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Objectives: We evaluated outcomes associated with transradial vs. transfemoral approaches and vorapaxar in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI) in the TRACER trial., Background: Vorapaxar reduces ischemic events but increases the risk of major bleeding., Methods: We compared 30-day and 2-year major adverse cardiac events (MACE: cardiovascular death, myocardial infarction, stroke, recurrent ischemia with rehospitalization, and urgent coronary revascularization) and noncoronary artery bypass graft (CABG)-related bleedings in 2,192 transradial and 4,880 transfemoral patients undergoing PCI after adjusting for confounding variables, including propensity for transradial access., Results: Overall, 30-day GUSTO moderate/severe and non-CABG TIMI major/minor bleeding occurred less frequently in transradial (0.9% vs. 2.0%, P = 0.001) vs. transfemoral (1.1% vs. 2.5%, P = 0.005) patients. A similar reduction was seen at 2 years (3.3% vs. 4.7%, P = 0.008; 3.3% vs. 4.9%, P < 0.001, respectively). Transradial was associated with an increased risk of ischemic events at 30 days (OR 1.38, 95% CI 1.11-1.72; P = 0.004), driven primarily by increased periprocedural myocardial infarctions. At 2 years, rates of MACE were comparable (HR 1.14, 95% CI 0.98-1.33; P = 0.096). Although bleeding rates were higher with vorapaxar in transfemoral vs. transradial patients, there was no significant treatment interaction. Also, the access site did not modulate the association between vorapaxar and MACE., Conclusions: Transradial access was associated with lower bleeding rates and similar long-term ischemic outcomes, suggesting transradial access is safer than transfemoral access among ACS patients receiving potent antiplatelet therapies. Because of the nonrandomized allocation of arterial access, these results should be considered exploratory. © 2015 Wiley Periodicals, Inc., (© 2015 Wiley Periodicals, Inc.)

Background: Antithrombotic therapy plays an important role in the treatment of non-ST-segment elevation acute coronary syndromes (NSTE ACS) but is associated with bleeding risk. Advanced age may modify the relationship between efficacy and safety., Methods: Efficacy and safety of vorapaxar (a protease-activated receptor 1 antagonist) was analyzed across ages as a continuous and a categorical variable in the 12,944 patients with NSTE ACS enrolled in the TRACER trial. To evaluate the effect of age, Cox regression models were developed to estimate hazard ratios (HRs) with the adjustment of other baseline characteristics and randomized treatment for the primary efficacy composite of cardiovascular death, myocardial infarction (MI), stroke, recurrent ischemia with rehospitalization, or urgent coronary revascularization, and the primary safety composite of moderate or severe Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) bleeding., Results: The median age of the population was 64years (25th, 75th percentiles = 58, 71). Also, 1,791 patients (13.8%) were ≤54years of age, 4,968 (38.4%) were between 55 and 64 years, 3,979 (30.7%) were between 65 and 74 years, and 2,206 (17.1%) were 75years or older. Older patients had higher rates of hypertension, renal insufficiency, and previous stroke and worse Killip class. The oldest age group (≥75years) had substantially higher 2-year rates of the composite ischemic end point and moderate or severe GUSTO bleeding compared with the youngest age group (≤54years). The relationships between treatment assignment (vorapaxar vs placebo) and efficacy outcomes did not vary by age. For the primary efficacy end point, the HRs (95% CIs) comparing vorapaxar and placebo in the 4 age groups were as follows: 1.12 (0.88-1.43), 0.88 (0.76-1.02), 0.89 (0.76-1.04), and 0.88 (0.74-1.06), respectively (P value for interaction = .435). Similar to what was observed for efficacy outcomes, we did not observe any interaction between vorapaxar and age on bleeding outcomes. For the composite of moderate or severe bleeding according to the GUSTO classification, the HRs (95% CIs) comparing vorapaxar and placebo in the 4 age groups were 1.73 (0.89-3.34), 1.39 (1.04-1.86), 1.10 (0.85-1.42), and 1.73 (1.29-2.33), respectively (P value for interaction = .574)., Conclusion: Older patients had a greater risk for ischemic and bleeding events; however, the efficacy and safety of vorapaxar in NSTE ACS were not significantly influenced by age., (Copyright © 2016 Elsevier Inc. All rights reserved.)

We evaluated the interaction between protease-activated receptor-1 antagonist vorapaxar and concomitant glycoprotein (GP) IIb/IIIa receptor inhibitors in patients with non-ST-segment elevation acute coronary syndromes who underwent PCI. In Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome trial, 12,944 patients with non-ST-segment elevation acute coronary syndromes were randomized to vorapaxar or placebo. Administration of GP IIb/IIIa receptor inhibitors was allowed at the treating physician's discretion. We investigated whether use of GP IIb/IIIa receptor inhibitors modified vorapaxar's effect on non-coronary artery bypass grafting (CABG)-related bleeding at 7 days and ischemic events at 30 days. In total, 7,455 patients underwent PCI during index hospitalization. Of these, 2,023 patients (27.1%) received inhibitors and 5,432 (72.9%) did not. Vorapaxar was associated with a numerically higher rate of non-CABG-related moderate/severe Global Use of Strategies to Open Occluded Arteries (GUSTO) bleeding at 7 days compared with placebo in those who did (1.3% vs 1.0%) and did not (0.6% vs 0.4%) receive GP IIb/IIIa receptor inhibitors. Ischemic end point rates at 30 days were not significantly lower with vorapaxar versus placebo. Increased rates of non-CABG GUSTO moderate/severe bleeding were observed in patients who received GP IIb/IIIa receptor inhibitors versus those who did not (adjusted hazard ratio [HR] 1.77, 95% confidence interval [CI] 0.43 to 7.35 in placebo arm; adjusted HR 2.02, 95% CI 0.62 to 6.61 in vorapaxar arm) and in those who received vorapaxar versus placebo (adjusted HR 1.54, 95% CI 0.36 to 6.56 in the GP IIb/IIIa group; adjusted HR 1.34, 95% CI 0.44 to 4.07 in the no-GP IIb/IIIa group). No interaction was found between vorapaxar and inhibitor use up to 7 days (P interaction = 0.89) nor at the end of the treatment (P interaction = 0.74); however, the event rate was low. Also, no interaction was observed for efficacy end points after PCI at 30 days or at the end of the treatment. In conclusion, GP IIb/IIIa receptor inhibitor use plus dual antiplatelet therapy in a population with non-ST-segment elevation myocardial infarction planned for PCI was frequent but did not interact with vorapaxar's efficacy or safety. Nonetheless, GP IIb/IIIa receptor inhibitors and vorapaxar were associated with increased bleeding risk, and their combined use may result in additive effects on bleeding rates., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Protease-activated receptor 1 antagonism with vorapaxar represents a novel strategy for platelet inhibition. In TRACER, vorapaxar was compared with placebo plus standard of care among 12,944 patients with non-ST-segment elevation acute coronary syndromes. We anticipated that most patients would have received clopidogrel as part of standard care. We investigated the modification of vorapaxar's effect associated with clopidogrel use over time., Methods: The marginal structural model method was used to estimate causal modification of vorapaxar effect by use of clopidogrel over time. The primary outcomes were the composite of cardiovascular death, myocardial infarction, or stroke and Global Use of Strategies to Open Occluded Coronary Arteries moderate or severe bleeding. The event accrual period excluded the time during which clopidogrel was clinically warranted., Results: Among 12,887 patients who received study medication, 11,117 (86.3%) received clopidogrel before randomization, of whom 38.5% stopped later in the trial (median time to stoppage 200 days with placebo; interquartile range [IQR] 14-367) (186 days with vorapaxar; IQR 17-366). In total, 1,770 (13.7%) patients were not on clopidogrel at randomization, of whom 47.8% started afterward (median time to start 2 days; IQR 2-4). During the period of event accrual, vorapaxar was associated with a 26% reduction in the composite of cardiovascular death, myocardial infarction, or stroke when used with clopidogrel (hazard ratio [HR] 0.74; 95% CI 0.60-0.91) and a 24% reduction when used without clopidogrel (HR 0.76; 95% CI 0.56-1.02) (interaction; P = .89). The hazard of Global Use of Strategies to Open Occluded Coronary Arteries bleeding with vorapaxar was not significantly different without clopidogrel (HR 1.33; 95% CI 0.81-2.20) or with clopidogrel (HR 1.09; 95% CI 0.76-1.56) (interaction; P = .53)., Conclusions: We observed no interaction between vorapaxar and clopidogrel after non-ST-segment elevation acute coronary syndromes on efficacy or safety outcomes, supporting a complementary role of protease-activated receptor 1 and P2Y12 antagonism., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: In the TRACER trial, vorapaxar, a protease-activated receptor-1 antagonist, plus standard care in non-ST-segment elevation acute coronary syndrome (NSTE ACS) patients did not significantly reduce the primary composite end point but reduced a key secondary end point and significantly increased bleeding. History of peripheral artery disease (PAD) was a risk-enrichment inclusion criterion. We investigated the efficacy and safety of vorapaxar in NSTE ACS patients with documented PAD., Methods: TRACER was a double-blind, randomized trial comparing vorapaxar with placebo in 12,944 patients with NSTE ACS., Results: In total, 936 (7.2%) patients had a history of PAD. Ischemic events occurred more frequently among patients with PAD (25.3%) versus no PAD (12.2%, P < .001), and Global Use of Strategies to Open Occluded Coronary Arteries moderate/severe bleeding was more common in PAD (9.1%) versus no PAD (5.0%, P = .004). Similar rates of the composite end point (cardiovascular death, myocardial infarction, or stroke) occurred in patients with PAD treated with vorapaxar and placebo (21.7% vs 24.8%, P interaction = .787). Patients with PAD treated with vorapaxar, when compared with placebo, also had a numerical reduction in peripheral revascularization procedures (8.1% vs 9.0%, P = .158) and a lower extremity amputation rate (0.9% vs 1.5%, P = .107). Vorapaxar increased Global Use of Strategies to Open Occluded Coronary Arteries moderate/severe bleeding similarly in patients with PAD (hazard ratio 1.47, 95% CI 0.89-2.45) and without (hazard ratio 1.48, 95% CI 1.22-1.79; P interaction = .921)., Conclusions: Patients with NSTE ACS and PAD were at increased risk for ischemic events. Lower rates of ischemic end points, peripheral revascularization, and amputation with vorapaxar did not reach statistical significance but warrant further investigation. Vorapaxar increased bleeding in both patients with and without PAD at a similar magnitude of risk., (Copyright © 2014 Mosby, Inc. All rights reserved.)

Background: This study characterized a medically managed population in a non-ST-segment elevation acute coronary syndrome (NSTEACS) cohort and evaluated prognosis and outcomes of vorapaxar vs. placebo., Methods: In the TRACER study, 12,944 NSTEACS patients were treated with standard care and vorapaxar (a novel platelet protease-activated receptor-1 antagonist) or placebo. Of those, 4194 patients (32.4%) did not undergo revascularization during index hospitalization, and 8750 (67.6%) underwent percutaneous coronary intervention or coronary artery bypass grafting. Patients managed medically were heterogeneous with different risk profiles, including 1137 (27.1%) who did not undergo coronary angiography. Patients who underwent angiography but were selected for medical management included those without evidence of significant coronary artery disease (CAD), with prior CAD but no new significant lesions, and with significant lesions who were not treated with revascularization., Results: Cardiovascular event rates were highest among those without angiography and lowest in the group with angiography but without CAD. In the medically managed cohort, 2-year primary outcome (cardiovascular death, myocardial infarction, stroke, recurrent ischaemia with rehospitalization, urgent coronary revascularization) event rates were 16.3% with vorapaxar and 17.0% with placebo (HR 0.99, 95% CI 0.83-1.17), with no interaction between drug and management strategy (p=0.75). Key secondary endpoint (cardiovascular death, myocardial infarction, stroke) rates were 13.4% with vorapaxar and 14.9% with placebo (HR 0.89, 95% CI 0.74-1.07), with no interaction (p=0.58). Vorapaxar increased GUSTO moderate/severe bleeding numerically in medically managed patients (adjusted HR 1.46, 95% CI 0.99-2.15)., Conclusions: NSTEACS patients who were initially medically managed had a higher risk-factor burden, and one-third had normal coronary arteries. Outcome in the medically managed cohort was significantly related to degree of CAD, highlighting the importance of coronary angiography. Efficacy and safety of vorapaxar appeared consistent with the overall trial results., (© The European Society of Cardiology 2014.)

The therapeutic potential of vorapaxar in patients with non-ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention (PCI) is unknown. This prespecified analysis of a postrandomization subgroup evaluated the effects of vorapaxar compared with placebo among Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) participants undergoing PCI, focusing on the implanted stent type (drug-eluting stent [DES] vs bare-metal stent [BMS]). Among 12,944 recruited patients, 7,479 (57.8%) underwent PCI during index hospitalization, and 3,060 (40.9%) of those patients received exclusively BMS, whereas 4,015 (53.7%) received DES. The median (twenty-fifth, seventy-fifth percentiles) duration of thienopyridine therapy was 133 days (47, 246) with BMS and 221 days (88, 341) with DES. At 2 years among patients undergoing PCI, the primary (cardiovascular death, myocardial infarction, stroke, recurrent ischemia with rehospitalization, or urgent coronary revascularization) and secondary (cardiovascular death, myocardial infarction, or stroke) end points did not differ between vorapaxar and placebo groups, which was consistent with the treatment effect observed in the overall study population (p value for interaction = 0.540). However, the treatment effect trended greater (p value for interaction = 0.069) and the risk for bleeding in patients taking vorapaxar versus placebo appeared attenuated in BMS-only recipients. After adjustment for confounders, the interaction was no longer significant (p value = 0.301). The covariate that mostly explained the stent-type-by-treatment interaction was the duration of clopidogrel therapy. In conclusion, among patients with PCI, the effect of vorapaxar is consistent with the overall TRACER results. Patients who received a BMS underwent shorter courses of clopidogrel therapy and displayed trends toward greater ischemic benefit from vorapaxar and lesser bleeding risk, compared with patients who received a DES., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Vorapaxar is an antagonist of the protease activated receptor-1 (PAR-1), the principal platelet thrombin receptor. The Thrombin Receptor Antagonist for Clinical Event Reduction (TRACER) trial evaluated vorapaxar compared to placebo in non-ST-elevation (NSTE)-acute coronary syndrome (ACS) patients. It was the study's objective to assess the pharmacodynamic effects of vorapaxar versus placebo that included aspirin or a thienopyridine or, frequently, a combination of both agents in NSTE-ACS patients. In a substudy involving 249 patients, platelet aggregation was assessed by light transmittance aggregometry (LTA) in 85 subjects (41 placebo, 44 vorapaxar) using the agonists thrombin receptor activating peptide (TRAP, 15 μM), adenosine diphosphate (ADP, 20 μM), and the combination of collagen-related peptide (2.5 μg/ml) + ADP (5 μM) + TRAP (15 μM) (CAT). VerifyNow® IIb/IIIa and vasodilator-stimulated phosphoprotein (VASP) phosphorylation assays were performed, and platelet PAR-1 expression, plasma platelet/endothelial and inflammatory biomarkers were determined before and during treatment. LTA responses to TRAP and CAT and VerifyNow results were markedly inhibited by vorapaxar. Maximal LTA response to TRAP (median, interquartile range) 2 hours post loading dose: placebo 68% (53-75%) and vorapaxar 3% (2-6%), p<0.0001. ADP inhibition was greater in the vorapaxar group at 4 hours and one month (p<0.01). In contrast to the placebo group, PAR-1 receptor number in the vorapaxar group at one month was significantly lower than the baseline (179 vs 225; p=0.004). There were significant changes in selected biomarker levels between the two treatment groups. In conclusion, vorapaxar caused a potent inhibition of PAR-1-mediated platelet aggregation. Further studies are needed to explore vorapaxar effect on P2Y12 inhibition, PAR-1 expression and biomarkers and its contribution to clinical outcomes.

Objectives: This study evaluated effects of protease-activated receptor-1 antagonist vorapaxar (Merck, Whitehouse Station, New Jersey) versus placebo among the TRACER (Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome) study patients with non-ST-segment elevation acute coronary syndromes undergoing coronary artery bypass grafting (CABG)., Background: Platelet activation may play a key role in graft occlusion, and antiplatelet therapies may reduce ischemic events, but perioperative bleeding risk remains a major concern. Although the TRACER study did not meet the primary quintuple composite outcome in the overall population with increased bleeding, an efficacy signal with vorapaxar was noted on major ischemic outcomes, and preliminary data suggest an acceptable surgical bleeding profile. We aimed to assess efficacy and safety of vorapaxar among CABG patients., Methods: Associations between treatment and ischemic and bleeding outcomes were assessed using time-to-event analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using the Cox hazards model. Event rates were estimated using the Kaplan-Meier method., Results: Among 12,944 patients, 1,312 (10.1%) underwent CABG during index hospitalization, with 78% on the study drug at the time of surgery. Compared with placebo CABG patients, vorapaxar-treated patients had a 45% lower rate of the primary endpoint (i.e., a composite of death, myocardial infarction, stroke, recurrent ischemia with rehospitalization, or urgent coronary revascularization during index hospitalization) (HR: 0.55; 95% CI: 0.36 to 0.83; p = 0.005), with a significant interaction (p = 0.012). The CABG-related Thrombolysis In Myocardial Infarction major bleeding was numerically higher with vorapaxar, but not significantly different between vorapaxar and placebo (9.7% vs. 7.3%; HR: 1.36; 95% CI: 0.92 to 2.02; p = 0.12), with no excess in fatal bleeding (0% vs. 0.3%) or need for reoperation (4.7% vs. 4.6%)., Conclusions: In non-ST-segment elevation acute coronary syndrome patients undergoing CABG, vorapaxar was associated with a significant reduction in ischemic events and no significant increase in major CABG-related bleeding. These data show promise for protease-activated receptor 1 antagonism in patients undergoing CABG and warrant confirmatory evidence in randomized trials. (Trial to Assess the Effects of SCH 530348 in Preventing Heart Attack and Stroke in Patients With Acute Coronary Syndrome [TRA·CER] [Study P04736AM3]; NCT00527943)., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) trial compared vorapaxar and placebo in 12,944 high-risk patients with non-ST-segment elevation acute coronary syndrome. We explored aspirin (ASA) use and its association with outcomes. Kaplan-Meier event rates were compared in groups defined by ASA dose (low, medium, and high). Landmark analyses with covariate adjustment were performed for 0 to 30, 31 to 180, and 181 to 365 days. Of 12,515 participants, 7,523, 1,049, and 3,943 participants were treated with low-, medium-, and high-dose ASA at baseline, respectively. Participants enrolled in North America versus elsewhere were more often treated with a high dose at baseline (66% vs 19%) and discharge (60% vs 3%). Unadjusted cardiovascular death, myocardial infarction, stroke, hospitalization for ischemia, or urgent revascularization event rates tended to be higher with higher baseline ASA (18.45% low, 19.13% medium, and 20.27% high; p for trend = 0.15573). Unadjusted and adjusted hazard ratios (95% confidence intervals) for effect of vorapaxar on cardiovascular (unadjusted p for interaction = 0.065; adjusted p for interaction = 0.140) and bleeding (unadjusted p for interaction = 0.915; adjusted p for interaction = 0.954) outcomes were similar across groups. Landmark analyses showed similar safety and efficacy outcomes with vorapaxar and placebo by ASA dose at each time point except for 0 to 30 days, when vorapaxar tended to be worse for efficacy (hazard ratio 1.13, 95% confidence interval 0.89 to 1.44, p for interaction = 0.0157). In conclusion, most TRACER participants were treated with low-dose ASA, although a high dose was common in North America. High-dose participants tended to have higher rates of ischemic and bleeding outcomes. Although formal statistical testing did not reveal heterogeneity in vorapaxar's effect across dose subgroups, consistent trends support use of low-dose ASA with other antiplatelet therapies., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Aims: The TRA·CER trial compared vorapaxar, a novel platelet protease-activated receptor (PAR)-1 antagonist, with placebo in 12 944 patients with high-risk non-ST-segment elevation acute coronary syndromes (NSTE ACS). In this analysis, we explored the effect of vorapaxar on myocardial infarction (MI)., Methods and Results: A blinded, independent central endpoint adjudication committee prospectively defined and classified MI according to the universal MI definition, including peak cardiac marker value (creatine kinase-MB [CK-MB] and/or troponin). Because the trial failed to meet its primary endpoint, these analyses are considered exploratory. During a median follow-up of 502 days, 1580 MIs occurred in 1319 patients. The majority (n = 1025, 64.9%) were type 1 (spontaneous) MI, followed by type 4a [percutaneous coronary intervention (PCI)-related] MI (n = 352; 22.3%). Compared with placebo, vorapaxar reduced the hazard of a first MI of any type by 12% [hazard ratio (HR), 0.88; 95% confidence interval (CI), 0.79-0.98; P = 0.021] and the hazard of total number of MIs (first and subsequent) by 14% (HR, 0.86; 95% CI, 0.77-0.97; P = 0.014), an effect that was sustained over time. Vorapaxar reduced type 1 MI by 17% (HR, 0.83; 95% CI, 0.73-0.95; P = 0.007). Type 4a MIs were not significantly reduced by vorapaxar (HR, 0.90; 95% CI, 0.73-1.12; P = 0.35). Vorapaxar effect was consistent across MI sizes defined by peak cardiac marker elevations and across key clinical subgroups; however, in patients not treated with thienopyridine at baseline (HR, 0.65; 95% CI, 0.46-0.92) compared with patients who received thienopyridine (HR, 0.91; 95% CI, 0.81-1.02), there was a trend towards a higher effect (Pint = 0.077)., Conclusion: The PAR-1 antagonist vorapaxar was associated with a reduction of MI, including total number of infarctions. This reduction was sustained over time and was mostly evident in type 1 MI, the most common type of MI observed.

Background: Vorapaxar is a new oral protease-activated-receptor 1 (PAR-1) antagonist that inhibits thrombin-induced platelet activation., Methods: In this multinational, double-blind, randomized trial, we compared vorapaxar with placebo in 12,944 patients who had acute coronary syndromes without ST-segment elevation. The primary end point was a composite of death from cardiovascular causes, myocardial infarction, stroke, recurrent ischemia with rehospitalization, or urgent coronary revascularization., Results: Follow-up in the trial was terminated early after a safety review. After a median follow-up of 502 days (interquartile range, 349 to 667), the primary end point occurred in 1031 of 6473 patients receiving vorapaxar versus 1102 of 6471 patients receiving placebo (Kaplan-Meier 2-year rate, 18.5% vs. 19.9%; hazard ratio, 0.92; 95% confidence interval [CI], 0.85 to 1.01; P=0.07). A composite of death from cardiovascular causes, myocardial infarction, or stroke occurred in 822 patients in the vorapaxar group versus 910 in the placebo group (14.7% and 16.4%, respectively; hazard ratio, 0.89; 95% CI, 0.81 to 0.98; P=0.02). Rates of moderate and severe bleeding were 7.2% in the vorapaxar group and 5.2% in the placebo group (hazard ratio, 1.35; 95% CI, 1.16 to 1.58; P<0.001). Intracranial hemorrhage rates were 1.1% and 0.2%, respectively (hazard ratio, 3.39; 95% CI, 1.78 to 6.45; P<0.001). Rates of nonhemorrhagic adverse events were similar in the two groups., Conclusions: In patients with acute coronary syndromes, the addition of vorapaxar to standard therapy did not significantly reduce the primary composite end point but significantly increased the risk of major bleeding, including intracranial hemorrhage. (Funded by Merck; TRACER ClinicalTrials.gov number, NCT00527943.).