Randomisation will be performed via a randomisation module in the national Swedish MS registry. The patients will be randomised in a 1:1 ratio and receive their treatments in accordance with clinical practice. Thus, the study will mimic the real-life situation in which the treatments will be administered which involves both positive and negative consequences. As positive consequence the result of the study will have a high degree of validity in relation to expected outcome in clinical practice. As negative consequence there may be psychological effects of knowing which medication one is receiving. Since both drugs probably are perceived as positive treatment options in MS today it is unlikely that there will be a predominant placebo effect of either of the treatment options.