Obeticholic Acid (OCA) in Primary Sclerosing Cholangitis (PSC)

Inclusion Criteria:

- Male or female aged 18 to 75 years

- Must provide written informed consent and agree to comply with the trial protocol

- Must have a diagnosis of PSC (based on cholangiography at any point in time)

- Alkaline phosphatase (ALP) at Screening ≥ 2x ULN

- Total bilirubin at Screening < 2.5x ULN.

- For subjects with concomitant inflammatory bowel disease (IBD):

1. Colonoscopy (if subject has a colon) or other appropriate endoscopic procedure within 12 months of Day 0 confirming no dysplasia or colorectal cancer

2. Subjects with Crohn's Disease (CD) must be in remission as defined by a Crohn's Disease Activity Index (CDAI) <150.

3. Subjects with ulcerative colitis (UC) must either be in remission or have mild disease. Remission is defined as a partial Mayo score of ≤2 with no individual sub-score exceeding 1. Mild disease is defined as a partial Mayo score ≤3 with no individual sub-score exceeding 1 point.

- For subjects being administered UDCA as part of their standard of care, the dose must have been stable for ≥ 3 months prior to, and including, Day 0 and must not have exceeded 20 mg/kg/day during this time.

- Subjects being administered biologic treatments (eg, anti-tumor necrosis factor (TNF) or anti-integrin monoclonal antibodies), immunosuppressants, systemic corticosteroids, or statins, must have been on a stable dose for ≥ 3 months prior to, and including, Day 0 and should plan to remain on a stable dose throughout the trial.

- Contraception: female subjects of childbearing potential must use ≥ 1 effective method (≤1% failure rate) of contraception during the trial and until 4 weeks following the last dose of IP (including long term safety extension doses).

Exclusion Criteria:

- Evidence of a secondary cause of sclerosing cholangitis at Screening

- Immunoglobulin G4 (IgG4) > 4x ULN at Screening or evidence of IgG4 sclerosing cholangitis

- Small duct cholangitis in the absence of large duct disease

- Presence of clinical complications of chronic liver disease or clinically significant hepatic decompensation, including:

- Current Child Pugh classification B or C

- History of, or current diagnosis or suspicion of, cholangiocarcinoma or other hepatobiliary malignancy, or biliary tract dysplasia.

- History of liver transplantation, or current model of end stage liver disease score ≥ 12

- History of, or current, cirrhosis with complications, including history or presence of spontaneous bacterial peritonitis hepatocellular carcinoma or hepatic encephalopathy (as assessed by the investigator)

- Current known portal hypertension with complications, including known gastric or large esophageal varices, poorly controlled or diuretic resistant ascites, history of variceal bleeds, or related therapeutic or prophylactic interventions (e.g., beta blockers, insertion of variceal bands or transjugular intrahepatic portosystemic shunt [TIPS])

- History of, or current, hepatorenal syndrome (type I or II) or Screening serum creatinine > 2 mg/dL (178 μmol/L)

- Platelet count < 50 x 10⁹/L

- Current clinical evidence of dominant strictures that are considered clinically relevant in the opinion of the Investigator or current biliary stent at Screening

- Current cholecystitis or evidence of current biliary obstruction due to gallstones. Asymptomatic gallstones that are not considered a safety risk in the opinion of the Investigator might be acceptable subject to discussion and agreement with the Medical Monitor.

- Colonic dysplasia within ≤ 5 years prior to Day 0

- History of small bowel resection

- History of other chronic liver diseases, including, but not limited to, primary biliary cirrhosis (PBC), alcoholic liver disease, non-alcoholic fatty liver disease (NAFLD), autoimmune hepatitis, hepatitis B virus (unless seroconverted and no positive Hepatitis B Virus DNA), hepatitis C virus and overlap syndrome

- Known Gilbert's syndrome or history of elevations in unconjugated (indirect) bilirubin >ULN or unconjugated (indirect) bilirubin >ULN at Screening

- Known history of human immunodeficiency virus (HIV) infection

- Currently experiencing, or experienced within ≤ 3 months of Screening, pruritus requiring systemic or enteral treatment

- Known or suspected acute cholangitis in the 3 months prior to, and including, Day 0 including cholangitis treated with antibiotics

- Administration of antibiotics is prohibited ≤1 month of Day 0 (unless subject is on a stable prophylaxis dose for at least 3 months prior to Day 0).

- Administration of the following medications is prohibited ≤ 6 months of Day 0 and throughout the trial: fenofibrate or other fibrates and potentially hepatotoxic medications (including α-methyl-dopa, sodium valproic acid, isoniazide, or nitrofurantoin).

- IBD flare during Screening (up to and including Day 0), where "flare" is defined as follows:

- UC flare: partial Mayo Score ≥5, and

- CD flare: CDAI ≥250

- Evidence of deleterious effects of alcohol abuse (as assessed by the investigator) or excessive alcohol consumption (>4 units/day for males, >2 units/day for females)

- Known or suspected use of illicit drugs or drugs of abuse (allowed if medically prescribed or indicated) within 3 months of Day 0

- If female: known pregnancy, or has a positive urine pregnancy test (confirmed by a positive serum pregnancy test), or lactating

- Other concomitant disease, malignancy, or condition likely to significantly decrease life expectancy to less than the duration of the trial (e.g., moderate to severe congestive heart failure)

- Participation in another investigational drug, biologic, or medical device trial within 30 days prior to Screening

- History of noncompliance with medical regimens, or subjects who are considered to be potentially unreliable

- Blood or plasma donation within 30 days prior to Day 0

- Mental instability or incompetence such that the validity of informed consent or compliance with the trial is uncertain.