Monthly Monitoring of Plasma NfL in Treated Relapsing-remitting Multiple Sclerosis to Detect Persistent Infraclinical Disease Activity

Inclusion criteria

• Patient with RRMS according to 2024 McDonald's criteria.
• Less than 10 years from disease onset.
• Active RRMS (EDA) observed during the last 24 months: relapse and/or NELs and/or CELs as compared to a previous MRI performed within 24 months (± 3 months).
• Current MET (IFN, GA, TE, fumarates) for less than 24 months.
• Standard MRI follow-up scan performed less than 90 days before inclusion.
• Clinically stable disease for at least 30 days.
• Patients included in observational studies and cohorts (OFSEP, PROMISE …) will be eligible for inclusion in MoMo-NfL.
• For women with reproductive potential: negative pregnancy test at the time of inclusion and use of an effective method to avoid pregnancy for the duration of the trial.
• Patients able to adhere to the study visit schedule.
• Patient must have signed and given the consent.
• Patient affiliated or beneficiary of a health insurance plan.

Exclusion criteria

• Pregnant or breastfeeding woman.
• Patient unable to perform brain and/or spinal cord MRI scans.
• Patient not willing to perform monthly blood punctures.
• Patient treated with HET (S1P agonists, natalizumab, ocrelizumab, ofatumumab, rituximab, alemtuzumab, cladribine, mitoxantrone).
• Patient with a relapse within 6 months before inclusion.
• Patient with CELs within 3 months before inclusion.
• Patient with progressive MS.
• Patient unable to sign the consent.
• It is impossible to correctly inform the patient.
• Patient already participating in therapeutic research or in an exclusion period. The exclusion period corresponds to five half-lives (t1/2) of the experimental drug.
• Patient under judicial protection, or is an adult under guardianship.
• Female patients who are pregnant or breastfeeding or of reproductive potential who are not willing to employ effective birth control for the duration of the trial.