Reversal agents in development for the new oral anticoagulants

The new oral anticoagulants have many advantages over vitamin K antagonists, but they are still associated with a troublesome incidence of major bleeding. Additionally, the absence of a reversal agent for the new oral anticoagulants is a barrier to their more widespread use. Currently, there are 3 potential reversal agents in development: idarucizumab is a humanized murine monoclonal antibody fragment directed specifically at dabigatran; andexanet alfa is a recombinant modified decoy factor Xa that binds to factor Xa inhibitors; and PER977 is a small molecule that binds to factor Xa and IIa inhibitors and to heparin-based anticoagulants through charge interaction. These agents have undergone phase I clinical testing, appear to be well tolerated in healthy volunteers, and are effective in neutralizing their respective targets. All 3 are currently undergoing or entering into a phase II or III clinical study. This article reviews the available data for idarucizumab, andexanet alfa, and PER977.