Study to Assess Immune Function and MRI Disease Activity in RRMS Patients When Switching From Natalizumab to Gilenya

Exclusion Criteria

• •1. Patients with a history of chronic disease of the immune system other than MS, which requires systemic immunosuppressive treatment, or a known immunodeficiency syndrome.
• •2. Patients with Crohn´s disease or ulcerative colitis.
• •3. Patients who have been treated with:
• •* systemic corticosteroids or immunoglobulins within 1 month prior to baseline.
• •* immunosuppressive medications such as azathioprine, cyclophosphamide or methotrexate within 3 months prior to baseline.
• •* monoclonal antibodies (excluding natalizumab) within 3 months prior to baseline.
• •* cladribine or mitoxantrone at any time.
• •4. History of malignancy of any organ system (other than cutaneous basal cell carcinoma).
• •5. Uncontrolled diabetes mellitus (HbA1c \>7%).
• •6. Diagnosis of macular edema during Screening Phase.
• •7. Severe active infections, active chronic infection.
• •8. Negative for varicella-zoster virus immunoglobulin G antibodies prior to baseline.
• •9. Patients that received any live or live-attenuated vaccine (including varicella-zoster virus or measles) within 1 month prior to baseline.
• •10. Patients who have received total lymphoid irradiation or bone marrow transplantation.
• •11. Patients with any medically unstable condition, as assessed by the investigator.
• •12. Patients with certain cardiovascular conditions and/or findings in the screening ECG.
• •13. Patients with certain lung diseases.
• •14. Patients with certain hepatic conditions.
• •15. Patients with a screening white blood cell (WBC) count \<3,500/mm3 or lymphocyte count \<800/mm3.
• •16. Patients with certain neurologic/psychiatric disorders:
• •17. Patients unable to undergo MRI scans, including claustrophobia or history of hypersensitivity to gadolinium-diethylenetriaminepentacetate (Gd-DTPA).
• •18. Patients who have received an investigational drug or therapy within 180 days or 5 half-lives before baseline, whichever is longer.
• •19. Pregnant or nursing (lactating) women, confirmed by a positive human chorionic gonadotropin laboratory.
• •20. Women of child-bearing potential unless they are using effective contraception during the study and for 5 half-lives after stopping treatment. In case of use of oral contraception women should have been stable on the same medication for a minimum of 3 months before baseline.
• •21. History of hypersensitivity to the study drugs or to drugs of similar chemical classes.
• •22. Prior participation in a trial with fingolimod.