vorapaxar and Hemorrhage

Vorapaxar is the first protease-activated receptor-1 inhibitor approved for clinical use. Its main indication is the reduction in thrombotic cardiovascular events in patients with previous myocardial infarction or symptomatic peripheral artery disease. Areas covered: This article reviews the pharmacokinetics of vorapaxar and its potential use in secondary prevention after an acute coronary syndrome. Expert opinion: Vorapaxar inhibits platelet aggregation mediated by thrombin. This effect is carried out without affecting to coagulation parameters and bleeding times. This drug has showed a significant reduction of cardiovascular events in patients with chronic atherosclerosis but not during the admission for an acute coronary syndrome. The rate of major bleeding found in patients treated with vorapaxar in randomized trials was consistently higher than placebo in most of the analyzed subgroups. For this reason, cautious evaluation of risk-benefit profiles should be required before prescribing this drug.

Topics: Acute Coronary Syndrome; Animals; Hemorrhage; Humans; Lactones; Platelet Aggregation Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Receptor, PAR-1; Secondary Prevention

This article reviews the pharmacology, clinical efficacy, and safety of vorapaxar in reducing cardiovascular risk. Vorapaxar is a tricyclic himbacine-derived reversible inhibitor of platelet surface protease activator receptor-1, which prevents thrombin from activating platelets. Two Phase III clinical trials and multiple subanalyses from the two trials with vorapaxar have been published. In patients with recent acute coronary syndrome, vorapaxar, when added to standard therapy, did not reduce the composite cardiovascular end point. In contrary, in a study of secondary prevention for patients with cardiovascular diseases, vorapaxar reduced the risk of cardiovascular death or ischemic events (myocardial infarction, stroke) in patients with stable atherosclerosis who were receiving standard therapy. Vorapaxar is approved in the US for use with aspirin and/or clopidogrel in the secondary prevention of thrombogenic cardiovascular events in stable patients with peripheral arterial disease or a history of myocardial infarction. Vorapaxar increases risk of bleeding and is contraindicated in patients with previous cerebrovascular events. It is essential to balance individual patient's bleeding risk to any further cardiovascular benefits that they may get. Future investigation is also needed to evaluate use of vorapaxar with newer antiplatelet agents such as ticagrelor and cangrelor, as well as its role as monotherapy.

Topics: Animals; Blood Platelets; Cardiovascular Diseases; Drug Therapy, Combination; Hemorrhage; Humans; Lactones; Patient Selection; Platelet Aggregation; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Risk Assessment; Risk Factors; Treatment Outcome

Despite the use of therapies recommended in practice guidelines for secondary prevention in patients with atherosclerotic coronary artery disease, the residual risk for cardiovascular events remains high. Some of the residual risk is believed to result from incomplete platelet inhibition with current therapy. Vorapaxar is a first-in-class, novel antiplatelet agent that acts by antagonizing the PAR-1 receptor, inhibiting thrombin-mediated platelet activation. Vorapaxar was recently approved by the Food and Drug Administration for secondary prevention of cardiovascular events in patients with a history of myocardial infarction or peripheral artery disease who do not have a history of transient ischemic attack or stroke. We review the data from two key phase III cardiovascular outcome trials with vorapaxar: TRACER and TRA 2P-TIMI 50. We will focus on identifying the key patient populations that should be identified for treatment, highlight practical clinical issues when prescribing vorapaxar, and review unanswered questions. Vorapaxar should be considered in patients at high risk for recurrent ischemic events and low risk of bleeding.

Topics: Animals; Blood Platelets; Coronary Artery Disease; Hemorrhage; Humans; Lactones; Myocardial Infarction; Patient Selection; Plaque, Atherosclerotic; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Recurrence; Risk Assessment; Risk Factors; Secondary Prevention; Signal Transduction; Treatment Outcome

To review the pharmacology, efficacy, and safety of vorapaxar, a protease activator receptor-1 (PAR-1) antagonist, in the management of atherosclerotic diseases.. Peer-reviewed clinical trials and review articles were identified from MEDLINE and Current Content database (both 1966 to December 31, 2014) using the search terms vorapaxar and protease activator receptor antagonist.. A total of 30 clinical studies were identified (16 clinical trials, including subanalyses, 14 related to pharmacology, pharmacokinetics, and pharmacodynamics and drug interactions).. Two phase III clinical trials with vorapaxar have been published. In patients with non-ST segment elevation myocardial infarction (MI), vorapaxar failed to significantly reduce the primary efficacy end point (composite of cardiovascular death, MI, stroke, recurrent ischemia with hospitalization, and urgent coronary revascularization). Conversely, in a study of secondary prevention for patients with cardiovascular disease, the composite end point of cardiovascular death, MI, or stroke was significantly reduced. In both trials, the safety end points of major/minor bleeding were increased compared with placebo. In the secondary prevention trial, an increased incidence of intracranial hemorrhage led to the exclusion of patients with a prior history of stroke.. Vorapaxar is approved for use with aspirin and/or clopidogrel in the secondary prevention of cardiovascular events in stable patients with peripheral arterial disease or a history of MI. However, the addition of vorapaxar to other antiplatelets can significantly increase the risk of bleeding. It is, therefore, essential to balance the need for further reduction of risk of thrombotic event with patient's individual bleeding risk.

Topics: Atherosclerosis; Cardiovascular Diseases; Clinical Trials, Phase III as Topic; Hemorrhage; Humans; Lactones; Myocardial Infarction; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Risk; Secondary Prevention; Stroke; Treatment Outcome

Atherothrombosis and its clinical manifestations are among the leading causes of death in the developed world. The current standard-of-care antiplatelet therapy for the treatment of such events comprises aspirin and a thienopyridine or ticagrelor. However, recurrent ischemic events due to residual cardiovascular risk are a common phenomenon in these patients. It is believed that this residual risk is caused, at least in part, by thrombin, which signals through protease-activated receptors (PARs) and especially PAR-1. Thus, PAR-1 antagonism could represent an effective approach in the treatment of atherothrombotic disease. In this context, two potent and selective agents have been developed, vorapaxar and atopaxar. However, only vorapaxar has completed phase 3 clinical trials. In the present review, the main pharmacodynamic and pharmacokinetic properties of the PAR-1 antagonists are briefly described and the latest clinical data on vorapaxar are presented.

Topics: Clinical Trials as Topic; Coronary Artery Bypass; Drug Therapy, Combination; Hemorrhage; Humans; Imines; Lactones; Myocardial Infarction; Percutaneous Coronary Intervention; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Receptors, Thrombin; Stents; Stroke; Thrombosis

Acute myocardial infarction (AMI) is generally attributed to coronary atherothrombotic disease. Platelet activation is essential for thrombus formation and is thus an important target for pharmacological intervention to prevent and treat AMI. Despite contemporary treatment with dual antiplatelet therapy, including acetylsalicylic acid and adenosine diphosphate receptor antagonists, patients with prior AMI remain at increased risk of future thrombotic events. This has stimulated the search for more potent antithrombotic agents. Among these is the oral protease-activated receptor-1 antagonist vorapaxar, which represents a new oral antiplatelet agent to reduce thrombotic risk in patients with atherothrombotic disease. The TRACER and the TRA 2°P-TIMI 50 trials concluded that vorapaxar in addition to standard therapy reduced ischemic adverse cardiac events. A remarkable benefit was observed in patients with stable atherosclerotic disease, particularly those with a previous history of AMI. Although favorable effects were seen in reduction of adverse cardiac events, this was associated with excess major and intracranial bleeding, particularly in patients at high risk of bleeding and those with a history of stroke or transient ischemic attack. Currently, the lack of a reliable individualized risk stratification tool to assess patients for thrombotic and bleeding tendencies in order to identify those who might gain most net clinical benefit has led to limited use of vorapaxar in clinical practice. Vorapaxar may find a niche as an adjunct to standard care in patients at high risk of thrombotic events and who are at low risk of bleeding.

Topics: Animals; Hemorrhage; Humans; Lactones; Myocardial Infarction; Platelet Aggregation Inhibitors; Pyridines; Thrombosis

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, dosage and administration, cost, and place in therapy of vorapaxar in the secondary prevention of atherosclerotic events are reviewed.. Vorapaxar is a highly selective, reversible antagonist of protease-activated receptor-1 expressed on platelets. Vorapaxar competitively inhibits thrombin from activating the receptor, thereby decreasing platelet aggregation. Vorapaxar is rapidly absorbed and distributed, with peak plasma levels being reached within 60-90 minutes. Vorapaxar's effective half-life is three to four days and its terminal elimination half-life is eight days. Vorapaxar sulfate 2.5 mg (equivalent to 2.08 mg of vorapaxar) orally daily without a loading dose was clinically effective for the secondary prevention of ischemic events in patients with a history of myocardial infarction (MI) or with peripheral arterial disease (PAD) without a history of stroke. Phase II and III trials of vorapaxar given with aspirin or a thienopyridine or both demonstrated a reduction in the primary endpoint of cardiovascular death, MI, and stroke in patients with a history of MI or coronary artery disease and PAD. Patients with a history of stroke were found to have an increased rate of intracranial hemorrhage (ICH), which led to a boxed warning placed on vorapaxar's labeling to warn of the increased risk for bleeding in patients with a history of stroke.. Vorapaxar is a novel antiplatelet agent that has demonstrated efficacy in reducing atherosclerotic events in patients with a history of MI or PAD without a history of stroke, transient ischemic attack, or ICH when taken in combination with aspirin and clopidogrel.

Topics: Aspirin; Clopidogrel; Drug Interactions; Drug Therapy, Combination; Half-Life; Hemorrhage; Humans; Lactones; Myocardial Infarction; Myocardial Ischemia; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Receptor, PAR-1; Secondary Prevention; Stroke; Thrombosis; Ticlopidine

Atherosclerosis is frequently caused by clot blockage of the coronary or peripheral arteries, and may lead to myocardial infarction (MI) or peripheral arterial disease (PAD). Despite advancements in management of atherosclerosis, mortality and ischemic rates remain high. Vorapaxar is a protease activated receptor-1 (PAR-1) antagonist, and prevents thrombin activation of PAR-1 receptors on platelets.. Vorapaxar was studied in 2 landmark trials in patients with acute coronary syndrome (ACS) and in those with history of atherosclerosis. For patients with ACS, vorapaxar did not significantly reduce rates of the primary efficacy outcome as compared to placebo. For patients with a history of atherosclerosis, vorapaxar significantly reduced rates of primacy outcome. However, in both landmark trials, vorapaxar significantly increased risks of bleeding, and significantly increases risks of intracranial hemorrhage in patients with a history of stroke. Vorapaxar was approved in 2014 in the US for patients with a history of MI or PAD, and in the European Union for patients with a history of MI.. Use of vorapaxar may be limited due to its high potential for causing bleeding. Efficacy of vorapaxar in addition to aspirin and prasugrel or ticagrelor for the management of ACS should be studied in the future.

Topics: Acute Coronary Syndrome; Animals; Atherosclerosis; Hemorrhage; Humans; Lactones; Platelet Aggregation Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Receptor, PAR-1; Risk; Stroke; Thrombosis

The optimal utilization of antiplatelet therapy in patients with renal impairment (RI) following acute coronary syndromes (ACS) represents an urgent, unmet and yet unsolved need with regards to the choice of agents, duration of treatment and potential dose/regimen adjustment. The lack of any large randomized trials designed and powered specifically in such high-risk patients, absence of the uniformed efficacy and safety data reporting policy to the FDA and endless overoptimistic publications based on post hoc analyses of primary trials sometimes exaggerating benefits and hiding risks, clouds reality. In addition, triaging RI patients is problematic due to ongoing kidney deterioration and the fact that such patients are prone to both vascular occlusions and bleeding. The authors summarize available FDA-confirmed evidence from the latest trials with approved antiplatelet agents, namely clopidogrel (CAPRIE, CURE, CREDO, CLARITY, CHARISMA); prasugrel (TRITON, TRILOGY); ticagrelor (PLATO, and PEGASUS); and vorapaxar (TRACER and TRA2P) in RI patient cohorts on top of aspirin as part of dual antiplatelet therapy (DAPT). We deliberately avoided any results unless they were verified by the FDA, with the exception of the recent PEGASUS, since Agency reviews are not yet available. Despite differences among the trials and DAPT choices, RI patients universally experience much higher (HR = 1.3-3.1) rates of primary endpoint events, and bleeding risks (HR = 1.7-3.6). However, only ticagrelor increases creatinine and uric acid levels above that of clopidogrel; has the worst incidence of serious adverse events, more adverse events, and inferior outcomes in patients with severe (eGFR <30 ml/min), especially in the lowest (eGFR <15 ml/min) RI subsets. Clopidogrel, prasugrel and vorapaxar appear safer. Moreover, less aggressive half dose (5 mg/daily) prasugrel and strict DAPT, are well justified in RI, but not predominantly triple strategies with vorapaxar as tested in TRA2P and especially in TRACER. In conclusion, data from clinical trials, their sub-studies and affiliated FDA reviews indicate that RI cause more vascular occlusions and bleeding in ACS patients treated with DAPT. Among the novel antiplatelet agents, prasugrel and vorapaxar, but probably not ticagrelor, offer advantage in RI patients.

Topics: Acute Coronary Syndrome; Adenosine; Clinical Trials as Topic; Clopidogrel; Comparative Effectiveness Research; Glomerular Filtration Rate; Hemorrhage; Humans; Lactones; Patient Selection; Platelet Aggregation Inhibitors; Prasugrel Hydrochloride; Pyridines; Renal Insufficiency; Ticagrelor; Ticlopidine

Patients with acute coronary syndrome (ACS) usually receive acetylsalicylic acid plus an adenosine diphosphate (ADP) receptor inhibitor to reduce the long-term risk of recurrent events. However, patients receiving standard antiplatelet prophylaxis still face a substantial risk of recurrent events. Strategies involving 3 antithrombotic agents with different modes of action have now been tested. In Thrombin Receptor Antagonists for Clinical Event Reduction (TRA-CER), compared with standard care alone, bleeding complications including intracranial hemorrhage (ICH) were increased with the addition of vorapaxar, without efficacy benefit. In Trial to Assess the Effects of SCH 530348 in Preventing Heart Attack and Stroke in Patients With Atherosclerosis (TRA 2°P-TIMI 50), the addition of vorapaxar reduced recurrent events compared with standard care in stable patients with prior myocardial infarction. This study was terminated early in patients with prior stroke owing to excess ICH, though an increased risk of ICH or fatal bleeding was not detected in patients with prior myocardial infarction. The Apixaban for Prevention of Acute Ischemic and Safety Events 2 (APPRAISE-2) trial of standard-dose apixaban added to standard care in patients with ACS was also stopped early owing to excess serious bleeding. However, in Rivaroxaban in Combination With Aspirin Alone or With Aspirin and a Thienopyridine in Patients With Acute Coronary Syndromes (ATLAS ACS 2 TIMI 51), fatal bleeding or fatal ICH did not increase with low-dose rivaroxaban added to low-dose acetylsalicylic acid-based standard care compared with standard care alone. In that trial, a significant reduction of recurrent vascular events was shown with 3 antithrombotic regimens compared with standard care. Therefore, depending on drug dose and patient population, further reductions in recurrent vascular events after ACS may be possible in future clinical practice, with a favorable benefit-risk profile.

Topics: Acute Coronary Syndrome; Anticoagulants; Benzimidazoles; beta-Alanine; Clinical Trials as Topic; Coronary Thrombosis; Dabigatran; Hemorrhage; Humans; Imines; Lactones; Morpholines; Platelet Activation; Platelet Aggregation Inhibitors; Pyrazoles; Pyridines; Pyridones; Rivaroxaban; Secondary Prevention; Thiophenes; Thrombin

Platelet activation with subsequent aggregation is a complex process leading to thrombus formation, which remains a key component for atherothrombotic manifestations, in particular myocardial infarction. Therefore, antiplatelet therapies are pivotal for the treatment of these patients. Current oral antiplatelet therapies used for secondary prevention of ischemic recurrences include aspirin and adenosine diphosphate P2Y12 platelet-receptor antagonists. However, despite these therapies, patients who have experienced a myocardial infarction remain at risk for ischemic recurrences. Therefore, more aggressive secondary prevention measures have been an area of research, including identifying additional targets modulating platelet-activation and -aggregation processes. Among these, thrombin-mediated platelet activation via protease-activated receptors (PARs) has been subject to extensive clinical investigation. Several PAR-1 receptor antagonists have been developed. However, vorapaxar is the only one that has completed large-scale clinical investigation. The present manuscript will provide an overview on the role of thrombin-mediated signaling, the impact of PAR-1 blockade with vorapaxar on ischemic and bleeding outcomes, and the potential role for vorapaxar in clinical practice.

Topics: Animals; Blood Platelets; Hemorrhage; Humans; Lactones; Molecular Targeted Therapy; Myocardial Infarction; Platelet Aggregation; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Risk Factors; Secondary Prevention; Signal Transduction; Treatment Outcome

Acute coronary syndrome (ACS) constitutes a group of pathophysiological entities resulting from reduced blood flow in the coronary arteries leading to decreased or improper functioning or death of heart muscle. Such patients are usually prescribed combination antiplatelet drug therapy, containing acetylsalicylic acid (aspirin) and an adenosine diphosphate receptor inhibitor to prevent recurrence of ischemic events. The combination prophylactic therapy to certain extend has been successful in preventing secondary complications including ischemic/thrombotic events in these patients. However, research is still on for newer advances in anti-thrombotic therapy that can further prevent secondary complications of Acute Coronary Syndrome. Vorapaxar is a newer drug recommended along with aspirin or clopidogril for prevention of recurrence of cardiac events. Vorapaxar, a thrombin receptor antagonist acts by reversible inhibition of the protease-activated receptor-1 (PAR-1). PAR-1 is expressed on platelets, and it inhibits platelet aggregation, both thrombin-induced and thrombin receptor agonist peptide (TRAP)-induced. Various trials world -wide have documented its efficacy as an anti-platelet agent for preventing recurrent cardiovascular ischemic events but at the expense of increased bleeding complications including intracranial haemorrhage (ICH), when compared to standard therapy alone. For the same reason, vorapaxar is contraindicated in patients with prior stroke, transient ischemic attack and ICH. U.S. Food and Drug Administration (FDA) approved vorapaxar in May 2014 as an antiplatelet agent along with standard anti-platelet therapy for the reduction of recurring thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. Vorapaxar is developed and marketed by Merck Sharp Dohme and is available by the brand name 'Zontivity' as 2.5 mg oral tablet equivalent to 2.08 mg of vorapaxar sulfate. There are two patents protecting this drug.

Topics: Acute Coronary Syndrome; Animals; Blood Platelets; Drug Therapy, Combination; Hemorrhage; Humans; Lactones; Patient Selection; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Risk Factors; Signal Transduction; Treatment Outcome

Vorapaxar (SCH 530348) and atopaxar (E5555) are oral protease-activated receptor-1 (PAR-1) antagonists with high bioavailability. They inhibits thrombin induced platelet aggregation by competitively inhibiting PAR-1. We systematically evaluated the evidence for the efficacy and safety of all PAR-1 antagonists as well as for the individual drugs vorapaxar and atopaxar in different databases-PubMed, EMBASE, Scopus, and Cochrane register of Controlled Clinical Trials (CENTRAL).We selected randomized controlled trials of PAR-1 antagonists that reported on cardiovascular mortality as a clinical outcome. The random-effects Mantel-Haenszel model was used to evaluate the effect of PAR-1 antagonists on cardiovascular mortality. Seven trials were selected (N = 42,355) for analysis. PAR-1 antagonists as a class, as well as individually, were associated with a non-significant numerically lower risk of cardiovascular mortality than that seen with agents used in the control group; RR, 0.93; 95% CI, 0.83-1.04; P = 0.20). No heterogeneity was noted. However, PAR-1 antagonists also appeared to increase the risk of bleeding significantly. PAR-1 antagonists appear to be associated with some reduction in the risk of cardiovascular mortality; however the significantly higher bleeding risk noted with PAR-1 antagonists appear to mandate a very careful selection of patients that may benefit without a substantially increased risk of bleeds.

Topics: Coronary Artery Disease; Hemorrhage; Humans; Imines; Lactones; Platelet Aggregation Inhibitors; PubMed; Pyridines; Randomized Controlled Trials as Topic; Receptor, PAR-1

Currently available antiplatelet agents have shown improved short- and long-term clinical outcomes but are associated with increased bleeding risk, and the rates of recurrent ischemic events still remain high. Selective inhibition of protease-activated receptor-1 for thrombin represents a potential novel strategy to reduce ischemic events without increasing the risk of bleeding. Two protease-activated receptor-1 antagonists are currently being evaluated in clinical trials: SCH 530348 and E5555. Results of phase II trials have shown that SCH 530348, when added to standard antiplatelet therapy, was well tolerated and not associated with increased bleeding risk. Two large-scale phase III trials assessing the efficacy of SCH 530348 in addition to the standard of care are currently ongoing. This review provides an outline of the current status of understanding on platelet thrombin-receptor antagonist SCH 530348, focusing on its pharmacologic properties and clinical development.

Topics: Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Drug Design; Hemorrhage; Humans; Lactones; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Receptors, Thrombin

Ischemic heart disease remains the number one cause of death in the world despite advances in invasive and pharmacologic therapies. An ongoing area of research is the central role of platelets in atherothrombosis. Many therapeutic strategies have been developed over the last few decades affecting different platelet receptors to alter platelet-mediated thrombosis including targeting the receptors for thromboxane A(2), adenosine diphosphate, and fibrinogen. However, despite the use of pharmacologic agents directed at these pathways, residual morbidity and mortality still exist. Therefore, identifying agents that more favorably balance a reduction in ischemic events while minimizing bleeding events is an ongoing mission. Thrombin is known to be the most potent stimulant of platelet-mediated thrombosis whose action on the platelet is through a family of receptors known as the protease-activated receptors (PARs). Activation through the PAR-1 receptor, in particular, results in an early and intense response by the platelet to thrombin, and it is the primary thrombin receptor on platelets, thus making it a potentially desirable target for therapy. Most recently, two PAR-1 antagonists, atopaxar and vorapaxar, have been tested in clinical trials. Generally, the results show a reduction in ischemic event rates, but an increase in bleeding event rates. This article will summarize the current state of the literature and consider the role these drugs might play in the future for the prevention of ischemic heart disease events.

Topics: Acute Coronary Syndrome; Blood Platelets; Coronary Artery Disease; Hemorrhage; Humans; Imines; Lactones; Myocardial Infarction; Platelet Activation; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Thrombin; Treatment Outcome

Thrombin receptor antagonists blocking protease-activated receptor-1 (PAR-1) on platelets represent a new class of oral antiplatelet agents for patients with atherothrombotic disease manifestations.. We investigated the safety and efficacy of PAR-1 antagonists in patients with coronary artery disease (CAD).. Randomized, placebo-controlled trials of the PAR-1 antagonists atopaxar or vorapaxar in CAD patients were identified. The primary safety endpoint was the composite of Thrombolysis In Myocardial Infarction (TIMI) clinically significant bleeding. The primary efficacy endpoint was the composite of death, myocardial infarction (MI) or stroke.. A total of 41 647 patients from eight trials were included. PAR-1 antagonists were associated with higher risks of TIMI clinically significant (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.39-1.57, P < 0.001), major (OR 1.46, 95% CI 1.28-1.67, P < 0.001) and minor (OR 1.67, 95% CI 1.40-2.00, P < 0.001) bleeding than placebo in the fixed-effects model. PAR-1 antagonists reduced the composite of death, MI or stroke as compared with placebo (OR 0.87, 95% CI 0.81-0.92, P < 0.001), driven by a lower risk of MI (OR 0.85, 95% CI 0.78-0.92, P < 0.001). Conversely, PAR-1 antagonists and placebo did not differ in terms of risk of death (OR 0.99, 95% CI 0.90-1.09, P = 0.81) or stroke (OR 0.96, 95% CI 0.84-1.10, P = 0.59).. PAR-1 antagonists decrease ischemic events in patients with CAD as compared with placebo, mainly driven by a reduction in MI, at the cost of an increased risk of clinically significant bleeding.

Topics: Blood Platelets; Chi-Square Distribution; Coronary Artery Disease; Evidence-Based Medicine; Hemorrhage; Humans; Imines; Lactones; Myocardial Infarction; Odds Ratio; Platelet Aggregation Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Receptor, PAR-1; Risk Assessment; Risk Factors; Stroke; Treatment Outcome

Coronary artery disease is a leading cause of morbidity and mortality worldwide. Platelet activation and subsequent thrombus formation play a central role in disease progression and development of acute coronary syndromes (ACS). Despite widespread use of single and dual antiplatelet therapies in atherothrombotic disease, ischemic complications remain common. Therefore, the need exists for new antiplatelet agents that are more effective, but with acceptable safety profiles (i.e., do not increase risk of bleeding). Antiplatelet agents available at present are effective in blocking the cyclo-oxygenase, ADP-mediated and final common (IIb/IIIa receptor) pathways for platelet activation. Recently, there has been more interest in inhibition of the proteinase-activated receptor-1 (PAR-1), which blocks thrombin-mediated platelet activation.. This review covers the pharmacology, pharmacokinetics and development of the new PAR(1) antagonist, SCH 530348 in a review of all publications relevant to the topic over the last 10 years. Phase II clinical trials indicate that addition of this agent to current antiplatelet regimens may provide additional antithrombotic protection without an increase in bleeding. Results of the ongoing Phase III trials, examining the use of SCH 530348 in patients with ACS and for secondary prevention of ischemic events are anxiously awaited.. The review is a summary of all pharmacologic properties and current clinical data available on the PAR1 antagonist SCH 530348. The readers will be introduced to its novel mechanism of action, advantages over current antiplatelet agents and potential future applications should ongoing clinical trials confirm its efficacy in reducing platelet activity.. SCH 530348 is a new, orally administered antiplatelet agent that blocks the protease-activated thrombin receptor on the platelet. Early clinical data indicate that it is associated with a lower risk of bleeding. However, its efficacy in improving clinical outcomes in patients with coronary disease remains to be confirmed in ongoing Phase III clinical trials.

Topics: Administration, Oral; Animals; Blood Platelets; Clinical Trials as Topic; Coronary Disease; Evidence-Based Medicine; Hemorrhage; Humans; Lactones; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Thrombosis; Treatment Outcome

Atherothrombotic disease is the leading cause of death worldwide. Currently, dual antiplatelet therapy with aspirin and ADP receptor antagonists has shown improved short- and long-term clinical outcomes but is associated with increased bleeding risk, and the rates of recurrent ischemic events still remain high. Selective inhibition of the principal protease-activated receptor (PAR)-1 for thrombin, the most potent platelet activator, represents a promising novel strategy to reduce ischemic events without increasing the risk of bleeding. Two PAR-1 antagonists are currently being tested in clinical trials: SCH 530348 and E5555. Both have demonstrated an antiplatelet effect without increasing bleeding time in preclinical trials. Results of Phase II trials showed that SCH 530348, in addition to standard antiplatelet therapy, was well tolerated and not associated with increased bleeding risk. The safety and tolerability of E5555 is being evaluated in patients with coronary artery disease and non-ST-segment elevation acute coronary syndrome in four Phase II clinical trials. Two large-scale Phase III trials assessing the efficacy of SCH 530348 in addition to the standard of care are currently ongoing. This article provides an overview of the current status of knowledge on platelet thrombin receptor antagonists, focusing on pharmacologic properties and clinical development.

Topics: Animals; Clinical Trials as Topic; Hemorrhage; Humans; Imines; Lactones; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Receptors, Thrombin; Thrombosis

Antiplatelet agents play an essential role in the treatment of acute coronary syndrome (ACS). Thienopyridines are a class of drugs that function via inhibition of the adenosine diphosphate (ADP) P2Y12 platelet receptors. Currently, clopidogrel, a second generation thienopyridine, is the main drug of choice and the combination of aspirin and clopidogrel is administered orally for the treatment of ACS. Clopidogrel, is a pro-drug that needs to be metabolized in the liver and intestines to form active metabolites. Prasugrel, a third generation thienopyridine, was approved for use in Europe in February 2009, and is currently available in the United Kingdom. All thienopyridines however, have pharmacological limitations that lead to a search for more effective non-thienopyridine P2Y12 inhibitors. Promising results have been reported with ticagrelor, an oral first reversible, direct-acting inhibitor of the P2Y12 receptor. Ticagrelor is the first oral P2Y12 receptor binding antagonist that does not require metabolic activation. Furthermore, ticagrelor has at last 1 active metabolite, which has very similar pharmacokinetics to the parent compound. Therefore, ticagrelor has more rapid onset and more pronounced platelet inhibition than other antiplatelet agents. The safety and efficacy of ticagrelor compared with clopidogrel in ACS patient has been recently evaluated by the PLATelet inhibition and patient Outcomes (PLATO) trial. Ticagrelor compared with clopidogrel had a significantly greater reduction in the death rate from vascular causes, myocardial infarction, or stroke without major bleeding. There was however, an increase in non-procedure related bleeding, dyspnoea and ventricular pauses in the first week of treatment. Further studies on new antiplatelet agents are needed to establish a new "gold standard" antiplatelet therapy.

Topics: Acute Coronary Syndrome; Adenosine; Adenosine Monophosphate; Biotransformation; Clinical Trials as Topic; Clopidogrel; Hemorrhage; Humans; Lactones; Piperazines; Platelet Aggregation Inhibitors; Prasugrel Hydrochloride; Purinergic P2 Receptor Antagonists; Pyridines; Receptors, Purinergic P2; Receptors, Purinergic P2Y12; Thiophenes; Ticagrelor; Ticlopidine

Protease-activated receptor-1 antagonism by vorapaxar could facilitate arteriovenous fistula maturation but may increase bleeding risk.. The primary objective of the Vorapaxar Study for Maturation of arteriovenous fistula for Hemodialysis Access (VorapAccess) was to determine if vorapaxar improves arteriovenous fistula functional maturation in patients with end-stage renal disease.. VorapAccess was a randomized, placebo-controlled, double-blind pilot trial comparing 2.5 mg vorapaxar per day with placebo for twelve weeks starting on day two after arteriovenous fistula creation. The primary outcome was time to functional maturation defined as successful cannulation for six hemodialysis sessions within three weeks. The planned sample size was 50 participants. The study was terminated early after withdrawal of planned financial support. Given the small number of randomized patients, we performed descriptive analyses without inference testing.. A total of 13 participants were randomly allocated study drug (six vorapaxar and seven placebo). The median age was 56 years and seven participants (54%) were female. The median (minimum-maximum) days to functional maturation were 169 (77-287) days in the vorapaxar group and 145 (48-198) days in the placebo group. Six of the 13 (46%) participants had arteriovenous fistula functional maturation within 180 days; two of six (33%) in the vorapaxar group and four of seven (57%) in the placebo group. There was one bleeding event in the placebo group.. Fewer than half of participants had functional maturation within 180 days after surgery, suggesting a major need for agents or strategies that enhance arteriovenous fistula maturation.

Topics: Aged; Arteriovenous Shunt, Surgical; California; Double-Blind Method; Early Termination of Clinical Trials; Female; Hemorrhage; Humans; Kidney Failure, Chronic; Lactones; Male; Middle Aged; Pilot Projects; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Renal Dialysis; Risk Factors; Time Factors; Treatment Outcome; Upper Extremity

Intensive antithrombotic therapy reduces major adverse cardiovascular events (MACE) and major adverse limb events (MALE) in patients with peripheral artery disease (PAD). Recent studies have suggested heterogeneity in risk and benefit in those with and without concomitant coronary artery disease (CAD) and peripheral revascularization. We evaluated the risk of MACE and MALE in patients with PAD stratified by history of concomitant CAD and prior peripheral revascularization and whether the efficacy and safety of vorapaxar were similar in these subgroups. The TRA 2°P-TIMI 50 trial randomized 26,449 patients with prior MI, ischemic stroke, or PAD to vorapaxar or placebo. This analysis examined the effect of vorapaxar in a broad population of 6136 patients with PAD. Overall, vorapaxar significantly reduced MACE (HR 0.85, 95% CI 0.73, 0.99;

Topics: Aged; Coronary Artery Disease; Endovascular Procedures; Female; Fibrinolytic Agents; Hemorrhage; Humans; Lactones; Male; Middle Aged; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Risk Factors; Time Factors; Treatment Outcome; Vascular Surgical Procedures

Patients with renal disease are often undertreated with antiplatelet therapy due to concerns about bleeding. Vorapaxar blocks platelet activation via the PAR-1 receptor and reduces cardiovascular events in patients with stable atherosclerosis, but with increased bleeding. We examined the efficacy and safety of vorapaxar in patients with impaired renal function. TRA2°P-TIMI 50 randomized patients with stable atherosclerosis to vorapaxar or. We analyzed patients with eGFR assessed who qualified with a history of MI or PAD (without stroke or TIA) (n = 19,932). Cox models assessed the risk of CV events and bleeding by quartile of baseline eGFR in the placebo arm and then by randomized assignment. Net clinical outcome (NCO) was predefined as CV death, MI, stroke, or GUSTO severe bleeding. Patients with lower eGFR tended to be older, female, have hypertension, hyperlipidemia or prior PAD. In the placebo arm, baseline eGFR in the lowest quartile was associated with a 26% higher risk of CV death, MI or stroke (Q1:Q4 HR

Topics: Aged; Atherosclerosis; Cardiovascular Diseases; Female; Glomerular Filtration Rate; Hemorrhage; Humans; Kidney Diseases; Lactones; Male; Middle Aged; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Risk; Secondary Prevention; Treatment Outcome

Variation in platelet response to thrombin may affect the safety and efficacy of PAR antagonism. The Thr120 variant of the common single nucleotide polymorphism (SNP) rs773902 in the protease-activated receptor (PAR) 4 gene is associated with higher platelet aggregation compared to the Ala120 variant. We investigated the relationship between the rs773902 SNP with major bleeding and ischemic events, safety, and efficacy of PAR1 inhibition in 6177 NSTE ACS patients in the TRACER trial. There was a lower rate of GUSTO moderate/severe bleeding in patients with the Thr120 variant. The difference was driven by a lower rate in the smaller homozygous group (recessive model, HR 0.13 [0.02-0.92] P = 0.042). No significant differences were observed in the ischemic outcomes. The excess in bleeding observed with PAR1 inhibition was attenuated in patients with the Thr120 variant, but the interactions were not statistically significant. In summary, lower major bleeding rates were observed in the overall TRACER cohort with the hyperreactive PAR4 Thr120 variant. The increase in bleeding with vorapaxar was attenuated with the Thr120 variant, but we could not demonstrate an interaction with PAR1 inhibition. These findings warrant further exploration, including those of African ancestry where the A allele (Thr120) frequency is ~65%.

Topics: Acute Coronary Syndrome; Aged; Female; Genetic Variation; Genotype; Hemorrhage; Humans; Ischemia; Lactones; Male; Middle Aged; Platelet Aggregation Inhibitors; Polymorphism, Single Nucleotide; Pyridines; Randomized Controlled Trials as Topic; Receptor, PAR-1; Receptors, Thrombin

Increased D-dimer concentrations are associated with poor cardiovascular and other clinical outcomes in people with treated HIV infection. Proteinase activated receptor-1 (PAR-1) is activated by thrombin and overexpressed by immune cells from HIV-infected people. We aimed to study the efficacy of vorapaxar, a licensed inhibitor of PAR-1, in reducing HIV-associated hypercoagulation and inflammation.. This was a multicentre, double-blind, randomised, placebo-controlled trial done in seven hospital clinics in Australia and the USA. Eligible participants were HIV-infected, aviraemic, were receiving stable antiretroviral therapy, and had D-dimer concentrations greater than 200 ng/mL. We randomly assigned participants (1:1) using computer-generated block lists of size two to receive vorapaxar (2·5 mg orally daily) or matched placebo for 12 weeks. Participants were reviewed and had a blood sample taken at weeks 1, 4, 8, and 12 during treatment, and at a final visit at week 18. The primary endpoint was treatment group difference in changes from baseline D-dimer concentrations after 8-12 weeks of treatment, and was assessed in the modified intention-to-treat population (participants who had at least one dose of study drug or one follow-up visit). This trial is registered with ClinicalTrials.gov, number NCT02394730, and is closed to new participants.. Vorapaxar had no effect on D-dimer concentrations in HIV-infected patients receiving stable antiretroviral therapy but at risk of poor outcomes. Alternative approaches are needed to reduce hypercoagulation, inflammation, and adverse long-term outcomes in patients with treated HIV infection.. Australian National Health and Medical Research Council, US National Cancer Institute, National Institutes of Health.

Topics: Anti-HIV Agents; Biomarkers; Double-Blind Method; Female; Fibrin Fibrinogen Degradation Products; Hemorrhage; HIV Infections; Humans; Inflammation; Lactones; Male; Middle Aged; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; T-Lymphocytes; Thrombophilia

Dual antiplatelet therapy reduces non-fatal ischaemic events after acute coronary syndrome (ACS) but increases bleeding to a similar extent. We sought to determine the prognostic impact of myocardial infarction (MI) vs. bleeding during an extended follow-up period to gain insight into the trade-off between efficacy and safety among patients after ACS.. In 12 944 patients with non-ST-segment elevation ACS from the Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) trial, we investigated the relative impact of MI and bleeding occurring >30 days post-ACS and subsequent all-cause mortality. Bleeding was graded according to Bleeding Academic Research Consortium (BARC) criteria. MI was associated with a five-fold increase in mortality. BARC type 2 and 3, but not type 1, bleeding had a significant impact on mortality. MI was associated with a greater risk of mortality compared with BARC 2 [relative risk (RR) 3.5; 95% confidence interval (CI) 2.08-4.77; P < 0.001] and BARC 3a bleeding (RR 2.23; 95% CI 1.36-3.64; P = 0.001), and a risk similar to BARC 3b bleeding (RR 1.37; 95% CI 0.81-2.30; P = 0.242). Risk of death after MI was significantly lower than after BARC 3c bleeding (RR 0.22; 95% CI 0.13-0.36; P < 0.001). MI and bleeding had similar time-associations with mortality, which remained significant for several months, still being higher early after the event.. In patients treated with antiplatelet therapy after ACS, both MI and bleeding significantly impacted mortality with similar time-dependency. Although BARC 2 and 3a bleeding were less prognostic for death than MI, the risk of mortality was equivalent between BARC 3b bleeding and MI, and was higher following BARC 3c bleeding.

Topics: Acute Coronary Syndrome; Aged; Cause of Death; Double-Blind Method; Drug Administration Schedule; Drug Therapy, Combination; Female; Follow-Up Studies; Hemorrhage; Humans; Lactones; Male; Middle Aged; Non-ST Elevated Myocardial Infarction; Platelet Aggregation Inhibitors; Pyridines; Receptors, Thrombin

Vorapaxar is effective in the prevention of secondary atherothrombotic events, although the efficacy/safety balance appears less favorable in the treatment of patients with non-ST-segment elevation (NSTE) acute coronary syndrome (ACS). We hypothesized that patients with NSTE ACS already receiving thienopyridine prior to the ACS event may show differential efficacy/safety effects with vorapaxar vs. placebo added to their standard care.. We studied 12,944 patients from the Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) trial with respect to thienopyridine use before admission for the index NSTE ACS event. The primary endpoint was a composite of cardiovascular death, myocardial infarction, stroke, rehospitalization for ischemia, and urgent revascularization. The key secondary endpoint was a composite of cardiovascular death, myocardial infarction, and stroke. Safety endpoints were bleeding complications.. TRACER was largely conducted in thienopyridine-naïve patients with unknown tolerance to multiple antiplatelet treatments. Patients receiving thienopyridine before the index event may have had an attenuated increase in bleeding when adding vorapaxar, whereas concomitantly adding vorapaxar and thienopyridine in naïve patients may have uncovered a latent susceptibility to bleeding.

Topics: Acute Coronary Syndrome; Aged; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Platelet Aggregation Inhibitors; Pyridines; Secondary Prevention; Treatment Outcome

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.. Vorapaxar reduces ischemic events but increases the risk of major bleeding.. 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.. 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.. 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.

Topics: Acute Coronary Syndrome; Aged; Catheterization, Peripheral; Female; Femoral Artery; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Patient Readmission; Percutaneous Coronary Intervention; Platelet Aggregation Inhibitors; Punctures; Pyridines; Radial Artery; Recurrence; Retreatment; Risk Factors; Stroke; Time Factors; Treatment Outcome

The Bleeding Academic Research Consortium (BARC) scale has been proposed to standardize bleeding endpoint definitions and reporting in cardiovascular trials. Validation in large cohorts of patients is needed.. This study sought to investigate the relationship between BARC-classified bleeding and mortality and compared its prognostic value against 2 validated bleeding scales: TIMI (Thrombolysis In Myocardial Infarction) and GUSTO (Global Use of Strategies to Open Occluded Arteries).. We analyzed bleeding in 12,944 patients with acute coronary syndromes without ST-segment elevation, with or without early invasive strategy. The main outcome measure was all-cause death.. During follow-up (median: 502 days), noncoronary artery bypass graft (CABG) bleeding occurred in 1,998 (15.4%) patients according to BARC (grades 2, 3, or 5), 484 (3.7%) patients according to TIMI minor/major, and 514 (4.0%) patients according to GUSTO moderate/severe criteria. CABG-related bleeding (BARC 4) occurred in 155 (1.2%) patients. Patients with BARC (2, 3, or 4) bleeding had a significant increase in risk of death versus patients without bleeding (BARC 0 or 1); the hazard was highest in the 30 days after bleeding (hazard ratio: 7.35; 95% confidence interval: 5.59 to 9.68; p < 0.0001) and remained significant up to 1 year. The hazard of mortality increased progressively with non-CABG BARC grades. BARC 4 bleeds were significantly associated with mortality within 30 days (hazard ratio: 10.05; 95% confidence interval: 5.41 to 18.69; p < 0.0001), but not thereafter. Inclusion of BARC (2, 3, or 4) bleeding in the 1-year mortality model with baseline characteristics improved it to an extent comparable to TIMI minor/major and GUSTO moderate/severe bleeding.. In patients with acute coronary syndromes without ST-segment elevation, bleeding assessed with the BARC scale was significantly associated with risk of subsequent death up to 1 year after the event and risk of mortality increased gradually with higher BARC grades. Our results support adoption of the BARC bleeding scale in ACS clinical trials. (Trial to Assess the Effects of Vorapaxar [SCH 530348; MK-5348] in Preventing Heart Attack and Stroke in Participants With Acute Coronary Syndrome [TRACER] [Study P04736]; NCT00527943).

Topics: Acute Coronary Syndrome; Aged; Coronary Artery Bypass; Double-Blind Method; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Platelet Aggregation Inhibitors; Prognosis; Pyridines; Risk Assessment; Severity of Illness Index; Stents; Stroke

Patients with stable ischemic heart disease and previous myocardial infarction (MI) vary in their risk for recurrent cardiovascular events. Atherothrombotic risk assessment may be useful to identify high-risk patients who have the greatest potential to benefit from more intensive secondary preventive therapy such as treatment with vorapaxar.. We identified independent clinical indicators of atherothrombotic risk among 8598 stable, placebo-treated patients with a previous MI followed up for 2.5 years (median) in TRA 2°P-TIMI 50 [Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events-TIMI 50]. The efficacy and safety of vorapaxar (SCH 530348; MK-5348) were assessed by baseline risk among patients with previous MI without prior stroke or transient ischemic attack for whom there is a clinical indication for vorapaxar. End points were cardiovascular death, MI, or ischemic stroke and GUSTO (Global Use of Strategies to Open Occluded Coronary Arteries) severe bleeding.. The 9 independent risk predictors were age, diabetes mellitus, hypertension, smoking, peripheral arterial disease, previous stroke, previous coronary bypass grafting, heart failure, and renal dysfunction. A simple integer-based scheme using these predictors showed a strong graded relationship with the rate of cardiovascular death/MI/ischemic stroke and the individual components (P for trend <0.001 for all). High-risk patients (≥3 risk indicators; 20% of population) had a 3.2% absolute risk reduction in cardiovascular disease/MI/ischemic stroke with vorapaxar, and intermediate-risk patients (1-2 risk indicators; 61%) had a 2.1% absolute risk reduction (P<0.001 each), translating to a number needed to treat of 31 and 48. Bleeding increased across risk groups (P for trend<0.01); however, net clinical outcome was increasingly favorable with vorapaxar across risk groups. Fatal bleeding or intracranial hemorrhage was 0.9% with both treatments in high-risk patients.. Stratification of baseline atherothrombotic risk can assist with therapeutic decision making for vorapaxar use for secondary prevention after MI.. URL: https://www.clinicaltrials.gov. Unique identifier: NCT00526474.

Topics: Aged; Atherosclerosis; Double-Blind Method; Female; Hemorrhage; Humans; Kaplan-Meier Estimate; Lactones; Male; Middle Aged; Myocardial Infarction; Myocardial Ischemia; Platelet Aggregation Inhibitors; Proportional Hazards Models; Pyridines; Recurrence; Risk Assessment; Secondary Prevention; Treatment Outcome

Vorapaxar is a protease-activated receptor-1 antagonist approved by the U.S. Food and Drug Administration (FDA) for the reduction of thrombotic cardiovascular (CV) events in patients with a history of myocardial infarction (MI) and peripheral artery disease (PAD), without a previous stroke or transient ischemic attack (TIA).. We examined the efficacy and safety of vorapaxar in the intended use population, considering 20,170 patients randomized in the multinational, double-blinded, placebo-controlled TRA 2°P-TIMI 50 trial. Of these, 16,897 qualified with a history of MI in the prior 2 weeks to 1 year and 3273 with PAD. At baseline 97% of the patients were treated with aspirin, 71% with a thienopyridine, and 93% a statin. At 3 years, the endpoint of CV death, MI, or stroke was significantly reduced with vorapaxar compared with placebo (7.9% versus 9.5%, HR, 0.80; 95% CI 0.73 to 0.89; P<0.001). Vorapaxar also significantly reduced the composite of CV death, MI, stroke, and urgent coronary revascularization (10.1% versus 11.8%, HR, 0.83; 95% CI 0.76 to 0.90; P<0.001), as well as the rate of CV death or MI (P<0.001). The safety endpoint of GUSTO moderate or severe bleeding, was increased in the vorapaxar group (3.7 versus 2.4, HR, 1.55; 95% CI 1.30 to 1.86, P<0.001). Intracranial bleeding (ICH) was 0.6% versus 0.4%, P=0.10 with vorapaxar versus placebo, with fatal bleeding 0.2% versus 0.2%; P=0.70.. In patients with prior MI or PAD who have not had a previous stroke or TIA, vorapaxar added to standard therapy is effective for long-term secondary prevention of thrombotic CV events, while increasing moderate or severe bleeding.. URL: clinicaltrials.gov Unique Identifier: NCT00526474.

Topics: Aged; Double-Blind Method; Drug Approval; Female; Hemorrhage; Humans; Ischemic Attack, Transient; Kaplan-Meier Estimate; Lactones; Male; Middle Aged; Myocardial Infarction; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Recurrence; Risk Factors; Secondary Prevention; Stroke; Time Factors; Treatment Outcome; United States; United States Food and Drug Administration

Perioperative antiplatelet agents potentially increase bleeding after non-ST-segment elevation (NSTE) acute coronary syndromes (ACS). The protease-activated receptor 1 antagonist vorapaxar reduced cardiovascular events and was associated with increased bleeding versus placebo in NSTE ACS, but its efficacy and safety in noncardiac surgery (NCS) remain unknown. We aimed to evaluate ischemic, bleeding, and long-term outcomes of vorapaxar in NCS after NSTE ACS.. In the TRACER trial, 2202 (17.0%) patients underwent major or minor NCS after NSTE ACS over 1.5 years (median); continuing study treatment perioperatively was recommended. The primary ischemic end point for this analysis was cardiovascular death, myocardial infarction, stent thrombosis, or urgent revascularization within 30 days of NCS. Safety outcomes included 30-day NCS bleeding and GUSTO moderate/severe bleeding. Overall, 1171 vorapaxar and 1031 placebo patients underwent NCS. Preoperative aspirin and thienopyridine use was 96.8% versus 97.7% (P=0.235) and 89.1% versus 86.1% (P=0.036) for vorapaxar versus placebo, respectively. Within 30 days of NCS, no differences were observed in the primary ischemic end point between vorapaxar and placebo groups (3.4% versus 3.9%; adjusted odds ratio 0.81, 95% CI 0.50 to 1.33, P=0.41). Similarly, no differences in NCS bleeding (3.9% versus 3.4%; adjusted odds ratio 1.41, 95% CI 0.87 to 2.31, P=0.17) or GUSTO moderate/severe bleeding (4.2% versus 3.7%; adjusted odds ratio 1.15, 95% CI, 0.72 to 1.83, P=0.55) were observed. In a 30-day landmarked analysis, NCS patients had a higher long-term risk of the ischemic end point (adjusted hazard ratio 1.62, 95% CI 1.33 to 1.97, P<0.001) and GUSTO moderate/severe bleeding (adjusted hazard ratio 5.63, 95% CI 3.98 to 7.97, P<0.001) versus patients who did not undergo NCS, independent of study treatment.. NCS after NSTE ACS is common and associated with more ischemic outcomes and bleeding. Vorapaxar after NSTE ACS was not associated with increased perioperative ischemic or bleeding events in patients undergoing NCS.

Topics: Acute Coronary Syndrome; Aged; Double-Blind Method; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Pyridines; Receptor, PAR-1; Surgical Procedures, Operative; Treatment Outcome

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.. 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.. 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).. 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.

Topics: Acute Coronary Syndrome; Aged; Double-Blind Method; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Platelet Aggregation Inhibitors; Pyridines; Recurrence; Risk Factors; Stroke; Treatment Outcome

Clinical trials traditionally use time-to-first-event analysis embedded within the composite endpoint of cardiovascular death (CVD), myocardial infarction (MI), or stroke. However, many patients have >1 event, and this approach may not reflect overall experience. We addressed this by analyzing all cardiovascular events in TRACER.. TRACER randomized 12 944 patients with non-ST-segment elevation acute coronary syndromes to placebo or to protease-activated receptor 1 antagonist vorapaxar with a median follow-up of 502 days (interquartile range, 349 to 667). Analysis of vorapaxar's effect on recurrent CVD, MI, or stroke was prespecified using the Wei, Lin, and Weissfeld approach. Vorapaxar did not reduce the first occurrence of the primary endpoint of CVD, MI, stroke, revascularization, or rehospitalization for recurrent ischemia, but reduced the secondary composite endpoint of CVD, MI, or stroke (14.7% vorapaxar vs. 16.4% placebo; hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.81 to 0.98; P=0.02; number needed to treat [NNT], 81). Recurrent secondary events occurred in 2.7% of patients. Vorapaxar reduced overall occurrences of ischemic events, first and subsequent (HR, 0.88; 95% CI, 0.80 to 0.98; P=0.02; NNT, 51). Also, there was a trend indicating that vorapaxar reduced the expanded endpoint, including revascularization and rehospitalization for recurrent ischemia (HR, 0.92; 95% CI, 0.84 to 1.01; P=0.09). Vorapaxar increased overall occurrences of moderate and severe Global Use of Strategies to Open Occluded Coronary Arteries bleeding (HR, 1.42; 95% CI, 1.21 to 1.66; P<0.001) and Thrombolysis in Myocardial Infarction clinically significant bleeding (HR, 1.550; 95% CI, 1.403 to 1.713; P<0.001).. Vorapaxar reduced overall occurrences of ischemic events, but increased bleeding. These exploratory findings broaden our understanding of vorapaxar's potential and expand our understanding of the value of capturing recurrent events.. ClinicalTrials.gov. Unique identifier: NCT00527943.

Topics: Acute Coronary Syndrome; Aged; Cardiovascular Diseases; Double-Blind Method; Female; Hemorrhage; Humans; Ischemia; Lactones; Male; Middle Aged; Myocardial Infarction; Platelet Aggregation Inhibitors; Proportional Hazards Models; Pyridines; Recurrence; Secondary Prevention; Stroke; Treatment Outcome

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.. 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.. 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).. 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.

Topics: Acute Coronary Syndrome; Aged; Clopidogrel; Drug Monitoring; Drug Therapy, Combination; Electrocardiography; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Platelet Aggregation Inhibitors; Pyridines; Secondary Prevention; Stroke; Survival Analysis; Ticlopidine; Treatment Outcome

Vorapaxar is a novel antagonist of protease-activated receptor-1, the primary receptor for thrombin on human platelets that is also present on vascular endothelium and smooth muscle. Patients with peripheral artery disease are at risk of systemic atherothrombotic events, as well as acute and chronic limb ischemia and the need for peripheral revascularization.. The Trial to Assess the Effects of SCH 530348 in Preventing Heart Attack and Stroke in Patients With Atherosclerosis (TRA2°P-TIMI 50) was a randomized, double-blind, placebo-controlled trial of vorapaxar in 26 449 patients with stable atherosclerotic vascular disease (myocardial infarction, stroke, or peripheral artery disease). Patients with qualifying peripheral artery disease (n=3787) had a history of claudication and an ankle-brachial index of <0.85 or prior revascularization for limb ischemia. The primary efficacy end point was cardiovascular death, myocardial infarction, or stroke, and the principal safety end point was Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO) bleeding. In the peripheral artery disease cohort, the primary end point did not differ significantly with vorapaxar (11.3% versus 11.9%; hazard ratio, 0.94; 95% confidence interval, 0.78-1.14; P=0.53). However, rates of hospitalization for acute limb ischemia (2.3% versus 3.9%; hazard ratio, 0.58; 95% confidence interval, 0.39-0.86; P=0.006) and peripheral artery revascularization (18.4% versus 22.2%; hazard ratio, 0.84; 95% confidence interval, 0.73-0.97; P=0.017) were significantly lower in patients randomized to vorapaxar. Bleeding occurred more frequently with vorapaxar compared with placebo (7.4% versus 4.5%; hazard ratio, 1.62; 95% confidence interval, 1.21-2.18; P=0.001).. Vorapaxar did not reduce the risk of cardiovascular death, myocardial infarction, or stroke in patients with peripheral artery disease; however, vorapaxar significantly reduced acute limb ischemia and peripheral revascularization. The beneficial effects of protease-activated receptor-1 antagonism on limb vascular events were accompanied by an increased risk of bleeding.

Topics: Aged; Ankle Brachial Index; Cohort Studies; Comorbidity; Double-Blind Method; Extremities; Female; Follow-Up Studies; Hemorrhage; Humans; Ischemia; Kaplan-Meier Estimate; Lactones; Male; Middle Aged; Myocardial Infarction; Peripheral Arterial Disease; Pyridines; Receptor, PAR-1; Risk Factors; Stroke; Thrombin; Treatment Outcome

Vorapaxar is a new oral protease-activated-receptor 1 (PAR-1) antagonist that inhibits thrombin-induced platelet activation.. 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.. 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.. 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.).

Topics: Acute Coronary Syndrome; Aged; Angioplasty; Cardiovascular Diseases; Combined Modality Therapy; Coronary Artery Bypass; Double-Blind Method; Drug Therapy, Combination; Female; Follow-Up Studies; Hemorrhage; Humans; Intracranial Hemorrhages; Kaplan-Meier Estimate; Lactones; Male; Middle Aged; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1

Thrombin potently activates platelets through the protease-activated receptor PAR-1. Vorapaxar is a novel antiplatelet agent that selectively inhibits the cellular actions of thrombin through antagonism of PAR-1.. We randomly assigned 26,449 patients who had a history of myocardial infarction, ischemic stroke, or peripheral arterial disease to receive vorapaxar (2.5 mg daily) or matching placebo and followed them for a median of 30 months. The primary efficacy end point was the composite of death from cardiovascular causes, myocardial infarction, or stroke. After 2 years, the data and safety monitoring board recommended discontinuation of the study treatment in patients with a history of stroke owing to the risk of intracranial hemorrhage.. At 3 years, the primary end point had occurred in 1028 patients (9.3%) in the vorapaxar group and in 1176 patients (10.5%) in the placebo group (hazard ratio for the vorapaxar group, 0.87; 95% confidence interval [CI], 0.80 to 0.94; P<0.001). Cardiovascular death, myocardial infarction, stroke, or recurrent ischemia leading to revascularization occurred in 1259 patients (11.2%) in the vorapaxar group and 1417 patients (12.4%) in the placebo group (hazard ratio, 0.88; 95% CI, 0.82 to 0.95; P=0.001). Moderate or severe bleeding occurred in 4.2% of patients who received vorapaxar and 2.5% of those who received placebo (hazard ratio, 1.66; 95% CI, 1.43 to 1.93; P<0.001). There was an increase in the rate of intracranial hemorrhage in the vorapaxar group (1.0%, vs. 0.5% in the placebo group; P<0.001).. Inhibition of PAR-1 with vorapaxar reduced the risk of cardiovascular death or ischemic events in patients with stable atherosclerosis who were receiving standard therapy. However, it increased the risk of moderate or severe bleeding, including intracranial hemorrhage. (Funded by Merck; TRA 2P-TIMI 50 ClinicalTrials.gov number, NCT00526474.).

Topics: Aged; Brain Ischemia; Cardiovascular Diseases; Double-Blind Method; Female; Hemorrhage; Humans; Intracranial Hemorrhages; Kaplan-Meier Estimate; Lactones; Male; Middle Aged; Myocardial Infarction; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Retreatment; Risk; Secondary Prevention; Stroke

An antithrombotic drug is needed that safely reduces cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). We therefore assessed the tolerability and safety of SCH 530348-an oral platelet protease-activated receptor-1 antagonist.. We randomly assigned patients aged 45 years or older and undergoing non-urgent PCI or coronary angiography with planned PCI to an oral loading dose of SCH 530348 (10 mg, 20 mg, or 40 mg) or matching placebo in a 3:1 ratio in a multicentre international study. Those in the SCH 530348 group who subsequently underwent PCI (primary PCI cohort) continued taking an oral maintenance dose (0.5 mg, 1.0 mg, or 2.5 mg per day), and patients in the placebo group continued placebo for 60 days. The primary endpoint was the incidence of clinically significant major or minor bleeding according to the thrombolysis in myocardial infarction (TIMI) scale. Both investigators and patients were unaware of treatment allocation. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00132912.. 257 patients were assigned to placebo and 773 to SCH 530348. The primary endpoint occurred in 2 (2%) of 129, 3 (3%) of 120, and 7 (4%) of 173 patients, respectively, in the SCH 530348 10 mg, 20 mg, and 40 mg groups compared with 5 (3%) of 151 patients in the placebo group (p=0.5786). TIMI major plus minor bleeding occurred in 3 (2%) of 136, 5 (4%) of 139, and 4 (3%) of 138 patients given SCH 530348 0.5 mg, 1.0 mg, and 2.5 mg once per day, respectively (p=0.7561).. Oral SCH 530348 was generally well tolerated and did not cause increased TIMI bleeding, even when administered concomitantly with aspirin and clopidogrel. Further testing in phase III trials to accurately define the safety and efficacy of SCH 530348 is warranted.

Topics: Angioplasty, Balloon, Coronary; Coronary Disease; Double-Blind Method; Drug-Related Side Effects and Adverse Reactions; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Platelet Aggregation Inhibitors; Pyridines; Receptors, Thrombin

Thrombin potently activates platelets via interaction with the protease-activated receptor 1. SCH 530348 is a novel antiplatelet agent that selectively inhibits the cellular actions of thrombin via antagonism of the protease-activated receptor 1. Because SCH 530348 does not interfere with other pathways for hemostasis, it is possible that SCH 530348 reduces thrombosis with less increase in bleeding than do other potent antiplatelet agents.. TRA 2 degrees P-TIMI 50 is a phase III, randomized, double-blind, placebo-controlled, multinational clinical trial designed to evaluate the efficacy and safety of SCH 530348 during long-term treatment of patients with established atherosclerotic disease receiving standard therapy (up to 27,000). Eligible patients with a history of myocardial infarction, ischemic stroke, or peripheral arterial disease are randomized 1:1 to SCH 530348 2.5 mg daily or matched placebo until the end of study. Randomization is stratified by the qualifying disease and planned use of a thienopyridine. The primary end point is the composite of cardiovascular death, myocardial infarction, stroke, or urgent coronary revascularization. The major secondary end point is the composite of cardiovascular death, myocardial infarction, or stroke. The evaluation of long-term safety includes bleeding defined by the GUSTO and TIMI criteria. Recruitment began in September 2007. The trial will continue until 2,279 primary end points and 1,400 secondary end points are recorded with expected completion in 36 to 44 months from first enrollment.. TRA 2 degrees P-TIMI 50 is evaluating whether a new approach to platelet inhibition via interruption of thrombin-mediated platelet activation reduces major cardiovascular events with a favorable safety profile in patients with established atherosclerosis.

Topics: Adult; Atherosclerosis; Double-Blind Method; Hemorrhage; Humans; Lactones; Platelet Activation; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Research Design; Treatment Outcome

Quantitative benefit-risk (B-R) assessments are used to characterize treatment by combining key benefits and risks into a single metric but have historically been done for the "average" patient. Our aim was to conduct an individualized assessment for the oral antiplatelet vorapaxar by combining trial and real-world data to further personalize the treatment profiles.. Using linked UK health care databases, we developed risk prediction equations for key ischemic and bleeding events using Cox proportional hazards models. Trial hazard ratios, relative to placebo, were applied to baseline risk estimates to compute expected attributable risks, summed to derive a per-patient net clinical benefit (NCB). High risk subgroups were defined a priori, and Gaussian mixture models (GMM) were fit to characterize the NCB distribution and identify subgroups with similar NCBs.. NCB was consistently positive for all subgroups, likely due to the outcome correlation, and would remain positive with a 12-fold increase in bleeding risk. GMMs identified three distinct NCB subgroups. Compared with the middle/lower NCB subgroups, those with a higher NCB tended to be older, female, and have higher CV disease burden.. Personalized B-R assessments are feasible and clinically valuable and can be used to better predict who would benefit most from therapy.

Topics: Age Factors; Aged; Aged, 80 and over; Clinical Decision-Making; Comorbidity; Databases, Factual; Feasibility Studies; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Normal Distribution; Patient Selection; Placebos; Platelet Aggregation Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; Secondary Prevention; Sex Factors; Treatment Outcome; United Kingdom

Topics: Age Factors; Aged; Aged, 80 and over; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; Secondary Prevention; Stroke; Thrombosis; Time Factors; Treatment Outcome

To evaluate long-term health benefits and risks of adding vorapaxar (VOR) to the standard care antiplatelet therapy (SC) of aspirin and/or clopidogrel, among a population with a recent myocardial infarction (MI) and/or peripheral artery disease (PAD).. In a state-transition model, patients transition between health states (event-free, recurrent MI, stroke, death), while at risk of experiencing non-transition-related revascularization and non-fatal bleeding events. Risk equations developed from the TRA 2°P-TIMI 50 trial's patient-level data were used to predict cardiovascular (CV) outcomes over longer time horizons. Additional sources, including trials and US-based observational studies, informed the inputs for short-term CV risk, non-CV death, and health-related quality of life. Survival and quality-adjusted life-years (QALYs) were estimated over a lifetime horizon, discounted at 3% per year.. Within a cohort of 7361 patients with recent MI and/or PAD, VOR + SC relative to SC alone yielded 176 fewer CV events (MIs, strokes, or CV deaths), but 27 more major bleeding events. VOR + SC was associated with increased life expectancy and health benefits (19.93 undiscounted life-years [LYs], 9.57 discounted QALYs vs. 19.61 undiscounted LYs, 9.41 discounted QALYs). The results were most sensitive to scenarios varying time of vorapaxar initiation, and the assumptions in the 90 day period post-MI. Additional analyses showed that add-on vorapaxar provides consistent incremental benefits in high-risk subgroups.. This study contributes to the growing literature on secondary prevention add-on therapy, as results from these modeling analyses suggest that adding vorapaxar to SC for patients at high atherothrombotic risk can provide long-term health benefits.

Topics: Aspirin; Clopidogrel; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Quality of Life; Quality-Adjusted Life Years; Secondary Prevention; Stroke; Thrombosis; Ticlopidine

The TRA 2°P-TIMI 50 trial showed the addition of vorapaxar to standard care (SC) antiplatelet therapy reduced the combined risk of death, myocardial infarction (MI), and stroke, while exhibiting an increase in moderate, but not other bleeding events.. Our objective was to estimate the long-term health benefits and risks of vorapaxar as an add-on to SC treatment (lifetime aspirin and up to 12 months of clopidogrel) for patients with a prior MI and without a history of cerebrovascular disease.. In the state transition model we developed, the patients transition between states due to recurrent MI, stroke, or death, and are at risk of non-fatal bleeding. Risk equations were developed from individual patient-level data from the TRA 2°P-TIMI 50 trial to predict long-term cardiovascular (CV) outcomes. Additional sources informed inputs for case fatality, bleeding rates on SC, risk of non-CV death, and utilities.. Over a lifetime horizon, fewer CV events and more bleeding events occurred in the vorapaxar (VOR) + SC arm, relative to the SC-only arm. These results were ultimately accompanied by an increase in life expectancy and health benefits associated with add-on vorapaxar treatment, as the VOR + SC arm yielded an average of 8.27 discounted quality-adjusted life-years (QALYs) compared with an average of 7.96 discounted QALYs in the SC-only arm.. This model framework leveraged novel risk equations to make long-term projections of CV events in a population at high risk of recurrence. Model results suggest vorapaxar is most effective as add-on therapy to SC antiplatelet treatment when initiated upon hospital discharge post-MI.

Topics: Aspirin; Cardiovascular System; Clopidogrel; Hemorrhage; Humans; Lactones; Myocardial Infarction; Platelet Aggregation Inhibitors; Pyridines; Secondary Prevention; Stroke; Thrombosis; Ticlopidine; Treatment Outcome

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.. 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.. 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).. 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.

Topics: Acute Coronary Syndrome; Age Factors; Aged; Cardiovascular Diseases; Double-Blind Method; Female; Hemorrhage; Humans; Lactones; Male; Middle Aged; Myocardial Infarction; Myocardial Revascularization; Patient Readmission; Platelet Aggregation Inhibitors; Proportional Hazards Models; Pyridines; Randomized Controlled Trials as Topic; Recurrence; Stroke; Treatment Outcome

Vorapaxar is a novel protease-activated receptor-1 (PAR-1) antagonist recently approved for the reduction of thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. Patients who received vorapaxar in addition to standard of care antiplatelet therapy had an increased incidence of major bleeding events compared with placebo. To assess whether platelet transfusion can restore hemostasis in primates on triple antiplatelet therapy, template bleeding times were assessed concurrently in the buccal mucosa, finger pad, and distolateral tail of anesthetized cynomolgus macaques to evaluate bleeding with vorapaxar as either monotherapy or in combination with aspirin or aspirin and clopidogrel. Aspirin (5mg/kg, IV) or vorapaxar (1mg/kg, PO) alone had no significant effect on bleeding times in the three vascular beds examined. A modest (<2-fold) increase in bleeding time was achieved in the three beds with the dual combination of aspirin and vorapaxar. Major increases in bleeding time were achieved in the three beds with the triple combination of aspirin (5mg/kg, IV), vorapaxar (1mg/kg, PO), and clopidogrel (1mg/kg, PO). Transfusion of fresh human platelet rich plasma, but not platelet poor plasma, reversed the increase in bleeding time in the triple therapy group. Transfusion of human platelets may be a viable approach in situations requiring a rapid reversal of platelet function in individuals treated with triple anti-platelet therapy that includes vorapaxar.

Topics: Animals; Aspirin; Bleeding Time; Clopidogrel; Drug Therapy, Combination; Hemorrhage; Humans; Lactones; Macaca fascicularis; Platelet Aggregation Inhibitors; Platelet Transfusion; Pyridines; Receptors, Thrombin; Ticlopidine

Designing of smart clinical trials is critical for regulatory approval and future drug utilization. Importantly, trial design should be reconsidered if the interim analyses suggest unexpected harm, or conflicting results were yielded from the other trials within the same therapeutic area. With regard to antiplatelet agents, the perfect example is redesigning of the ongoing PRoFESS trial by eliminating aspirin from clopidogrel arm after the earlier MATCH trial results became available. The goal was to aseess the unchanged TRACER trial design in light of the evidence yielded from the earlier completed TRITON trial. TRACER was designed as a triple versus dual antiplatelet trial in NSTEMI patients with no previous long-term outcome data supporting such aggressive strategy. TRITON data represented dual versus dual antiplatelet therapy, and became available before TRACER enrollment starts revealing prasugrel front-loaded early vascular benefit predominantly in STEMI patients with the growing over time bleeding and cancer risks. Moreover, large prasugrel NSTEMI TRITON cohort exhibited trend towards excess mortality in experimental arm warning against aggressive TRACER design. The long-term TRITON results in general, and especially in the NSTEMI patients challenge unchanged TRACER trial design. Applying dual, rather than triple antiplatelet therapy protocol modification should be considered in TRACER to minimize bleeding, cancer, and non-cardiovascular death risks.

Topics: Acute Coronary Syndrome; Aspirin; Clinical Trials as Topic; Clopidogrel; Drug Evaluation; Drug Therapy, Combination; Hemorrhage; Humans; Lactones; Neoplasms; Platelet Aggregation Inhibitors; Prasugrel Hydrochloride; Pyridines; Research Design; Ticlopidine

Topics: Hemorrhage; Humans; Lactones; Myocardial Infarction; Patient Selection; Peripheral Arterial Disease; Platelet Aggregation Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Receptor, PAR-1; Thrombosis

Dual anti-platelet therapy (DAPT) with aspirin and a P2Y12 antagonist is standard of care to reduce risk of thrombosis, but does not directly target thrombin-dependent platelet activation. Therefore, PAR-1 antagonist addition to DAPT (i.e., triple anti-platelet therapy; TAPT) may improve the efficacy of treatment, though at the expense of an increase in bleeding risk. Using an in vitro transfusion model, we evaluated if platelet function loss associated with TAPT can be remedied by the addition of drug-naïve platelets.. To mimic TAPT, platelet-rich plasma (PRP) prepared from consented DAPT patients (DPRP) was incubated with a vorapaxar at therapeutic plasma levels (TPRP). To simulate platelet transfusions, TPRP was mixed with increasing proportions of drug-naïve PRP (NPRP). Platelet function recovery was assessed by light transmission aggregometry (LTA), aggregate morphology, and P-selectin expression.. LTA results demonstrated that 20% NPRP was required to restore the ADP aggregation response in TPRP to the response observed in DPRP and 40% NPRP recovered aggregation to >65%. Higher NPRP fractions (60%) were required to restore the platelet reactivity using TRAP-6 (SFLLRN) or arachidonic acid (AA). PAR-4 aggregation was unaffected by platelet antagonists. A decrease in single, free platelets and incorporation of mepacrine-labeled naïve platelets into aggregates occurred with increasing NPRP portions. Upon agonist activation, the surface density and percent of P-selectin positive platelets increased linearly upon addition of NPRP.. This in vitro model demonstrated that administration of drug-naïve platelets can be a useful strategy for reversing overall platelet inhibition observed with TAPT.

Topics: Apoptosis Regulatory Proteins; Arachidonic Acid; Aspirin; Blood Platelets; Blood Transfusion; Clopidogrel; Flow Cytometry; Hemorrhage; Humans; Lactones; P-Selectin; Peptide Fragments; Platelet Activation; Platelet Aggregation; Platelet Aggregation Inhibitors; Platelet Function Tests; Platelet Transfusion; Purinergic P2Y Receptor Antagonists; Pyridines; Receptors, Proteinase-Activated; Receptors, Purinergic P2Y12; Ticlopidine

Topics: Acute Coronary Syndrome; Clinical Trials Data Monitoring Committees; Drug Approval; Hemorrhage; Humans; Lactones; Plaque, Atherosclerotic; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Risk Assessment; United States

Emergency department physicians, along with hospitalists and interventional cardiologists, provide first-line care for patients experiencing symptoms potentially associated with acute coronary syndromes (ACS). Because these health care providers encounter and manage patients with varying degrees of risk, a clear understanding of the modes of action, benefits, and limitations of various therapeutic options is crucial for achieving optimal outcomes in the acute-care setting. Oral antiplatelet therapy has a major role in the acute care of patients with suspected ACS due to the critical role of platelets in the pathophysiology of disease. The current standard-of-care oral antiplatelet therapy for ACS is aspirin in combination with a P2Y12 adenosine diphosphate (ADP) receptor antagonist, most commonly clopidogrel. Aspirin and P2Y12 antagonists have both demonstrated efficacy in reducing morbidity and mortality in patients with ACS, but are also associated with increased bleeding risk compared with controls. Additionally, despite dual oral antiplatelet therapy, patients remain at substantial residual risk for ischemic events due to thrombotic episodes driven by platelet activation pathways that are not inhibited by these agents, including the protease-activated receptor (PAR)-1 platelet activation pathway, stimulated by thrombin. Novel oral antiplatelet agents in advanced clinical development include a direct and more readily reversible P2Y12 antagonist, ticagrelor, as well as a new class of PAR-1 antagonists, which includes vorapaxar and atopaxar. Ticagrelor has shown a significant ischemic benefit and an increase in non-surgical bleeding over clopidogrel in the large phase 3 Platelet Inhibition and Patient Outcomes trial. Results of phase 2 trials with PAR-1 antagonists suggest that these agents may provide incremental reduction in ischemic events without a bleeding liability. This hypothesis is being evaluated in 2 large ongoing phase 3 trials with vorapaxar, including the Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRA*CER) trial in patients with non-ST-segment elevation ACS.

Topics: Acute Coronary Syndrome; Adenosine; Administration, Oral; Aspirin; Cardiology; Clopidogrel; Drug Therapy, Combination; Emergency Medicine; Hemorrhage; Hospitalists; Humans; Imines; Lactones; Patient Selection; Platelet Aggregation Inhibitors; Practice Guidelines as Topic; Purinergic P2Y Receptor Antagonists; Pyridines; Receptor, PAR-1; Risk Factors; Ticagrelor; Ticlopidine; Treatment Outcome

Topics: Angioplasty, Balloon, Coronary; Clopidogrel; Coronary Artery Disease; Hemorrhage; Humans; Lactones; Platelet Aggregation Inhibitors; Pyridines; Randomized Controlled Trials as Topic; Receptors, Thrombin; Severity of Illness Index; Thrombin; Ticlopidine

Morbidity and mortality in patients with atherothrombotic disease remain high despite the use of antiplatelet therapy with aspirin and an ADP receptor antagonist. Selective inhibition of the principal protease-activated receptor (PAR)-1 for thrombin, the most potent agonist for platelet activation, represents a promising novel strategy to reduce thrombosis and ischaemic events. SCH 530348, a potent thrombin receptor antagonist (TRA) selective for PAR-1, has been evaluated in preclinical studies, demonstrating complete and sustained inhibition of thrombin/TRAP-induced platelet aggregation without a concomitant increase in the risk of bleeding. Phase 2 studies in patients undergoing non-urgent or urgent PCI showed that treatment with SCH 530348 in addition to the standard of care (aspirin plus an ADP receptor antagonist) is not associated with an increased risk of TIMI bleeding and is well tolerated, with a rate of adverse events comparable to standard therapy alone. These studies also demonstrated that the use of SCH 530348 in combination with aspirin and an ADP receptor antagonist may reduce the incidence of major adverse cardiac events, specifically periprocedural myocardial infarction, vs aspirin plus an ADP receptor antagonist alone. On the basis of these encouraging results, 2 ongoing large phase 3 randomized trials are evaluating the efficacy and safety of SCH 530348 in combination with the standard-of-care therapy in approximately 35,000 patients with NSTE ACS or established atherosclerosis.

Topics: Administration, Oral; Antithrombins; Atherosclerosis; Clinical Trials as Topic; Hemorrhage; Humans; Lactones; Platelet Aggregation Inhibitors; Pyridines; Receptors, Thrombin; Safety; Thrombin

Atherothrombotic disease is a leading public health problem. Although current antiplatelet agents, such as aspirin and adenosine diphosphate (ADP)-receptor antagonists, reduce the morbidity and mortality associated with atherothrombotic disease, the residual risk for ischemic events remains substantial. The high residual risk despite dual antiplatelet therapy can be attributed to the fact that platelets possess multiple pathways of activation that are not all inhibited by aspirin and ADP-receptor antagonists. Among these, binding of thrombin to the proteinase-activated receptor 1 (PAR(1)) is the most potent platelet activation pathway. In addition, the PAR(1) pathway does not appear to be essential for initiating hemostasis. Inhibition of the PAR(1) receptor thus offers a possible new therapeutic approach with a potentially improved benefit-to-risk profile for treatment of patients with atherothrombotic disease. Preclinical and clinical studies have confirmed that SCH 530348, a potent, orally active thrombin-receptor antagonist selective for PAR(1), does not increase bleeding liability when added to dual antiplatelet therapy. Currently, two large ongoing phase 3 clinical trials are evaluating the efficacy and safety of SCH 530348 in combination with the standard of care in patients with acute coronary syndromes as well as for secondary prevention in patients with previous history of atherothrombotic disease.

Topics: Animals; Atherosclerosis; Clinical Trials as Topic; Disease Models, Animal; Drug Therapy, Combination; Hemorrhage; Humans; Lactones; Platelet Aggregation Inhibitors; Pyridines; Receptor, PAR-1; Risk Factors; Thrombosis