This is a prospective randomised phase 3 study comparing a novel treatment protocol of Rituximab with a present first line disease modifying drug regarding both clinical, radiological and biochemical parameters. This will be measured via clinical investigations, MRI and Cerebrospinal fluid analyses. Each patient will have one treating physician responsible for all ongoing medical questions and decisions regarding continuation in the study and one examining physician performing the blinded Expanded Disability Status Scale examination and assessments of exacerbations. The coordinating nurse will administer the study-related tests and administer the rituximab infusions. In order to keep the examining physician blinded the patients receiving disease modifying drug will receive infusions with sodium chloride solution at the same interval as the rituximab arm is receiving. In both instances an opaque cover bag will shield the content of the infusion solution. In this case the examining physician will not be able to identify rituximab patients in case of accidental meetings on the neurology unit.