The Sponsor decided to terminate this study in favor of development of subcutaneous administration.

To assess the safety and tolerability of ascending doses of CSL730 after a single intravenous (IV) infusion in healthy Caucasian and Japanese subjects

Inclusion Criteria:

• Healthy males or females (postmenopausal or surgically sterile only) aged ≥ 20 to ≤ 55 years and of Caucasian or Japanese descent

Exclusion Criteria:

• Evidence of a clinically significant medical condition, disorder, or disease as judged by Investigator and / or study Medical Monitor.
• History of asthma (with the exception of childhood asthma that has resolved), chronic obstructive pulmonary disease, or recurrent or current respiratory infections; splenectomy; or recurrent or current gastrointestinal infections.
• Evidence of active or latent tuberculosis.
• Known or suspected hypersensitivity to the IP, to any excipients of the IP, humanized monoclonal antibodies, or Fc fusion protein therapeutics.
• History, or current diagnosis, of substance use disorder.
• Any abnormal clinical laboratory values deemed clinically significant by the Investigator and / or study Medical Monitor.
• Positive serology test result for human immunodeficiency virus antibody, hepatitis virus B surface antigen or hepatitis virus C antibody at Screening.
• Donation or loss of ≥ 480 mL of whole blood within 2 months or donation of plasma within 14 days before Day -1.
• Plans to participate in another investigational drug study while enrolled in this study, or has participated in any other investigational drug study in which they were known to have been administered a monoclonal antibody or biological IP within 4 months, any other investigational drug study within 60 days or > 3 investigational drug studies within 12 months before IP administration.