Inclusion Criteria:  Physician diagnosis of HDA-RRMS as defined by clinical or radiological features Treatment initiation with cladribine tablet monotherapy on or after 22 August 2017 and at least 3 years before enrolment Completion of Year 1 treatment of cladribine tablets (Week 1 and Week 2 treatment, per recommended dose in Year 1: 1.75 milligrams per kilogram [mg/kg] body weight, cumulatively)  Exclusion Criteria:  Received cladribine tablet treatment within an interventional clinical trial during the study period Received treatment with any investigational therapy for RRMS in the 6 months prior to cladribine tablet treatment initiation