Abstract Number: LB 01.2
Meeting: ISTH 2021 Congress
Background: The role of factor XI in postoperative venous thromboembolism is uncertain. Abelacimab is a monoclonal antibody that binds factor XI and locks it in its zymogen conformation.
Aims: The purpose of this study was to compare the efficacy and safety of abelacimab and enoxaparin in patients undergoing total knee arthroplasty.
Methods: In this open-label, parallel group, phase 2 study, we randomized 412 patients to one of three single intravenous postoperative abelacimab doses (30, 75 or 150mg) or to 40mg enoxaparin given subcutaneously once daily. The primary efficacy outcome was the incidence of venous thromboembolism detected by mandatory venography of the operated leg or documented symptomatic events. The principal safety outcome was clinically relevant bleeding, defined as the composite of major and clinically relevant nonmajor bleeding, up to 30 days after surgery.
Results: The primary efficacy outcome occurred in 13 of 102 patients (13%), 5 of 99 patients (5%), and 4 of 98 patients (4%), in the 30mg, 75mg and150mg abelacimab dose groups, respectively, and in 22 of 101 patients (22%) in the enoxaparin group (Figure). The 30mg abelacimab regimen was noninferior to enoxaparin and the 75mg and 150mg abelacimab regimens were superior (P<0.001). Clinically relevant bleeding occurred in 2%, 2% and none of the patients in the respective abelacimab groups and in none of the patients given enoxaparin.
Conclusions: The results indicate that factor XI is important for postoperative venous thromboembolism. Factor XI inhibition with a single intravenous dose of abelacimab was effective for prevention of venous thromboembolism after knee arthroplasty and was associated with a low risk of bleeding (funded by Anthos Therapeutics; ANT-005 TKA, Eudract_number:2019-003756-37).
To cite this abstract in AMA style:Verhamme P, Yi A, Segers A, Salter J, Bloomfield D, Buller H, Raskob G, Weitz . Abelacimab for Prevention of Venous Thromboembolism [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/abelacimab-for-prevention-of-venous-thromboembolism/. Accessed May 16, 2022.
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