Ciraparantag, an anticoagulant reversal drug: mechanism of action, pharmacokinetics, and reversal of anticoagulants

Ciraparantag, an anticoagulant reversal agent, is a small molecule specifically designed to bind noncovalently by charge-charge interaction to unfractionated heparin and low-molecular-weight heparin. It shows binding characteristics that are similar to those of direct oral anticoagulants (DOACs). A dynamic light-scattering methodology was used to demonstrate ciraparantag's binding to the heparins and DOACs and its lack of binding to a variety of proteins including coagulation factors and commonly used drugs. Ciraparantag reaches maximum concentration within minutes after IV administration with a half-life of 12 to 19 minutes. It is primarily hydrolyzed by serum peptidases into 2 metabolites, neither of which has substantial activity. Ciraparantag and its metabolites are recovered almost entirely in the urine. In animal models of bleeding (rat tail transection and liver laceration), a single IV dose of ciraparantag given at peak concentrations of the anticoagulant, but before the bleeding injury, significantly reduced the blood loss. Ciraparantag, given after the bleeding injury, also significantly reduced blood loss. It appears to have substantial ability to reduce blood loss in animal models in which a variety of anticoagulants are used and has potential as a useful DOAC reversal agent.