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Study of SAR441566 and methotrexate in adults with moderate to severe rheumatoid arthritis

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What is this trial about?

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

This study focuses on people with rheumatoid arthritis, a condition that causes joint inflammation, pain, and stiffness. The research evaluates a new medication called SAR441566 used together with methotrexate in people who have moderate to severe form of the disease. SAR441566 is a substance that works by blocking specific signals that cause inflammation in the body.

The study aims to determine if SAR441566 combined with methotrexate works better than placebo with methotrexate in treating moderate to severe rheumatoid arthritis. The treatment will be given as tablets taken by mouth. The study will last for 12 weeks, during which participants will receive either the study medication or placebo along with their regular methotrexate treatment.

Throughout the study, doctors will monitor how well the treatment works and check for any side effects. They will measure improvements in joint symptoms and overall disease activity. Blood samples will be collected to measure the amount of study medication in the body. This research is conducted as a phase 2 study, which means it is part of the early stages of testing this new treatment.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment period start

    You will receive either SAR441566 tablets or a placebo (inactive substance) to take alongside your current methotrexate treatment

    Your current methotrexate dose (between 10-25 mg per week) will remain unchanged during the study

    You will continue taking folic/folinic acid supplements as part of your methotrexate treatment

  2. Step 2

    Regular monitoring - Week 1 to 12

    Your joint pain and swelling will be regularly assessed

    Blood tests will be performed to measure C-reactive protein levels (a marker of inflammation)

    The study team will monitor how well your body responds to the treatment combination

    Blood samples will be taken to measure the levels of study medication in your system

  3. Step 3

    12-week assessment

    Your progress will be evaluated using the American College of Rheumatology (ACR) scoring system

    This assessment measures improvements in your joint symptoms and overall condition

    Your disease activity will be measured using a special score called DAS-28 CRP

    Any side effects or health changes you experience will be recorded

  4. Step 4

    Study completion

    The study will evaluate if adding SAR441566 to methotrexate treatment helps improve rheumatoid arthritis symptoms

    Your participation will help determine the effectiveness and safety of this new treatment combination

Who can join the trial?

9 criteria

  • You must be an adult with rheumatoid arthritis diagnosed at least 3 months ago, with symptoms present for at least 6 months
  • You must have moderate to severe active disease with:
    • At least 6 tender joints
    • At least 6 swollen joints
    • High levels of C-reactive protein (a blood test that measures inflammation) of 4 mg/L or higher
    • You must have been taking methotrexate (a medication that reduces inflammation) for at least 12 consecutive weeks, with a stable dose for at least 6 weeks before screening
    • Your methotrexate dose must be between 10 to 25 mg per week, and you must also take folic or folinic acid supplements
    • You must have shown inadequate response to methotrexate treatment despite proper dose increases
    • Your Body Mass Index (BMI) must be between 18 and 35 (BMI is a measure of body fat based on height and weight)
    • Both men and women can participate

Who cannot join the trial?

15 criteria

  • History of active tuberculosis (TB) or other serious infections
  • Presence of severe liver disease (significant problems with liver function)
  • Uncontrolled high blood pressure
  • History of cancer within the past 5 years (except successfully treated non-melanoma skin cancer)
  • Current or recent serious heart conditions including heart failure
  • Pregnant women or women planning pregnancy during the study period
  • Recent treatment with live vaccines (vaccines containing weakened but living microorganisms)
  • Treatment with other biological medications (specialized drugs that target specific parts of the immune system) within the past 3 months
  • Severe allergic reactions to similar medications in the past
  • Presence of other autoimmune diseases (conditions where the immune system attacks the body)
  • Significant kidney problems or abnormal kidney function tests
  • Active or chronic hepatitis B or C infection
  • History of blood disorders or significantly abnormal blood test results
  • Current drug or alcohol abuse
  • Mental health conditions that could interfere with study participation
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Investigated drugs

  • SAR441566

    is an experimental medication that works by blocking a specific protein called TNFR1, which is involved in inflammation. It is being studied as a new treatment for rheumatoid arthritis. This medication is taken together with methotrexate to potentially improve its effectiveness in treating joint inflammation and pain.

  • Methotrexate

    is a commonly used medication for treating rheumatoid arthritis. It helps reduce inflammation and slow down joint damage by affecting the immune system. It is considered a standard treatment for rheumatoid arthritis and in this study is used in combination with SAR441566.

What is already known about the treatment

  • SAR441566

    An investigational small molecule drug specifically designed to inhibit TNFR1 (Tumor Necrosis Factor Receptor 1) signaling, administered in combination with methotrexate for the treatment of moderate to severe rheumatoid arthritis. Currently in Phase 2 clinical trials, this medication represents a novel approach to treating autoimmune conditions by selectively targeting inflammatory pathways. The drug works at the molecular level by blocking TNFR1 signaling, which plays a crucial role in inflammation associated with rheumatoid arthritis, and belongs to the class of targeted immunomodulatory agents.

  • Methotrexate

    A well-established disease-modifying antirheumatic drug (DMARD) typically administered orally or by injection on a weekly basis for the treatment of rheumatoid arthritis. This medication works by interfering with cell growth and inflammation by blocking the metabolism of folic acid, effectively suppressing the immune system's overactive response in autoimmune conditions. Methotrexate is considered a first-line treatment for rheumatoid arthritis and is often used in combination with other medications to enhance therapeutic outcomes.

Investigated diseases

Rheumatoid Arthritis - A chronic inflammatory condition that primarily affects the joints throughout the body. The disease occurs when the immune system mistakenly attacks the body's own tissues, particularly the joint linings, causing inflammation, swelling, and pain. Over time, this inflammation can lead to deterioration of joint cartilage and bones, resulting in joint deformity and reduced mobility. The condition typically affects multiple joints symmetrically, meaning the same joints on both sides of the body are affected. Common symptoms include joint stiffness (especially in the morning), swelling, warmth in affected areas, and fatigue. The disease usually develops gradually, starting with smaller joints in the fingers and toes before potentially progressing to larger joints like knees, hips, and shoulders.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-503910-60-00Protocol codeDRI17821Estimated enrolment821 patientsSponsorSanofi-Aventis Recherche & Developpement

sourced from the EU Clinical Trials Register and site verification

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