Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Not yet recruiting

Efficacy and Safety of REGN7508, REGN9933, and Rivaroxaban in Adults with Peripheral Artery Disease after Recent Lower‑Extremity Revascularization

Verified siteRegistered drug
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Featured sites

Sites that work closely with us on this trial

What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on adults who have recently undergone a procedure to restore blood flow in the legs, a condition that occurs in people with Peripheral Artery Disease. The investigational medicines are two injectable antibodies, REGN7508 and REGN9933, which work by blocking a protein called Factor XI that helps blood clot. For comparison, participants may receive the oral blood‑thinner rivaroxaban, an injection that looks like a harmless solution, or a harmless placebo that contains no active drug.

The purpose of the study is to determine whether the new antibodies can lower the risk of serious clot‑related problems such as heart attack, stroke, severe leg artery blockage, or major limb amputation, while also assessing their impact on significant bleeding. After being randomly assigned to one of the treatment groups, participants receive the assigned medication for several months and attend regular check‑ups where doctors monitor health, record any clot events or bleeding, and perform routine blood tests. The study follows each participant for a defined period to collect information on safety and effectiveness.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline visit and randomization

    After you consent to join the study, you will attend a baseline visit where basic health information and required tests are collected.

    Based on the study design, you will be randomly assigned to receive either rivaroxaban, regn7508, regn9933, or a placebo injection.

  2. Step 2

    Start of study medication

    On the day of randomization you will begin taking the study medication assigned to you.

    If you are assigned to rivaroxaban, you will take one 5 mg tablet by mouth each day.

    If you are assigned to regn7508 or regn9933, you will receive an injection of a powder that is mixed for infusion; the exact dose is defined by the study protocol and will be given by trained staff.

    If you receive the placebo, you will receive an injection that looks identical to the active study drugs.

  3. Step 3

    Medication dosing schedule

    The oral tablet (rivaroxaban) is taken once daily at the same time each day.

    The injectable medications (regn7508, regn9933, or placebo) are administered according to the study schedule, which may be weekly, monthly, or at another interval specified by the protocol; the exact timing will be explained by the study team.

  4. Step 4

    Regular follow‑up visits

    You will attend scheduled clinic visits throughout the trial to have blood tests, vital‑sign checks, and questionnaires completed.

    During each visit the staff will assess you for any signs of clotting events (such as limb pain, heart attack, stroke) and for any bleeding problems.

    The frequency of visits is set by the study protocol and may be every few weeks or months.

  5. Step 5

    Ongoing safety monitoring

    Outside of clinic visits you should report any new symptoms, especially sudden leg pain, loss of color in a limb, chest pain, shortness of breath, or unusual bleeding.

    The study team will record any major thrombotic events or bleeding events that occur during the study period.

  6. Step 6

    End of treatment and final assessment

    At the end of the predetermined treatment period you will have a final visit where all remaining study medication is stopped.

    Final blood tests, physical examinations, and questionnaires will be completed to evaluate the overall effect of the medication.

    After the final assessment the study will be closed for you, and you will receive information about any further follow‑up that may be recommended.

Who can join the trial?

11 criteria

  • Had a successful lower extremity revascularization (LER)—a procedure to restore blood flow in a leg artery located below the external iliac artery—performed within the past 10 days because of reduced blood flow (ischemia) caused by atherosclerotic disease (plaque buildup in arteries).
  • Has at least one of the following risk factors that increase the chance of major blood‑clot events:
    • Underwent a bypass surgery using an artificial tube called a prosthetic graft.
    • Received an endovascular (through‑the‑vessel) treatment that included placing a stent (a small metal mesh tube) to keep the artery open.
    • The treated artery segment (the “target lesion”) is longer than 15 cm.
    • Has a previous history of lower‑extremity revascularization or an amputation related to peripheral artery disease (PAD) before the current procedure.
    • Has type 2 diabetes mellitus that requires medication.
    • Has symptomatic coronary artery disease (blockage in the heart’s arteries that causes symptoms) as defined in the study.
    • Has chronic kidney disease (long‑term kidney damage) as defined in the study.
    • Is 75 years of age or older.
    • Meets any additional inclusion requirements that are listed in the study protocol (“Other protocol‑defined inclusion criteria”).
    • Is an adult patient; both men and women are eligible to participate.

Who cannot join the trial?

7 criteria

  • Has any active medical condition that requires long‑term blood‑thinner medication after the first artery‑opening procedure, including a disorder called triple positive antiphospholipid syndrome (an immune problem that makes clots more likely).
  • Has a known tendency to bleed (bleeding diathesis), a very low platelet count (less than 50,000 platelets per microliter of blood), a history of a spontaneous brain bleed (non‑traumatic intracerebral hemorrhage), a brain vessel disease called cerebral amyloid angiopathy, or an unrepaired abnormal brain blood vessel (cerebrovascular malformation).
  • Has had a recent heart artery‑opening procedure (coronary revascularization) as described in the study plan.
  • For Cohort 2 only: Has very poor kidney function, measured by an estimated Glomerular Filtration Rate (eGFR)dialysis), or is expected to start dialysis in the next 12 weeks.
  • Has any other illness or treatment that would make participation unsafe or would prevent completing the full study period.
  • Has an allergy, strong sensitivity, or any reason not to use the study drugs (REGN7508, REGN9933, or rivaroxaban for Cohort 2) or their inactive ingredients (excipients).
  • Any other exclusion reasons that are listed in the detailed study protocol.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Not yet recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

  • Rivaroxaban

    is a pill taken by mouth that helps prevent blood clots. In this study it is used as a standard treatment to compare how well the new medicines work in preventing clot‑related problems after leg artery procedures.

  • REGN7508

    is an experimental medicine given by injection. It is a type of monoclonal antibody that blocks a protein called Factor XI, which plays a role in forming blood clots. The trial tests whether this medicine can reduce serious clot events and bleeding problems after recent lower‑extremity artery procedures.

  • REGN9933

    is another experimental injection. Like REGN7508, it is a monoclonal antibody that targets Factor XI to help control clotting. The study evaluates if this drug can safely lower the risk of major clot events and bleeding in patients who have recently had lower‑extremity revascularization.

What is already known about the treatment

  • Rivaroxaban

    This medication is taken as a 5 mg oral tablet taken by mouth. It is an approved drug that is widely used to prevent blood clots after surgery or in people at risk of stroke. Rivaroxaban works by directly blocking the protein factor Xa, which stops the clotting process. It belongs to the class of direct oral anticoagulants.

  • Cenvacibart

    Cenvacibart is supplied as a powder that is mixed with liquid and given by injection into a vein. It is an experimental monoclonal antibody that is still being studied in clinical trials for patients with peripheral artery disease who have had recent artery procedures. The drug binds to factor XI, a protein that helps start clot formation, and blocks its activity to reduce clot risk. It is classified as an anti‑factor XI monoclonal antibody.

  • Amrecibart

    Amrecibart is also provided as a powder for solution and is administered by intravenous injection. Like cenvacibart, it is an investigational monoclonal antibody currently being tested for safety and effectiveness in preventing clot‑related events after lower‑limb artery surgery. It works by attaching to factor XI and preventing this protein from triggering the clotting cascade. It falls under the same anti‑factor XI monoclonal antibody class.

Investigated diseases

  • Peripheral Artery Disease

    It is a condition where the arteries in the legs become narrowed or blocked, reducing blood flow. It often causes leg pain during walking, known as claudication. As it worsens, pain may occur at rest and wounds can develop. The reduced circulation can lead to tissue death if not managed.

  • Acute Limb Ischemia

    This is a sudden loss of blood flow to a leg or arm, causing severe pain, pale skin, and loss of sensation. It usually results from a clot that blocks an artery. If the blockage persists, muscle and tissue can die quickly. Prompt restoration of blood flow is needed to prevent permanent damage.

  • Myocardial Infarction

    Commonly called a heart attack, it occurs when a coronary artery becomes blocked, stopping blood to part of the heart muscle. The affected area can become damaged and stop working properly. Symptoms include chest pressure, shortness of breath, and sweating. Ongoing blockage can enlarge the damaged area.

  • Ischemic Stroke

    This happens when a blood vessel in the brain is blocked, cutting off oxygen to brain tissue. The loss of oxygen can cause sudden weakness, speech problems, or vision changes. Damage spreads as the brain cells die. Quick restoration of flow can limit the area affected.

  • Venous Thromboembolism

    This term covers blood clots that form in deep veins (deep‑vein thrombosis) and can travel to the lungs (pulmonary embolism). A clot in a leg vein may cause swelling, pain, and warmth. If it moves to the lungs, it can cause sudden shortness of breath. The condition can progress from a small clot to a larger blockage.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522954-37-00Protocol codeR9933-PAD-2394Estimated enrolment7 050 patientsSponsorRegeneron Pharmaceuticals Inc.

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.