Inclusion Criteria:  Participants with confirmed diagnosis of RRMS diagnosed by the treating physician according to applicable clinical practice guidelines -(currently McDonald 2017 criteria), with high disease activity Participants should have been treated with the same first-line DMD (Interferons, Glatiramer Acetate, Teriflunomide, DMF) and at a stable dose for at least one year prior to switch to Cladribine tablets and should have been prescribed Cladribine tablets, according to the decision of the treating physician, prior to enrollment in the study. Any washout period and/or washout methods required before switching (such as elimination of Teriflunomide) must have been conducted, according to the decision of the treating physician Required history data should be available: Multiple Sclerosis (MS) data for the 12-months pre-baseline period (annualized relapse rate); MS Medication History (prior DMDs) Fulfilment of the criteria for treatment with Cladribine tablets per standard of care in accordance with the local Summary of Product Characteristics (SmPC)  Exclusion Criteria:  Contraindications to use of cladribine tablets according to the SmPC Participants with history of alcohol or drug abuse that could potentially interfere with their participation in the study Participants that have received Cladribine in the past Concurrent participation in an investigational study in which participant assessment and/or treatment may be dictated by a protocol