Inclusion Criteria:

1. Definite or probable PBC diagnosis (consistent with American Association for the Study of Liver Diseases [AASLD] and the European Association for the Study of the Liver [EASL] practice guidelines; Lindor 2009; EASL 2009), as demonstrated by the presence of ≥2 of the following 3 diagnostic factors:
   • History of elevated Alkaline phosphatase levels for at least 6 months prior to Day 0
   • Positive antimitochondrial antibody (AMA) titer or if AMA negative or in low titer (<1:80) PBC-specific antibodies (anti-GP210 and/or anti-SP100 and/or antibodies against the major M2 components [PDC-E2, 2-oxo-glutaric acid dehydrogenase complex])
   • Liver biopsy consistent with PBC
2. A mean total bilirubin >ULN and ≤3x ULN or an ALP >5x ULN
3. Age ≥18 years
4. Taking Ursodeoxycholic acid (UDCA) for at least 12 months (stable dose for ≥3 months) prior to Day 0, or unable to tolerate UDCA (no UDCA for ≥3 months) prior to Day 0
5. Contraception: Female subjects must be postmenopausal, surgically sterile, or if premenopausal, be prepared to use ≥1 effective (≤1% failure rate) method of contraception during the trial and for 30 days after the end of treatment (EOT) visit. Effective methods of contraception are considered to be:
   • Hormonal (e.g. contraceptive pill, patch, intramuscular implant or injection; or
   • Double barrier method, i.e. (a) condom (male or female) or (b) diaphragm, with spermicide; or
   • Intrauterine device (IUD); or
   • Vasectomy (partner); or
   • Abstinence, if in line with the preferred and usual lifestyle of the subject
6. Must provide written informed consent and agree to comply with the study protocol

Exclusion Criteria:

1. History or presence of other concomitant liver diseases including:
   • Hepatitis C virus infection
   • Active Hepatitis B infection; however, subjects who have seroconverted (hepatitis B surface antigen and hepatitis B e antigen negative) may be included in this study after consultation with the medical monitor
   • Primary sclerosing cholangitis (PSC)
   • Alcoholic liver disease
   • Definite autoimmune liver disease or overlap hepatitis
   • Nonalcoholic steatohepatitis (NASH)
   • Gilbert's Syndrome
2. Presence of clinical complications of PBC or clinically significant hepatic decompensation, including:
   • History of liver transplant, current placement on a liver transplant list, or current Model of End Stage Liver Disease (MELD) score >12. Subjects who are placed on a transplant list despite a relatively early disease stage (for example per regional guidelines) may be eligible as long as they do not meet any of the other exclusion criteria
   • Cirrhosis with complications, including history (within the past 12 months) or presence of:
     • Variceal bleed
     • Uncontrolled ascites
     • Encephalopathy
     • Spontaneous bacterial peritonitis
   • Known or suspected hepatocellular carcinoma
   • Prior transjugular intrahepatic portosystemic shunt procedure
   • Hepatorenal syndrome (type I or II) or screening serum creatinine >2 mg/dL (178 μmol/L)
3. Mean total bilirubin >3x ULN
4. Subjects who have undergone gastric bypass procedures (gastric lap band is acceptable) or ileal resection or plan to undergo either of these procedures
5. Other medical conditions that may diminish life expectancy, including known cancers (except carcinomas in situ or other stable, relatively benign conditions such as chronic lymphatic leukemia)
6. If female: plans to become pregnant, known pregnancy or a positive urine pregnancy test (confirmed by a positive serum pregnancy test), or lactating
7. Known history of human immunodeficiency virus infection
8. Medical conditions that may cause nonhepatic increases in ALP (eg, Paget's disease or fractures within 3 months)
9. Other clinically significant medical conditions that are not well controlled or for which medication needs are anticipated to change during the study
10. History of alcohol abuse or other substance abuse within 1 year prior to Day 0
11. Participation in another investigational product, biologic, or medical device study within 30 days prior to Screening. Participation in a previous study of OCA is allowed with 3 months washout prior to enrollment in this study
12. Mental instability or incompetence, such that the validity of informed consent or ability to be compliant with the study is uncertain
13. History of known or suspected clinically significant hypersensitivity to OCA or any of its components