An Investigational Study of ESK-001 in Participants With Normal Liver Function and Participants With Mild, Moderate, and Severe Liver Damage

Key Inclusion Criteria for All Participants: * Body mass index between 18.0 and 40.0 kg/m2 Key Inclusion Criteria for Participants with Hepatic Impairment: * Diagnosis of chronic (\> 6 months), stable hepatic impairment with no clinically significant changes within 30 days prior to dosing, as determined by medical history Key Exclusion Criteria for All Participants: * Uncontrolled treated/untreated hypertension (systolic blood pressure ≥ 160 mmHg and/or diastolic blood pressure ≥ 105 mmHg), or uncontrolled treated/untreated hypotension (systolic blood pressure \< 90 mmHg and/or diastolic blood pressure \< 50 mmHg), or resting pulse rate \< 45 or \> 100 bpm. Measurements may be repeated once in order to determine eligibility Key Exclusion Criteria for Healthy Volunteer: * Significant history or clinical manifestation of any metabolic, allergic, dermatological, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, neurological, respiratory, endocrine, or psychiatric disorder, as determined by the investigator or designee. * Positive hepatitis panel and/or positive human immunodeficiency virus test. Key Exclusion Criteria for Participants with Hepatic Impairment: * History of any uncontrolled or unstable renal, hematological, gastrointestinal, neurological, endocrine, or psychiatric disorder, as determined by the investigator or designee, within 6 months prior to screening. * History or current diagnosis of uncontrolled or significant cardiac disease indicative of a significant risk of safety for participation in the study. * Liver function tests outside the appropriate reference ranges that are not consistent with hepatic dysfunction, as determined by the investigator or designee. * QTcF \> 480 ms for males or \> 490 ms for females at screening or check-in, as confirmed from the mean of the original value and 2 repeats.