A Study to Investigate the Pharmacokinetics and Safety of Remibrutinib in Participants With Hepatic Impairment Compared With Matched Healthy Participants

Inclusion Criteria: All participants Male and non-childbearing potential female participants 18 to 70 years of age, inclusive, at Screening. Must be a non-smoker or a light smoker who smokes no more than 10 cigarettes (or equivalent) per day, at Screening. Smokers must agree to smoke no more than 5 cigarettes (or equivalent) per day from check-in until after Study Completion evaluations. Participants with mild, moderate and severe HI (Groups 1, 2 and 3) Must weigh at least 50 kg to participate in the study, and must have a body mass index (BMI) within the range of 18.0 to 35.0 kg/m2, inclusive, at Screening. Has impaired hepatic function as defined by the Child-Pugh classification for severity of liver disease and has a Child-Pugh score in line with one of the following HI groups at Screening: Group 1; mild (Class A); Child-Pugh score 5-6, inclusive. Group 2; moderate (Class B); Child-Pugh score 7-9, inclusive. Group 3; severe (Class C); Child-Pugh score 10-15, inclusive. Participants with other stable medical disorders such as controlled diabetes, hyperlipidemia, hypothyroidism, etc., may be eligible as long as they are considered appropriate for enrollment as determined by the Investigator by past medical history, physical examination, ECG and clinical laboratory tests at Screening. Healthy control participants (Group 4) Each healthy participant must match the age (± 10 years) and body weight (± 20%) of participants in Groups 1 and 2 (Part 1) and/or Group 3 (Part 2). Must be in good health as determined by medical history, physical examination, ECG and clinical laboratory tests at Screening. Exclusion Criteria: All participants History of hypersensitivity to the study treatment or its excipients or to drugs of similar chemical classes. History or presence of malignancy of any organ system (other than treated localized basal cell or squamous cell carcinoma of the skin or in-situ cervical cancer), treated or untreated, within the past 5 years of Screening, regardless of whether there is evidence of local recurrence or metastases. History or presence of any ongoing, chronic or recurrent infectious disease (including tuberculosis, atypical mycobacterioses, listeriosis, aspergillosis). Participants with mild and moderate HI (Groups 1 and 2) Severe complications of liver disease within the preceding 3 months of Screening. Emergency room visit or hospitalization due to liver disease within the preceding 3 months of Screening. Has received liver transplant at any time in the past and/or is on immunosuppressant therapy at Screening. Clinically significant abnormal findings in physical examination, ECG or clinical laboratory evaluations, not consistent with known liver disease. Participants having had myocardial infarction < 5 years of Screening are not eligible to participate, participants having had myocardial infarction ≥ 5 years of Screening can be eligible to participate. Participants with severe HI (Group 3) Severe complications of liver disease within the preceding 3 months of Screening. Emergency room visit or hospitalization due to liver disease within the preceding 1 month of Screening. Has received liver transplant at any time in the past and/or is on immunosuppressant therapy at Screening. Clinically significant abnormal findings in physical examination, ECG or clinical laboratory evaluations, not consistent with known liver disease. Participants having had myocardial infarction < 5 years of Screening are not eligible to participate, participants having had myocardial infarction ≥ 5 years of Screening can be eligible to participate. Encephalopathy Grade 3 or worse within 28 days of planned first dosing of study treatment. Serum ammonia level > 200 μg/dL at Screening or Baseline. INR > 2.3 at Screening or Baseline. Transjugular intrahepatic portosystemic shunt and/or have undergone portacaval shunting.Documented presence of esophagus varices (stage III or IV) based on the evaluation of the participant's medical history at Screening and Baseline. History, clinical evidence or suspicion of a hepato-cellular carcinoma (HCC) based on sonographical and/or laboratory results (i.e. α-Fetoprotein (AFP) > 12 IU/mL [2 × upper limit of normal [ULN] at screening). Severe ascites and/or pleural effusion. Participants with clinical evidence or suspected acute liver failure as judged by the Investigator. Healthy control participants (Group 4) Significant illness which has not resolved within 2 weeks prior to first dosing of study treatment. Liver disease or liver injury as indicated by abnormal liver function tests at Screening. Any single parameter of alanine aminotransferase (ALT), AST, gamma-glutamyl transferase (GGT) or alkaline phosphatase (ALP) exceeding 1.2 x upper limit of normal (ULN) or ≥ 1.5 x ULN total bilirubin (TBL) OR any elevation above ULN of more than one parameter of ALT, AST, GGT, ALP or TBL. Hemoglobin levels below 11.0 g/dL for males and 10.0 g/dL for females at Screening or Baseline.