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

Not Applicable

Not yet recruiting

• Conditions: Atrial Fibrillation (AF)
• Interventions: Drug: REGN7508; Drug: REGN9933; Drug: Apixaban

• Registration Number: NCT07175428
• Lead Sponsor: Regeneron Pharmaceuticals

Brief 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.

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.

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)

Detailed Description

Not available

Study Timeline

• Status Verified: 2025-07
• Study First Submitted: 2025-09-09
• Study First Submitted QC: 2025-09-09
• Last Update Submitted: 2025-09-09
• Study First Posted: 2025-09-16
• Last Update Posted: 2025-09-16
• Study Start: 2025-10-21
• Primary Completion: 2027-04-26
• Study Completion: 2027-04-26

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 1200

Inclusion Criteria

1. 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

2. Meets one of the following:

   1. 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
   2. CHA2DS2-VA score ≥3 or
   3. CHA2DS2-VA score of 2 and at least 1 enrichment criteria as described in the protocol

3. Must have a Prothrombin Time/International Normalization Ratio (PT/INR) <2.5 at the time of randomization if taking warfarin or another Vitamin K Antagonist (VKA)

Key

Exclusion Criteria

1. Has a mechanical heart valve prosthesis (Note: transcatheter aortic valve replacement is not an exclusion)
2. Has known moderate-to-severe mitral stenosis
3. Has had successful ablation therapy or Left Atrial Appendage (LAA) occlusion/exclusion, or planned ablation or LAA occlusion/exclusion as described in the protocol
4. Had an ischemic stroke within 2 days prior to randomization
5. Has Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimated Glomerular Filtration Rate (eGFR) <15 mL/min/1.73m^2 within 14 days prior to randomization or on dialysis or expected to be started as described in the protocol
6. Has a history of central nervous system bleeding within 30 days prior to randomization

Note: Other protocol-defined Inclusion/ Exclusion criteria apply

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
REGN7508	REGN7508	-
REGN9933	REGN9933	-
Apixaban	Apixaban	-

Primary Outcome Measures

Name	Time	Method
Incidence of any bleeding	12 weeks	Defined as the composite of International Society on Thrombosis and Haemostasis (ISTH) major bleeding, ISTH Clinically Relevant Non-Major (CRNM) bleeding, or minor bleeding

Secondary Outcome Measures

Name	Time	Method
Incidence of ISTH CRNM bleeding	12 weeks
Incidence of minor bleeding	12 weeks
Number of ISTH major bleeding events	12 weeks
Number of ISTH CRNM bleeding events	12 weeks
Number of minor bleeding events	12 weeks
Incidence of the composite of ISTH major bleeding or ISTH CRNM bleeding	12 weeks
Incidence of ISTH major bleeding	12 weeks
Incidence of Treatment-Emergent Adverse Events (TEAEs)	Approximately 25 weeks
Severity of TEAEs	Approximately 25 weeks
Incidence of the composite of stroke or systemic embolism	Approximately 12 weeks
Incidence of Antidrug Antibodies (ADA) to REGN7508	12 weeks
Magnitude of ADA to REGN7508	12 weeks
Incidence of ADA to REGN9933	12 weeks
Magnitude of ADA to REGN9933	12 weeks
Concentrations of REGN7508	Approximately 25 weeks
Concentrations of REGN9933	Approximately 25 weeks
Change from baseline in activated Partial Thromboplastin Time (aPTT)	Approximately 25 weeks
Change from baseline in Prothrombin Time (PT)	Approximately 25 weeks