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NCT Number: NCT07626411

Stroke and Systemic Embolism Prevention in Adult Participants With Atrial Fibrillation

This study is researching an experimental drug called REGN7508 (called "study drug") and how it compares against another treatment called apixaban. The study is focused on people who have atrial fibrillation, which means that the heart beats too fast and unevenly.

The aim of the study is to see how safe and effective REGN7508 is in preventing stroke and/or systemic embolism in participants with atrial fibrillation and how it compares against participants that will receive apixaban in this study.

The study is looking at several other research questions, including:

* What side effects may happen from taking the study drug * Whether the body makes antibodies against the study drug (which could make the study drug less effective or could lead to side effects)

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Key information

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

  • Has AF or flutter (paroxysmal or persistent), not considered to be secondary to a reversible cause, and an indication for indefinite anticoagulation treatment as described in the protocol
  • Meets one of the following:
  • CHA2DS2-VA [C: Congestive heart failure; H: Hypertension; A2: Age ≥75 years (double points); D: Diabetes mellitus; S2: Stroke or TIA or Systemic embolism (double points); V: Vascular disease; A: Age 65-74 years] score ≥2 and Oral Anticoagulant (OAC) naïve OR
  • CHA2DS2-VA score ≥3 OR
  • CHA2DS2-VA score of 2 AND at least 1 enrichment criteria as described in the protocol
  • Must have an International Normalized Ratio (INR) <2.5 at the time of randomization if taking warfarin or another Vitamin K Antagonist (VKA)

Key Exclusion Criteria:

  • Has a mechanical heart valve prosthesis (Note: transcatheter aortic valve replacement is not an exclusion)
  • Has known moderate-to-severe mitral stenosis
  • Has had a successful ablation therapy without documented recurrent AF or a participant after Left Atrial Appendage (LAA) occlusion/exclusion or plan for ablation or LAA occlusion/exclusion within the next 6 months starting from randomization
  • Had an ischemic stroke within 2 days prior to randomization
  • Has persistent, uncontrolled hypertension (per investigator's discretion)
  • Has estimated Glomerular Filtration Rate (eGFR) <15 mL/min/1.73m2 within 30 days prior to randomization or is on dialysis or expected to be started on dialysis within the next 6 months starting from randomization

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

Placebo

Drug

Administered per the protocol

Primary outcomes

  1. Time to first occurrence of stroke (ischemic, hemorrhagic, or of unspecified type) or systemic embolism

    Time frame: Approximately 36 months

  2. Time to first occurrence of International Society on Thrombosis and Haemostasis (ISTH) major bleeding or ISTH Clinically Relevant Non-Major (CRNM) bleeding

    Time frame: Approximately 36 months

Secondary outcomes

  1. Time to first occurrence of stroke (ischemic, hemorrhagic, or of unspecified type), systemic embolism, ISTH major bleeding, or ISTH CRNM bleeding

    Time frame: Approximately 36 months

  2. Time to first occurrence of stroke (ischemic, hemorrhagic, or of unspecified type), systemic embolism, or ISTH major bleeding

    Time frame: Approximately 36 months

  3. Time to first occurrence of stroke (ischemic, hemorrhagic, or of unspecified type), systemic embolism, ISTH major bleeding, or all-cause death

    Time frame: Approximately 36 months

  4. Time to first occurrence of ISTH major bleeding

    Time frame: Approximately 36 months

  5. Time to first occurrence of hemorrhagic stroke, intracerebral hemorrhage, or hemorrhagic transformation of an ischemic stroke

    Time frame: Approximately 36 months

  6. Time to occurrence of fatal bleeding

    Time frame: Approximately 36 months

  7. Number of ISTH major bleeding events

    Time frame: Approximately 36 months

  8. Number of ISTH CRNM bleeding events

    Time frame: Approximately 36 months

  9. Number of minor bleeding events

    Time frame: Approximately 36 months

  10. Time to all-cause death

    Time frame: Approximately 36 months

  11. Occurrence of Treatment-Emergent Adverse Events (TEAEs)

    Time frame: Approximately 39 months

  12. Severity of TEAEs

    Time frame: Approximately 39 months

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

    Time frame: Approximately 36 months

  14. Magnitude of ADA to REGN7508

    Time frame: Approximately 36 months

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, Randomized, Multicenter, Double-blind Study to Assess Stroke and Systemic Embolism Prevention With REGN7508, a Monoclonal Antibody Against Factor XI, Versus Apixaban in Participants With Atrial Fibrillation (ROXI-EVEREST)

Acronym: ROXI-EVEREST

Important dates

Study start
2026
Primary completion
2029
Study completion
2029
First posted
Jun 4, 2026
Registry last updated
Jun 4, 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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