Pilot Study to Assess Disease Stability in a Natalizumab to Dimethyl Fumarate Crossover Design

This is an investigator initiated, single site, open-label, single arm observational study examining the initial efficacy and tolerability of dimethyl fumarate in a real world clinical setting for patients with a relapsing form of Multiple Sclerosis (MS) when crossed over from natalizumab therapy.

The decision to cross over from natalizumab to DMF will be made by the patient and the prescribing physician and must precede enrollment in the study.

MS disease status and history will be gathered from the patient's medical records. Patients will be followed for the first 24 weeks of their transition from natalizumab. Assessments will be performed at Baseline and every 4 weeks thereafter for 24 weeks. These assessments may include:

• Expanded Disability Status Scale (EDSS)
• Relapse Assessment
• Patient Reported Outcomes (PRO) including quality of life, fatigue, and cognition outcome measures
• Magnetic Resonance Imaging (MRI)
• Laboratory testing

Study drop outs due to DMF intolerability or other etiologies will be encouraged to complete the trial even if placed on alternative therapies.

Inclusion criteria

• JCV Indec of 1.5 of greater and currently receiving natalizumab therapy for at least 24 months
• Decision to treat with DMF must precede enrollment
• Ability to understand the purpose and risk of the study and provide authorization for the use of protected health information in accordance with the monitoring agency
• Men or women >= 18 years at time of informed consent
• Naive to DMF or fumaric acid esters
• Confirmed diagnosis of a relapsing form of MS as verified by their treating physician

Exclusion criteria

• Inability ot comply with study requirements as outlined in the informed consent
• Known active malignancies or any other major co morbidity that, in the opinion of the Investigator, would affect the outcome of the study
• Pregnancy or breastfeeding
• Previous treatment with dimethyl fumarate