with prasugrel versus 48.9% +/- 27.0% with clopidogrel for 5 micromol/L ADP and 78.8% +/- 9.2% versus 35.0% +/- 24.5%, respectively, for 20 micromol/L ADP (P < .001). Response to prasugrel was more consistent compared to clopidogrel (P < .01). The lower IPA response to clopidogrel was associated with lower plasma concentrations of its active metabolite (P < .001)., Conclusions: Prasugrel 60 mg LD results in more rapid, potent, and consistent inhibition of platelet function than clopidogrel 300 mg LD. Lower IPA responses to clopidogrel were associated with lower concentrations of its active metabolite.

Dual antiplatelet therapy represents an important advance for patients with established cardiovascular disease. Variable platelet response and potential resistance to therapy have emerged with aspirin and clopidogrel. There is no clear and accepted definition of clopidogrel resistance, but patients with lower responses to clopidogrel are at risk for ischemic events, particularly when they undergo percutaneous coronary intervention. Inconsistent nomenclature about this lower response has led to confusion about its potential clinical importance. The concern about nomenclature is less important than answers to key questions such as its mechanisms, how and in whom to measure platelet function, what levels of inhibition are associated with failure of therapy, what levels are adequate for improved clinical outcomes, and in what ways therapy could be altered in patients with lower responses to improve measures of platelet function and clinical outcomes. One option may be to target more aggressive intervention (higher loading and maintenance doses of clopidogrel or alternative agents) to specific patients who are at greater risk and/or least responsive to standard therapies. Clinically useful risk stratification requires an easily performed and reproducible measure of platelet aggregation, as well as standardized definitions of response that correlate with clinical outcomes. Point-of-care assays of platelet function may ultimately improve the ability of clinicians to modify therapy on the basis of response.

Background: Dual antiplatelet therapy with aspirin and clopidogrel is standard for prevention of thrombotic complications of percutaneous coronary intervention (PCI). Prasugrel is a thienopyridine that is more potent, more rapid in onset, and more consistent in inhibition of platelets than clopidogrel. TRITON-TIMI 38 is designed to compare prasugrel with clopidogrel in moderate to high-risk patients with acute coronary syndrome (ACS)., Study Design: TRITON-TIMI 38 is a phase 3, randomized, double-blind, parallel-group, multinational, clinical trial. Approximately 13,000 patients with moderate to high-risk ACS undergoing PCI (9500 unstable angina/non-ST-segment elevation myocardial infarction [MI], 3500 ST-segment elevation MI) will be randomized to prasugrel 60 mg loading dose followed by 10 mg daily or clopidogrel 300 mg loading dose followed by 75 mg daily for up to 15 months. The primary end point is the time of the first event of cardiovascular death, MI, or stroke. Analyses will be performed first in the unstable angina/non-ST-segment elevation MI cohort and, conditionally, on the whole ACS population. Major safety end points include TIMI major and minor bleeding unrelated to coronary artery bypass graft surgery., Conclusions: TRITON-TIMI 38 is a phase 3 comparison of prasugrel versus clopidogrel in patients with moderate to high-risk ACS undergoing PCI. In addition, it is the first large-scale clinical events trial to assess whether a thienopyridine regimen that achieves a higher level of inhibition of platelet aggregation than the standard therapy results in an improvement in clinical outcomes.

Objectives: This study was designed to determine the relationship between clopidogrel and early ST-segment resolution (STRes) and the interaction of the two with clinical outcomes after fibrinolysis., Background: ST-segment resolution is an early noninvasive marker of coronary reperfusion., Methods: The CLARITY-TIMI 28 (Clopidogrel as Adjunctive Reperfusion Therapy-Thrombolysis in Myocardial Infarction 28) trial randomized 3,491 patients with ST-segment elevation myocardial infarction (STEMI) undergoing fibrinolysis to clopidogrel versus placebo. ST-segment resolution was defined as complete (>70%), partial (30% to 70%), or none (<30%)., Results: Electrocardiograms were valid for interpretation in 2,431 patients at 90 min and 2,087 at 180 min. There was no difference in the rate of complete STRes between the clopidogrel and placebo groups at 90 min (38.4% vs. 36.6% at 90 min). When patients were stratified by STRes category, treatment with clopidogrel resulted in greater benefit among those with evidence of early STRes, with greater odds of an open artery at late angiography in patients with partial (odds ratio [OR] 1.4, p = 0.04) or complete (OR 2.0, p < 0.001) STRes, but no improvement in those with no STRes at 90 min (OR 0.89, p = 0.48) (p for interaction = 0.003). Clopidogrel was also associated with a significant reduction in the odds of an in-hospital death or myocardial infarction in patients who achieved partial (OR 0.30, p = 0.003) or complete STRes at 90 min (OR 0.49, p = 0.056), whereas clinical benefit was not apparent in patients who had no STRes (OR 0.98, p = 0.95) (p for interaction = 0.027). By 30 days, the clinical benefit of clopidogrel was predominately seen in patients with complete STRes., Conclusions: Clopidogrel appears to improve late coronary patency and clinical outcomes by preventing reocclusion of open arteries rather than by facilitating early reperfusion.

Background: Despite the current standard antiplatelet regimen of aspirin and clopidogrel (with or without glycoprotein IIb/IIIa inhibitors) in percutaneous coronary intervention patients, periprocedural and postprocedural ischemic events continue to occur. Prasugrel (CS-747, LY640315), a novel potent thienopyridine P2Y(12) receptor antagonist, has the potential to achieve higher levels of inhibition of ADP-induced platelet aggregation than currently approved doses of clopidogrel., Methods and Results: Joint Utilization of Medications to Block Platelets Optimally-Thrombolysis In Myocardial Infarction 26 (JUMBO-TIMI 26) was a phase 2, randomized, dose-ranging, double-blind safety trial of prasugrel versus clopidogrel in 904 patients undergoing elective or urgent percutaneous coronary intervention. Patients were randomized to either standard dosing with clopidogrel or 1 of 3 prasugrel regimens. Subjects were monitored for 30 days for bleeding and clinical events. The primary end point of the trial was clinically significant (TIMI major plus minor) non-CABG-related bleeding events in prasugrel- versus clopidogrel-treated patients. Hemorrhagic complications were infrequent, with no significant difference between patients treated with prasugrel or clopidogrel in the rate of significant bleeding (1.7% versus 1.2%; hazard ratio, 1.42; 95% CI, 0.40, 5.08). In prasugrel-treated patients, there were numerically lower incidences of the primary efficacy composite end point (30-day major adverse cardiac events) and of the secondary end points myocardial infarction, recurrent ischemia, and clinical target vessel thrombosis., Conclusions: In this phase 2 study, which was designed to assess safety when administered at the time of percutaneous coronary intervention, prasugrel and clopidogrel both resulted in low rates of bleeding. The results of this trial serve as a foundation for the large phase 3 clinical trial designed to assess both efficacy and safety.