Clinical Trial

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

Study acronym: ROXI-ASPEN

Recruiting Phase 3

Summary

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)

Protocol Amendment History 6 changes

notable Trial sites expanded: 28 -> 32 locations 2026-07-23

notable Trial sites expanded: 23 -> 28 locations 2026-07-10

notable Trial sites expanded: 19 -> 23 locations 2026-06-18

critical Primary endpoint(s) modified 2026-06-04

notable Trial sites expanded: 16 -> 19 locations 2026-06-04

notable Trial sites expanded: 10 -> 13 locations 2026-04-10

Trial Details

NCT Number	NCT07213778
Lead Sponsor	Regeneron Pharmaceuticals
Conditions	Symptomatic Venous Thromboembolism (VTE)
Enrollment	2,000 participants
Start Date	2025-11-24
Primary Completion	2027-05-17 (estimated)
Study Completion	2027-07-16 (estimated)
Updated on ClinicalTrials.gov	2026-07-22