rivaroxaban and vorapaxar

The role of anticoagulants and antiplatelet agents in tumour growth and prognosis is not new, and currently under intense investigation. Some randomised data strongly suggest that this association exists, but it is complex, and not necessarily pointed at the same direction. The potential mechanisms responsible for such harmful association include a direct hazard of novel antithrombotics on cancer, indirect promotion of tumour growth, easier metastatic dissemination due to instability of platelet-tumour cell aggregates, or/and inability to keep cancer cells locally in situ are considered. The latest randomised evidence ultimately rejected the drug-specific cancer risks, clearly indicating the class-effect. In lay terms "cancers follow bleeding", which seems to be true for antithrombotic agents in general. Significant excess of solid cancers which was similar after prasugrel in TRITON, and with vorapaxar in TRACER trials was confirmed by the FDA reviews. Later, extra cancer deaths reported following clopidogrel and prasugrel in DAPT, and after ticagrelor in PEGASUS are also of concern. However, there are remaining controversies with regard to published cancer risks after ticagrelor (PLATO), or another vorapaxar trial (TRA2P), while full disclosure of separate clopidogrel and prasugrel cancer data in DAPT is still lacking. In short, if we apply moderate antiplatelet strategies for over two years, or aggressive regimens including triple therapy for much less than one year, the solid cancer risks emerge. Currently, more delicate platelet inhibition, and shorter exposure to dual oral antiplatelet agents should prevail.

Topics: Adenosine; Animals; Anticarcinogenic Agents; Aspirin; Blood Platelets; Carcinogenicity Tests; Clopidogrel; Colonic Neoplasms; Drug Therapy, Combination; Female; Humans; Lactones; Male; Mice; Multicenter Studies as Topic; Neoplasm Metastasis; Neoplasms; Neoplasms, Experimental; Neoplastic Cells, Circulating; Platelet Aggregation Inhibitors; Prasugrel Hydrochloride; Pyridines; Randomized Controlled Trials as Topic; Rivaroxaban; Sex Factors; Species Specificity; Ticagrelor; Ticlopidine; Time Factors

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

Acute coronary syndrome (ACS) encompasses acute myocardial infarction (MI) and unstable angina. Activation of platelets and coagulation cascade plays a central role in the development of ACS. Over the past decade, there have been substantial improvements in the strategies for secondary prevention of ACS, including the development of more potent oral antiplatelet agents such as prasugrel and ticagrelor. However, therapies with even better efficacy and safety profiles and more rapid onset and offset of action would be desirable.. This review discusses the advantages and disadvantages of the currently available antithrombotic agents and describes the findings from recent clinical trials of three novel agents; cangrelor (an intravenous P2Y12 receptor antagonist), vorapaxar (protease-activated receptor-1 inhibitor) and rivaroxaban (an oral factor Xa inhibitor).. Cangrelor appears more promising than clopidogrel when a very rapid onset and reversal of antiplatelet effect is needed. Vorapaxar in addition to standard oral antiplatelet therapy was effective in patients with prior MI, but was not safe in patients with a prior stroke. Low dose rivaroxaban decreased cardiovascular events and mortality in patients post-ACS compared to placebo, although bleeding was increased.

Topics: Acute Coronary Syndrome; Adenosine Monophosphate; Fibrinolytic Agents; Humans; Lactones; Morpholines; Platelet Aggregation Inhibitors; Pyridines; Rivaroxaban; Thiophenes

In addition to its central role in coagulation, thrombin is involved in non-hemostatic activities such as inflammation. Direct inhibition of thrombin activity (e.g. with dabigatran) or reducing its generation by inhibition of Factor Xa (e.g. with rivaroxaban) may therefore have anti-inflammatory effects.. Microarray experiments were performed to identify transcriptome-wide changes in mRNA expression levels induced by thrombin in the presence and absence of the PAR-1 antagonist vorapaxar in primary human umbilical vein endothelial cells (HUVECs). On this basis, HUVECs were incubated with recalcified plasma, with or without rivaroxaban (0.3-3000nM), dabigatran (0.3-10,000nM), or vorapaxar (0.3-10nM). Expression levels of preselected pro-inflammatory genes were quantified by real-time PCR.. Vorapaxar abolished 67 of the 69 transcripts altered by more than twofold on addition of thrombin to HUVECs. ELAM-1, VCAM-1, ICAM-1, MCP-1, IL-8, CXCL1, and CXCL2 were among the genes most strongly induced by thrombin. Inflammatory gene expression after stimulation of thrombin generation was concentration-dependently suppressed by vorapaxar, dabigatran, and rivaroxaban. However, dabigatran at low concentrations (3-300nM) increased significantly the expression levels of CXCL1, CXCL2, IL-8, ELAM-1, MCP-1, and tissue factor.. In HUVECs, plasma-induced transcriptional changes are mediated by thrombin-induced PAR-1 activation. Rivaroxaban downregulated the expression of pro-inflammatory markers and tissue factor to a similar extent to dabigatran.

Topics: Antithrombins; Dabigatran; Endothelial Cells; Factor Xa Inhibitors; Human Umbilical Vein Endothelial Cells; Humans; Inflammation; Lactones; Pyridines; Receptor, PAR-1; Rivaroxaban; Thrombin; Transcriptome

Several key reports from the American Heart Association meeting, held in Orlando (FL, USA) in November 2011, are presented related to anti-thrombotic therapy in acute coronary syndrome and the use of dronedarone in permanent atrial fibrillation is discussed in this brief (and selective) overview of this meeting. A summary of the ATLAS-TIMI-51, TRACER and PALLAS trials is provided.

Topics: Acute Coronary Syndrome; American Heart Association; Amiodarone; Anti-Arrhythmia Agents; Anticoagulants; Atrial Fibrillation; Clinical Trials as Topic; Dronedarone; Fibrinolytic Agents; Humans; Lactones; Morpholines; Pyrazoles; Pyridines; Pyridones; Rivaroxaban; Thiophenes; Treatment Outcome; United States; Venous Thromboembolism