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Taking people in CanadaPhase 3

REGN7508 compared with apixaban to prevent stroke in atrial fibrillation

Compares REGN7508 with apixaban for preventing stroke in adults with atrial fibrillation.

Plain-language title generated from the registry record
Registry title: Stroke and Systemic Embolism Prevention in Adult Participants With Atrial Fibrillation

Key facts

Where
Hamilton, Longueuil, and Sherbrooke, CanadaSee the 3 sites
Phase
Phase 3

Where in Canada

  • Premiere Clinical Trial NetworkHamilton, CanadaTaking people
  • Viacar Recherches Cliniques inc.Longueuil, CanadaTaking people
  • Diex Recherche Inc.Sherbrooke, CanadaTaking people

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  4. What happens if I want to stop?
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Trial details

Who runs it
Regeneron Pharmaceuticals
Trial code
NCT07626411EU 2025-521617-97-00
Record updated
5 November 2026
Original description
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.Read full original descriptionShow less

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)

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)

Inclusion: 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).

Exclusion: 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 a mechanical heart valve prosthesis (Note: transcatheter aortic valve replacement is not an exclusion); 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; Has known moderate-to-severe mitral stenosis.

ClinicalTrials.gov NCT07626411 · EU CTIS 2025-521617-97-00