Study to Assess Safety & Efficacy of GKT137831 in Patients With Primary Biliary Cholangitis Receiving Ursodiol.

Inclusion Criteria

• Male or female aged 18 to 80 years, inclusive.
• Willing and able to give written informed consent and to comply with the requirements of the study.
• PBC diagnosis as demonstrated by the presence of ≥ 2 of the following 3 diagnostic factors:
• History of elevated ALP levels (> ULN) for at least 6 months
• Positive anti-mitochondrial antibody (AMA) titer or if AMA negative or in low titer ( 1.2 unless subject is on anticoagulant therapy.
• ALT > 3 x ULN.
• Total bilirubin > 1 x ULN.
• Planned or current plasmapheresis or other extra-corporeal treatments (e.g., molecular adsorbent recirculation system (MARS)) for treatment-refractory pruritus.
• History of liver transplantation, current placement on a liver transplant list or current Model for End Stage Liver Disease (MELD) score ≥ 15.
• Cirrhosis with complications, including history or presence of: spontaneous bacterial peritonitis, hepatocellular carcinoma.
• Hepatorenal syndrome (type I or II) or Screening serum creatinine > ULN.
• Competing etiology for liver disease (e.g., hepatitis C, active hepatitis B, non-alcoholic steatohepatitis (NASH), alcoholic liver disease (ALD), autoimmune hepatitis, primary sclerosing cholangitis, Gilbert's Syndrome).
• Subjects receiving prohibited medications within 3 months of Screening (Visit 1) according to the list (a, b and c) provided in Section 6.6.2.
• Treatment with any investigational agent within 4 weeks of Visit 1 or 5 half-lives of the investigational medicinal product (whichever is longer).
• A history of long QT syndrome.
• Evidence of any of the following cardiac conduction abnormalities during the screening period:
• A QTc Fredericia interval >450 milliseconds for males and >470 milliseconds for females.
• A second or third degree atrioventricular block not successfully treated with a pacemaker.
• History of cancer in the preceding 5 years, except adequately treated non-melanoma skin cancer, carcinoma in situ of the cervix, in situ prostate cancer, in situ breast ductal carcinoma, or superficial bladder cancer stage 0).
• The occurrence of any acute infection requiring systemic antibiotic therapy within the 2 weeks prior the Screening Visit (Visit 1), or human immunodeficiency virus (HIV) infection.
• A history of bone marrow disorder including aplastic anemia, or marked anemia defined as hemoglobin < 10.0 g/dL (or 6.2 mmol/L).
• Any condition which, in the opinion of the Investigator, constitutes a risk or contraindication for the participation of the subject in the study, or which could interfere with the study objectives, conduct, or evaluation.