NOR-MS

Treatment tested

• Rituximab

  B-lymphocyte antigen CD20 binding agent

• Cladribine

  DNA inhibitor

Other measures (5)

Inclusion Criteria: * Age between 18 and 65 years * A diagnosis of relapsing MS according to the 2017 McDonald criteria * Disease activity seen as either a clinical relapse or MRI activity during the last 12 months * EDSS between 0 and 5.5 * Thrombocytes and leukocytes within normal range, and lymphocytes above 0.8 x10 9/L before first dose of study medication * A) For women of childbearing potential: accepting to use adequate contraception in the trial period. If randomized to cladribine, women who use systemic hormonal contraception must accept to use additional barrier contraception during each treatment cycle and for four weeks after each treatment cycle. * B) For men: If randomized to cladribine, accepting to use adequate contraception in the safety period of 6 months after each treatment cycle. * Able to understand written and spoken Norwegian or English * Able to complete treatment or follow-ups in the study (e.g. no contraindications for MRI, severe psychiatric disease, drug abuse or plans of moving) * Signed informed consent Exclusion Criteria: * Any contraindication or increased risk of side-effects from rituximab or cladribine (such as ongoing acute or chronic infection, live vaccination less than 4 weeks before start of treatment or planned live vaccination, immunocompromised, previous or active malignant disease, ongoing glucocorticoid treatment or allergy against any products of the medication) * Previous use of any of cladribine, rituximab, alemtuzumab, ocrelizumab, hematopoietic stem cell therapy (HSCT) or other immunosuppression with long lasting effects * Fingolimod or natalizumab treatment within the last six months before inclusion * Current pregnancy or lactation

The main aim and overall objective of the study is to assess whether rituximab is non-inferior to cladribine for the treatment of relapsing MS. Secondly, the investigators will test specific blood and MRI biomarkers that may contribute to future personalized treatment for MS patients. Furthermore, the investigators want to evaluate the health economic consequences of the two therapies.