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A Study in Patients With Acute Major Bleeding to Evaluate the Ability of Andexanet Alfa to Reverse the Anticoagulation Effect of Direct and Indirect Oral Anticoagulants (Extension Study)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02329327
Recruitment Status : Completed
First Posted : December 31, 2014
Last Update Posted : October 8, 2020
Population Health Research Institute
Information provided by (Responsible Party):
Portola Pharmaceuticals

Brief Summary:
The purpose of this study is to evaluate the hemostatic efficacy of andexanet alfa in patients receiving a factor Xa inhibitor who are experiencing an acute major bleed. The safety of andexanet will also be studied.

Condition or disease Intervention/treatment Phase
Bleeding Biological: Andexanet Phase 3

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 479 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Other
Official Title: Prospective, Open-Label Study of Andexanet Alfa in Patients Receiving a Factor Xa Inhibitor Who Have Acute Major Bleeding (ANNEXA-4)
Study Start Date : January 2015
Actual Primary Completion Date : September 24, 2020
Actual Study Completion Date : September 24, 2020

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Bleeding

Arm Intervention/treatment
Experimental: Single Arm Biological: Andexanet

Primary Outcome Measures :
  1. Proportion of patients with excellent or good hemostasis [ Time Frame: Stopping major bleed at 12 hours from the start of andexanet bolus ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No


  1. Acute major bleeding episode requiring urgent reversal of anticoagulation; defined by at least one of the following:

    • Acute bleeding that is potentially life-threatening, OR
    • Acute bleeding associated with a fall in hemoglobin level by ≥2 g/dL, OR
    • Acute bleeding associated with a hemoglobin level of ≤8 g/dL if no baseline hemoglobin is available, OR
    • Acute bleeding in a critical area or organ such as intraspinal, pericardial, or intracranial.
  2. If bleeding is intracranial or intraspinal, the patient must have undergone a head CT or MRI scan demonstrating the bleeding.
  3. Patient received or is believed to have received one of the following within 18 hours prior to andexanet administration: apixaban, rivaroxaban, edoxaban or enoxaparin.
  4. For patients with intracranial bleeding, there must be a reasonable expectation that andexanet treatment will commence within 2 hours of the baseline imaging evaluation.


  1. The patient is scheduled to undergo surgery in less than 12 hours, with the exception of minimally invasive surgery/procedures.
  2. A patient with an intracerebral hemorrhage has any of the following:

    • Glasgow coma score < 7, OR
    • Intracerebral hematoma > 60 cc as assessed by CT or MRI
  3. Patients with visible, musculoskeletal or intra-articular bleeding as their qualifying bleed.
  4. Expected survival of less than 1 month
  5. Recent history (within 2 weeks) of a diagnosed thrombotic event (TE) as follows: venous thromboembolism, myocardial infarction, disseminated intravascular coagulation (DIC), cerebral vascular accident, transient ischemic attack, unstable angina pectoris hospitalization or severe peripheral vascular disease within 2 weeks prior to screening.
  6. Severe sepsis or septic shock at the time of Screening.
  7. Pregnant or a lactating female.
  8. Patient has received any of the following drugs or blood products within 7 days of Screening:

    • Vitamin K antagonist (VKA)
    • Dabigatran
    • Prothrombin Complex Concentrate products (PCC) or recombinant factor VIIa (rfVIIa)
    • Whole blood, plasma fractions
  9. Treated with an investigational drug <30 days prior to Screening
  10. Planned administration of PCC, fresh frozen plasma (FFP) or rfVIIa from Screening until within 12 hours after the end of the andexanet infusion.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02329327

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Sponsors and Collaborators
Portola Pharmaceuticals
Population Health Research Institute
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Portola Pharmaceuticals Identifier: NCT02329327    
Other Study ID Numbers: 14-505
First Posted: December 31, 2014    Key Record Dates
Last Update Posted: October 8, 2020
Last Verified: October 2020
Keywords provided by Portola Pharmaceuticals:
Factor Xa Inhibitors
Additional relevant MeSH terms:
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Pathologic Processes