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Study on the Safety and Tolerability of Abelacimab Compared to Rivaroxaban in Patients with Atrial Fibrillation

Fast replyRegistered drugNo placebo
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What is this trial about?

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

This clinical trial is focused on studying a heart condition known as Atrial Fibrillation, which causes an irregular and abnormally fast heart rate. The study aims to compare the safety and how well two different treatments are tolerated. The treatments being compared are a study drug called Abelacimab (also known by its code name MAA868) and another drug called Rivaroxaban. Abelacimab is given as a solution for infusion, which means it is administered through a needle into a vein, while Rivaroxaban is taken as film-coated tablets by mouth.

The purpose of the study is to evaluate the effect of Abelacimab compared to Rivaroxaban on the rate of major or clinically relevant non-major bleeding events. Participants in the study will receive either Abelacimab or Rivaroxaban and will be monitored over a period of time to observe any bleeding events that occur. The study will help determine which treatment is safer and better tolerated for patients with atrial fibrillation.

Throughout the study, participants will be closely observed to track the time to the first occurrence of major bleeding events as defined by the International Society on Thrombosis and Haemostasis (ISTH). The study will also look at the time to the first occurrence of major or minor bleeding events. This information will help healthcare professionals understand the safety profile of Abelacimab compared to Rivaroxaban in managing atrial fibrillation.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, the patient will be required to provide written informed consent. This is a formal agreement to participate in the trial after understanding its purpose and procedures.

  2. Step 2

    Initial assessment

    An initial assessment will be conducted to confirm eligibility. This includes verifying age, medical history of atrial fibrillation, and other health criteria.

  3. Step 3

    Randomization

    The patient will be randomly assigned to receive either the study drug abelacimab or the comparator drug rivaroxaban.

  4. Step 4

    Medication administration

    If assigned to abelacimab, the patient will receive a 150 mg/ml solution for infusion, administered subcutaneously. The frequency and duration will be specified by the study protocol.

    If assigned to rivaroxaban, the patient will take either 20 mg or 15 mg film-coated tablets orally. The dosage and frequency will be determined based on individual health needs and study guidelines.

  5. Step 5

    Monitoring and follow-up

    Regular monitoring will occur to evaluate the safety and tolerability of the medication. This includes checking for any bleeding events and other side effects.

    Follow-up visits will be scheduled to assess the patient's health status and response to the treatment.

  6. Step 6

    Extension period

    If the patient continues with the study treatment at the end of the trial, they may enter an extension period. Consent will be required to participate in this phase.

  7. Step 7

    Completion of the trial

    The trial is estimated to end by October 23, 2025. Upon completion, a final assessment will be conducted to evaluate the overall outcomes and any long-term effects of the treatment.

Who can join the trial?

7 criteria

  • Able to provide written informed consent before the first study assessment is performed. This means you agree to participate and understand what the study involves.
  • Male and female patients who are **55 years old or older**.
  • Have a history of **Atrial Fibrillation (AF)** or **atrial flutter** with planned long-term use of blood-thinning medication. Patients with newly diagnosed AF can also join.
  • Have a **CHA2DS2-VASc score** of **4 or higher**, or a score of **3** with at least one of the following conditions:
    • Planned use of **antiplatelet medication** (like aspirin or P2Y12 inhibitors) during the trial.
    • **Creatinine clearance (CrCl)** of **50 ml/min or less** using the Cockcroft-Gault equation, which is a way to measure kidney function.
    • For the extension period of the study, you must be continuing the study treatment from the randomized part of the trial at the end of treatment visit.
    • For the extension period, you must be able to provide written informed consent to continue in this part of the study.

Who cannot join the trial?

9 criteria

  • Patients with a history of **bleeding disorders**. This means any condition that makes it hard for the blood to clot, leading to excessive bleeding.
  • Patients who have had a **stroke** in the past 6 months. A stroke is when blood flow to a part of the brain is stopped, causing brain cells to die.
  • Patients with **severe liver disease**. The liver is an organ that helps with digestion and removing toxins from the body. Severe disease means the liver is not working well.
  • Patients with **kidney disease** that requires dialysis. Dialysis is a treatment that does the work of the kidneys when they are not functioning properly.
  • Patients who are currently taking other **anticoagulant medications**. These are drugs that help prevent blood clots.
  • Patients with **uncontrolled high blood pressure**. This means blood pressure that is consistently too high and not managed by medication or lifestyle changes.
  • Patients who are pregnant or breastfeeding. This is to ensure the safety of both the mother and the baby.
  • Patients with a known allergy to the study drugs. An allergy is when the body's immune system reacts to a substance as if it is harmful.
  • Patients who have participated in another clinical trial within the last 30 days. This is to avoid any interference with the results of the study.
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Investigated drugs

  • Abelacimab

    is a medication being studied for its ability to reduce bleeding events in patients with atrial fibrillation. It is being tested in two different doses to see how well it works and how safe it is for patients. The goal is to find out if it can be a better option compared to other treatments.

  • Rivaroxaban

    is a medication that is already used to prevent blood clots in patients with atrial fibrillation. In this study, it is used as a comparison to see how well abelacimab performs in reducing bleeding events. Rivaroxaban helps to prevent strokes and other complications by thinning the blood.

What is already known about the treatment

  • Abelacimab

    Abelacimab is administered as an injection and is currently being studied in clinical trials for its safety and tolerability in patients with atrial fibrillation. It is not yet widely used in medical practice, as it is still under investigation. The main therapeutic indication for abelacimab is to prevent bleeding events in patients with atrial fibrillation. At the molecular level, abelacimab works by inhibiting Factor XI, a protein involved in blood clot formation. It is classified as an anticoagulant.

  • Rivaroxaban

    Rivaroxaban is taken orally in tablet form and is an established medication used to prevent blood clots in patients with atrial fibrillation. It is widely recognized in medical literature and practice. The primary therapeutic use of rivaroxaban is to reduce the risk of stroke and systemic embolism in these patients. Rivaroxaban works by inhibiting Factor Xa, an essential component in the blood clotting process. It belongs to the pharmacological class of anticoagulants.

Investigated diseases

Atrial Fibrillation – Atrial fibrillation is a common heart rhythm disorder where the heart's upper chambers (atria) beat irregularly and often rapidly. This irregular rhythm can lead to poor blood flow and may cause symptoms such as palpitations, shortness of breath, and fatigue. The condition can vary in duration, with some episodes lasting minutes and others persisting for longer periods. Over time, atrial fibrillation can lead to complications such as blood clots, which may increase the risk of stroke. The progression of the disease can be influenced by factors like age, underlying heart conditions, and lifestyle. Managing atrial fibrillation often involves monitoring the heart's rhythm and addressing any contributing health issues.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-509066-38-00Protocol codeCMAA868A2204/ANT-006Estimated enrolment1 287 patientsSponsorAnthos Therapeutics Inc.

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