Effectiveness of DMF and Its Impact on PROs in Suboptimal GA Responders With RMS

Key Inclusion Criteria: * Have the ability to understand the purpose and risks of the study and provide signed and dated informed consent and authorization to use Protected Health Information in accordance with national and local patient privacy regulations. * Have the ability to read and understand written English. * Have access to the internet and are able to complete online assessments on a computer * Have a relapsing form of Multiple Sclerosis and satisfy the approved therapeutic indication for dimethyl fumarate (DMF) per the United States Prescribing Information (USPI). * Are being treated for relapsing forms of multiple sclerosis (MS) with glatiramer acetate (GA) but, per the Prescribing Physician, have a suboptimal response (e.g., suboptimal efficacy, intolerance, or poor adherence) to GA or have stopped treatment with GA for relapsing forms of MS as a result of suboptimal response within 30 days of enrollment. * Have decided to initiate treatment with dimethyl fumarate (DMF) under routine clinical care. The decision to initiate treatment with DMF must precede enrollment. * Have a complete blood count (CBC) available within 6 months of initiation of treatment with dimethyl fumarate (DMF). Key Exclusion Criteria: * Are unwilling or unable to comply with study requirements, or, are deemed unsuitable for study participation at the discretion of the Prescribing Physician. * Have major comorbid conditions that would preclude their participation in the study as determined by the Prescribing Physician. * Have a history of malignancy. (Patients with basal cell carcinoma that has been completely excised prior to study entry remain eligible.) * Have a history of and/or current serious infections. * Are pregnant or breastfeeding, or are planning to become pregnant or breastfeed. * Are receiving concomitant disease modifying therapies other than glatiramer acetate (GA) or have initiated treatment with a new disease-modifying therapy since discontinuation of glatiramer acetate (GA). * Are currently enrolled in any other clinical studies, with the exception of the dimethyl fumarate (DMF) Pregnancy Registry. * Have received prior treatment with dimethyl fumarate (DMF). NOTE: Other protocol defined Inclusion/Exclusion criteria may apply