Inclusion Criteria:
* Healthy males aged 19 to 55 years (inclusive) at the time of signing the ICF.
* Body mass index between 18.0 and 32.0 kg/m2 (inclusive).
* Ability to swallow and retain oral medication.
Exclusion Criteria:
* History of uncontrolled or unstable cardiovascular, respiratory, renal, gastrointestinal, endocrine, hematopoietic, psychiatric, and/or neurological disease within 6 months of screening.
* Resting pulse \< 40 bpm or \> 100 bpm, confirmed by repeat testing at screening.
* History or presence of an abnormal ECG before initial dose administration that, in the investigator's opinion, is clinically significant (QTcF interval \> 450 milliseconds \[may increase the risk associated with participating in the study or may confound ECG data analysis\], QRS interval \> 120 milliseconds, and PR interval \> 220 milliseconds).
* Presence of a malabsorption syndrome possibly affecting drug absorption (eg, Crohn disease or chronic pancreatitis).
* History of irregular bowel movements (eg, irritable bowel syndrome, frequent episodes of diarrhea, or constipation defined by less than 1 bowel movement on average per 2 days) or lactose intolerant.
* History of malignancy within 5 years of screening, with the exception of cured basal cell or squamous cell carcinoma of the skin, ductal carcinoma in situ, or prostate cancer.
* Current or recent (≤ 6 months of screening), clinically significant gastrointestinal disease or surgery or any history of gastrointestinal surgery (including cholecystectomy, excluding appendectomy and uncomplicated hernia repair) that is anticipated to affect the absorption of study treatment.
* Any major surgery within ≤ 6 months of screening.
* Donation of blood to a blood bank within 4 weeks of screening (within 2 weeks for plasma only).
* Blood transfusion within 4 weeks of check-in.
* Positive test for hepatitis B virus, HCV, or HIV.
• Note: Participants whose results are compatible with prior immunization or immunity due to infection for hepatitis B may be included at the discretion of the investigator.
* History of significant alcohol use within 3 months of screening, defined as regular alcohol consumption \> 21 units per week (1 unit = ½ pint beer or a 25-mL shot of 40% spirit, 1.5 to 2 units = 125-mL glass of wine, depending on type).
* Positive urine or breath test for ethanol or positive urine or serum screen for drugs of abuse that are not otherwise explained by permitted concomitant medications or diet.
* Exposure to significant diagnostic or therapeutic radiation (eg, serial x-ray, computed tomography scan, barium meal) or employment in a job requiring radiation exposure monitoring within 12 months prior to check-in.
* History of any significant drug allergy (such as anaphylaxis or hepatotoxicity) deemed clinically relevant by the investigator.
* Known hypersensitivity or severe reaction to INCB161734 or any excipients of INCB161734 (refer to the IB).
* Use of tobacco- or nicotine-containing products within 1 month of screening.
* eGFR \< 90 mL/min/1.73 m2 based on the site's preferred formula at screening. • Note: Assessment of eGFR may be repeated once if outside of the reference range.
Other protocol-defined Inclusion/Exclusion Criteria may apply.
