The objective of the study is to evaluate the effectiveness of CladT, in terms of disease stability and safety, as the last treatment option in ageing MS patients vs treatment continuation and discontinuation This observational study will use database from local cohorts (from France, Belgium, Switzerland). Patients included must meet the inclusion criteria: RRMS diagnosis for more than 10 years without secondary progression, no evidence of disease activity (no relapse, no new MRI lesion, no EDSS progression) for more than 5 years under a DMT, age≥ 45-year-old.

Analyses will be using dynamic propensity score to match patients who stopped treatment with patients who had the same probability of continuing / stopping current treatments but took CladT as exit therapy. Patients with a minimum of 24 months follow up will be included.

The investigators will ensure that CladT provide disease stability compared to treatment continuation / discontinuation in ageing MS patients by measuring:

• the percentage of patients free of relapse, and time to first relapse, defined as the appearance, recurrence, or aggravation of neurological symptoms for a period of at least 24 hours without fever.
• the percentage of patients free of EDSS progression confirmed for at least 6 months and until the end of patient follow up.
• the percentage of patients free of MRI activity, defined as new or enlarged T2 lesions compared with the previous brain MRI scan or gadolinium enhancing T1 lesions.

Inclusion Criteria:

• Patient ≥45-year-old with RRMS
• Disease duration ≥10 years
• No evidence of disease activity ≥5 years under DMT
• EDSS score between 0 and 6.0 included

Exclusion Criteria:

• Progressive form of MS
• Patients without DMT
• EDSS score ≥6.5

This is a multicentric retrospective and controlled cohort with non-inferiority analysis. Patients will be matched 1:1 using propensity score on gender, age, MS duration, time before last relapse, EDSS score, DMTs.

The study will use retrospectively collected data within the date frame from 06/30/25 to 06/30/26.

Approximately 150 patients treated with cladribine will be identified and included in this study in 7 centers: Strasbourg, Lille, Montpellier, Nimes, Liège, Pelt, Lugano.