Clinical Trials of Direct Thrombin Inhibitors in Acute Ischaemic Syndromes

1997 ◽  
Vol 78 (01) ◽  
pp. 364-366 ◽  
Author(s):  
Harvey D White
1997 ◽  
Vol 78 (01) ◽  
pp. 367-376 ◽  
Author(s):  
Jean-Paul R Hermann ◽  
Michael J B Kutryk ◽  
Patrick W Serruys

Hematology ◽  
2004 ◽  
Vol 2004 (1) ◽  
pp. 424-438 ◽  
Author(s):  
Jeffrey I. Weitz ◽  
Saskia Middeldorp ◽  
William Geerts ◽  
John A. Heit

Abstract Venous thromboembolism, which includes deep vein thrombosis and pulmonary embolism, is the result of an imbalance among procoagulant, anticoagulant and profibrinolytic processes. This imbalance reflects a complex interplay between genetic and environmental or acquired risk factors. Genetic thrombophilic defects influence the risk of a first episode of thrombosis. How these defects influence the risk of recurrence in patients whose first episode of venous thromboembolism was unprovoked is less certain. Thus, when anticoagulants are stopped, patients with unprovoked venous thromboembolism have a risk of recurrence of at least 7% to 10% per year, even in the absence of an underlying thrombophilic defect. Consequently, there is a trend toward longer durations of anticoagulation therapy for these patients, which is problematic given the limitation of existing anticoagulants. This chapter provides an overview of the thrombophilic defects and how they influence the risk of venous thromboembolism. The chapter also details advances in anticoagulant therapy, focusing on new inhibitors of factor Xa and thrombin. In Section I, Dr. Saskia Middeldorp describes the various thrombophilic defects and reviews their relative importance in the pathogenesis of a first episode of venous thromboembolism. She then discusses the influence of these defects on the risk of recurrent thrombotic events in patients with unprovoked venous thromboembolism and in those whose thrombosis occurred in association with a known risk factor, such as surgery. In Section II, Dr. William Geerts reviews the pharmacology of new parenteral and oral factor Xa inhibitors and describes the results of the Phase II and III clinical trials with these agents. He then provides perspective on the potential advantages and drawbacks of these drugs for the prevention and treatment of venous thromboembolism. In Section III, Dr. John Heit focuses on direct thrombin inhibitors. He discusses their mechanism of action and compares and contrasts their pharmacological profiles prior to describing the results of Phase II and III clinical trials. Dr. Heit then provides perspective on the potential advantages and limitations of these drugs relative to existing anticoagulants.


Hematology ◽  
2008 ◽  
Vol 2008 (1) ◽  
pp. 245-250 ◽  
Author(s):  
Guy Young

AbstractThromboembolic complications are increasing in children and the use of anticoagulation has seen a dramatic increase despite the lack of randomized clinical trials. The most widely used agents in children are heparin, low-molecular-weight heparins (LMWH), and warfarin. These agents, however, have significant limitations that are exaggerated in children. Novel anticoagulants such as direct thrombin inhibitors and the selective factor Xa inhibitor, fondaparinux, have been approved for use in adults and have properties that suggest they may be safer and more efficacious than the standard agents; however, until recently, publications using these agents in children were limited to case reports. Recently, clinical trials for two direct thrombin inhibitors, bivalirudin and argatroban, have been completed and a clinical trial of fondaparinux is under way. This review will compare the standard agents with the novel agents and briefly review the results of the clinical trials.


2010 ◽  
Vol 30 (04) ◽  
pp. 212-216 ◽  
Author(s):  
R. Jovic ◽  
M. Hollenstein ◽  
P. Degiacomi ◽  
M. Gautschi ◽  
A. Ferrández ◽  
...  

SummaryThe activated partial thromboplastin time test (aPTT) represents one of the most commonly used diagnostic tools in order to monitor patients undergoing heparin therapy. Expression of aPTT coagulation time in seconds represents common practice in order to evaluate the integrity of the coagulation cascade. The prolongation of the aPTT thus can indicate whether or not the heparin level is likely to be within therapeutic range. Unfortunately aPTT results are highly variable depending on patient properties, manufacturer, different reagents and instruments among others but most importantly aPTT’s dose response curve to heparin often lacks linearity. Furthermore, aPTT assays are insensitive to drugs such as, for example, low molecular weight heparin (LMWH) and direct factor Xa (FXa) inhibitors among others. On the other hand, the protrombinase-induced clotting time assay (PiCT®) has been show to be a reliable functional assay sensitive to all heparinoids as well as direct thrombin inhibitors (DTIs). So far, the commercially available PiCT assay (Pefakit®-PiCT®, DSM Nutritional Products Ltd. Branch Pentapharm, Basel, Switzerland) is designed to express results in terms of units with the help of specific calibrators, while aPTT results are most commonly expressed as coagulation time in seconds. In this report, we describe the results of a pilot study indicating that the Pefakit PiCT UC assay is superior to the aPTT for the efficient monitoring of patients undergoing UFH therapy; it is also suitable to determine and quantitate the effect of LMWH therapy. This indicates a distinct benefit when using this new approach over the use of aPPT for heparin monitoring.


Sign in / Sign up

Export Citation Format

Share Document