Safety, Tolerability, and Pharmacokinetics of BGB-23339 in Healthy Japanese and Caucasian Subjects

Inclusion Criteria: Each subject must meet all of the following inclusion criteria to be considered eligible for participation in this study: 1. Signed informed consent form (ICF) and able to comply with study requirements 2. Healthy Japanese or Caucasian men and/or women of no childbearing potential aged ≥ 18 years and ≤ 55 years on the day of signing the ICF (or the legal age of consent), and to be specific: 1. For Part A only: Eligible Japanese subjects should have both biological parents and 4 biological grandparents of Japanese descent, and their 4 biological grandparents must be born in Japan. 2. For Part B only: Eligible Caucasian subjects should 1) have both biological parents and 4 biological grandparents of Caucasian descent, and 2) be matched by body weight (± 20% body weight \[kg\]), height (± 15% height \[centimeter (cm)\]) and sex to each Japanese subject receiving the highest dose level planned in Part A. 3. Subjects are in good general health as determined by the investigator or medically qualified designee, based on a medical evaluation including medical history, physical examination, laboratory tests and cardiac monitoring Exclusion Criteria: Subjects who meet any of the following criteria will be excluded from this study: Medical Conditions 1. History or presence of cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrinological, hematological, or neurological disorders capable of significantly altering the absorption, metabolism, or elimination of drugs; constituting a risk when taking the study drug; or interfering with the interpretation of data 2. Active herpes infection, including herpes simplex 1 and 2 and herpes zoster (demonstrated on physical examination and/or medical history ≤ 2 months before randomization) 3. Any malignancies within the past 5 years except for basal cell or squamous epithelial carcinomas of the skin that have been resected with no evidence of metastatic disease for 3 years 4. Positive HBV, HCV and HIV test 5. History or risk for tuberculosis (TB)