Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics After Single and Multiple Doses of LEO 142397 in Healthy People, Including Japanese

Key inclusion Criteria: * Body mass index of 18.0-32.0 kg/m2, inclusive. * In good health at screening and check-in as judged by the investigator based on medical history, physical examination, vital signs assessment, 12-lead electrocardiogram, and clinical laboratory evaluations: * Aspartate aminotransferase and alanine aminotransferase values ≤1.5 times the upper limit of normal. * Congenital nonhaemolytic hyperbilirubinaemia (including suspicion of Gilbert's syndrome) is not acceptable. * Haemoglobin value, neutrophil count, and lymphocyte count ≥ the lower limit of normal. * Female subjects of childbearing potential must use a highly effective form of birth control, in conjunction with adequate barrier contraception, from randomisation until 90 days after the follow-up visit. * Male subjects with female partner of childbearing potential must use adequate male barrier contraception, in conjunction with a highly effective form of female contraception for the partner, from randomisation until 90 days after the follow-up visit. Key exclusion criteria: * Any surgical or medical condition that might significantly alter the absorption, distribution, metabolism, or excretion of any drug. * Any medication, including St. John's wort, known to chronically alter drug absorption or elimination processes within 30 days prior to the first dose. * History of any significant infectious disease, as assessed by the investigator, within 2 weeks prior to the first dose. * Current active tuberculosis based on QuantiFERON-TB Gold test. * Positive hepatitis B surface antigen, hepatitis C virus antibody, or human immunodeficiency virus antibodies at screening. * Electrocardiogram abnormalities at screening or check-in. * Smoking of \>10 cigarettes per day, on average, within the last 3 months.