Pharmacokinetics, Safety and Tolerability of Single Doses of BIIB033 (Opicinumab) Produced by 2 Manufacturing Processes

Key Inclusion Criteria:

- - Ability to understand the purpose and risks of the study and provide signed and
dated informed consent and authorization to use confidential health information in
accordance with national and local subject privacy regulations.

- - Must have a body mass index of 18 to 32 kg/m2, inclusive.

- - All male participants and all female participants of childbearing potential must
practice highly effective methods of contraception during the study and be willing
and able to continue contraception for 6 months after being dosed with study
treatment. Male participants must not have unprotected sexual intercourse with a
female who is pregnant or breastfeeding during the study. Male participants must also
be willing to refrain from sperm donation for at least 6 months after dosing with
study treatment.

- - Must be in good health as determined by the Investigator (or designee), based on
medical history and screening evaluations.

Key Exclusion Criteria:

- - History of any clinically significant cardiac, endocrine, gastrointestinal,
hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic,
dermatologic, psychiatric, renal or other major disease, as determined by the
Investigator.

- - History of or ongoing malignant disease, including solid tumors and hematologic
malignancies (with the exception of basal cell carcinomas and squamous cell
carcinomas that have been completely excised and considered cured at least 12 months
prior to Day -1).

- - 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, or history of any allergic
reaction that in the opinion of the Investigator is likely to be exacerbated by any
component of the study treatment.

- - Prior exposure to BIIB033.

- - Female participants who are breastfeeding or pregnant at Screening or Day -1, or
plan to become pregnant during the study or during the 6 months following study drug
administration.

- - History of, or positive test result at Screening for, human immunodeficiency virus.

- - History of, or positive test result at Screening for, hepatitis C virus antibody or
hepatitis B virus (defined as positive for hepatitis B surface antigen or hepatitis B
core antibody).

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.