Andexanet alfa for reversal of factor Xa inhibitors: a critical review of the evidence

2019 ◽  
Vol 15 (6) ◽  
pp. 395-404
Author(s):  
Jameel Abdulrehman ◽  
John W Eikelboom ◽  
Deborah M Siegal
Keyword(s):  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Factor Xa ◽  
Factor Xa Inhibitors ◽  
Activity Levels ◽  
Reversal Agents ◽  
Life Threatening ◽  
Andexanet Alfa ◽  
Anticoagulated Patients

Direct oral anticoagulants are associated with lower rates of bleeding than vitamin K antagonists, but life-threatening bleeding still occurs. Andexanet alfa is a catalytically inactive recombinant modified human factor Xa molecule that reverses the anticoagulant effect of direct and indirect acting factor Xa inhibitors. In the ANNEXA-4 study, treatment with andexanet was associated with a 92% reduction in median anti-Xa activity levels and excellent or good hemostasis in 82% of patients presenting with serious bleeding while receiving apixaban or rivaroxaban. In this review, we discuss the burden of bleeding in anticoagulated patients and the need for reversal agents, review the mechanism of action of andexanet and critically evaluate the evidence for its efficacy and safety.

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.

A Review on the Use of Reversal Agents of Direct Oral Anticogulant Drugs in Case of Gastrointestinal Bleeding

2020 ◽  
Vol 15 ◽  
Author(s):  
Veronica Ojetti ◽  
Angela Saviano ◽  
Mattia Brigida ◽  
Luisa Saviano ◽  
Alessio Migneco ◽  
...  
Keyword(s):  
Gastrointestinal Bleeding ◽  
Major Bleeding ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Medical Emergency ◽  
Management Approach ◽  
Emergency Setting ◽  
Reversal Agents ◽  
Life Threatening ◽  
Andexanet Alfa

Background : Major bleeding is a life-threatening condition and a medical emergency with high mortality risk. It is often the complication of anticoagulant’s intake. Anticoagulants are commonly used for the prevention and the treatment of thrombotic events. The standard therapy with vitamin K antagonist (warfarin) has been frequently replaced by direct oral anticoagulants (DOACs). The latter agents (rivaroxaban, apixaban, edoxaban, dabigatran, betrixaban) showed a better efficacy and safety compared to standard warfarin treatment and they are recommended for the reduction of ischemic stroke. Literature data reported a high risk of gastrointestinal bleeding with DOACs, in particular with dabigatran and rivaroxaban. In case of life-threatening gastrointestinal bleeding, these patients could benefit from the use of reversal agents. Methods: We performed an electronic search on PUBMED of the literature concerning reversal agents for DOACs and gastrointestinal bleeding in the Emergency Department from 2004 to 2020. AIM: This review summarizes the current evidences about three reversal agents idarucizumab, andexanet alfa and ciraparantag, and the use of the first two in the emergency setting in patients with an active major bleeding or who need urgent surgery to offer physicians indications for a better management approach in order to increase patient’s safety. Conclusion: Although these agents have been marketed for five years (idarucizumab) and two years (andexanet alfa) respectively, and despite guidelines considering antidotes as first-line agents in treating life-threatening hemorrhage when available, these antidotes seem to gain access very slowly in the clinical practice. Cost, logistical aspects and need for plasma level determination of DOAC for an accurate therapeutic use probably have an impact on this phenomenon.. An expert multidisciplinary bleeding team should be established so as to implement international guidelines based on local resources and organization.

scholarly journals Difficult Intraoperative Heparinization Following Andexanet Alfa Administration

2019 ◽  
Vol 3 (4) ◽  
pp. 390-394 ◽  
Author(s):  
C. James Watson ◽  
Sara Zettervall ◽  
Matthew Hall ◽  
Michael Ganetsky
Keyword(s):  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Factor Xa ◽  
Hemodynamic Instability ◽  
The United States ◽  
Major Hemorrhage ◽  
Reversal Agents ◽  
Abdominal Aortic ◽  
United States Food ◽  
Andexanet Alfa

Direct oral anticoagulants are now commonplace, and reversal agents are recently becoming available. Andexanet alfa (AnXa), approved by the United States Food and Drug Administration in 2018, is a novel decoy molecule that reverses factor Xa inhibitors in patients with major hemorrhage. We present a case of a 70-year-old man taking rivaroxaban with hemodynamic instability from a ruptured abdominal aortic aneurysm. He received AnXa prior to endovascular surgery, and intraoperatively he could not be heparinized for graft placement. Consideration should be given to the risks and benefits of AnXa administration in patients who require anticoagulation after hemorrhage has been controlled.

scholarly journals Reversal of direct oral anticoagulants: a practical approach

Hematology ◽  
2016 ◽  
Vol 2016 (1) ◽  
pp. 612-619 ◽  
Author(s):  
Andrew W. Shih ◽  
Mark A. Crowther
Keyword(s):  
Phase 1 ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Antibody Fragment ◽  
Factor Xa ◽  
Factor Xa Inhibitors ◽  
Severe Bleeding ◽  
Thrombin Time ◽  
Ancillary Benefits ◽  
Reversal Agents

Abstract Direct oral anticoagulants (DOACs) have at least noninferior efficacy compared with other oral anticoagulants and have ancillary benefits, including overall better safety profiles, lack of the need for routine monitoring, rapid onset of action, and ease of administration. Reversal of these agents may be indicated in certain situations such as severe bleeding and for perioperative management. DOAC-associated bleeding should be risk stratified: patients with moderate or severe bleeding should have the DOAC discontinued and reversal strategies should be considered. Laboratory testing has limited utility in the acute management of bleeding; thrombin time and activated partial thromboplastin time may be useful for excluding clinically relevant levels of dabigatran. Prothrombin time is potentially useful for rivaroxaban and edoxaban, but calibrated anti-Xa assays are optimal for determining clinically relevant levels of factor Xa inhibitors. Because specific reversal agents are not widely available, supportive care and interventions for local hemostasis remain the cornerstones of therapy in the patient with DOAC-associated bleeding. Nonspecific reversal agents should be considered only in the event of severe bleeding because their efficacy is unknown, and they are associated with risk of thrombosis. Recent results from phase 3/4 studies demonstrate efficacy for an antidote to dabigatran (idarucizumab, a monoclonal antibody fragment with specificity for dabigatran) and an antidote to factor Xa inhibitors (andexanet alfa, a recombinant and inactive form of factor Xa that binds inhibitors). A universal reversal agent (ciraparantag) for many anticoagulants, including the DOACs, shows promise in results from phase 1 and 2 studies.

scholarly journals Monitoring and reversal of direct oral anticoagulants

Hematology ◽  
2015 ◽  
Vol 2015 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Adam Cuker ◽  
Deborah Siegal
Keyword(s):  
Prothrombin Complex Concentrate ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Antibody Fragment ◽  
Factor Xa ◽  
Factor Xa Inhibitors ◽  
Severe Bleeding ◽  
Thrombin Time ◽  
Reversal Agents ◽  
Routine Monitoring

Abstract Although the direct oral anticoagulants (DOACs) do not require routine monitoring and reduce bleeding compared with warfarin, there are special circumstances in which laboratory measurement or reversal of their anticoagulant effect may be indicated. The dilute thrombin time and ecarin-based assays are able to quantify dabigatran across a broad range of concentrations, but are not widely available. A normal thrombin time excludes clinically relevant levels and a normal activated partial thromboplastin time probably excludes excess levels of dabigatran. Factor Xa inhibitors may be quantified with an anti-Xa assay calibrated with drug-specific standards. A normal prothrombin time probably excludes excess levels of rivaroxaban and edoxaban, but not apixaban. Patients with minor and moderate DOAC-associated bleeding can be treated with supportive care and general hemostatic measures. Nonspecific reversal agents (eg, prothrombin complex concentrate, activated prothrombin complex concentrate) are of unproven benefit, carry a risk of thrombosis, and should be reserved for severe bleeding. Specific reversal agents, such as idarucizumab (a monoclonal antibody fragment that binds dabigatran) and andexanet alfa (a recombinant factor Xa variant that binds factor Xa inhibitors but lacks coagulant activity), are in clinical development.

Monitoring and reversal of direct oral anticoagulants

Hematology ◽  
2015 ◽  
Vol 2015 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Adam Cuker ◽  
Deborah Siegal
Keyword(s):  
Prothrombin Complex Concentrate ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Antibody Fragment ◽  
Factor Xa ◽  
Factor Xa Inhibitors ◽  
Severe Bleeding ◽  
Thrombin Time ◽  
Reversal Agents ◽  
Routine Monitoring

Although the direct oral anticoagulants (DOACs) do not require routine monitoring and reduce bleeding compared with warfarin, there are special circumstances in which laboratory measurement or reversal of their anticoagulant effect may be indicated. The dilute thrombin time and ecarin-based assays are able to quantify dabigatran across a broad range of concentrations, but are not widely available. A normal thrombin time excludes clinically relevant levels and a normal activated partial thromboplastin time probably excludes excess levels of dabigatran. Factor Xa inhibitors may be quantified with an anti-Xa assay calibrated with drug-specific standards. A normal prothrombin time probably excludes excess levels of rivaroxaban and edoxaban, but not apixaban. Patients with minor and moderate DOAC-associated bleeding can be treated with supportive care and general hemostatic measures. Nonspecific reversal agents (eg, prothrombin complex concentrate, activated prothrombin complex concentrate) are of unproven benefit, carry a risk of thrombosis, and should be reserved for severe bleeding. Specific reversal agents, such as idarucizumab (a monoclonal antibody fragment that binds dabigatran) and andexanet alfa (a recombinant factor Xa variant that binds factor Xa inhibitors but lacks coagulant activity), are in clinical development.

scholarly journals Reversing targeted oral anticoagulants

Hematology ◽  
2014 ◽  
Vol 2014 (1) ◽  
pp. 518-523 ◽  
Author(s):  
Maureane Hoffman ◽  
Dougald M. Monroe
Keyword(s):  
Factor Viia ◽  
Oral Anticoagulants ◽  
Factor Xa ◽  
Novel Oral Anticoagulants ◽  
Factor Xa Inhibitors ◽  
Invasive Procedures ◽  
Prothrombin Complex Concentrates ◽  
Reversal Agents ◽  
Life Threatening ◽  
Orally Active

Abstract Dabigatran, rivaroxaban, and apixaban are orally active anticoagulants that are approved in many countries. Dabigatran inhibits thrombin, whereas rivaroxaban and apixaban are factor Xa inhibitors. In clinical trials, these novel oral anticoagulants were at least as effective as warfarin for preventing stroke in patients with atrial fibrillation, but with a lower rate of serious bleeding. However, the lack of true antidotes for these agents has caused concern when patients suffer life-threatening bleeding or trauma or require emergent invasive procedures. True antidotes are under development for all of these agents. In the meantime, activated and nonactivated prothrombin complex concentrates have been used as reversal agents. Factor VIIa may also be effective for reversal of the factor Xa inhibitors. Reversal of novel oral anticoagulants by these hemostatic agents has not been studied in bleeding human patients, so their true efficacy and appropriate dosing are not known.

scholarly journals Impact of Idarucizumab and Andexanet Alfa on DOAC Plasma Concentration and ClotPro® Clotting Time: An Ex Vivo Spiking Study in A Cohort of Trauma Patients

2021 ◽  
Vol 10 (16) ◽  
pp. 3476
Author(s):  
Daniel Oberladstätter ◽  
Christoph J. Schlimp ◽  
Johannes Zipperle ◽  
Marcin F. Osuchowski ◽  
Wolfgang Voelckel ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Healthy Volunteers ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Factor Xa ◽  
Factor Xa Inhibitors ◽  
Clotting Time ◽  
Andexanet Alfa ◽  
The Impact

Specific antagonists have been developed for the reversal of direct oral anticoagulants (DOAC). We investigated the impact of these reversal agents on the plasma concentration and visco-elastic test results of dabigatran and factor Xa inhibitors. After baseline measurements of dabigatran, the plasma concentration, and the visco-elastic ClotPro® ecarin clotting time (ECA-CT), we added the reversal agent Idarucizumab in vitro and these two analyses were repeated. Likewise, the baseline plasma concentration of apixaban, edoxaban, and rivaroxaban as well as ClotPro® Russell’s viper venom test clotting time (RVV-CT) were measured and reanalyzed following Andexanet alfa spiking. We analyzed fifty blood samples from 37 patients and 10 healthy volunteers. Idarucizumab decreased the measured dabigatran plasma concentration from 323.9 ± 185.4 ng/mL to 5.9 ± 2.3 ng/mL and ECA-CT from 706.2 ± 344.6 s to 70.6 ± 20.2 s, (all, p < 0.001). Andexanet alfa decreased the apixaban concentration from 165.1 ± 65.5 ng/mL to 9.8 ± 8.1 ng/mL, edoxaban from 152.4 ± 79.0 ng/mL to 36.4 ± 19.2 ng/mL, and rivaroxaban from 153.2 ± 111.8 ng/mL to 18.1 ± 9.1 ng/mL (all p < 0.001). Andexanet alfa shortened the RVV-CT of patients with apixaban from 239.2 ± 71.7 s to 151.1 ± 30.2 s, edoxaban from 288.2 ± 65.0 s to 122.7 ± 37.1 s, and rivaroxaban from 225.9 ± 49.3 s to 103.7 ± 12.1 s (all p < 0.001). In vitro spiking of dabigatran-containing blood with Idarucizumab substantially reduced the plasma concentration and ecarin-test clotting time. Andexanet alfa lowered the concentration of the investigated factor Xa-inhibitors but did not normalize the RVV-CT. In healthy volunteers’ blood, Idarucizumab spiking had no impact on ECA-CT. Andexanet alfa spiking of non-anticoagulated blood prolonged RVV-CT (p = 0.001), potentially as a consequence of a competitive antagonism with human factor Xa.

Direct oral anticoagulants (DOAC) – Management of emergency situations

2017 ◽  
Vol 37 (04) ◽  
pp. 257-266 ◽  
Author(s):  
Edelgard Lindhoff-Last
Keyword(s):  
Vitamin K ◽  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Real Life ◽  
Bleeding Complications ◽  
Severe Bleeding ◽  
Emergency Operations ◽  
Reversal Agents ◽  
Life Threatening

SummaryThe worldwide increase in the aging population and the associated increase in the prevalence of atrial fibrillation and venous thromboembolism as well as the widespread use of direct oral anticoagulants (DOAC) have resulted in an increase of the need for the management of bleeding complications and emergency operations in frail, elderly patients, in clinical practice. When severe bleeding occurs, general assessment should include evaluation of the bleeding site, onset and severity of bleeding, renal function, and concurrent medications with focus on anti-platelet drugs and nonsteroidal anti-inflammatory drugs (NSAID). The last intake of the DOAC and its residual concentration are also relevant. The site of bleeding should be immediately localized, anticoagulation should be interrupted, and local measures to stop bleeding should be taken. In life-threatening bleeding or emergency operations immediate reversal of the antithrombotic effect may be indicated. If relevant residual DOAC-concentrations are expected and surgery cannot be postponed, prothrombin complex concentrate (PCC) and/or a specific antidote should be given. While idarucizumab, the specific antidote for dabigatran, has been recently approved for clinical use, the recombinant factor X protein andexanet alfa, an antidote for the reversal of inhibitors of coagulation factor Xa, and ciraparantag, a universal antidote, are not available. Future cohort studies are necessary to assess the efficacy and safety of specific and unspecific reversal agents in “real-life” conditions. This was the rationale for introducing the RADOA-registry (RADOA: Reversal Agent use in patients treated with Direct Oral Anticoagulants or vitamin K antagonists), a prospective non-interventional registry, which will evaluate the effects of specific and unspecific reversal agents in patients with life-threatening bleeding or emergency operations either treated with DOACs or vitamin K antagonists.

scholarly journals DOACs- balance between thrombosis and bleeding - A Review

2020 ◽  
Vol 12 (2) ◽  
pp. 32-36
Author(s):  
Emilija Lazarova Trajkovska
Keyword(s):  
Vitamin K Antagonists ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Bleeding Event ◽  
Common Side Effect ◽  
Clotting Factors ◽  
Bleeding Events ◽  
Real World Data ◽  
Reversal Agents ◽  
Life Threatening

Bleeding is a common side effect of anticoagulant use. However, the majority of bleeding events are not life-threatening and can be managed conservatively. The first step in managing any significant bleeding event is to temporarily stop using the anticoagulant. The aim of this review was to determine the appropriate management strategy for an acutely bleeding patient on DOACs.  Direct oral anticoagulants (DOACs) are now widely used in treatment of venous thromboembolism (VTE) and are recommended first-line over vitamin K antagonists (VKAs) in non-cancer associated VTE. Until recently, supportive measures and infusion of clotting factors were the only available options for reversal of DOACs. Within the last 4 years, approval of specific antidotes has led to hopes for improved outcomes in DOAC-related acute bleeding, however limitations remain including cost, availability and "real-world" data. In severe and life-threatening bleeding events, use of non-specific (e.g. PCC) or specific (e.g. idarucizumab, andexanet alpha) reversal agents are recommended. However, further data is needed to compare outcomes between these two management strategies and identify the cost-effectiveness of these various strategies.

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