Imatinib for Multiple Sclerosis (MS) Relapses

Inclusion Criteria: * An acute exacerbation, relapse, in persons with RRMS, either newly diagnosis or on treatment with one of the long-term immunomodulatory drugs, or possible MS where the diagnosis is supported by typical MRI or cerebrospinal fluid changes typical of MS (this enables inclusion of persons with a first neuroinflammatory bout, with high risk of developing MS before fulfilling the McDonald criteria for definite MS, or high risk for developing MS in the category clinically isolated syndrome (CIS)/possible MS with supporting MRI lesions and/or cerebrospinal fluid aberrations suggesting intra-thecal immunoglobulin synthesis with oligoclonal bands/and/or increased free Kappa Light chains. The relapse should be deemed to require relapse treatment by the investigator and affect a functional domain with a minimum of grade 2. * 18-55 years of age * Affection of any of the following EDSS sub-domains representing the targeted neurological deficit: 1. Visual function. grade 0-6, 2. Brain stem function grade 0-5. 3. Pyramidal function, grade 0-6. 4. Cerebellar function, grade 0-5. 5. Sensory function grade 0-6, and deterioration at least one step in any of these EDSS domains * EDSS ≤ 6 before the acute exacerbation * Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, if they are using effective methods of contraception during the study. Acceptable birth control methods are those with a failure rate of less than 1% per year when used consistently and correctly according to CTFG, September 2014 "Recommendations related to contraception and pregnancy testing in clinical trials". Such methods include: 1. Combined (estrogen and progestogen containing hormonal contraception associated with inhibition of ovulation. * oral * intravaginal * transdermal 2. progestogen-only hormonal contraception associated with inhibition of ovulation * oral * injectable * implantable 3. intrauterine device (IUD) 4. intrauterine hormone-releasing system (IUS) 5. bilateral tubal occlusion 6. total abstinence or vasectomized partner. Exclusion Criteria: * A pseudo-relapse should be excluded, as deemed by the experienced treating neurologist, and as evidenced by an active infection, likely with fever, with reappearing new signs and symptoms in a previously affected neurological function. * Inability to provide informed consent * Concomitant medication with drugs which may increase the plasma concentration of Imatinib - ketoconazole, itraconazole , erythromycin and clarithromycin * Concomitant medication with drugs which may decrease the plasma concentration of Imatinib: dexamethasone, phenytoin, carbamazepin, rifampicin, phenobarbital, fosphenytoin, primidon, Hypericum perforatum (St John's wort). * Female patients with childbearing potential, if pregnancy cannot be excluded by pregnancy test (urine point-of-care pregnancy test). * Patient is participating in other interventional study * General infection or any other condition judged by the treating neurologist to contra-indicate Imatinib * Any laboratory deviation of general bodily functions such as kidney, or renal function judged to be of clinical significance by the treating neurologist constitutes an exclusion criteria. * Patients with a positive Hepatitis B-DNA test result or serology indicating latent infection.