臨床研究等提出・公開システム

Date of registration	Aug. 06, 2026
Last modified on	Aug. 06, 2026
Trial ID	jRCT2031260365

Scientific Title	A Phase 3, Randomized, Multicenter, Double-blind Study to Assess Stroke and Systemic Embolism Prevention with REGN7508, a Monoclonal Antibody Against Factor XI, Versus Apixaban in Participants with Atrial Fibrillation (ROXI-EVEREST)
Public Title	Stroke and Systemic Embolism Prevention in Adult Participants with Atrial Fibrillation (ROXI-EVEREST)

Contact for Scientific Queries	Name	Inomata Hyoe
	Affiliation	Regeneron Japan KK
	Address	Toranomon Hills Station Tower 18F 2-6-1 Toranomon, Minato-ku, Tokyo
	Telephone	+81-3-6630-7478
	E-mail	Clinicaltrial-sciences@regeneron.com
Contact for Public Queries	Name	Regeneron Japan Contact for Clinical Trial
	Affiliation	Regeneron Japan KK
	Address	Toranomon Hills Station Tower 18F 2-6-1 Toranomon, Minato-ku, Tokyo
	Telephone	+81-3-6630-7478
	E-mail	Clinicaltrial-sciences@regeneron.com

Recruitment status	Pending

Anticipated date of first enrollment		Oct. 15, 2026
Target sample size		1552
Study Type		Interventional
Study Design	allocation	randomized controlled trial
	masking	double blind
	control	active control
	assignment	parallel assignment
	purpose	prevention purpose
Key inclusion & exclusion criteria	Inclusion Criteria	1. Has AF or flutter (paroxysmal or persistent), not considered 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: a. 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 >=2 and Oral Anticoagulant (OAC) naive OR b. CHA2DS2-VA score >=3 OR c. CHA2DS2-VA score of 2 AND at least 1 enrichment criteria as described in the protocol 3. Must have an International Normalized Ratio (INR) <2.5 at the time of randomization if taking warfarin or another Vitamin K Antagonist (VKA) Note: Other protocol-defined Inclusion criteria apply
	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 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 6 months starting from randomization 4. Had an ischemic stroke within 2 days prior to randomization 5. Has persistent, uncontrolled hypertension (per investigator's discretion) 6. Has estimated Glomerular Filtration Rate (eGFR) <15 mL/min/1.73m2 within 30 days prior to randomization or is on dialysis or expected to be started on dialysis within the next 6 months starting from randomization Note: Other protocol-defined Exclusion criteria apply
	Age Minimum	18age old over
	Age Maximum	No limit
	Gender	Both
Health Condition(s) or Problem(s) Studied		Atrial Fibrillation (AF)
Intervention(s)		Experimental: REGN7508 + Placebo - Drug: REGN7508 Administered per the protocol - Drug: Placebo Administered per the protocol Active Comparator: Apixaban + Placebo - Drug: Apixaban Administered per the protocol - Drug: Placebo Administered per the protocol
Primary Outcome(s)		- Time to first occurrence of stroke (ischemic, hemorrhagic, or of unspecified type) or systemic embolism - Time to first occurrence of International Society on Thrombosis and Haemostasis (ISTH) major bleeding or ISTH Clinically Relevant Non-Major (CRNM) bleeding
Secondary Outcome(s)		- Time to first occurrence of stroke (ischemic, hemorrhagic, or of unspecified type), systemic embolism, ISTH major bleeding, or ISTH CRNM bleeding - Time to first occurrence of stroke (ischemic, hemorrhagic, or of unspecified type), systemic embolism, or ISTH major bleeding - Time to first occurrence of stroke (ischemic, hemorrhagic, or of unspecified type), systemic embolism, ISTH major bleeding, or all-cause death - Time to first occurrence of ISTH major bleeding - Time to first occurrence of hemorrhagic stroke, intracerebral hemorrhage, or hemorrhagic transformation of an ischemic stroke - Time to occurrence of fatal bleeding - Number of ISTH major bleeding events - Number of ISTH CRNM bleeding events - Number of minor bleeding events - Time to all-cause death - Occurrence of Treatment-Emergent Adverse Events (TEAEs) - Severity of TEAEs - Occurrence of Anti-Drug Antibodies (ADA) to REGN7508 - Magnitude of ADA to REGN7508

Primary Sponsor	Regeneron Pharmaceuticals, Inc.

Name of Certified Review Board	Review Board of Human Rights and Ethics for Clinical Studies Institutional Review Board
Address	2-2-1, Kyobashi, Chuo-ku, Tokyo, Tokyo
Telephone	+81-3-6665-0572
E-Mail	soudan@hurecs.org

Plan to share IPD	Yes
Plan description	All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.

Secondary ID(s)	NCT07626411
Issuing Authority	ClinicalTrials.gov

Countries of Recruitment（Except Japan）	Argentina/Australia/Austria/Belgium/Brazil/Bulgaria/Canada/Chile/Colombia/Czechia/Germany/Greece/Hungary/India/Italy/Latvia/Malaysia/Mexico/Netherlands/Poland/Portugal/Republic of Korea/Romania/Spain/Sweden/Taiwan/Turkey/United Kingdom/United States of America