Andexanet Alfa: a Good Antidote against Anti Xa Agents

Andexanet alfa induces rapid reversion of Xa inhibitor effect in patients with active major bleeding, according to preliminary observations of the ongoing study ANNEXA-4, currently randomizing patients.


This work was presented in Rome in the context of the European Society of Cardiology annual meeting, and simultaneously published in the New England Journal of Medicine.


Andexanet alfa is a recombinant human factor Xa decoy protein that binds factor Xa inhibitors to remove them from circulation. The ANNEXA-4 trial is currently randomizing patients with major bleeding within 18 hours after their last dose of factor Xa inhibitors.


The first 67 patients have been presented: 32 were on rivaroxaban, 31 on apixaban, and 4 on enoxaparin. Bleeding events were 49% digestive and 42% intracranial.


Andexanet alfa is administered in a bolus dose followed by an infusion. After bolus administration, the anti Xa factor activity dropped 89% for those on rivaroxaban and 93% for those on apixaban. At 12 hours, the infusion corrected clinical hemostasis in 79% of patients.


Original Title: Andexanet alfa for acute major bleeding associated with factor Xa inhibitors.

Presenter: Stuart Connolly.


We value your opinion. You are more than welcome to leave your comments, thoughts, questions or suggestions here below.