Andexanet Alfa, the Possible Alternative to Protamine for Reversal of Unfractionated Heparin

2020 ◽  
Vol 55 (2) ◽  
pp. 261-264
Author(s):  
John N. Maneno ◽  
Genevieve Lynn Ness
Keyword(s):  
Unfractionated Heparin ◽  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Hospital Setting ◽  
Factor Xa ◽  
Thrombin Inhibitors ◽  
Thrombin Time ◽  
Reversal Agent

The recent shortage of protamine prompted an investigation of alternatives for reversal of unfractionated heparin. Heparin is an anticoagulant utilized in the hospital setting. Available options for anticoagulation include direct oral anticoagulants, vitamin K antagonists, thrombin inhibitors, low-molecular-weight heparins, and heparin. Protamine is the approved reversal agent for heparin with few alternatives under investigation. Although andexanet was designed as an antidote for apixaban and rivaroxaban, in vitro studies show that in a dose-dependent technique, andexanet had near full reversal of heparin, reversed anti–factor Xa activity, and neutralized anticoagulant effects of activated partial thromboplastin time and thrombin time induced by heparin.

scholarly journals Direct oral anticoagulants and venous thromboembolism

2016 ◽  
Vol 25 (141) ◽  
pp. 295-302 ◽  
Author(s):  
Massimo Franchini ◽  
Pier Mannuccio Mannucci
Keyword(s):  
Venous Thromboembolism ◽  
Vitamin K Antagonists ◽  
Dabigatran Etexilate ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Factor Xa ◽  
Thrombin Inhibitors ◽  
Vein Thrombosis ◽  
Direct Anticoagulants ◽  
Deep Vein

Venous thromboembolism (VTE), consisting of deep vein thrombosis and pulmonary embolism, is a major clinical concern associated with significant morbidity and mortality. The cornerstone of management of VTE is anticoagulation, and traditional anticoagulants include parenteral heparins and oral vitamin K antagonists. Recently, new oral anticoagulant drugs have been developed and licensed, including direct factor Xa inhibitors (e.g. rivaroxaban, apixaban and edoxaban) and thrombin inhibitors (e.g. dabigatran etexilate). This narrative review focusses on the characteristics of these direct anticoagulants and the main results of published clinical studies on their use in the prevention and treatment of VTE.

scholarly journals Applied Nanotechnologies in Anticoagulant Therapy: From Anticoagulants to Coagulation Test Performance of Drug Delivery Systems

Applied Nano ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 98-117
Author(s):  
Yuri B. G. Patriota ◽  
Luíse L. Chaves ◽  
Evren H. Gocke ◽  
Patricia Severino ◽  
Mônica F. R. Soares ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Anticoagulant Therapy ◽  
Test Performance ◽  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Delivery Systems ◽  
Reversal Agent ◽  
Laboratory Assessment ◽  
Administration Routes

Heparin-based delivery systems have been explored to improve their therapeutic efficacy and to reduce toxicity for different administration routes. Regardless of the applied drug delivery system (DDS), the evaluation of anticoagulant performance is instrumental for the development of a suitable DDS. The understanding of the range of anticoagulant assays, together with their key applications and limitations, is essential both within the context of scientific research and for clinical usage. This review provides an overview of the current anticoagulant therapy and discusses the advantages and limitations of currently available anticoagulant assays. We also discuss studies involving low-molecular-weight heparin (LMWH)-based nanocarriers with emphasis on their anticoagulation performance. Conventional anticoagulants have been used for decades for the treatment of many diseases. Direct oral anticoagulants have overcome some limitations of heparins and vitamin K antagonists. However, the lack of an accurate laboratory assessment, as well as the lack of a factor “xaban” (Xa) inhibitor reversal agent, remains a major problem associated with these anticoagulants. LMWHs represent anticoagulant agents with noteworthy efficacy and safety, and they have been explored to improve their outcomes with various nanocarriers through several administration routes. The main problems related to LMWHs have been surmounted, and improved efficiency may be achieved through the use of DDSs.

scholarly journals Heparin is more effective than apixaban in inhibiting in vitro contact activated coagulation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M.M Engelen ◽  
C Van Laer ◽  
M Jacquemin ◽  
C Vandenbriele ◽  
K Peerlinck ◽  
...  
Keyword(s):  
Thrombin Generation ◽  
Heart Valves ◽  
Thrombus Formation ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Mechanical Heart Valves ◽  
Contact Activation

Abstract Introduction Contact of blood with artificial surfaces such as mechanical support devices, catheters, and mechanical heart valves activates the contact activation (CA) pathway of coagulation. Furthermore, recent animal data and clinical studies suggest a more important contribution of CA in pathological thrombus formation in other cardiovascular diseases. Direct oral anticoagulants (DOACs) are recommended as first-line treatment in most patients who require long-term anticoagulation. However, because DOACs directly inhibit a single downstream coagulation factor (thrombin (fXIIa) or factor Xa (fXa)), it has been suggested that their efficacy could be reduced in the presence of strong activation of the CA pathway as compared to anticoagulants that target multiple, more upstream located coagulation factors. Purpose To compare the efficacy of a DOAC (apixaban) and heparin to suppress thrombin generation in the presence of strong CA pathway activation. Methods Pooled platelet-poor plasma was spiked with either apixaban (dissolved in DMSO and PBS) or unfractionated heparin to achieve therapeutic plasma levels. SynthASil, a commercially available mixture of phospholipids and silica, was used to stimulate the CA pathway in two different dilutions (1–80 and 5–80). Downstream coagulation was accessed by Thrombin Generation Test using Thrombinoscope by Stago and associated Thrombin Calibrator (activity 640 nM). The endogenous thrombin potential (area under the thrombin generation curve; ETP), peak thrombin generation (PTG), time to peak (ttPeak) and time to start (ttStart) were accessed. Results With decreasing concentrations of apixaban, stimulation with the lower dose SynthASil reveals an increasing ETP and PTG. As expected, ttPeak and ttStart decreased. Even supratherapeutic levels of apixaban (i.e. 1120 ng/mL) could not inhibit thrombin from being generated, in striking contrast with UFH where no thrombin was formed. Using a five times higher dose of SynthASil showed comparable ETP for all concentrations of apixaban, allocated around the control value. PTG, however, slightly increased with decreasing concentrations of apixaban. ttPeak and ttStart slightly decreased. Except for the subtherapeutic UFH concentration of 0,114 IU/mL, no thrombin was generated with UFH. Conclusion UFH is more effective in inhibiting downstream thrombin generation compared to apixaban as a response to activation of the CA pathway in vitro. These findings could help explain why direct inhibitors were not able to show non-inferiority in patients with mechanical heart valves and support the development of specific CA pathway inhibitors for patients with conditions that activate the CA pathway. Thrombin generation curves Funding Acknowledgement Type of funding source: None

scholarly journals Reversal Strategies for Intracranial Hemorrhage Related to Direct Oral Anticoagulant Medications

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Alok Dabi ◽  
Aristides P. Koutrouvelis
Keyword(s):  
Side Effects ◽  
Intracranial Hemorrhage ◽  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Factor Xa ◽  
Coagulation Cascade ◽  
Reversal Agents ◽  
United States Food ◽  
Life Threatening

Direct oral anticoagulants (DOACs) are a new class of anticoagulants that directly inhibit either thrombin or factor Xa in the coagulation cascade. They are being increasingly used instead of warfarin or other vitamin K antagonists (VKAs). Adverse side effects of DOACs may result in hemorrhagic complications, including life-threatening intracranial hemorrhage (ICH), though to a much lesser degree than VKAs. Currently there are relatively limited indications for DOACS but their usage is certain to expand with the availability of their respective specific reversal agents. Currently, only idarucizumab (antidote for dabigatran) has been United States Food and Drug Administration- (FDA-) approved, but others (andexanet-α and ciraparantag) may be approved in near future, and the development and availability of such reversal agents have the potential to dramatically change the current anticoagulant use by providing reversal of multiple oral anticoagulants. Until all the DOACs have FDA-approved reversal agents, the treatment of the dreaded side effects of bleeding is challenging. This article is an attempt to provide an overview of the management of hemorrhage, especially ICH, related to DOAC use.

scholarly journals The Severity of Intracranial Hemorrhages Measured by Free Hemoglobin in the Brain Depends on the Anticoagulant Class: Experimental Data

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Kyle M. Ware ◽  
Douglas L. Feinstein ◽  
Israel Rubinstein ◽  
Prudhvi Battula ◽  
Jose Otero ◽  
...  
Keyword(s):  
Vitamin K ◽  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Factor Xa ◽  
Hemoglobin Concentration ◽  
Thrombin Inhibitor ◽  
Free Hemoglobin ◽  
Intracranial Hemorrhages ◽  
The Brain

Background and Purpose. Anticoagulant therapy is broadly used to prevent thromboembolic events. Intracranial hemorrhages are serious complications of anticoagulation, especially with warfarin. Direct oral anticoagulants reduce but do not eliminate the risk of intracranial hemorrhages. The aim of this study is to determine the degree of intracranial hemorrhage after application of anticoagulants without additional triggers. Methods. Rats were treated with different anticoagulant classes (vitamin K antagonists, heparin, direct thrombin inhibitor, and factor Xa inhibitor). Brain hemorrhages were assessed by the free hemoglobin concentration in the brain parenchyma. Results. Vitamin K antagonists (warfarin and brodifacoum) significantly increased free hemoglobin in the brain. Among direct oral anticoagulants, thrombin inhibitor dabigatran also significantly increased free hemoglobin in the brain, whereas treatment with factor Xa inhibitor rivaroxaban did not have significant effect on the free hemoglobin concentration. Conclusions. Our data indicates that the severity of brain hemorrhages depends on the anticoagulant class and it is more pronounced with vitamin K antagonists.

scholarly journals Update on Edoxaban for the Prevention and Treatment of Thromboembolism: Clinical Applications Based on Current Evidence

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Ali Zalpour ◽  
Thein Hlaing Oo
Keyword(s):  
Vitamin K Antagonists ◽  
Dabigatran Etexilate ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Factor Xa ◽  
Coagulation Factors ◽  
Current Evidence ◽  
Thrombin Inhibitor ◽  
Prevention And Treatment ◽  
Financial Impacts

Vitamin K antagonists (VKA) and heparins have been utilized for the prevention and treatment of thromboembolism (arterial and venous) for decades. Targeting and inhibiting specific coagulation factors have led to new discoveries in the pharmacotherapy of thromboembolism management. These targeted anticoagulants are known as direct oral anticoagulants (DOACs). Two pharmacologically distinct classes of targeted agents are dabigatran etexilate (Direct Thrombin Inhibitor (DTI)) and rivaroxaban, apixaban, and edoxaban (direct oral factor Xa inhibitors (OFXaIs)). Emerging evidence from the clinical trials has shown that DOACs are noninferior to VKA or low-molecular-weight heparins in the prevention and treatment of thromboembolism. This review examines the role of edoxaban, a recently approved OFXaI, in the prevention and treatment of thromboembolism based on the available published literature. The management of edoxaban in the perioperative setting, reversibility in bleeding cases, its role in cancer patients, the relevance of drug-drug interactions, patient satisfaction, financial impacts, and patient education will be discussed.

scholarly journals Direct oral anticoagulant monitoring: what laboratory tests are available to guide us?

Hematology ◽  
2019 ◽  
Vol 2019 (1) ◽  
pp. 194-197 ◽  
Author(s):  
Ravi Sarode
Keyword(s):  
Clinical Decision Making ◽  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Rapid Assessment ◽  
Clinical Decision ◽  
The United States ◽  
Thrombin Inhibitor ◽  
Thrombin Time ◽  
Clinical Scenarios

Abstract Direct oral anticoagulants (DOACs) are increasingly used in the treatment and prophylaxis of thromboembolism because of several advantages over vitamin K antagonists, including no need for laboratory monitoring. However, it has become increasingly important in certain clinical scenarios to know either actual DOAC concentration (quantitative) or presence of DOAC (qualitative). These clinical conditions include patients presenting with major bleeding or requiring urgent surgery who may need a reversal or hemostatic agent, extremes of body weight, failed therapy, etc. Prothrombin time and activated partial thromboplastin time are variably affected by factor Xa inhibitors (FXaIs) and direct thrombin inhibitor (DTI), respectively, depending on reagents’ sensitivity, and hence, they cannot be relied on confidently. Thrombin time is highly sensitive to very low amounts of DTI; thus, normal value rules out a clinically significant amount. Liquid chromatography mass spectrometry accurately measures DOAC levels but is clinically impractical. Dilute thrombin time and ecarin-based assays using appropriate calibrators/controls provide an accurate DTI level. Anti-Xa assay using corresponding FXaI calibrators/controls provides accurate drug levels. However, these assays are not readily available in the United States compared with some other parts of the world. Heparin assays using anti-Xa activity often have a linear relationship with calibrated FXaI assays, especially at the lower end of on-therapy levels, and they may provide rapid assessment of drug activity for clinical decision making. Currently, there is very limited knowledge of DOAC effect on viscoelastic measurements. Although there is uniformity in expression of DOAC concentrations in nanograms per milliliter, a universal FXaI DOAC assay is urgently needed.

Old and new anticoagulants

2011 ◽  
Vol 31 (01) ◽  
pp. 21-27 ◽  
Author(s):  
U. Harbrecht
Keyword(s):  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Factor Xa ◽  
New Oral Anticoagulants ◽  
Thrombin Inhibitors ◽  
Clotting Factor ◽  
Direct Thrombin Inhibitors ◽  
Self Monitoring ◽  
New Anticoagulants ◽  
Gastrointestinal Side Effects

SummaryVitamin-K-antagonists (VKA) and heparins have been complementary anticoagulants for prevention and treatment of thrombosis for almost 70 years. In contrast to heparins, VKA have not been modified pharmacologically, however treatment surveillance has improved by introducing INR and self-monitoring/management. Disclosure of the molecular basis of interaction with VKORC1, the target enzyme of VKA, has helped to better understand coumarin sensitivity and resistance. New oral anticoagulants have now been approved and stimulated expectations in patients and physicians to get rid of the burdening frequent controls of VKA without loss of efficacy and safety.This review will summarize the development and profile of the new substances. Main difference compared to VKA is their direct mode of action against one clotting factor which is factor IIa in dabigatran and factor Xa in rivaroxaban and other “xabanes” currently under intensive investigation. Half lifes of the new anticoagulants are much shorter than that of the mainly used coumarins (phenprocoumon, warfarin), making “anticoagulation bridging” unnecessary before surgery. Therapeutic width of direct thrombin inhibitors and factor Xa inhibitors is broader and they are given at fixed doses. Clinical studies in thromboprophylaxis, thromboembolism and atrial fibrillation indicate at least non-inferiority or even superior efficacy compared with enoxaparin and VKA at comparable safety outcomes. Limitations of the new substances may arise from gastrointestinal side effects, mode of metabolism and route of elimination. Specific antidots are not available for none of them.Undoubtedly, the new oral anticoagulants are very promising. But, although thousands of study patients already have been treated, there are questions to be answered such as treatment adherence in absence of monitoring, safety and efficacy in risk patients, dosage adjustment and interactions with other drugs, before conclusions can be drawn towards their potential to replace VKA.

New anticoagulants – towards the development of an "ideal" anticoagulant

VASA ◽  
2009 ◽  
Vol 38 (1) ◽  
pp. 13-29 ◽  
Author(s):  
Haas
Keyword(s):  
Unfractionated Heparin ◽  
Vitamin K Antagonists ◽  
Dabigatran Etexilate ◽  
Factor Xa ◽  
Rapid Onset ◽  
Factor Ix ◽  
Thrombin Inhibitors ◽  
Therapeutic Monitoring ◽  
Direct Thrombin Inhibitors ◽  
Onset Of Action

Currently available anticoagulants, such as unfractionated heparin, low molecular weight heparins and vitamin K antagonists, have proved effective in the prevention and treatment of thromboembolic disorders. However, these drugs have some drawbacks, such as unpredictability (in the case of unfractionated heparin), non-specificity and parenteral mode of administration, which limit their use in the clinical setting. There is a need for new agents with efficacy similar to that of these classes of anticoagulants and none of their associated drawbacks. Advances are being made in the development of more convenient and more specific drugs, with the aim to improve substantially the prevention and management of thromboembolic disorders. This review will emphasize how the development of an ideal anticoagulant, with potential benefits including high efficacy, safety, low levels of bleeding, fixed dosing, rapid onset of action, ability to bind clot-bound coagulation factors and no requirement for therapeutic monitoring, is a considerable challenge. This review will present the most relevant preclinical data, as well as the clinical studies performed to date, for several drug classes. Direct thrombin inhibitors, such as dabigatran etexilate, will be reviewed, as well as indirect (fondaparinux and idraparinux) and direct (rivaroxaban, apixaban, among others) Factor Xa inhibitors, Factor IXa inhibitors and monoclonal antibodies against Factor IX/IXa.

Heparin induced thrombocytopenia

2015 ◽  
Vol 35 (04) ◽  
pp. 372-375 ◽  
Author(s):  
N. A. Viniou ◽  
P. Diamantopoulos ◽  
J. Barbetseas ◽  
E. A. Sanidas
Keyword(s):  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Treatment Options ◽  
Factor Xa ◽  
Additional Treatment ◽  
Thrombin Inhibitors ◽  
Factor Xa Inhibitors ◽  
Clinical Aspects ◽  
Heparin Induced Thrombocytopenia

SummaryHeparin induced thrombocytopenia (HIT) is a prothrombotic syndrome initiated by platelet-activating auto-antibodies with potentially devastating complications. Once the diagnosis of HIT is suspected, discontinuation of heparin and treatment with an alternative anticoagulant are mandatory. While established drugs for HIT are no longer available, parenteral factor Xa inhibitors, thrombin inhibitors and perhaps the direct oral anticoagulants provide additional treatment options. The aim of this review was to highlight the current clinical aspects regarding HIT focusing on the role of novel medications.

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