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Study on Frexalimab for Patients with Relapsing Multiple Sclerosis

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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 the effects of a new treatment for Multiple Sclerosis (MS), specifically targeting those with the relapsing form of the disease. The treatment being tested is called Frexalimab, which is a type of medication known as a monoclonal antibody. Monoclonal antibodies are proteins designed to target specific parts of the immune system. In this study, Frexalimab is being compared to a placebo to see how well it works in reducing new active brain lesions, which are areas of damage in the brain that can be seen on an MRI scan.

The purpose of the study is to assess the effectiveness and safety of Frexalimab in people with relapsing MS. Participants in the study will receive either Frexalimab or a placebo through an injection, which can be given either intravenously (directly into a vein) or subcutaneously (under the skin). The study will monitor participants over a period of time to observe any changes in their condition and to check for any side effects. The main focus will be on the number of new brain lesions that develop over the course of the study.

Throughout the study, researchers will also keep track of any adverse events, which are any unwanted effects that participants might experience. Additionally, they will measure the presence of antidrug antibodies, which are immune responses that can occur when the body reacts to the medication. The study aims to provide valuable information on whether Frexalimab can be a beneficial treatment option for those living with relapsing MS.

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

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes verifying age, diagnosis of relapsing multiple sclerosis, and recent medical history.

    Participants must be between 18 and 55 years old, have a documented relapse history, and meet specific body weight and BMI criteria.

  2. Step 2

    Randomization and treatment assignment

    Participants are randomly assigned to receive either the test product frexalimab or a matched placebo. This process is double-blind, meaning neither the participant nor the study team knows which treatment is being administered.

  3. Step 3

    Treatment administration

    The assigned treatment, either frexalimab or placebo, is administered as a solution for injection. The route of administration is either intravenous (IV) or subcutaneous (SC).

    The frequency and dosage of the treatment are determined by the study protocol and are monitored throughout the trial.

  4. Step 4

    Monitoring and assessments

    Regular monitoring is conducted to assess the number of new active brain lesions, particularly Gadolinium-enhancing T1 lesions at week 12.

    Participants are also monitored for any adverse events or serious adverse events until week 316.

  5. Step 5

    Antibody and pharmacokinetic analysis

    Blood samples are collected to analyze the presence of antidrug antibodies (ADA) and to evaluate pharmacokinetic parameters such as Cmax, tmax, AUC0-tau, and t1/2z until week 316.

  6. Step 6

    Completion and follow-up

    The study is estimated to conclude by August 23, 2027. Participants will have follow-up assessments to ensure their well-being and to gather final data for the study.

Who can join the trial?

6 criteria

  • Participant must be between 18 and 55 years old at the time of signing the consent form.
  • The participant must have been diagnosed with **RMS**. This includes **relapsing-remitting MS** and **secondary progressive MS** with relapses. **MS** stands for **Multiple Sclerosis**, a condition affecting the brain and spinal cord.
  • The participant must have had at least one documented relapse in the past year, or two documented relapses in the past two years, or at least one active **Gd-enhancing brain lesion** on an **MRI** scan in the past 6 months before screening. A **Gd-enhancing brain lesion** is a specific type of spot seen on an **MRI** scan, which is a detailed imaging test of the brain.
  • Body weight must be between 45 and 120 kg, and **BMI** (Body Mass Index) must be between 18.0 and 35.0 kg/m² at the time of screening. **BMI** is a measure that uses height and weight to estimate body fat.
  • Participants must use contraception methods that comply with local regulations for those taking part in clinical studies. This applies to both men and women.
  • Participants must be able to provide signed informed consent, meaning they understand the study and agree to participate.

Who cannot join the trial?

7 criteria

  • Patients who are pregnant or breastfeeding cannot participate.
  • Individuals with a history of severe allergic reactions to the study medication are excluded.
  • Patients with other serious health conditions that could interfere with the study are not eligible.
  • Participants who have used certain medications that might affect the study results are not allowed.
  • Individuals who have participated in another clinical trial recently may be excluded.
  • Patients with a history of substance abuse or addiction might not be eligible.
  • Anyone unable to comply with the study procedures or follow-up visits will be excluded.
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Investigated drugs

SAR441344 is a monoclonal antibody designed to act as a CD40L-antagonist. It is being studied for its potential to reduce the number of new active brain lesions in participants with relapsing multiple sclerosis. This medication works by targeting specific proteins involved in the immune response, which may help in managing the symptoms and progression of multiple sclerosis.

What is already known about the treatment

SAR441344 – This medication is administered as an injection and is currently being studied in clinical trials for its potential use in treating relapsing multiple sclerosis. It is a monoclonal antibody that works by blocking CD40L, a molecule involved in the immune response, which may help reduce inflammation and the formation of new brain lesions. SAR441344 is classified as an immunomodulatory agent, and its development is focused on improving outcomes for patients with multiple sclerosis by targeting specific pathways in the immune system.

Investigated diseases

Multiple Sclerosis – Multiple Sclerosis is a chronic disease that affects the central nervous system, particularly the brain and spinal cord. It occurs when the immune system mistakenly attacks the protective sheath (myelin) that covers nerve fibers, leading to communication problems between the brain and the rest of the body. Over time, the disease can cause permanent damage or deterioration of the nerves themselves. Symptoms vary widely and can include fatigue, difficulty walking, numbness or tingling, muscle weakness, and problems with coordination and balance. The progression of the disease can be unpredictable, with periods of remission and relapses. The severity and specific symptoms can differ greatly from person to person.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-513527-17-00Protocol codeACT16877Estimated enrolment176 patientsSponsorSanofi-Aventis Recherche & Developpement

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