NCT05618808

A Trial to Learn How Well REGN9933 Works for Preventing Blood Clots After Knee Replacement Surgery in Adult Participants

A Phase 2, Multicenter, Randomized, Open-Label, Active-Control Study of REGN9933, a Factor XI Monoclonal Antibody, for Prevention of Venous Thromboembolism After Elective, Unilateral, Total Knee Arthroplasty

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 373 (actual)
• Sponsor: Regeneron Pharmaceuticals · Industry
• Sex: All
• Age: 50 Years
• Healthy volunteers: Not accepted

Summary

The primary objective of the study is to evaluate the efficacy of REGN9933 for the prevention of venous thromboembolism (VTE) after unilateral total knee arthroplasty (TKA), compared to enoxaparin The secondary objectives of the study are: * To evaluate the bleeding risk (ie, major and clinically relevant non-major \[CRNM\] bleeding) of REGN9933 after unilateral TKA through time of venography, compared to enoxaparin * To assess overall safety and tolerability of REGN9933 in participants undergoing TKA * To evaluate the efficacy of REGN9933 in prevention of clinically relevant VTE, compared to enoxaparin * To evaluate the efficacy of REGN9933 in prevention of deep venous thrombosis (DVT) detected by venography, compared to enoxaparin * To evaluate the pharmacokinetics (PK) of REGN9933 after single intravenous (IV) administration * To assess pharmacodynamic (PD) effects of REGN9933 on intrinsic and extrinsic coagulation pathways * To assess immunogenicity following a single dose of REGN9933 over time * To compare the efficacy of enoxaparin and apixaban in prevention of VTE after unilateral TKA

Conditions

• Venous Thromboembolism

Interventions

Type	Name	Description
DRUG	REGN9933	Participants will receive a single dose of REGN9933 by IV infusion
DRUG	Enoxaparin	Participants will receive enoxaparin by SC administration daily through the time of venography (or day 12, whichever is earlier)
DRUG	Apixiban	Participants will receive apixaban orally twice a day through the time of venography (or day 12, whichever is earlier)

Timeline

• Start date: 2023-05-24
• Primary completion: 2024-05-27
• Completion: 2024-05-27
• First posted: 2022-11-16
• Last updated: 2025-08-29
• Results posted: 2025-07-16

Locations

16 sites across 7 countries: Belgium, Bulgaria, Canada, Hungary, Latvia, Lithuania, Poland

Regulatory

• FDA-regulated drug study