Lead Sponsor: University of California, San Francisco

Collaborators: Mayo Clinic, Children's Hospital of Philadelphia, University of Alabama at Birmingham, Massachusetts General Hospital, University of Texas, The Cleveland Clinic, Boston Children's Hospital, New York University, Washington University School of Medicine, Children's Hospital Colorado, Ann & Robert H Lurie Children's Hospital of Chicago, Baylor College of Medicine, Primary Children's Hospital, Loma Linda University, State University of New York at Buffalo, Children's National Med Center

Lead Sponsor: Genzyme, a Sanofi Company

Intervention / Treatment: DRUG: Placebo, DRUG: Teriflunomide

Lead Sponsor: Genzyme, a Sanofi Company

Intervention / Treatment: DRUG: Other H1 antagonist, DRUG: Methylprednisolone, DRUG: Glatiramer acetate, DRUG: Prednisolone, DRUG: Ranitidine, DRUG: Acyclovir, DRUG: Alemtuzumab GZ402673, DRUG: Beta-Interferon, DRUG: Ceterizine, DRUG: Dexchlorpheniramine, DRUG: Paracetamol, DRUG: Diphenydramine