Evaluating the Efficacy and Safety of Transitioning Patients From Natalizumab to Ocrelizumab

This is a multicenter, prospective, open-label, Phase IV clinical trial. Patients with relapsing forms of Multiple Sclerosis (MS), ages 18 to 65, who have received a stable dose of NTZ for 12 or more consecutive months, and have been free of relapses, disability worsening or Magnetic Resonance Imaging (MRI) progression 6 months prior to the transition screening visit will be eligible for the study. After informed consent to participate has been obtained, the patient will have physical exam (PE), non-blinded Expanded Disability Status Scale (EDSS), MRI, Multiple Sclerosis Impact Scale (MSIS-29) and labs done for the screening visit to determine eligibility. Brain MRI with and without contrast will be performed with the standard MS protocol. MRIs will be performed with 3mm slice thickness with no gaps between slices. Patients will receive their first dose of OCR 4 to 6 weeks after the last dose of NTZ. Other baseline measures, including physical exam, EDSS, MSIS-29, and labs will be performed within 4 weeks of screening. Physical exam, non-blinded EDSS, and labs will be performed at month 3, month 6, month 9, and month 12. MSIS-29 will be performed at months 6 and 12. In addition, MRIs will be performed at months 3, 6, and 12.