Recruiting
Phase 3

REGN7508 & REGN9933

Sponsor:

Regeneron Pharmaceuticals

Code:

NCT07430956

Conditions

Atrial Fibrillation (AF)

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

REGN7508

REGN9933

Placebo

Study Details

Brief summary:

This study is researching 2 different experimental drugs called REGN7508 and REGN9933 (called "study drugs"). The study is focused on people who have atrial fibrillation, which means that the heart beats too fast and unevenly. When this happens, blood cannot move smoothly through the heart; it can slow down or pool in one spot, which can lead to the formation of blood clots.

REGN7508 and REGN9933 are designed to help stop blood clots forming in patients with atrial fibrillation. The aim of the study is to see how effective and safe REGN7508 and REGN9933, individually, are in preventing ischemic stroke or systemic embolism in people with atrial fibrillation who cannot or may choose to not take blood thinners.

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

  • What side effects may happen from taking REGN7508 or REGN9933
  • How well does REGN7508 or REGN9933 lower the risk of having an ischemic stroke and/or systemic embolism compared to the placebo
  • How well does REGN7508 or REGN9933 lower the risk of having a major health problem affecting heart and blood circulation compared to placebo
  • How well does REGN7508 or REGN9933 lower the risk of death compared to placebo
  • How much REGN7508 or REGN9933 is in the blood at different times
  • Whether the body makes antibodies against REGN7508 or REGN9933 (which could make the study drugs less effective or could lead to side effects)

Conditions

Atrial Fibrillation (AF)

Study ID

NCT07430956

Start date

Apr 3, 2026

Status verified date

Oct, 2026

Completion date

Jun 26, 2029

Anticipated

Primary completion date

Mar 28, 2029

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Key Inclusion Criteria:

1. Has AF or flutter (paroxysmal or persistent), not considered to be secondary to a reversible cause
2. At moderate to high risk for stroke defined as:

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 ≥4 OR
2. CHA2DS2-VA score of 3 AND at least 1 enrichment criteria as described in the protocol
3. Shared decision making between the participant and provider determining that the bleeding risk of Oral Anticoagulant (OAC) therapy outweighs the benefits, making the participant unsuitable for OAC therapy as described in the protocol

Key Exclusion Criteria:

1. Has a mechanical heart valve prosthesis (Note: transcatheter aortic valve replacement is not an exclusion)
2. Had an ischemic stroke within 2 days prior to randomization
3. Has persistent, uncontrolled hypertension (per investigator's discretion)
4. Has a history of Central Nervous System (CNS) bleeding within 30 days prior to randomization
5. Has a life expectancy less than 12 months
6. Has participated in a prior Factor XI (FXI) inhibitor study

Note: Other protocol-defined Inclusion/ Exclusion criteria apply

Study Design

Enrollment

2628 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Prevention

Interventions and Outcome Measures

Arms

experimental: REGN7508

experimental: REGN9933

placebo comparator: Placebo

Interventions

REGN7508

Administered per the protocol

REGN9933

Administered per the protocol

Placebo

Administered per the protocol

Primary outcome measure

  • Time to first occurrence of ischemic stroke or systemic embolism [ Time Frame: Up to 36 months ]
  • Time to first occurrence of International Society on Thrombosis and Haemostasis (ISTH) major bleeding [ Time Frame: Up to 36 months ]

Central Contacts and Locations

Central contacts

Clinical Trials Administrator

844-734-6643clinicaltrials@regeneron.com

Locations

SEC Clinical Research

Recruiting

Dothan, Alabama, United States, 36305

Sun City Clinical Research

Recruiting

Glendale, Arizona, United States, 85351

Arkansas Cardiology P.A.

Recruiting

Little Rock, Arkansas, United States, 72205

Mission Cardiovascular Research Institute

Recruiting

Fremont, California, United States, 94538

National Institute of California Heart and Vein Specialists

Recruiting

Huntington Beach, California, United States, 92648

Profound Research LLC at San Diego Cardiovascular Associates

Recruiting

La Jolla, California, United States, 92037

Valley Clinical Trials, LLC dba Flourish Research

Recruiting

Northridge, California, United States, 91325

Profound Research LLC at Southern California Heart Specialists

Recruiting

Pasadena, California, United States, 91105

FOMAT - Comprehensive Cardiovascular Care

Recruiting

Santa Maria, California, United States, 93454

Cardiology Associates Medical Group

Recruiting

Ventura, California, United States, 93003

Interventional Cardiology Medical Group

Recruiting

West Hills, California, United States, 91307

East Coast Institute for Research, Jacksonville

Recruiting

Jacksonville, Florida, United States, 32216

South Florida Research Organization LLC

Recruiting

Medley, Florida, United States, 33166

Sec Clinical Research

Recruiting

Pensacola, Florida, United States, 32503

Cardiovascular Center of Sarasota Foundation for Research and Education

Recruiting

Sarasota, Florida, United States, 34239

Clinical Site Partners, LLC DBA Flourish Research

Recruiting

Winter Park, Florida, United States, 32789

Atlanta Clinical Research Centers

Recruiting

Atlanta, Georgia, United States, 30342

NSC Research, Inc

Recruiting

Johns Creek, Georgia, United States, 30024

Franciscan Physician Network, Indiana Heart Physicians

Recruiting

Indianapolis, Indiana, United States, 46237

Indiana Medical Research

Recruiting

Merrillville, Indiana, United States, 46410

Profound Research, Powers Health Medical Group - Electrophysiology

Recruiting

Munster, Indiana, United States, 46321

Monroe Research, LLC

Recruiting

West Monroe, Louisiana, United States, 71291

Profound Research, Cardiology and Vascular Associates (CAVA) - Bloomfield Hills

Recruiting

Bloomfield Hills, Michigan, United States, 48304

Profound Research, Millennium Cardiology

Recruiting

Farmington Hills, Michigan, United States, 48334

Flint Clinical Research

Recruiting

Flint, Michigan, United States, 48503

AA Medical Research Center (MRC)

Recruiting

Flint, Michigan, United States, 48504

Jackson Heart Clinic

Recruiting

Jackson, Mississippi, United States, 39216

Super Health Pharmacy

Recruiting

Staten Island, New York, United States, 10309

Hawthorne Health, Moose Pharmacy of Concord

Recruiting

Concord, North Carolina, United States, 28025

K&R Research LLC

Recruiting

Marion, Ohio, United States, 43302

AnMed Health

Recruiting

Anderson, South Carolina, United States, 29621

Monument Health Clinical Research

Recruiting

Rapid City, South Dakota, United States, 57701

Tennessee Center for Clinical Trials

Recruiting

Tullahoma, Tennessee, United States, 37388

PharmaTex Research

Recruiting

Amarillo, Texas, United States, 79106

PanAmerican Clinical Research

Recruiting

Brownsville, Texas, United States, 78520

Southwest Family Medicine Associates

Recruiting

Dallas, Texas, United States, 75235

East Texas Cardiology

Recruiting

Houston, Texas, United States, 77002

Synergy Group Medical,LLC

Recruiting

Houston, Texas, United States, 77036

Synergy Groups Medical

Recruiting

Houston, Texas, United States, 77061

Heart Institute of East Texas

Recruiting

Lufkin, Texas, United States, 75901

Texas Institute of Cardiology PA

Recruiting

McKinney, Texas, United States, 75071

Synergy Group Medical, LLC

Recruiting

Missouri City, Texas, United States, 77459

Conquest Research

Recruiting

Vienna, Virginia, United States, 22182

Hamilton Medical Research Group (HMRG)

Recruiting

Hamilton, Ontario, Canada, L8L 5G4

More Information

Sponsor

Regeneron Pharmaceuticals

Last update posted

Oct 14, 2026

Last verified

Oct, 2026

Keywords

  • Blood clots
  • Ischemic stroke
  • Systemic embolism
  • Pulmonary embolism
  • Venous Thromboembolism (VTE)

Trial information was received from ClinicalTrials.gov and was last updated on 2026-10-23. This information was provided to ClinicalTrials.gov by Regeneron Pharmaceuticals on 2026-10-14. Recruitment status is synced daily from ClinicalTrials.gov and may not reflect the sponsor's current status. Confirm during your call.