Clinical study terminated due to preclinical safety findings in non-human primates.

The primary objective of the study is to evaluate the safety and tolerability of single ascending intravenous (IV) doses and a single subcutaneous (SC) dose of BIIB063 in healthy volunteers. The secondary objectives of the study are to estimate the PK parameters of single ascending IV doses of BIIB063; to estimate the PK parameters and absolute bioavailability (F) of a single SC dose of BIIB063; and to evaluate the immunogenicity of single ascending doses of BIIB063.

Key Inclusion Criteria:

• All male subjects and all female subjects of childbearing potential must practice at least 1 highly effective method of contraception (i.e., contraceptive measure with a failure rate of <1% per year; estrogen-containing contraceptives are prohibited) during the study and be willing and able to continue contraception for 4 months after being dosed with study treatment. Male subjects must also be willing to refrain from sperm donation for at least 4 months after the last dose of study treatment. Male subjects must not have unprotected sexual intercourse with a female who is pregnant or breastfeeding during the study.
• Must have a body mass index between 18 and 30 kg/m2, inclusive.
• Must be in good health as determined by the Investigator, based on medical history, physical examination, and 12-lead ECG.

Key Exclusion Criteria:

• History of or positive test result at screening for human immunodeficiency virus, hepatitis C virus antibody, or hepatitis B virus (defined as positive for hepatitis B surface antigen [HBsAg] or hepatitis B core antibody [HBcAb]).
• 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.
• Personal or family history of cardiovascular disease under the age of 50 years, inherited disorder of coagulation (e.g., Factor V Leiden, protein C or S deficiency), or anti-phospholipid Ab syndrome (APS).
• History of meningococcal vaccination or meningococcal meningitis, or history of hypersensitivity to single components of meningococcal vaccines (including MENVEO), any other CRM197, diphtheria toxoid, or meningococcal-containing vaccine.
• History of tuberculosis (TB) or positive QuantiFERON®-TB Gold test
• Personal history of thromboembolic events
• Treatment with any prescription or over-the-counter medication within 14 days prior to randomization (excluding vitamins, dietary supplements, herbal preparations, progestin-only birth control, and paracetamol up to 4 g/day for no more than 5 consecutive days).
• Current enrollment or a plan to enroll in any interventional clinical study in which an investigational treatment or approved therapy for investigational use is administered within 3 months
• Current enrollment or a plan to enroll in any other drug, biologic or device clinical study, or treatment with an investigational drug or approved therapy for investigational use within 3 months
• Blood donation (1 unit or more) within 3 months prior to randomization.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply