REGN7508 in Adult Participants for Prevention of Cancer-Associated Thrombosis (ROXI-CAT-I)

A Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Assess Efficacy and Safety of REGN7508, a Monoclonal Antibody Against FXI, for Primary Prophylaxis of Cancer-Associated Thrombosis for Participants With Solid Tumors Undergoing Cancer Treatment (ROXI-CAT-I)

This study is researching an experimental drug called REGN7508 (called "study drug"). The study is focused on the prevention of Cancer-Associated Thrombosis (CAT) in participants.

The aim of the study is to see how effective the study drug is in preventing blood clots in participants with solid tumors who are currently receiving anticancer treatment or planning to start anticancer treatment within a month of being assigned to a study treatment, or recovering from surgery, and how the study drug compares to placebo for CAT.

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

• What side effects may happen from taking the study drug
• How much study drug is in the blood at different times
• Whether the body makes antibodies against the study drug (which could make the study drug less effective or could lead to side effects)

Study Overview

• Status: Recruiting
• Conditions: Cancer-Associated Thrombosis (CAT)
• Intervention / Treatment: Drug: Placebo; Drug: REGN7508

• Study Type: Interventional
• Enrollment (Estimated): 1120
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Clinical Trials Administrator; Phone Number: 844-734-6643; Email: clinicaltrials@regeneron.com

Study Locations

• Georgia
  • Tbilisi, Georgia, 0159
    • Recruiting
    • Institute of Clinical Oncology
  • Tbilisi, Georgia, 0112
    • Recruiting
    • Llc Todua Clinic
  • Tbilisi, Georgia, 0186
    • Recruiting
    • Caucasus Medical Centre
  • Tbilisi, Georgia, 0144
    • Recruiting
    • Tbilisi State Medical University and Ingorokva High Medical Technology University Clinic
  • Tbilisi, Georgia, 0179
    • Recruiting
    • LTD Cancer Research Centre
  • Tbilisi, Georgia, 0179
    • Recruiting
    • JSC Evex Hospitals - Caraps Medline
  • Tbilisi, Georgia, 0102
    • Recruiting
    • American Hospital Tbilisi
  • Adjara
    • Batumi, Adjara, Georgia, 6000
      • Recruiting
      • LTD High Technology Hospital Medcenter
  • Imereti
    • Kutaisi, Imereti, Georgia, 4600
      • Recruiting
      • Krystyna Kiel Oncology Center
• United States
  • Florida
    • Hialeah, Florida, United States, 33013
      • Recruiting
      • Bioresearch Partner- Hialeah Hospital
    • North Miami Beach, Florida, United States, 33169
      • Recruiting
      • Helios Clinical Research
  • Texas
    • El Paso, Texas, United States, 79902
      • Recruiting
      • El Paso Medical Research Institute (Medresearch Inc)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

1. Has a histologically confirmed diagnosis of malignant solid tumors which are locally advanced or metastatic as described in the protocol
2. Has a Khorana thromboembolic risk score ≥2 during screening period or harbors a somatic documented tumor genetic variant known to be associated with a similar increased risk of VTE as described in the protocol
3. Has an Eastern Cooperative Oncology Group (ECOG) Performance Status 0 to 2 at the time of screening and day 1 prior to the first dose of study intervention

Key Exclusion Criteria:

1. Has known bleeding conditions (eg, Hemophilia A or B, von Willebrand's disease), hemorrhagic tumor sites, or other conditions with a high risk for bleeding (eg, hepatic disease associated with coagulopathy)
2. Has a cancer diagnosis consisting solely of basal cell or squamous cell skin carcinoma
3. Has a primary brain tumor or brain metastases as described in the protocol
4. Has proximal lower extremity DVT locally detected by Compression Ultrasound (CUS) during screening period
5. Has any condition that, as judged by the investigator, may confound the results of the study or would place the participant at increased risk of harm if he/she participated in the study

Note: Other Protocol Defined Inclusion/ Exclusion Criteria Apply

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo	Drug: Placebo; Administered per the protocol
Experimental: REGN7508	Drug: REGN7508; Administered per the protocol; Other Names: cenvacibart

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Time-to-first event of centrally adjudicated International Society of Thrombosis and Hemostasis (ISTH) major bleeding or Clinically Relevant Non-Major (CRNM) bleeding	Through 6 months
Time-to-first event of centrally adjudicated VTE (DVT, PE) or ATE, or thromboembolism- or ATE-related death	Through 6 months

Secondary Outcome Measures

Outcome Measure	Time Frame
Occurrence of Treatment-Emergent Adverse Events (TEAEs)	Up to day 245
Severity of TEAEs	Up to day 245
Magnitude of ADA to REGN7508	Up to day 245
Time-to-first event of the centrally adjudicated symptomatic or incidental VTE (DVT, PE) or ATE and thromboembolism- or ATE-related death	Through 6 months
Time-to-first event of symptomatic VTE	Through 6 months
Time-to-first event of symptomatic DVT	Through 6 months
Time-to-first event of symptomatic non-fatal PE	Through 6 months
Time-to-first event of thromboembolism-related death	Through 6 months
Time-to-first event of incidental VTE	Through 6 months
Time-to-first event of incidental upper extremity or incidental proximal lower extremity DVT	Through 6 months
Time-to-first event of incidental non-fatal PE (in a segmental or larger pulmonary artery)	Through 6 months
Time-to-first event of asymptomatic VTE (Asymptomatic DVT detected by lower extremities ultrasound)	Through 6 months
Time-to-first event of ATE	Through 6 months
Time-to-first event of ATE-related death	Through 6 months
Time-to-first event of centrally adjudicated VTE (DVT, PE), or thromboembolism-related death	Through 6 months
Occurrence of Anti-Drug Antibody (ADA) to REGN7508	Up to day 245

Collaborators and Investigators

• Sponsor: Regeneron Pharmaceuticals
• Investigators: Study Director: Clinical Trial Management, Regeneron Pharmaceuticals

Study record dates

Study Major Dates

• Study Start (Actual): March 9, 2026
• Primary Completion (Estimated): January 23, 2030
• Study Completion (Estimated): May 6, 2030

Study Registration Dates

• First Submitted: February 6, 2026
• First Submitted That Met QC Criteria: February 12, 2026
• First Posted (Actual): February 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 22, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Venous Thromboembolism (VTE); Deep Vein Thrombosis (DVT); Pulmonary Embolism (PE); Arterial Thromboembolism (ATE); Solid tumors (cancers); Clinically Relevant Non-Major (CRNM) bleeding; International Society of Thrombosis and Hemostasis (ISTH)
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Respiratory Tract Diseases; Lung Diseases; Embolism and Thrombosis; Embolism; Thromboembolism; Thrombosis; Pathological Conditions, Signs and Symptoms; Neoplasms; Pulmonary Embolism; Venous Thrombosis; Hemorrhage; Venous Thromboembolism
• Other Study ID Numbers: R7508-CAT-2392; 2024-519298-21-00 (Ctis)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing.

IPD Sharing Time Frame

When Regeneron has:

• received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development
• made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry)
• the legal authority to share the data, and
• ensured the ability to protect participant privacy

• IPD Sharing Access Criteria: Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No