NCT07175428 · Regeneron Pharmaceuticals
Safety in Adult Participants With Atrial Fibrillation Who Are Treated With Anticoagulation
(ROXI-ATLAS)
What this study is about
This study is researching experimental drugs called REGN7508 and REGN9933. The study is focused on participants who have atrial fibrillation, which means that the heart beats too fast and unevenly. REGN7508 and REGN9933 are designed to help stop blood clots forming in patients with atrial fibrillation.
View original scientific description
This study is researching experimental drugs called REGN7508 and REGN9933. The study is focused on participants who have atrial fibrillation, which means that the heart beats too fast and unevenly. 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 well REGN7508 and REGN9933 work in patients that get medicine for their atrial fibrillation. The bleeding effects of REGN7508 and REGN9933 will be compared to another medicine (apixaban), which is available on the market to treat and prevent formation of blood clots.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Has AF or flutter (paroxysmal or persistent), not felt 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 \[C: Congestive heart failure; H: Hypertension; A2: Age ≥75 years (double points); D: Diabetes mellitus; S2: Stroke or TIA or Thromboembolism (double points); V: Vascular disease; A: Age 65-74 years\] 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 Normalization 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 successful ablation therapy or Left Atrial Appendage (LAA) occlusion/exclusion, or planned ablation or LAA occlusion/exclusion as described in the protocol
- Had an ischemic stroke within 2 days prior to randomization
- Has estimated Glomerular Filtration Rate (eGFR) \<15 mL/min/1.73m\^2 within 30 days prior to randomization or on dialysis or expected to be started as described in the protocol
- Has a history of central nervous system bleeding within 30 days prior to randomization Note: Other protocol-defined Inclusion/ Exclusion criteria apply
Where
- Dothan, Alabama
- Fairhope, Alabama
- Covina, California
- Encinitas, California
- Fremont, California
- Huntington Beach, California
- Pasadena, California
- Pomona, California
- Santa Rosa, California
- Ventura, California
- West Hills, California
- Cutler Bay, Florida
And 25 more locations — see the full list below.
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 8, 2026 · Source of record for eligibility and locations