Safety, Tolerability, and Pharmacokinetics of Single and Multiple Doses of BIIB033 in Healthy Japanese Participants

Key Inclusion Criteria: * Japanese subjects must have been born in Japan, and their biological parents and grandparents must all have been of Japanese origin. * Subjects who have lived out of Japan for more than 5 years must not have significantly modified their diets since leaving Japan. * Must be a nonsmoker or light smoker (\<10 cigarettes per day) and be willing to abstain from using tobacco and tobacco-containing products during the Inpatient Period and for at least 48 hours prior to Day -1, Day 14 (for Cohort 3), and all outpatient visits. * Must have a body mass index of 18 to 32 kg/m2, inclusive. Key Exclusion Criteria: * History of any clinically significant cardiac, endocrine, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, psychiatric, renal, or other major disease, as determined by the Investigator. * Serious infection (e.g., pneumonia, septicemia) as determined by the Investigator within the 3 months prior to Day -1. * Fever or bacterial or viral infection (including upper respiratory tract infection) within 2 weeks prior to Day -1. * History of severe allergic or anaphylactic reactions. NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.