Inclusion Criteria:

1. Male or female subject age 18-76 years

2. Diagnosis of PSC consistent with the guidelines published by the American Association
for the Study of Liver Diseases (AASLD).39 All subjects must have an elevated serum
ALP of at least 1.5 times upper limit of normal at baseline plus cholangiographic
evidence of PSC, as demonstrated by magnetic resonance imaging, endoscopic retrograde
cholangiography, direct cholangiography, or liver biopsy.

3. Total bilirubin at screening must be ≤ 2 times upper limit of normal

4. An ultrasound (or equivalent imaging modality) that excludes biliary obstruction and
malignancy within 6 months of study entry,

5. If a patient is on any of the following medications and/or supplements, he or she is
expected to remain on the same daily dose through the treatment period: UDCA,
azathioprine, prednisone (or an equivalent steroid compound), methotrexate, a
5-aminosalicylic acid, biologic therapy, and/or a probiotic.

6. If a patient has been on obeticholic acid or other experimental therapies for PSC,
they must complete a 3 month washout period before study entry

7. PSC with or without inflammatory bowel disease, such as ulcerative colitis or Crohn's
disease

8. Must agree to comply with the study protocol and provide informed consent.

Exclusion Criteria:

1. Administration of an antibiotic within 3 months prior to the study,

2. Pregnancy or attempting to become pregnant or breastfeeding,

3. Presence of any of the following:

i. Hepatitis B infection

ii. Hepatitis C infection (antibody positive); patients with a history of hepatitis C
infection will be eligible for this study if they have undetectable levels of HCV RNA

iii. Other cholestatic liver diseases such as primary biliary cholangitis and
cholestatic diseases of pregnancy

iv. Metabolic liver diseases such as Wilson's disease and hemochromatosis

v. Inherited diseases of the liver such as ?-1 antitrypsin deficiency

vi. Immunoglobulin G4-related cholangitis

vii. PSC with concomitant autoimmune hepatitis (AIH) and/or primary biliary
cholangitis (previously known as primary biliary cirrhosis)

viii. Secondary sclerosing cholangitis (SSC),

ix. Active acute ascending cholangitis requiring antibiotics

x. CCA (malignant biliary stricture, neoplasm, and cytology/histopathology or positive
fluorescence in situ hybridization (FISH) consistent with adenocarcinoma of the bile
duct)

xi. A liver biopsy, if one has been previously obtained, which showed non-alcoholic
steatohepatitis (NASH). Patients with suspected fatty liver by imaging will not be
excluded

xii. Presence of complications of advanced PSC such as hepatic encephalopathy, portal
hypertension, hepato-renal syndrome and hepato-pulmonary syndrome,

xiii. History of liver transplantation, anticipated need for liver transplantation
within 12 months from randomization, or a Model of End Stage Liver Disease (MELD)
score of ≥15

xiv. Ongoing alcohol abuse (>4 drinks per day for men, and >2 drinks per day for
women)

xv. History of allergic reaction to vancomycin,

xvi. Moderate-to-severe renal impairment with a calculated creatinine clearance of <
60mL/min

xvii. HIV/AIDS,

xviii. Any other conditions or abnormalities that, in the opinion of the investigator,
may compromise the safety of the subject or interfere with the subject participating
in or completing the study.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 2/8/2024. Questions regarding updates should be directed to the study team contact.