Patient description: The patient is a 20 year old Caucasian female presents to the clinic with one-sided vision lost and facial weakness, dysarthria and numbness lasting for 1 day. She visited her PCP and underwent brain MRI which revealed a single plaque in the brainstem. After few months, she experienced lower extremities weakness led to balance problem. The second MRI revealed another lesion in the left cerebral hemisphere. The diagnosis of Relapsing Remitting Multiple Sclerosis (RRMS) is confirmed after the second MRI. Her past surgical history is significant for a C-section 2 years ago and she has a one child. She is divorced and is not currently in any sexual relationship. She smokes 10 cigarettes per day and drinks alcohol occasionally. She is working as an editor in a publisher company and she is happy that she can keep working from home most of the time. She is under the treatment of RRMS from 7 months ago.

Clinical trial eligibility criteria: eligible ages (years): 10.0-17.0,  Relapsing-Remitting Multiple Sclerosis Key Must have a body weight of ≥30 kg Must have a diagnosis of RRMS (consensus definition for pediatric RRMS [Krupp 2007]) Must be ambulatory with a baseline EDSS score between 0 and 5.5, inclusive Must have experienced at least 1 of the following 3 conditions: a) at least 1 relapse within the last 12 months prior to Day 1 with a prior brain MRI demonstrating lesions consistent with MS; b) at least 2 relapses within the last 24 months prior to Day 1, with a prior brain MRI demonstrating lesions consistent with MS; c) evidence of Gd-enhancing lesions of the brain on an MRI performed within the 6 weeks prior to Day 1 Must be neurologically stable, with no evidence of relapse within 50 days prior to Day 1 and no evidence of corticosteroid treatment within 30 days prior to Day 1 Subjects of childbearing potential who are sexually active must be willing to practice effective contraception during the study and be willing and able to continue contraception for at least 30 days after their final dose of study treatment. Key  Primary progressive, secondary progressive, or progressive relapsing MS (as defined by [Lublin and Reingold 1996]). These conditions require the presence of continuous clinical disease worsening over a period of at least 3 months. Subjects with these conditions may also have superimposed relapses but are distinguished from relapsing-remitting subjects by the lack of clinically stable periods or clinical improvement Disorders mimicking MS, such as other demyelinating disorders (e.g., acute disseminated encephalomyelitis), systemic autoimmune disorders (e.g., Sjögren disease, lupus erythematosus), metabolic disorders (e.g., dystrophies), and infectious disorders History of premalignant or malignant disease. Subjects with basal cell carcinoma that has been completely excised prior to screening will remain eligible History of severe allergic or anaphylactic reactions, or known drug hypersensitivity to DMF, fumaric acid esters, or interferon beta-1a (IFN Beta-1a) History of abnormal laboratory results indicative of any significant endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, renal, and/or any other major disease that would preclude participation in a clinical study History of clinically significant cardiovascular, pulmonary, GI, dermatologic, growth, developmental, psychiatric (including depression), neurologic (other than MS), and/or other major disease that would preclude participation in a clinical study. -.History of human immunodeficiency virus An MS relapse that has occurred within 50 days prior to Day 1 AND/OR the subject has not stabilized from a previous relapse prior to Day 1 Other unspecified reasons that, in the opinion of the Investigator or Biogen Idec, make the subject unsuitable for enrollment For the PD/PK subset of subjects: subjects unable to swallow the BG00012 capsule whole. Key Treatment history Any previous treatment with Fumaderm (fumaric acid esters) or BG00012