NCT07626411From ClinicalTrials.govRecruiting

Stroke and Systemic Embolism Prevention in Adult Participants With Atrial Fibrillation

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)

Atrial Fibrillation (AF)

At a glance

Phase: Phase 3
Study type: Interventional
Sponsor: Regeneron Pharmaceuticals
Enrolment target: 15,364
Started: 10 August 2026
Main results due: 11 September 2029
Study sites: 34
Registry updated: 28 September 2026

Can you take part?

Aged 18 years and over.
Open to any sex.
You need the condition being studied — healthy volunteers are not accepted.

These are the headline rules only. Every study has a longer list, and whether you are eligible is decided by the research team at the site — never by this page.

Read the full eligibility criteria

Key Inclusion Criteria:

1. 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
2. Meets one of the following:

   1. 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
   2. CHA2DS2-VA score ≥3 OR
   3. CHA2DS2-VA score of 2 AND at least 1 enrichment criteria as described in the protocol
3. 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:

1. Has a mechanical heart valve prosthesis (Note: transcatheter aortic valve replacement is not an exclusion)
2. Has known moderate-to-severe mitral stenosis
3. 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
4. Had an ischemic stroke within 2 days prior to randomization
5. Has persistent, uncontrolled hypertension (per investigator's discretion)
6. 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

What this study is about

In the sponsor’s own words, from the registry.

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)

Study sites(34)

Advanced Cardiovascular
Alexander City, Alabama, United States
Recruiting
SEC Clinical Research
Dothan, Alabama, United States
Recruiting
Sun City Clinical Research
Glendale, Arizona, United States
Recruiting
Mission Cardiovascular Research Institute
Fremont, California, United States
Recruiting
National Institute of California Heart and Vein Specialists
Huntington Beach, California, United States
Recruiting
Profound Research LLC at San Diego Cardiovascular Associates
La Jolla, California, United States
Recruiting
Radin Cardiovascular Medical Group
Newport Beach, California, United States
Recruiting
Valley Clinical Trials, LLC dba Flourish Research
Northridge, California, United States
Recruiting
Southern California Heart Specialists
Pasadena, California, United States
Recruiting
Cardiology Associates Medical Group
Ventura, California, United States
Recruiting
Interventional Cardiology Medical Group
West Hills, California, United States
Recruiting
Nouvelle Clinical Research LLC
Cutler Bay, Florida, United States
Recruiting
Healix Clinical Research
New Smyrna Beach, Florida, United States
Recruiting
Sec Clinical Research
Pensacola, Florida, United States
Recruiting
Cardiovascular Center of Sarasota Foundation for Research and Education
Sarasota, Florida, United States
Recruiting
Atlanta Clinical Research Centers
Atlanta, Georgia, United States
Recruiting
NSC Research, Inc
Johns Creek, Georgia, United States
Recruiting
Profound Research, Powers Health Medical Group - Electrophysiology
Munster, Indiana, United States
Recruiting
Monroe Research, LLC
West Monroe, Louisiana, United States
Recruiting
Anderson Medical Research
Ft. Washington, Maryland, United States
Recruiting
Profound Research, Cardiology and Vascular Associates (CAVA) - Bloomfield Hills
Bloomfield Hills, Michigan, United States
Recruiting
Profound Research, Millennium Cardiology
Farmington Hills, Michigan, United States
Recruiting
Super Health Pharmacy
Staten Island, New York, United States
Recruiting
Hawthorne Health, Moose Pharmacy of Concord
Concord, North Carolina, United States
Recruiting
K&R Research LLC
Marion, Ohio, United States
Recruiting
Tennessee Center for Clinical Trials
Tullahoma, Tennessee, United States
Recruiting
PharmaTex Research
Amarillo, Texas, United States
Recruiting
PanAmerican Clinical Research
Brownsville, Texas, United States
Recruiting
Synergy Groups Medical
Houston, Texas, United States
Recruiting
West Houston Area Clinical Trial Consultants, LLC
Houston, Texas, United States
Recruiting
Synergy Group Medical, LLC
Missouri City, Texas, United States
Recruiting
Permian Research Foundation
Odessa, Texas, United States
Recruiting
Carient Heart & Vascular
Manassas, Virginia, United States
Recruiting
Conquest Research
Vienna, Virginia, United States
Recruiting

Showing 34 of 34 sites. 34 of the 34 sites on this study are recruiting right now — a site can stop enrolling while the study as a whole is still open.

Source: ClinicalTrials.gov record NCT07626411. Trialion does not run this study, is not paid to refer anyone to it, and cannot enrol you. Eligibility is always decided by the research team at the site.

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