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Background: The bleeding risk associated with direct oral anticoagulants (DOACs) remains a major concern, and rapid reversal of anticoagulant activity may be required. Although specific and nonspecific hemostatic biotherapies are available, there is a need for small-molecule DOAC reversal agents that are simple and cost-effective to produce, store, and administer., Objectives: To identify and characterize a small molecule with procoagulant activity as a DOAC reversal agent., Methods: We sought to identify a small procoagulant molecule by screening a chemical library with a plasma clotting assay. The selected molecule was assessed for its procoagulant properties and its ability to reverse the effects of the DOACs in a thrombin generation assay. Its activity as a DOAC reversal agent was also evaluated in a tail-clip bleeding assay in mice., Results: The hemostatic molecule (HeMo) dose-dependently promoted thrombin generation in plasma, with dose values effective in producing half-maximum response ranging between 3 and 5 μM, depending on the thrombin generation assay parameter considered. HeMo also restored impaired thrombin generation in DOAC-spiked plasma and reversed DOAC activity in the mouse bleeding model. HeMo significantly reduced apixaban-induced bleeding from 709 to 65 μL (vs 43 μL in controls; P  < .01) and dabigatran-induced bleeding from 989 to 155 μL (vs 126 μL in controls; P  < .01)., Conclusion: HeMo is a small-molecule procoagulant that can counterbalance hemostatic disruption by a thrombin inhibitor (dabigatran) or factor Xa inhibitors (apixaban and rivaroxaban). The compound's effective clot formation and versatility make it a possible option for managing the inherent hemorrhagic risk during DOAC therapy., (© 2024 The Authors.)

Direct oral factor Xa inhibitors are replacing vitamin K-dependent antagonists as anticoagulation treatment in many clinical scenarios. Trauma centers are noting an increase in patients presenting on these medications. The 2018 Food and Drug Administration approval of andexanet alfa provides an alternative anticoagulation reversal. Barriers may limit utilization of new medications including a lack of grade 1A evidence supporting the use of prothrombin complex concentrate (PCC) versus andexanet alfa and cost. To evaluate barriers of andexanet alfa utilization by trauma surgeons, a 15-question survey was conducted. There was a 9% completion rate (n = 89). The results revealed 23.5% would choose andexanet alfa as first-line treatment in children, and 25.8% as first-line treatment in adults. The majority of respondents, 64.7% and 67.4%, would use PCC preferentially in children and adults, respectively. Respondents indicated that cost burden was an overriding factor (76.3%); 42.4% cited lack of high-level efficacy data of andexanet alfa for reversal of factor Xa inhibitors. Additional double-blinded multi-institutional randomized controlled trials comparing 4F-PCC and andexanet alfa for factor Xa inhibitor reversal are needed to support efficacy especially with the increased cost associated., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Patients taking direct oral anticoagulants (DOACs) who then need an emergency invasive procedure require specialized management strategies. Appropriate patient evaluation includes assessment of the current anticoagulation state, including timing of the last dose. DOACs require particular coagulation assays to measure anticoagulation levels accurately, although standard coagulation screening tests may provide qualitative guidance. Specialty societies have endorsed general recommendations for patient management to promote hemostasis in anticoagulated patients requiring surgery or other invasive procedures. These include general stopping rules (such as ≥ 24 hours for low-risk procedures and ≥ 48 hours for high-risk surgery with normal renal function) for elective procedures. Bridging therapy when oral anticoagulant treatment is interrupted has recently been questioned, depending on the clinical scenario. Novel agents for the reversal of DOAC-induced anticoagulation have recently been developed. Idarucizumab, a humanized monoclonal antibody fragment that selectively binds dabigatran, was recently approved for clinical use in patients with life-threatening or uncontrolled bleeding, and for patients requiring emergency interventions. Idarucizumab can streamline the pre- and periprocedural anticoagulation management of dabigatran-treated patients, as it provides fast, complete, and sustainable reversibility. Andexanet alfa is an inactive, decoy factor Xa (FXa) molecule that binds FXa inhibitors, and ciraparantag is a synthetic molecule designed to bind fractionated and unfractionated heparins, and each of the currently approved DOACs. As clinical development of the additional anti-FXa-specific anticoagulant reversal agents proceeds, the respective role of each in the management of emergency bleeding events and invasive procedures will be better defined, and it is hoped they will make important contributions to patient care. [ABSTRACT FROM AUTHOR]

The direct oral anticoagulants (DOACs) provide a number of clinical advantages over vitamin K antagonists for the treatment of thromboembolism, including improved efficacy and safety, as well as no need for regular monitoring of anticoagulant effect. However, as with all anticoagulants, bleeding complications may occur, and anticoagulant reversal may be required in specific clinical situations, such as in patients experiencing spontaneous or traumatic bleeds, or in anticoagulated patients requiring emergency surgery or other invasive procedures. Therefore, several reversal agents for the DOACs are in development. This includes the specific reversal agent idarucizumab, which has been approved by the U.S. Food and Drug Administration and the European Medicines Agency for use in patients treated with dabigatran when urgent reversal of its anticoagulant effects is needed. Idarucizumab is a humanized monoclonal antibody fragment that binds with high affinity to free and thrombin-bound dabigatran, resulting in an almost irreversibly bound idarucizumabedabigatran complex and thereby neutralizing dabigatran's anticoagulant activity. The reversal of the anticoagulant effects of dabigatran by idarucizumab has been demonstrated in animal bleeding models, in healthy volunteers with a range of ages and renal function, and in anticoagulated patients. In the phase 1 trials, at doses of 2 g or greater, idarucizumab resulted in immediate and complete reversal of the dabigatran anticoagulant effects and was well tolerated. In the absence of dabigatran, idarucizumab showed no effect on coagulation parameters or thrombin formation. These findings provide initial evidence that idarucizumab could provide a safe and effective means of reversing anticoagulant activity in patients treated with dabigatran in need of emergency surgery or in emergency bleeding situations. [ABSTRACT FROM AUTHOR]

Bleeding is the commonest and most concerning adverse event associated with anticoagulants. Bleeding, depending on the severity, is managed in various ways, and for severe or life-threatening bleeding, specific antidotes are indicated and recommended. This review provides guidance relating to specific direct oral anticoagulant (DOAC) reversal agents, the antidotes. We discuss their indications for use, dosing, and potential side effects., Competing Interests: Conflicts of interest ATC has received research support from Alexion Pharmaceuticals, Bayer, Boehringer Ingelheim, Bristol-Myers-Squibb, Daiichi-Sankyo, Johnson & Johnson, Pfizer, Portola Pharmaceuticals, and Sanofi. He has received consultancy fees and/or honoraria from Abbott, AbbVie, ACI Clinical, Alexion Pharmaceuticals, Aplagon, Aspen, Bayer, Boehringer Ingelheim, Boston Scientific, Bristol-Myers Squibb, BTG, Daiichi-Sankyo, EmstoPA Ltd, EPG Health, GLG, Guidepoint Global Gulf Coast Developments, Janssen, Johnson & Johnson, JP Morgan, Leo Pharma, Lifesciences Consulting, McKinsey, Medscape, Navigant, Northstar Communications, Ono, Pfizer, Portola Pharmaceuticals, Sanofi, Temasak Capital, Total CME, TRN, and Windrose Consulting Group. KW and UF: none declared., (Copyright © 2022 Medinews (Cardiology) Limited.)

The main advantage of the direct oral anticoagulants over vitamin K antagonists is reduced rates of major bleeding, especially intracranial hemorrhage. While use of different clotting factor supplements have been used in patients with direct oral anticoagulant induced major bleeding or when there is need for urgent surgery, the lack of preclinical and clinical data are concerning. Idarucizumab is a specific antibody developed with a 350-fold greater affinity for dabigatran than its pharmacologic target thrombin. Andexanet is a modified factor Xa molecule that binds the direct and indirect Xa inhibitors without being enzymatically active. Ciraparantag, has potential to reverse the anticoagulant activity of multiple agents. The pharmacology, preclinical, and clinical data that have developed these specific antidotes are reviewed in this manuscript. [ABSTRACT FROM AUTHOR]