Four New Sets of Pre-Clinical Data Further Expands the Evidence Supporting Abelacimab

CAMBRIDGE, Mass., July 13, 2022 — Anthos Therapeutics, a clinical-stage biotechnology company developing innovative therapies for cardiovascular and metabolic diseases, announced that four new research updates were presented on abelacimab during the Venous Thromboembolism poster session at the ongoing International Society on Thrombosis and Haemostasis 2022 Congress in London, UK.

“Coagulation is a complex multilayered process and the potential benefits of inhibiting Factor XI are becoming increasingly clear.  These preclinical studies add important information characterizing the pharmacodynamic effects of abelacimab and further extend our understanding of the biological effects of Factor XI inhibition,” said Dan Bloomfield, Chief Medical Officer at Anthos Therapeutics. “With a growing body of evidence from ongoing studies both in the clinic and the lab, and a recent FDA Fast Track designation granted for abelacimab E in thrombosis associated with cancer, we are becoming increasingly confident about the potential of our novel dual-acting Factor XI/XIa inhibitor may offer in the future as a treatment advance.”

The details of each poster presentation are provided below:

PB0927 – Abelacimab does not influence the effects of two commonly used antiplatelet agents in vitro
This study investigated the effects of clinically relevant doses of abelacimab on the inhibition of platelet aggregation by commonly used antiplatelet agents, aspirin and ticagrelor, in vitro. It demonstrated that abelacimab did not affect the level of antiplatelet inhibition achieved either by aspirin or ticagrelor con rming that abelacimab will not interfere with the bene ts of these antiplatelet agents.

PB0925 – Abelacimab has no effect on platelet aggregation induced by TRAP-6 and collagen
FXI has been identi ed as a ligand to platelet receptors ApoER2 and GPIbα on the surface of stimulated platelets. This study demonstrated that abelacimab did not interfere with normal platelet aggregation following stimulation with collagen or thrombin receptor activating peptide-6 (TRAP-6) and compared with vehicle and active control (abciximab, anti-GP2b3a) suggesting that the binding of FXI to the platelet surface has no effect on primary hemostasis.

PB0548 – Abelacimab, a Factor XI/XIa Antibody Inhibits Clotting in Hemodialysis Circuits Ex Vivo
This study compared the effect of a combination of abelacimab and enoxaparin with enoxaparin alone, in an ex vivo model of hemodialysis that is aggressive due to the frequent recirculation of blood and a lack of endothelial cells.  Inhibition of FXI/FXIa by abelacimab combined with enoxaparin (but not enoxaparin alone) reduced and prevented device malfunction.   This provides support for testing abelacimab in patients on hemodialysis.

PB0926 – Low concentrations of rFVIIa bypass changes in ROTEM coagulation parameters induced by abelacimab in vitro.
While patients with severe factor XI (FXI) de ciency rarely have spontaneous bleeding, low doses of recombinant activated factor VII (rFVIIa) have been used and are effective in managing bleeding should it occur. This study was designed to evaluate whether low concentrations of rFVIIa could revert the changes in abelacimab-induced coagulation parameters as measured by rotational thromboelastometry (ROTEM) in whole blood in vitro assays from healthy individuals. As expected and similar to what has been observed in patients with Factor XI de ciency, these data suggest that low doses of rFVIIa can be used to manage bleeding in Factor XI inhibited patients  being treated with abelacimab.

About Abelacimab
Abelacimab is a novel, highly selective, fully human monoclonal antibody designed to induce effective hemostasis-sparing anticoagulation through Factor XI inhibition. Abelacimab targets the active domain of Factor XI, demonstrating dual inhibitory activity against both Factor XI and its activated form, Factor XIa.  Abelacimab can be administered intravenously (IV) to achieve rapid inhibition of Factor XI activity and then used subcutaneously (SC) monthly to maintain nearly complete inhibition in a chronic setting. In a PK/PD study, abelacimab administered IV provided profound suppression of Factor XI within one hour after the start of therapy and maintained near maximal inhibition for up to 30 days.1,2 In a Phase 2 study whose results were published in the New England Journal of Medicine in 2021, a single intravenous dose of abelacimab after knee surgery reduced the rate of venous thromboembolism by 80%, measured 10 days after surgery, compared to enoxaparin. Factor XI inhibition offers the1 promise of hemostasis-sparing anticoagulation for the prevention and treatment of arterial and venous thromboembolic events. Abelacimab is an investigational agent and has not been 3 approved for any indication.