Objectives:Current approaches to systemic antithrombotic therapy in support of extracorporeal membrane oxygenation are limited and are hampered by both thrombotic and hemorrhagic complications. An alternative approach is needed.Design:Inhibition of coagulation factor XI/activated factor XI is an appealing pathway for antithrombotic support of extracorporeal membrane oxygenation. Selective inhibition of the contact pathway of coagulation could reduce bleeding risk, and because factor XI is linked with the inflammatory and complement systems, it can also be viewed as a biologically plausible target for the prevention of abnormal thrombosis during extracorporeal membrane oxygenation.Conclusions:We introduce initial information on EP-7041, a parenteral, potent, and selective, small-molecule activated factor XIa inhibitor with pharmacodynamic and pharmacokinetic characteristics that appear well suited for use in a critical care environment.