A Study to Assess the Safety and Pharmacokinetics of INCB123667 When Administered Orally to Adult Participants With Severe Renal Impairment or End Stage Renal Disease

Inclusion Criteria: * Aged 18 to 85 years, inclusive, at the time of signing the ICF. * Severe renal impairment or ESRD based on CKD-EPI. * Body mass index of 18.0 to 43.0 kg/m2 (inclusive). * Willingness to avoid pregnancy or fathering children. Exclusion Criteria: * Participants who have a current, functioning organ transplant or are on the national transplant list and expected to receive a transplant within 3 months. * Participants with laboratory values outside the accepted range for participants with severe renal impairment or ESRD at screening. Participants with out-of-range values will be assessed by the investigator or designee for eligibility. * Tobacco or nicotine-containing product use of \> 10 cigarettes per day within 1 month before screening. * Participants who had a change in disease status within 30 days before screening, as documented by the participant's medical history, that is deemed clinically significant by the investigator. * Participants who have a history of paracentesis within 3 months prior to check-in. * Participants who required new medication or an increase in dose for renal disease within 3 months prior to check-in. * Participants who have a history of unstable diabetes mellitus (as evidenced by hemoglobin A1c ≥ 10.0%). Medications for treatment of diabetes mellitus must be reviewed and approved by the investigator and medical monitor. * Participants who had esophageal banding within 3 months prior to check-in or required any other treatment for gastrointestinal bleeding within 6 months prior to check-in. Other protocol-defined Inclusion/Exclusion Criteria may apply.