Can a Factor XI Inhibitor Provide the Anticoagulation Effectiveness of DOACs for AF While Improving Safety?

Although direct oral anticoagulants (DOACs) are effective anticoagulants for patients with atrial fibrillation (AF), bleeding events can be catastrophic or impair patient adherence. Because factor XI is thought to be important in thrombus propagation but to play only a minor role in hemostasis, enthusiasm has grown for considering XI/XIa inhibitors to reduce thrombosis risk without increasing bleeding (NEJM JW Oncol Hematol May 4 2018 and Blood 2018; 131:1899).

In the industry-sponsored, phase 2 AZALEA–TIMI 71 trial, investigators allocated 1287 patients with AF and moderate-to-high stroke risk in a 1:1:1 ratio to monthly subcutaneous abelacimab — a non–FDA approved human monoclonal antibody that inhibits factor XI/XIa activity — at 90 mg or…