Silent Progression Activity Monitoring - SPAM Study

Real-World Data (RWD) exploring the natural history of MS suggested that relapses do not significantly influence the progression of irreversible disability. Disability progression independent of relapses activity (PIRA) has been confirmed as a frequent relapsing-remitting multiple sclerosis (RRMS) phenomenon based on Randomized Clinical Trials (RCT). Recently, RWD demonstrated that the absence of markers of inflammation (No Evidence of Disease Activity (NEDA) at 2 years did not predict long-term stability. Silent progression has been proposed to describe the insidious disability that accrues many patients who satisfy traditional criteria for relapsing-remitting MS. In this study, the investigators would like to evaluate the occurrence of the SPMS in a population of RRMS patient with an Highly Active Treatment (HAT).

INCLUSION CRITERIA: - Patients with RRMS (2017 Mc Donald criteria) treated with highly active treatment in the first 5 years of symptoms onset, at least 1 year, with an EDSS below 4HAT start after April 12th 2007 (availability of Natalizumab)Naive or failure (or intolerability) to 1 or more first line DMT (injectables, teriflunomide, DMF).EDSS < or equal 4 when starting HAT EXCLUSION CRITERIA:Progressive relapsing MS at baselineClinical or basic MRI data unavailable after on-site visit.MS diagnostic > 5 years at baselineImmunosuppressive drugs (Azathioprine, Cyclophosphamide, Mycophenolate, Methotrexate) prescribed before HAT initiation