Skip to main content
OpenTrials
Recruiting

NCT Number: NCT07213778

REGN7508 Versus Acetylsalicylic Acid (ASA) for Venous Thromboprophylaxis After Total Knee Arthroplasty in Adult Participants

This study is researching an experimental drug called REGN7508 (called "study drug") and how it compares against another treatment called Acetylsalicylic Acid (ASA). The study is focused on adults undergoing elective, unilateral (one side) total knee replacement surgery.

The aim of the study is to see how effective the study drug is at preventing Venous Thromboembolism (VTE) and other related diseases after total knee replacement surgery compared to acetylsalicylic acid.

The study is looking at several other research questions, including:

* What side effects may happen from taking the study drug * How much study drug is in the blood at different times * Whether the body makes antibodies against the study drug (which could make the study drug less effective or could lead to side effects)

Recruiting

Interested in participating?

Request Info

Key information

Conditions

Symptomatic Venous Thromboembolism (VTE) Cardiovascular Diseases Embolism Embolism and Thrombosis Lung Diseases Pulmonary Embolism Respiratory Tract Diseases Thrombosis Vascular Diseases Venous Thrombosis

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Henry Dunant Hospital Center, Athens, Attica, Greece

Loading trial locations.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

  • Is undergoing a primary elective unilateral TKA
  • Is in good health based on laboratory safety testing as described in the protocol

Key Exclusion Criteria:

  • Any condition that, as assessed by the investigator, may confound the results of the study or pose an additional risk to the participant by study participation
  • History of bleeding in the 6 months prior to randomization requiring hospitalization or transfusion; history of intracranial or intraocular bleeding, excessive operative or post-operative bleeding, and traumatic spinal or epidural anesthesia; history of bleeding diathesis (eg, hemophilia A or B, von Willebrand's Factor deficiency)
  • History of thromboembolic disease or thrombophilia
  • History of platelet dysfunction
  • Has received or plans to receive preoperative enoxaparin on the day prior to TKA surgery

Note: Other protocol-defined Inclusion/ Exclusion criteria apply

Treatment and study plan

REGN7508

Drug

Administered per the protocol

Other names: cenvacibart

Acetylsalicylic acid (ASA)

Drug

Administered per the protocol

Placebo

Drug

Administered per the protocol

Primary outcomes

  1. Incidence of the composite endpoint of symptomatic VTE and all-cause death

    Time frame: Through day 30 visit

Secondary outcomes

  1. Time to first event of the composite endpoint of symptomatic VTE and all-cause death

    Time frame: Through day 30 visit

  2. Incidence of confirmed symptomatic Deep Vein Thrombosis (DVT)

    Time frame: Through day 30 visit

  3. Incidence of confirmed Pulmonary Embolism (PE)

    Time frame: Through day 30 visit

  4. Incidence of all-cause death

    Time frame: Through day 30 visit

  5. Time to first event of the confirmed symptomatic DVT

    Time frame: Through day 30 visit

  6. Time to first event of the confirmed PE

    Time frame: Through day 30 visit

  7. Time to the all-cause death

    Time frame: Through day 30 visit

  8. Incidence of the composite endpoint of major bleeding and Clinically Relevant Non-Major (CRNM) bleeding

    Time frame: Through day 30 visit

  9. Incidence of minor bleeding

    Time frame: Through day 30 visit

  10. Incidence of Treatment-Emergent Adverse Events (TEAEs)

    Time frame: Through day 90 visit

  11. Severity of TEAEs

    Time frame: Through day 90 visit

  12. Incidence of Anti-drug Antibody (ADA) to REGN7508

    Time frame: Through day 90 visit

  13. Magnitude of ADA to REGN7508

    Time frame: Through day 90 visit

  14. Concentrations of REGN7508

    Time frame: Through day 90 visit

Study contacts

Contact information is provided by the study sponsor or research team.

Clinical Trials Administrator

CONTACT

[email protected]

844-734-6643

Sponsors and collaborators

Lead sponsor

Regeneron Pharmaceuticals

Industry

Registry information

Official study title

A Phase 3, Multicenter, Double-Blinded, Randomized Study to Evaluate REGN7508, a Factor XI Monoclonal Antibody, Versus Acetylsalicylic Acid for Prophylaxis of Symptomatic Venous Thromboembolism After Elective Total Knee Arthroplasty (ROXI-ASPEN)

Acronym: ROXI-ASPEN

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Oct 9, 2025
Registry last updated
Jul 22, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.