Venous Thromboembolism (VTE) Prophylaxis With REGN7508 and REGN9933 in Adult and Adolescent Participants With a Peripherally Inserted Central Catheter (PICC) (ROXI-PEAK)

A Master Protocol for a Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of REGN7508 and REGN9933, Monoclonal Antibodies Against Factor XI, for Prophylaxis of Venous Thromboembolism in Participants With a Peripherally Inserted Central Catheter (PICC) (ROXI-PEAK)

This study is researching 2 different experimental drugs called REGN7508 and REGN9933 (called "study drugs"). The study is focused on people who have a tube placed in a vein to receive treatment (called Peripherally Inserted Central Catheter [PICC]). Patients with PICCs have a higher risk of getting blood clots which can block the veins (this is called Venous Thromboembolism [VTE]) and lead to serious health problems or be life threatening.

The aim of the study is to see how well REGN7508 and REGN9933 prevent blood clots compared to placebo after PICC placement and to see if these medications cause certain types of bleeding.

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

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

Study Overview

• Status: Not yet recruiting
• Conditions: Venous Thromboembolism (VTE)
• Intervention / Treatment: Drug: Placebo; Drug: REGN7508; Drug: REGN9933

• Study Type: Interventional
• Enrollment (Estimated): 1908
• Phase: Phase 3

Contacts and Locations

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

Participation Criteria

Eligibility Criteria

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

Description

Key Inclusion Criteria:

1. Is undergoing PICC placement for Intravenous (IV) administration of clinically indicated medications, including chemotherapy, antibiotics, TPN, and/or other indications as described in the protocol
2. Has Eastern Cooperative Oncology Group Performance (ECOG) Status ≤3 or equivalent functional status as described in the protocol
3. Has International Normalization Ratio (INR) and aPTT values no more than 25% above the upper limit as described in the protocol
4. Weighs at least 40 kg during the screening period

Key Exclusion Criteria:

1. Has a history of prior venous thrombosis in the arm and/or ipsilateral thoracic central veins in which the PICC is to be placed
2. Has acute leukemia, myelodysplastic syndrome, or primary and secondary myelofibrosis
3. Has unresected luminal gastrointestinal (GI) (including esophageal) or unresected genitourinary (GU) malignancy
4. Has current or history of known brain tumors or brain metastases
5. Has any major cardiovascular event within approximately the past 30 days prior to study administration
6. Pre-existing central venous catheter or indwelling spinal or epidural catheter during the screening period

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

3

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
Experimental: REGN9933	Drug: REGN9933; Administered per the protocol; Other Names: amrecibart

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Time-to-first event of centrally adjudicated VTE [symptomatic VTE or incidental VTE or asymptomatic VTE]	Approximately 6 months
Time-to-first event of centrally adjudicated International Society on Thrombosis and Haemostasis (ISTH)-defined major bleeding or Clinically Relevant Non-Major (CRNM) bleeding	Approximately 6 months

Secondary Outcome Measures

Outcome Measure	Time Frame
Time-to-first event of centrally adjudicated symptomatic VTE [symptomatic Deep Vein Thrombosis (DVT) or symptomatic non-fatal Pulmonary Embolism (PE) or VTE-related death]	Approximately 6 months
Time-to-first event of symptomatic DVT	Approximately 6 months
Time-to-first event of symptomatic non-fatal PE	Approximately 6 months
Time-to-first event of VTE-related death	Approximately 6 months
Time-to-first event of incidental VTE	Approximately 6 months
Time-to-first event of incidental upper extremity or incidental proximal lower extremity DVT	Approximately 6 months
Time-to-first event of incidental PE (in a segmental or larger pulmonary artery)	Approximately 6 months
Time-to-first event of asymptomatic VTE (Asymptomatic DVT detected by upper extremity ultrasound)	Approximately 6 months
Occurrence of Treatment-Emergent Adverse Events (TEAEs)	Up to approximately 9 months
Severity of TEAEs	Up to approximately 9 months
Concentrations of REGN7508	Up to approximately 9 months
Concentrations of REGN9933	Up to approximately 9 months
Change from baseline in activated Partial Thromboplastin Time (aPTT)	Up to approximately 9 months
Change from baseline in Prothrombin Time (PT)	Up to approximately 9 months
Occurrence of Anti-Drug Antibody (ADA) to REGN7508	Up to approximately 9 months
Magnitude of ADA to REGN7508	Up to approximately 9 months
Occurrence of ADA to REGN9933	Up to approximately 9 months
Magnitude of ADA to REGN9933	Up to approximately 9 months

Collaborators and Investigators

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

Study record dates

Study Major Dates

• Study Start (Estimated): August 20, 2026
• Primary Completion (Estimated): June 25, 2029
• Study Completion (Estimated): September 21, 2029

Study Registration Dates

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

Study Record Updates

• Last Update Posted (Actual): July 13, 2026
• Last Update Submitted That Met QC Criteria: July 6, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Peripherally Inserted Central Catheter (PICC); Blood clots
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Embolism and Thrombosis; Thromboembolism; Thrombosis; Venous Thromboembolism
• Other Study ID Numbers: R7508-DVT-25103; 2026-525288-42-00 (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