• Key Highlights
• The collaborative study with Coagulation Profile BV, Maastricht University and Leiden University Medical Center has been accepted for publication in Research and Practice in Thrombosis and Haemostasis and evaluates modified dilute Prothrombin Time (dPT) and dilute Russell’s Viper Venom Time (dRVVT) assays for patients on Factor Xa inhibitors
  
  
• Both assays showed dose‑dependent prolongation of clotting time when FXa inhibitors were present; clotting times were fully restored when VMX‑C001, a human recombinant modified Factor X, was added
  
  
• Clotting times measured by the assays correlated strongly with plasma concentrations of apixaban, rivaroxaban and edoxaban in samples from healthy volunteers and nursing home residents
  
  
• The study concludes that dPT and dRVVT can serve as surrogate endpoints in clinical studies of VMX‑C001 and may help monitor anticoagulation in emergency situations
  
  
• VMX‑C001 is designed to be insensitive to FXa inhibitors and rapidly restores normal coagulation; it is currently entering a pivotal global Phase 3 clinical trial.

Leiden, The Netherlands, 24 February 2026 – VarmX, a biotech company developing innovative approaches for the restoration of coagulation, today announced that a collaborative study describing sensitive assays to monitor coagulation restoration in the presence of FXa inhibitors by VMX‑C001 has been accepted for publication in Research and Practice in Thrombosis and Haemostasis.

The paper, “Coagulation assays for assessing the bypassing of factor Xa direct oral anticoagulants using VMX‑C001,” addresses an important clinical challenge: rapid and reliable assessment of anticoagulant activity in patients receiving FXa inhibitors who experience serious bleeding or require urgent surgery. Standard laboratory coagulation tests often lack the sensitivity to detect clinically relevant levels of FXa inhibitors and chromogenic anti-FXa tests are not suitable for assessment of coagulation restoration by VMX-C001. In this study, investigators modified two commercially available clotting assays—Dilute Prothrombin time (dPT) and dilute Russell’s Viper Venom Time (dRVVT)—to sensitively assess anticoagulation and its reversal.

Using plasma samples spiked with apixaban, rivaroxaban or edoxaban and samples from healthy subjects and nursing‑home residents receiving these medicines, the researchers showed that the modified dPT and dRVVT assays were highly sensitive to FXa inhibitors, producing a dose‑dependent prolongation of clotting time. Importantly, clotting times were fully restored when VMX‑C001 or high concentrations of andexanet alfa were added, and the assays demonstrated strong correlation between clotting time and drug concentration. These findings suggest the assays can serve as surrogate endpoints in future studies of VMX‑C001 and may aid clinicians in monitoring FXa inhibitor anticoagulation in acute situations.

VMX‑C001 is a human, recombinant modified Factor X protein designed to be insensitive to FXa inhibitors and to bypass their anticoagulant activity to restore coagulation. It is administered as a single dose and has been developed with significant clinical advantages, including universal dosing regardless of the specific FXa inhibitor used, rapid and easy administration, compatibility with heparin and no additional thrombotic risk. VMX‑C001 is preparing to enter a global Phase 3 study (EquilibriX‑S) evaluating its ability to restore coagulation in patients on FXa inhibitor who require urgent surgery. The program builds on regulatory momentum including U.S. FDA Fast Track Designation and a Phase 1 waiver in Japan.

Daniël Verhoef, Director of Research at VarmX, commented: “This publication underscores the robustness of VMX‑C001’s mechanism of action and our commitment to developing science‑driven solutions for patients on FXa inhibitors. The ability to rapidly and reliably measure bypassing of the anticoagulant effect of FXa inhibitors by VMX-C001 will be critical as we advance into Phase 3 trials and ultimately into clinical practice. We thank our partners at Coagulation Profile, Maastricht University and Leiden University Medical Center for their collaboration on this important work.”

Link to publication: Article Elsevier