REGN7508 Versus Acetylsalicylic Acid (ASA) for Venous Thromboprophylaxis After Total Knee Arthroplasty in Adult Participants
ROXI-ASPEN
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)
2 other identifiers
interventional
2,000
1 country
16
Brief Summary
This study is researching an experimental drug called REGN7508 versus Acetylsalicylic Acid (ASA) (each called "study drug"). 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)
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for phase_3
Started Nov 2025
16 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
October 3, 2025
CompletedFirst Posted
Study publicly available on registry
October 9, 2025
CompletedStudy Start
First participant enrolled
November 24, 2025
CompletedPrimary Completion
Last participant's last visit for primary outcome
May 17, 2027
ExpectedStudy Completion
Last participant's last visit for all outcomes
July 16, 2027
May 6, 2026
May 1, 2026
1.5 years
October 3, 2025
May 4, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
Incidence of the composite endpoint of symptomatic VTE and VTE-related death
Through day 30 visit
Secondary Outcomes (14)
Incidence of confirmed symptomatic Deep Vein Thrombosis (DVT)
Through day 30 visit
Incidence of confirmed Pulmonary Embolism (PE)
Through day 30 visit
Incidence of VTE-related death
Through day 30 visit
Time to first event of the composite endpoint of symptomatic VTE and VTE-related death
Through day 30 visit
Time to first event of confirmed symptomatic DVT
Through day 30 visit
- +9 more secondary outcomes
Study Arms (2)
REGN7508 and Placebo
EXPERIMENTALPlacebo and ASA
ACTIVE COMPARATORInterventions
Eligibility Criteria
You may qualify if:
- Is undergoing a primary elective unilateral TKA
- Is in good health based on laboratory safety testing as described in the protocol
You may not qualify if:
- 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
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (16)
Eisenhower Medical Center
Rancho Mirage, California, 92270, United States
Sky Ridge Medical Center
Lone Tree, Colorado, 80124, United States
Medical Research of Westchester - MPLUS Research Network
Miami, Florida, 33165, United States
Phoenix Clinical Research
Tamarac, Florida, 33321, United States
Endeavor Health
Skokie, Illinois, 60076, United States
The Orthopaedic Research Foundation, Inc.
Indianapolis, Indiana, 46278, United States
NextStage Clinical Research, St. Francis Medical Park
Wichita, Kansas, 67214, United States
Sinai Hospital of Baltimore, Inc.
Baltimore, Maryland, 21215, United States
Holy Name Medical Center
Teaneck, New Jersey, 07666, United States
Coastal Vascular Institute, PA
Wilmington, North Carolina, 28401, United States
University of Cincinnati
Cincinnati, Ohio, 45267, United States
The Ohio State University Wexner Medical Center
Columbus, Ohio, 43210, United States
Ohio Clinical Trials
Columbus, Ohio, 43212, United States
HD Research - Memorial Hermann Village
Houston, Texas, 77043, United States
Endeavor Clinical Trials
San Antonio, Texas, 78240, United States
Spokane Joint Replacement Center
Spokane, Washington, 99218, United States
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Study Officials
- STUDY DIRECTOR
Clinical Trial Management
Regeneron Pharmaceuticals
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 3
- Allocation
- RANDOMIZED
- Masking
- QUADRUPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
October 3, 2025
First Posted
October 9, 2025
Study Start
November 24, 2025
Primary Completion (Estimated)
May 17, 2027
Study Completion (Estimated)
July 16, 2027
Last Updated
May 6, 2026
Record last verified: 2026-05
Data Sharing
- IPD Sharing
- Will share
- Shared Documents
- STUDY PROTOCOL, SAP, ICF, CSR, ANALYTIC CODE
- Time Frame
- When Regeneron has: * received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development * made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry) * the legal authority to share the data, and * ensured the ability to protect participant privacy
- Access Criteria
- Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf
All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing