Clinical Research Directory

Inclusion Criteria : 1. Male or female over 18 years old; 2. Patients with Relapsing-remitting MS followed in the neurology service 3. Treated for more than 24 months with natalizumab; 4. Anti-JCV negative status at inclusion; 5. Ability to understand the purpose of the study and provide opposition to use protected health information in accordance with national and local subject privacy regulations. 6. Had available medical records to meet study objectives (i.e., SAE and selected AE of grade 2 from the past 12 infusions of natalizumab performed at the hospital before inclusion) 7. Had a cerebral MRI within the previous 12 months (+/- 6 months) which results are available in the medical record. Exclusion Criteria : 1. Patient having expressed their opposition to the use of their data; 2. Women who are pregnant or breastfeeding or intending to become pregnant during the study; 3. History of any clinically significant (as determined by the Investigator) cardiac, endocrinologic, hematologic, hepatic, immunologic, metabolic (including diabetes), urologic, pulmonary, neurologic (except for RRMS), dermatologic, psychiatric, renal, or other major disease that would preclude participation in a clinical study, in the opinion of the Investigator. 4. Patient under guardianship or under security measure