Prospective Evaluation of De-Escalation From antiCD-20 Therapies to Dimethyl Fumarate (Tecfidera) or Diroximel Fumarate (Vumerity)

Inclusion Criteria: * Diagnosed with relapsing forms of MS * \> 18 years of age at the time of initiation of de-escalation * No evidence of new inflammatory disease activity (no new T2/contrast enhancing lesions, absence of relapses) for at least two years prior to de-escalation * Have had multiple sclerosis related symptoms at least 3 years prior to baseline visit. * Taking an anti-CD20 therapy most recently as a DMT continuously for at least one year (have received at least 2 courses) prior to de-escalation. * Are 6-12 months from their last anti-CD20 infusion * Willing to follow the protocol * Able to undergo a brain MRI without anesthesia Exclusion Criteria: * Any progression of neurological symptoms in the year prior to the screening visit that would be consistent with progressive MS. * Use of any non-FDA-approved DMT or systemic corticosteroids in the last 2 years. (Note: Use of inhaled or topical steroids are not an exclusion criteria. Also, use of oral steroids for no greater than 14 days given for a non-MS condition is not exclusionary). * IgG levels \<300 mg/dL * lymphocytes \<800 cells/mm3 * EDSS \>6.5 * Is considering pregnancy at the screening visit * Prior use of alemtuzumab, mitoxantrone, cyclophosphamide, methotrexate, cyclosporine or any experimental MS treatment in the last 5 years. * Prior allergy to Vumerity * Other significant medical or psychiatric illness, if uncontrolled. Examples: uncontrolled hypertension, uncontrolled diabetes, uncontrolled asthma, uncontrolled depression * Cancers other than basal cell skin cancers within the last 5 years * Unable to give informed consent or follow the protocol. * Unable to undergo brain MRI. * History of other chronic neurological illnesses that might mimic MS with chronic or intermittent symptoms (i.e. ALS, myasthenia gravis, chronic neuropathy, etc.)