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Atrial Fibrillation (AF)Phase 2ROXI-ATLASNCT07175428

Safety in Adult Participants With Atrial Fibrillation Who Are Treated With Anticoagulation

A Phase 2 study testing REGN7508, REGN9933 and Apixaban in people with Atrial Fibrillation (AF), run by Regeneron Pharmaceuticals at 91 sites in 4 countries.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial summary

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. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Atrial Fibrillation (AF)
What is being tested?
REGN7508, REGN9933 and Apixaban
Could I receive a placebo?
No, everyone receives an active treatment
How many people
1,200 participants
Where
91 sitesin 4 countries
Study dates
20 Oct 2025to 21 Apr 2027
Phase
Phase 2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 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)

Who cannot join

  • 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

Trial locations and contacts

91 sites in 4 countries. Contact the study team or a site near you to ask about taking part.

Clinical Trials Administrator contact

844-734-6643

clinicaltrials@regeneron.com

91 sites in 4 countries

United States43 sites, 42 recruiting

  • PharmaTex Research

    Amarillo, Texas, 79106

    Recruiting

  • Grady Health System

    Atlanta, Georgia, 30303

    Recruiting

  • Health Sciences Research Building II

    Atlanta, Georgia, 30322

    Withdrawn

  • Beth Israel Lahey Health, Beth Israel Deaconess Medical Center (BIDMC)

    Boston, Massachusetts, 02215

    Recruiting

  • Alpine Research TC

    Clinton, Utah, 84015

    Recruiting

  • Valley Clinical Trials, Inc

    Covina, California, 91723

    Recruiting

  • Nouvelle Clinical Research LLC

    Cutler Bay, Florida, 33189

    Recruiting

  • SEC Clinical Research

    Dothan, Alabama, 36305

    Recruiting

  • North Coast Cardiology

    Encinitas, California, 92024

    Recruiting

  • Eastern Shore Research Institute

    Fairhope, Alabama, 36532

    Recruiting

  • Profound Research, Millennium Cardiology

    Farmington Hills, Michigan, 48334

    Recruiting

  • AA Medical Research Center (MRC)

    Flint, Michigan, 48504

    Recruiting

  • Mission Cardiovascular Research Institute

    Fremont, California, 94538

    Recruiting

  • Anderson Medical Research

    Ft. Washington, Maryland, 20744

    Recruiting

  • Moses Cone Hospital Operating Corporation dba Cone Health, Lebauer-Brodie Center for Cardiovascular Research

    Greensboro, North Carolina, 27401

    Recruiting

  • National Institute of California Heart and Vein Specialists

    Huntington Beach, California, 92648

    Recruiting

  • Indiana University

    Indianapolis, Indiana, 46202

    Recruiting

  • Blue Coast Research Center, LLC

    Indianapolis, Indiana, 46237

    Recruiting

  • Franciscan Physician Network, Indiana Heart Physicians

    Indianapolis, Indiana, 46237

    Recruiting

  • East Coast Institute for Research, Jefferson City

    Jefferson City, Tennessee, 37760

    Recruiting

  • NSC Research, Inc

    Johns Creek, Georgia, 30024

    Recruiting

  • Fairview Health Services

    Maplewood, Minnesota, 55109

    Recruiting

  • K&R Research LLC

    Marion, Ohio, 43302

    Recruiting

  • Advanced Medical Research

    Maumee, Ohio, 43537

    Recruiting

  • Complete Heart Care P.A.

    McKinney, Texas, 75071

    Recruiting

  • Texas Institute of Cardiology PA

    McKinney, Texas, 75071

    Recruiting

  • South Florida Research Organization LLC

    Medley, Florida, 33166

    Recruiting

  • Indiana Medical Research

    Merrillville, Indiana, 46410

    Recruiting

  • Inpatient Research Clinic LLC

    Miami Lakes, Florida, 33014

    Recruiting

  • Synergy Group Medical, LLC

    Missouri City, Texas, 77459

    Recruiting

  • Permian Research Foundation

    Odessa, Texas, 79761

    Recruiting

  • Profound Research LLC at Southern California Heart Specialists

    Pasadena, California, 91105

    Recruiting

  • Empire Clinical Research

    Pomona, California, 91767

    Recruiting

  • Monument Health Clinical Research

    Rapid City, South Dakota, 57701

    Recruiting

  • The Cardiovascular Center

    Redding, California, 96001

    Recruiting

  • Reid Physician Associates

    Richmond, Indiana, 47374

    Recruiting

  • Northbay Clinical Research Center

    Santa Rosa, California, 95405

    Recruiting

  • Cardiovascular Center of Sarasota Foundation for Research and Education

    Sarasota, Florida, 34239

    Recruiting

  • Tyler Cardiovascular Consultants

    Tyler, Texas, 75701

    Recruiting

  • Cardiology Associates Medical Group

    Ventura, California, 93003

    Recruiting

  • Interventional Cardiology Medical Group

    West Hills, California, 91307

    Recruiting

  • Monroe Research, LLC

    West Monroe, Louisiana, 71291

    Recruiting

  • Clinical Site Partners, LLC DBA Flourish Research

    Winter Park, Florida, 32789

    Recruiting

Other trials in United States

Brazil24 sites, 24 recruiting

  • Centro De Pesquisa Clinica Do Coracao

    Aracaju, Sergipe, 49055-530

    Recruiting

  • Cardiologia Assistencial e de Pesquisa Ltda (Cardresearch)

    Belo Horizonte, Minas Gerais, 30150-274

    Recruiting

  • Nucleo de Pesquisa do Hospital Cardiologico Costantini (NUPEC)

    Belo Horizonte, Minas Gerais, 30220-140

    Recruiting

  • Centro de Estudos Procardio

    Blumenau, Santa Catarina, 89010-022

    Recruiting

  • AngioKormann Blumenau

    Blumenau, Santa Catarina, 89020-430

    Recruiting

  • Faculdade de Medicina de Botucatu (UNESP)

    Botucatu, São Paulo, 18618-687

    Recruiting

  • Hospital Universitario Sao Francisco na Providencia de Deus

    Bragança Paulista, São Paulo, 12916-542

    Recruiting

  • Sociedade Hospitalar Angelina Caron

    Campina Grande do Sul, Paraná, 83430-973

    Recruiting

  • Instituto De Pesquisa Clinica de Campinas (Ipecc)

    Campinas, São Paulo, 13060-080

    Recruiting

  • Hospital da Pontificia Universidade Catolica (PUC) Campinas

    Campinas, São Paulo, 13060-904

    Recruiting

  • Quanta Diagnostico por Imagem

    Curitiba, Paraná, 80045-110

    Recruiting

  • Pontificia Universidade Catolica do Paraná (PUC) Trials

    Curitiba, Paraná, 80230-130

    Recruiting

  • Nucleo de Pesquisa Clínica SS

    Curitiba, Paraná, 80730-150

    Recruiting

  • Via Medica Research Center

    Goiânia, Goiás, 74223-130

    Recruiting

  • Hospital Ruy Azeredo

    Goiânia, Goiás, 74453-200

    Recruiting

  • Hospital das Clinicas da Universidade Federal de Goias

    Goiânia, Goiás, 74605-050

    Recruiting

  • Hospital Maternidade e Pronto Socorro Santa Lucia

    Poços de Caldas, Minas Gerais, 37706-106

    Recruiting

  • Hospital Ernesto Dornelles

    Porto Alegre, Rio Grande do Sul, 90160-092

    Recruiting

  • CoraCentro Pesquisa Clinica

    Porto Alegre, Rio Grande do Sul, 90840-440

    Recruiting

  • CLINICOR - Clinica Cardiologica Ltda

    Ribeirão Preto, São Paulo, 14026-900

    Recruiting

  • Instituto de Cardiologia de Santa Catarina

    São José, Santa Catarina, 88103-450

    Recruiting

  • Fundacao Faculdade Regional de Medicina de Sao Jose do Rio Preto, Centro Integrado de Pesquisa (CIP)

    São José do Rio Preto, São Paulo, 15090-000

    Recruiting

  • Instituto Dante Pazanese de Cardiologia

    São Paulo, 04012-909

    Recruiting

  • Eurolatino Medical Research

    Uberlândia, Minas Gerais, 38400-500

    Recruiting

Other trials in Brazil

Canada16 sites, 16 recruiting

  • University of Alberta Hospital - Cardiology

    Edmonton, Alberta, T6G 2G3

    Recruiting

  • Health sciences North - Cardiology

    Greater Sudbury, Ontario, P3E 5J1

    Recruiting

  • Hamilton Health Sciences Corporation

    Hamilton, Ontario, L8L 2X2

    Recruiting

  • Hamilton Medical Research Group (HMRG)

    Hamilton, Ontario, L8L 5G4

    Recruiting

  • Viacar Recherches Cliniques Inc. - Cardiologie

    Longueuil, Quebec, J4H 4B9

    Recruiting

  • GA Research Associates Ltd.

    Moncton, New Brunswick, E1G-1A7

    Recruiting

  • Montreal Heart Institute

    Montreal, Quebec, H1T 1C8

    Recruiting

  • Dr James Cha

    Oshawa, Ontario, L1J 2K1

    Recruiting

  • CHU de Quebec-Universite Laval

    Québec, G1R 2J6

    Recruiting

  • CISSS du Bas-Saint-Laurent - Hopital regional de Rimouski - Cardiologie

    Rimouski, Quebec, G5L 5T1

    Recruiting

  • Heart Health Institute Research Inc. - Cardiology

    Scarborough Village, Ontario, M1B 4Z8

    Recruiting

  • Centre Hospitalier Universitaire De Sherbrooke (CHUS) - Cardiologie

    Sherbrooke, Quebec, J1H 5N4

    Recruiting

  • Diex Recherche Inc.

    Sherbrooke, Quebec, J1LOK3

    Recruiting

  • CISSSLAN, Hopital Pierre-Le Gardeur

    Terrebonne, Quebec, J6V 2H2

    Recruiting

  • Diex Recherche Trois-rivieres

    Trois-Rivières, Quebec, G9A 4P3

    Recruiting

  • Victoria Cardiac Arrhythmia Trials

    Victoria, British Columbia, V8Z 0B9

    Recruiting

Other trials in Canada

Argentina8 sites, 8 recruiting

  • STAT Research Argentina

    Buenos Aires, 1060

    Recruiting

  • Centro de Investigacion Clinica

    Ciudad Autonoma de Buenos Aires, Buenos Aires, 1060

    Recruiting

  • Sanatorio Duarte Quiros

    Córdoba, 5002

    Recruiting

  • DIM Clinica Privada

    Ramos Mejía, Buenos Aires, 1704

    Recruiting

  • Fundacion Estudios Clinicos

    Rosario, Santa Fe Province, 2000

    Recruiting

  • Sanatorio Parque

    Rosario, Santa Fe Province, 2000

    Recruiting

  • Centro de Investigaciones Clinicas del Litoral

    Santa Fe, S3000FWO

    Recruiting

  • Centro de Investigaciones Medicas Temperley (CIMET)

    Temperley, Buenos Aires, B1834MJC

    Recruiting

Other trials in Argentina

About this study

Official title: A Phase 2, Randomized, Multicenter, Open-label, Blinded-endpoint Study to Evaluate the Safety of REGN7508 and REGN9933, Monoclonal Antibodies Against FXI, Versus Apixaban in Participants With Atrial Fibrillation (ROXI-ATLAS)

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.

Read more

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

  • What side effects may happen from taking REGN7508 or REGN9933
  • How well do the study drugs reduce the risk of having a stroke
  • How much of REGN7508 or REGN9933 is in the blood at different times
  • Whether the body makes antibodies against REGN7508 or REGN9933 (which could make the drugs less effective or could lead to side effects)
Being tested
REGN7508, REGN9933, Apixaban
Keywords
Bleeding, Stroke, Systemic embolism, Blood clots
Medical subject headings
Atrial Fibrillation, Hemorrhage, Stroke, Thrombosis

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • REGN7508Drug

    Also called cenvacibart

    Administered per the protocol

  • REGN9933Drug

    Also called amrecibart

    Administered per the protocol

  • ApixabanDrug

    Also called Eliquis

    Administered per the protocol

Study groups in NCT07175428
Study groupRoleWhat they receive
REGN7508ExperimentalNot described
Receives: Drug: REGN7508
REGN9933ExperimentalNot described
Receives: Drug: REGN9933
ApixabanActive comparatorNot described
Receives: Drug: Apixaban

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Incidence of any bleeding

    Defined as the composite of International Society on Thrombosis and Haemostasis (ISTH) major bleeding, ISTH Clinically Relevant Non-Major (CRNM) bleeding, or minor bleeding

    Measured: 12 weeks

Secondary outcomes (18)

  1. Incidence of the composite of ISTH major bleeding or ISTH CRNM bleeding

    Measured: 12 weeks

  2. Incidence of ISTH major bleeding

    Measured: 12 weeks

  3. Incidence of ISTH CRNM bleeding

    Measured: 12 weeks

  4. Incidence of minor bleeding

    Measured: 12 weeks

  5. Number of ISTH major bleeding events

    Measured: 12 weeks

  6. Number of ISTH CRNM bleeding events

    Measured: 12 weeks

  7. Number of minor bleeding events

    Measured: 12 weeks

  8. Incidence of Treatment-Emergent Adverse Events (TEAEs)

    Measured: Approximately 25 weeks

  9. Severity of TEAEs

    Measured: Approximately 25 weeks

  10. Incidence of the composite of stroke or systemic embolism

    Measured: Approximately 12 weeks

  11. Incidence of Antidrug Antibodies (ADA) to REGN7508

    Measured: 12 weeks

  12. Magnitude of ADA to REGN7508

    Measured: 12 weeks

  13. Incidence of ADA to REGN9933

    Measured: 12 weeks

  14. Magnitude of ADA to REGN9933

    Measured: 12 weeks

  15. Concentrations of REGN7508

    Measured: Approximately 25 weeks

  16. Concentrations of REGN9933

    Measured: Approximately 25 weeks

  17. Change from baseline in activated Partial Thromboplastin Time (aPTT)

    Measured: Approximately 25 weeks

  18. Change from baseline in Prothrombin Time (PT)

    Measured: Approximately 25 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted16 Sep 2025
  2. Study start20 Oct 2025
  3. Primary completion9 Feb 2027 (estimated)
  4. Study completion21 Apr 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Masking
Single blind
Who is masked
Outcomes assessor
Enrolment
1,200 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07175428
Sponsor's protocol ID
R7508-CVA-2393
Acronym
ROXI-ATLAS
Status last verified
Nov 2026
First submitted
9 Sep 2025
Last updated
5 Nov 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing REGN7508, REGN9933 and Apixaban in people with Atrial Fibrillation (AF), run by Regeneron Pharmaceuticals at 91 sites in 4 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 6 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 5 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 91 sites in United States, Brazil, Canada, Argentina. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Clinical Trials Administrator (844-734-6643, clinicaltrials@regeneron.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Incidence of any bleeding (time frame: 12 weeks). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT07175428.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Nov 2026.

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