Inclusion Criteria:  Age ≥ 18 and ≤75 years old at screening.  Definite or probable PBC diagnosis, as demonstrated by the presence of ≥ 2 of the following 3 diagnostic factors:  Biochemical evidence of cholestasis based on ALP elevation. Presence of AMA, or other PBC-specific autoantibodies, including sp100 or gp210, if AMA is negative. Liver biopsy consistent with PBC. Screening ALP ≥ 1.67× ULN Taking UDCA for at least 6 months (stable dose for ≥ 3 months) prior to Day 0, or unable to tolerate UDCA (no UDCA for ≥ 3 months) prior to Day 0.  Exclusion Criteria:  ALT or AST > 5× ULN; ALP >10× ULN History or presence of other concomitant liver diseases Child-Pugh grade B or C