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NCT Number: NCT07015905

REGN7508 Versus Apixaban and Enoxaparin for Thromboprophylaxis After Total Knee Arthroplasty in Adults

This study is researching an experimental drug called REGN7508 (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.

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

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Multi-profile Hospital for Active Treatment Hearth and Brain EAD, Pleven, Bulgaria

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
  • Body weight ≤130 kg at screening visit 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 as described in the protocol
  • History of thromboembolic disease or thrombophilia
  • History of major surgery, including brain, spinal, or ocular, or major trauma within approximately the past 6 months prior to randomization
  • Has an estimated Glomerular Filtration Rate (GFR) of <30 mL/min/1.73 m2 at the screening visit as described in the protocol

Note: Other protocol-defined Inclusion/ Exclusion Criteria apply

Treatment and study plan

REGN7508

Drug

Administered per the protocol

Other names: cenvacibart

Apixaban

Drug

Administered per the protocol

Enoxaparin

Drug

Administered per the protocol

Other names: Inhixa

Placebo

Drug

Administered per the protocol

Primary outcomes

  1. Incidence of the composite endpoint of asymptomatic or symptomatic Venous Thromboembolism (VTE) [including VTE-related death]

    Time frame: Through day 12 visit, approximately 14 days

Secondary outcomes

  1. Time-to-first event of the composite endpoint of asymptomatic or symptomatic VTE (including VTE-related death)

    Time frame: Through day 12 visit, approximately 14 days

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

    Time frame: Through day 12 visit, approximately 14 days

  3. Incidence of confirmed Pulmonary Embolism (PE)

    Time frame: Through day 12 visit, approximately 14 days

  4. Incidence of VTE-related death

    Time frame: Through day 12 visit, approximately 14 days

  5. Time-to-first event of confirmed symptomatic DVT

    Time frame: Through day 12 visit, approximately 14 days

  6. Time-to-first event of confirmed PE

    Time frame: Through day 12 visit, approximately 14 days

  7. Time to VTE-related death

    Time frame: Through day 12 visit, approximately 14 days

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

    Time frame: Through day 12 visit, approximately 14 days

  9. Incidence of the composite endpoint of asymptomatic or symptomatic VTE (including VTE-related death)

    Time frame: Through day 12 visit, approximately 14 days

  10. Incidence of minor bleeding

    Time frame: Through day 12 visit, approximately 14 days

  11. Incidence of Treatment Emergent Adverse Events (TEAEs)

    Time frame: Approximately day 90

  12. Occurrence of Anti-Drug Antibodies (ADA) to REGN7508

    Time frame: Approximately day 90

  13. Magnitude of ADA to REGN7508

    Time frame: Approximately day 90

  14. Concentrations of REGN7508

    Time frame: Approximately day 90

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, Randomized, Open-Label, Study to Evaluate REGN7508, A Factor XI Monoclonal Antibody, Versus Apixaban and Enoxaparin for Prophylaxis of Venous Thromboembolism After Elective Total Knee Arthroplasty (ROXI-APEX)

Acronym: ROXI-APEX

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Jun 11, 2025
Registry last updated
Jul 13, 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.

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