The objective of this study is to evaluate the risk of inflammatory disease activity by retrospectively comparing two therapeutic strategies (escalation group and induction group). The investigators also aim to identify factors associated with inflammatory relapse and treatment-related complications.

Inclusion Criteria:

• Patients with RRMS onset after age 50
• Patients who started their first disease-modifying therapy within 2 years of the first symptoms
• Patients Treated with moderately effective disease-modifying antirheumatic drugs (DMARDs) (teriflunomide, dimethyl fumarate or diroximel fumarate, glatiramer acetate, interferon beta, peginterferon)
• Patient treated with highly effective DMARDs (fingolimod, ponesimod, natalizumab, rituximab, ocrelizumab, ofatumumab, cladribine)

Exclusion Criteria:

- Patients with early progressive MS

Patients with RRMS onset after age 50