Early access
Sign in
Taking people in United StatesPhase 3

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

Key facts

Who runs it
Regeneron Pharmaceuticals
Where
Annapolis, Baltimore, Boston, Charlotte, Cincinnati, Columbus, Deerfield Beach, Delray Beach, Durham, Englewood, Hershey, Houston, Indianapolis, La Mesa, Lone Tree, McAllen, Miami, New York, Pittsburgh, Plymouth Meeting, Raleigh, Rancho Mirage, Riverside, Roanoke, Rochester, San Antonio, Skokie, South Miami, Spokane, St. George, Tamarac, Teaneck, Wichita, Williamsville, and Wilmington, United StatesSee the 42 sitesAlso in 5 other countries, 17 sites
Status
Recruiting
Phase
Phase 3
People taking part
2,000 people, planned
Started
24 Nov 2025
Expected to end
16 Jul 2027
Type of study
Interventional, 2 groupsOne group gets an existing treatment, for comparison.
Treatments tested
  • REGN7508
  • Acetylsalicylic Acid (ASA)
  • Placebo
Record updated
5 November 2026

Who can take part

Age
18 years and older
Sex
Women and men
Healthy volunteers
Cannot take part

The registry criteria, word for word

Show all 7 criteriaShow less

Who can take part

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

Who cannot take part

  • 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)
  • Has received or plans to receive preoperative enoxaparin on the day prior to TKA surgery; Note: Other protocol-defined Inclusion/ Exclusion criteria apply
  • 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 thromboembolic disease or thrombophilia
  • History of platelet dysfunction

Where in United States

Also in 5 other countries, 17 sites

  • Velocity Clinical Research, AnnapolisAnnapolis, United StatesContact: Clinical Trials AdministratorTaking people
  • Mercy Medical CenterBaltimore, United StatesContact: Clinical Trials AdministratorTaking people
  • Sinai Hospital of Baltimore, Inc.Baltimore, United StatesContact: Clinical Trials AdministratorTaking people
  • Boston Medical CenterBoston, United StatesContact: Clinical Trials AdministratorTaking people
  • Tufts Medical CenterBoston, United StatesContact: Clinical Trials AdministratorTaking people
  • Atrium Health Musculoskeletal Institute and Sports MedicineCharlotte, United StatesContact: Clinical Trials AdministratorTaking people
  • University of CincinnatiCincinnati, United StatesContact: Clinical Trials AdministratorTaking people
  • Ohio Clinical TrialsColumbus, United StatesContact: Clinical Trials AdministratorTaking people
  • The Ohio State University -Wexner Medical CenterColumbus, United StatesContact: Clinical Trials AdministratorTaking people
  • South Florida Joint Replacement CenterDeerfield Beach, United StatesContact: Clinical Trials AdministratorTaking people
  • Delray Physician Care CenterDelray Beach, United StatesContact: Clinical Trials AdministratorTaking people
  • Duke University Health System (Duke Health), Duke University HospitalDurham, United StatesContact: Clinical Trials AdministratorTaking people
  • HCA HealthONE CentennialEnglewood, United StatesContact: Clinical Trials AdministratorTaking people
  • Penn State Health Milton S. Hershey Medical CenterHershey, United StatesContact: Clinical Trials AdministratorTaking people
  • NextStage Clinical Research, All American Orthopedics and Sports MedicineHouston, United StatesContact: Clinical Trials AdministratorTaking people
  • HD Research - Memorial Hermann VillageHouston, United StatesContact: Clinical Trials AdministratorNo longer taking part
  • The Orthopaedic Research Foundation, Inc.Indianapolis, United StatesContact: Clinical Trials AdministratorTaking people
  • Horizon Clinical ResearchLa Mesa, United StatesContact: Clinical Trials AdministratorTaking people
  • HCA HealthONE, HCA HealthONE Sky RidgeLone Tree, United StatesContact: Clinical Trials AdministratorTaking people
  • Futuro Clinical TrialsMcAllen, United StatesContact: Clinical Trials AdministratorTaking people
  • Medical Research of Westchester - MPLUS Research NetworkMiami, United StatesContact: Clinical Trials AdministratorTaking people
  • Northwell Orthopaedic InstituteNew York, United StatesContact: Clinical Trials AdministratorTaking people
  • NYU LangoneNew York, United StatesContact: Clinical Trials AdministratorTaking people
  • University of PittsburghPittsburgh, United StatesContact: Clinical Trials AdministratorTaking people
  • Keystone Clinical Studies LLC, dba Flourish ResearchPlymouth Meeting, United StatesContact: Clinical Trials AdministratorTaking people
  • Eximia Equihealth Research-Raleigh. LLCRaleigh, United StatesContact: Clinical Trials AdministratorTaking people
  • The Vein and Vascular Center at Raleigh RadiologyRaleigh, United StatesContact: Clinical Trials AdministratorTaking people
  • Eisenhower Medical CenterRancho Mirage, United StatesContact: Clinical Trials AdministratorTaking people
  • CARI Clinical TrialsRiverside, United StatesContact: Clinical Trials AdministratorTaking people
  • Carilion ClinicRoanoke, United StatesContact: Clinical Trials AdministratorTaking people
  • University of Rochester Medical CenterRochester, United StatesContact: Clinical Trials AdministratorTaking people
  • Flourish Research - San Antonio (Formerly Clinical Trials of Texas)San Antonio, United StatesContact: Clinical Trials AdministratorTaking people
  • Endeavor Clinical TrialsSan Antonio, United StatesContact: Clinical Trials AdministratorNo longer taking part
  • Endeavor HealthSkokie, United StatesContact: Clinical Trials AdministratorTaking people
  • Larkin Community Hospital South MiamiSouth Miami, United StatesContact: Clinical Trials AdministratorTaking people
  • Spokane Joint Replacement CenterSpokane, United StatesContact: Clinical Trials AdministratorTaking people
  • DRx Clinical Research, LLCSt. George, United StatesContact: Clinical Trials AdministratorTaking people
  • Phoenix Clinical ResearchTamarac, United StatesContact: Clinical Trials AdministratorTaking people
  • Holy Name Medical CenterTeaneck, United StatesContact: Clinical Trials AdministratorTaking people
  • NextStage Clinical Research, St. Francis Medical ParkWichita, United StatesContact: Clinical Trials AdministratorTaking people
  • UBMD Orthopaedics and Sports MedicineWilliamsville, United StatesContact: Clinical Trials AdministratorTaking people
  • Coastal Vascular Institute, PAWilmington, United StatesContact: Clinical Trials AdministratorTaking people

About the trial

What the trial wants to find out

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.

Read full original descriptionShow less

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)

The 2 groups in the trial

  • REGN7508 and PlaceboTreatment being tested

    Treatment: REGN7508 and Placebo

  • Placebo and ASAExisting treatment, for comparison

    Treatment: Acetylsalicylic Acid (ASA) and Placebo

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
Official 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)
Record updated
5 November 2026