Cladribine Tablets Level of Response Predictors in Clinical Practice (CLODINA)

Inclusion Criteria: * Adult participants, male or female patients ≥ 18 years old at index date * Participants must voluntarily give written informed consent form (ICF). Patients must read and fully understand the ICF * Participants with confirmed diagnosis of RMS at index date, diagnosed by the treating physician according to applicable clinical practice guidelines (currently McDonald 2017 criteria), with high disease activity. * Required historical data should be available: number of relapses in the 12 months prior to index date, DMTs taken prior to index date, date of MS diagnosis, and data of at least 1 MRI prior to index date as specified in the drug Summary of Product Characteristics (SmPC) * Fulfillment of the indication for treatment with cladribine tablets at index date, per standard of care in accordance with the local SmPC * Meeting 1 of the following criteria: * Prospective participants: Having been prescribed with cladribine tablets or having taken at least one dose of cladribine tablets, with enrollment date prior to the second treatment week * Retrospective participants: Having taken at least one dose of cladribine tablets, with enrollment date during or after the second treatment week but not more than 3 years after the first dose of cladribine tablets Exclusion Criteria: * Contraindications to use of cladribine tablets according to the SmPC. * Any participant who had the first dose of cladribine tablets more than 3 years prior to enrollment * Any participant who is pregnant or plans to breast-feed while taking cladribine tablets, or any patient who or whose partner plans to become pregnant in Year 1 or within 6 months after the last dose in Year 2, or any participants who is unwilling or unable to use contraception per the SmPC * Have participated or participating in an interventional study since cladribine tablet initiation, in which participant assessment and/or treatment may be dictated by a protocol * Participants who, at the discretion of the Investigator, will not be able to provide reliable information for the study