Updated May 2026 · ClinicalTrials.gov

RECRUITINGPhase 3INTERVENTIONAL

Stroke and Systemic Embolism Prevention in Adult Participants With Atrial Fibrillation for Whom Oral Anticoagulation is Unsuitable

A Master Protocol for a Phase 3, Randomized, Multicenter, Double-blind Study to Assess Stroke and Systemic Embolism Prevention With REGN7508 and REGN9933, Monoclonal Antibodies Against Factor XI, Versus Placebo in Participants With Atrial Fibrillation for Whom Oral Anticoagulation is Unsuitable (ROXI-INCLINE)

Stroke and Systemic Embolism Prevention in Adult Participants With Atrial Fibrillation for Whom Oral Anticoagulation is Unsuitable (NCT07430956) is a Phase 3 interventional studying Atrial Fibrillation (AF), sponsored by Regeneron Pharmaceuticals. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

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)

What Stage of Research Is This?

Phase 3 trials confirm efficacy and safety in large patient groups (often 300–3,000+) and form the evidence base for an FDA approval submission. For Atrial Fibrillation (AF), Phase 3 studies typically randomize participants between the investigational treatment and either a placebo or current standard of care. A successful Phase 3 result is the threshold most treatments need to clear before regulatory approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 2,628 participants makes this one of the larger Atrial Fibrillation (AF) trials currently registered. Trials at this scale are typically global, run across many sites, and designed to generate the definitive evidence package for an FDA approval submission or a label expansion.

Who May Be Eligible (Plain English)

Key Who May Qualify: 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 Who Should NOT Join This Trial: 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 Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

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

Treatments Being Tested

DRUG

REGN7508

Administered per the protocol

DRUG

REGN9933

Administered per the protocol

DRUG

Placebo

Administered per the protocol

Locations (5)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

SEC Clinical Research

Dothan, Alabama, United States

Profound Research LLC at Southern California Heart Specialists

Pasadena, California, United States

Cardiology Associates Medical Group

Ventura, California, United States

AA Medical Research Center (MRC)

Flint, Michigan, United States

K&R Research LLC

Marion, Ohio, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT07430956), the sponsor (Regeneron Pharmaceuticals), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT07430956 clinical trial studying?

Who can participate in NCT07430956?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT07430956?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT07430956. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT07430956. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.