The purpose of this study is to determine the excretion kinetics and mass balance of fenebrutinib in healthy male subjects.

Inclusion Criteria:

• Healthy male subjects, between 18 and 60 years of age, inclusive
• Within body mass index range 18 to 32 kg/m2, inclusive
• In good health, determined by no clinically significant findings from medical history, 12-lead electrocardiogram (ECG), vital signs, and physical examination
• For males who are sterile: agreement to use a condom with a fertile or pregnant female partner from Day -1 until 90 days following Study Completion; for males who are fertile: agreement to use a condom with spermicide with a fertile or pregnant female partner from Day -1 until 90 days following Study Completion

Exclusion Criteria:

• History or symptoms of any significant disease
• History of significant hypersensitivity, intolerance, or allergy to any drug compound, food, or other substance, unless approved by the Investigator
• History of stomach or intestinal surgery or resection, except appendectomy, hernia repair, and cholecystectomy
• History of malignancy, except for non-melanoma skin carcinoma with 3-year disease-free follow-up
• Participation in any other investigational study drug trial in which receipt of an investigational study drug occurred within 30 days or 5 half-lives, whichever is longer, prior to Day -1
• Exposure to significant diagnostic or therapeutic radiation or current employment in a job requiring radiation exposure monitoring within 12 months prior to Day -1
• Participation in a radiolabeled drug study in which exposures are known to the Investigator within 4 months prior to Day -1, or participation in a radiolabeled drug study in which exposures are not known to the Investigator within 6 months prior to Day -1. The total 12-month exposure from this study and a maximum of 2 other studies must be within the Code of Federal Regulations (CFR) recommended levels considered state (per 21 CFR 361.1), e.g. less than 5,000 mrem whole body annual exposure