ROXI-ATLAS

Currently Recruiting: Participants and Sites

Study Drug/Intervention: REGN7508, REGN9933/Apixaban

Anticipated Sample Size: 1,200 Participants

Study Timeline: This study is expected to conclude in October 2027.

ClinicalTrials.gov ID: NCT07175428

Objective

Regeneron is conducting this study to assess whether treatment with REGN7508 and REGN9933, fully human monoclonal antibodies against the catalytic and apple 2 domains of Factor XI (FXI), respectively, leads to a lower incidence of bleeding compared to apixaban in participants with atrial fibrillation (AF).

Inclusion Criteria

• Is ≥18 years of age or the legal age of consent in the jurisdiction in which the study is taking place at the time of signing the informed consent
• Has AF or flutter (paroxysmal or persistent), not felt to be secondary to a reversible cause, and an indication for indefinite anticoagulation treatment
  • Note: AF must be documented on an electrocardiogram or rhythm strip (not a wearable device) within 1 year prior to randomization
• Meets one of the following:
  • CHA2DS2-VA score ≥2 and OAC naïve (target at least 50%) OR
  • CHA2DS2-VA score ≥3 OR
  • CHA2DS2-VA score of 2 AND at least 1 of the following enrichment criteria:
    • age ≥80 years as the risk factor for the score of 2
    • renal dysfunction with estimated glomerular filtration rate (eGFR) ≤50 mL/min/1.73m2 within 30 days prior to randomization
    • prior episode of non-traumatic major bleeding
    • current or planned use of single or dual agent antiplatelet therapy
    • weight ≤60 kg
    • previous stroke, transient ischemic attack, or systemic embolism as a risk factor for the score of 2
• Must have an international normalization ratio <2.5 at the time of randomization if taking warfarin or another vitamin K antagonist

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 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 12 weeks starting from randomization
• Had an ischemic stroke within 2 days prior to randomization
• Has eGFR ≤15 mL/min/1.73m2 within 30 days prior to randomization or on dialysis or expected to be started on dialysis within the next 12 weeks starting from randomization
• Has a history of central nervous system bleeding within 30 days prior to randomization

Participants with AF at risk for stroke or systemic embolism.

27 weeks, including the screening period.

Follow-Up

The treatment duration will be 12 weeks, followed by a 90-day follow-up period after the final treatment visit.

Regeneron Pharmaceuticals, Inc.

• Project PI: Manesh Patel, MD

• Project PL: Lizzie Elliot