A Study to Evaluate the Pharmacokinetics, Safety and Immunogenicity of BIIB800 Subcutaneously (SC) Compared to Actemra® in Healthy Male Participants

A Randomized, Double-Blind, Parallel-Group, Phase I Study to Evaluate the Pharmacokinetics, Safety and Immunogenicity of BIIB800 s.c. Compared to Actemra® in Healthy Male Participants

The primary objective of the study is to show equivalence in pharmacokinetics (PK) of BIIB800 and Actemra following SC administration of a single dose to healthy male participants. The secondary objective of the study is to evaluate PK over time, clinical safety, pharmacodynamic (PD) profiles and immunogenicity of BIIB800 and Actemra.

Key Inclusion Criteria:

• Have a body mass index between 18.5 and 29.9 kilograms per meter square (kg/m^2), inclusive.
• Total body weight between 60.0 and 90.0 kg, inclusive.
• Systolic blood pressure <135 millimeters of mercury (mmHg) or >85 mmHg at Screening, after being supine for at least 5 minutes.
• No clinically significant (as determined by the Investigator) 12-lead electrocardiogram (ECG) abnormalities, no cardiac pacemaker.

Key Exclusion Criteria:

• History or positive test result at Screening for human immunodeficiency virus (HIV).
• History of hepatitis C infection or positive test result at Screening for hepatitis C virus antibody.
• Current hepatitis B infection (defined as positive for hepatitis B surface antigen [HBsAg] and total hepatitis B core antibody [anti-HBc]).
• Serious infection (as determined by the Investigator) within the 6 months prior to Screening.
• History of systemic hypersensitivity reaction to the active drug substance, the excipients contained in the formulation, and if appropriate, any diagnostic agents to be administered during the study.
• History of immunodeficiency or other clinically significant immunological disorders, or autoimmune disorders.
• History of clinically significant (in the opinion of the Investigator) atopic allergy (e.g., asthma, urticaria, eczematous dermatitis, allergic rhinitis), hypersensitivity, or allergic reactions.
• History of angioedema.
• A positive diagnostic tuberculosis test result within 35 days prior to Day -1, defined as a positive QuantiFERON® test result or 2 successive indeterminate QuantiFERON test results.
• Any prior exposure to tocilizumab or to any other agent directly acting on IL-6 or on its receptors including investigational products (e.g., siltuximab, sarilumab etc.).
• Administration of immunoglobulins for anti-tetanus and anti-rabies post-exposure prophylaxis within 3 weeks prior to administration of study drug.
• Any live or attenuated immunization or vaccination given within 30 days prior to Day -1 or planned to be given during the study period.

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