Research and Practice in Thrombosis and Haemostasis (Nov 2024)
The anticoagulant effects of milvexian, a novel small molecule factor XIa inhibitor, are neutralized by activated prothrombin complex concentrates and recombinant factor VIIa in human plasma and whole blood in vitro
Abstract
Background: The development of anticoagulants that provide antithrombotic efficacy without a concomitant bleeding risk remains an unmet clinical need in thrombosis. Although direct oral anticoagulants (DOACs) have a reduced incidence of major bleeding compared with warfarin, they still carry a bleeding risk, resulting in a suboptimal therapeutic index. Epidemiologic data suggest that inhibiting activated factor XI (FXIa) may offer an improved safety profile with respect to bleeding risk compared with current-generation DOACs. Additionally, a phase II trial of milvexian in patients undergoing elective total knee replacement demonstrated robust dose-dependent efficacy with no statistically significant increase in bleeding. Nevertheless, the ability to rapidly and effectively correct FXIa inhibitor–induced anticoagulation may still be important in situations where patients experience uncontrolled bleeding or require emergency surgery. Objectives: We assessed the ability to normalize the anticoagulant effects of the novel small-molecule FXIa inhibitor milvexian (BMS-986177/JNJ-70033093) in vitro using commercially available prohemostatic agents. Methods: Milvexian-associated anticoagulation and correction was evaluated in activated partial thromboplastin time clotting assays, thromboelastography, and kaolin-initiated thrombin generation assays. Results: Activated prothrombin complex concentrates (PCCs) and recombinant factor (rF)VIIa corrected the anticoagulant effects of milvexian in activated partial thromboplastin time clotting assays, thromboelastography, and kaolin-initiated thrombin generation assays. In contrast, other agents, including PCCs, rFIX, and rFVIII, demonstrated either modest or no correction of milvexian-associated anticoagulation. Conclusion: This study demonstrated that currently available activated PCCs and rFVIIa normalize the anticoagulation induced by milvexian in vitro. The clinical utility of these agents remains to be established.
