A Research Study to Evaluate Safety and Efficacy of DUR-928 in Subjects With Primary Sclerosing Cholangitis (PSC)

Inclusion Criteria: * Verified diagnosis of primary sclerosing cholangitis (PSC) for at least 12 months, with or without inflammatory bowel disease (IBD). * Serum alkaline phosphatase (ALP) ≥ 1.5 times ULN and with no \>15% fluctuation in the past 3 months. * In subjects receiving treatment with ursodeoxycholic acid (UDCA), therapy must be stable for at least 3 months and at a dose not greater than 20 mg/kg/day. * Subjects of childbearing potential must agree to use a medically acceptable method of contraceptive to prevent pregnancy in the subject and/or the partner for the duration of their participation in the trial up to 2 months after the last study drug dosing. Exclusion Criteria: * Presence of documented secondary sclerosing cholangitis or small duct PSC * Bacterial cholangitis within 30 days prior to Screening * Presence of percutaneous drain or endoscopic bile duct stent * History of, or suspicion of cholangiocarcinoma. * Prior liver transplantation, or currently listed for liver transplantation * Presence of other concomitant liver diseases * Moderate to Severe active IBD or flare in colitis activity within the last 3 months * Any severe and/or untreated concomitant cardiovascular, renal, endocrine or psychiatric disorder * Any active malignant disease (within 3 years), other than non-melanomatous skin cancer * Human immunodeficiency virus (HIV) infection * Existing or intended pregnancy, or breast feeding * Has received medication from another clinical trial within the past 30 days