An Investigational Study to Evaluate the Cardiac Safety Assessment (TQTc Study) of ESK-001

Inclusion Criteria: * Healthy male and female subjects aged between 18 and 55 years, inclusive. Body mass index between ≥18.0 and ≤32.0 kg/m2, inclusive, and a minimum body weight of 45 kg. * Able to comprehend and willing to sign an ICF and to abide by the study restrictions. * In good health, determined by no clinically significant findings from medical history, 12-lead ECG, vital signs measurements, and clinical laboratory evaluations, and from the physical examination at screening or check-in, as assessed by the investigator (or designee). * Serum sodium, potassium, calcium, and magnesium levels are within the normal range at screening and check-in- Exclusion Criteria: * Positive hepatitis panel and/or positive human immunodeficiency virus test, hepatitis B surface antigen, or hepatitis C antibodies. * Alanine aminotransferase or aspartate aminotransferase \>1.5 times the upper limit of normal, at screening or check-in. * History of significant hypersensitivity, intolerance, or allergy to any drug compound, food, or other substance, as determined by the investigator (or designee). * Surgery within the past three months prior to the first study drug administration determined by the principal investigator to be clinically relevant. * History of stomach or intestinal surgery or resection that would potentially alter absorption and/or excretion of orally administered drugs (uncomplicated appendectomy and hernia repair are allowed). * History of Gilbert's syndrome or cholecystectomy surgery.