Clinical Research Directory

Inclusion Criteria: * Signing the informed consent form * Cladribine treatment is planned and indicated and is according to label * 45-55 years of age at the time of signing the research informed consent form * RRMS diagnosis in accordance with McDonald 2017 criteria Exclusion Criteria: * Patients with other neurodegenerative disease than MS * Abnormal lymphocyte counts * Patients with human immunodeficiency virus (HIV). * Patients with active chronic infection (tuberculosis or hepatitis). * Patients with active malignancy. * Patients with moderate or severe renal impairment (creatinine clearance \<60 mL/min) * Patients that are pregnant or breast-feeding * Corticosteroid treatment within 4 weeks of imaging * Patients with significant abnormal findings other than MS in the screening MRI. * Patients with claustrophobia, or a history of moderate to severe anxiety disorder or panic attacks (which could potentially lead to preterm termination of the imaging) * Contraindication to PET scan investigations * Exposure to experimental radiation in the past 12 months such that radiodosimetry limits would be exceeded by participating in this study. * Intolerance to previous PET scans; i.e. previous hypersensitivity reactions to any PET ligand or imaging agent or failure to participate in and comply with previous PET scans. * Patients with previous alemtuzumab administration * Patients with less than 6 months since previous administration of ocrelizumab or rituximab (or with abnormal B-cell counts) * Patients with less than 1 month since previous administration of other disease modifying therapy