In vitro comparison of the effects of abelacimab, dalteparin, and apixaban on catheter-induced clotting and thrombin generation

Background: Abelacimab is a fully human monoclonal antibody that binds factor XI, blocking its activation and activity. It is being compared with apixaban and dalteparin in patients with cancer-associated venous thromboembolism. Patients with cancer often have central venous catheters, which are prone to clotting. How abelacimab compares with apixaban and dalteparin for preventing catheter thrombosis is unknown. Objectives: The aim of this study was to compare the effects of abelacimab, apixaban, and dalteparin on the activated partial thromboplastin time (aPTT) and catheter-induced clotting and thrombin generation using an established plate-based catheter thrombosis model. Methods: The effect of abelacimab, apixaban, and dalteparin on the aPTT was determined. Human plasma containing abelacimab, apixaban, or dalteparin was added to wells of 96-well plates, with or without catheter segments. After incubation and recalcification, the time to clot formation and thrombin generation was measured. Results: All 3 anticoagulants prolonged the aPTT and suppressed catheter-induced clotting and thrombin generation in a concentration-dependent manner. At clinically relevant concentrations, dalteparin and abelacimab exerted more potent effects on the aPTT, catheter-induced clotting, and thrombin generation than apixaban. Conclusion: Abelacimab and dalteparin suppress catheter-induced clotting more effectively than apixaban. Clinical trials are needed to determine whether abelacimab prevents catheter-induced clotting in patients with cancer.