The purpose of this study is to evaluate the mass balance and safety of [14C] ABBV-903 in healthy male volunteers following a single oral dose administration.

Inclusion Criteria:

• Body Mass Index (BMI) is >= 18.0 to <= 32.0 kg/m2 after rounding to the tenths decimal at Screening and upon initial confinement.
• A condition of general good health, based upon the results of a medical history, physical examination, vital signs, laboratory profile and a 12-lead electrocardiogram (ECG).

Exclusion Criteria:

• History: of epilepsy, any clinically significant cardiac, respiratory (except mild asthma as a child), endocrine, metabolic, renal, hepatic, gastrointestinal, Gilbert's Syndrome, hematologic or psychiatric disease or disorder, or any uncontrolled medical illness
• History of any clinically significant illness/infection/major febrile illness, hospitalization, or any surgical procedure within 30 days prior to study drug administration.
• Consider fathering a child or donating sperm during the study and for 94 days after study drug administration.
• Has had significant exposure to radiation for professional or medical reasons (e.g., serial x-rays or computed tomography scans, barium meal, current employment in a job requiring radiation exposure monitoring), except dental x-rays, within 12 months prior to study drug administration.