Study to investigate the efficacy and safety of two doses of K-808 (pemafribate) in subjects with PBC.

Inclusion Criteria:

• Male or female participant who has a PBC diagnosis as demonstrated by the presence of ≥2 of the following three diagnostic criteria:

  • History of ALP above ULN for at least 6 months
  • History of positive antimitochondrial antibody (AMA) titer or positive PBC-specific antinuclear antibody (ANA) titer
  • Historical liver biopsy consistent with PBC

• Participant has the following qualifying biochemistry value at Screening:

  • ALP ≥1.5 × ULN

• Participant is ≥18 years of age at consent.

• Participant meets all other eligibility criteria outlined in the Clinical Study Protocol.

Exclusion Criteria:

• Participant meets any one of the following criteria at Screening:

  • ALP>10 × ULN
  • ALT or AST >5 × ULN
  • Hepatitis C treatment within 5 years of Screening, or active hepatitis C as defined by positive hepatitis C antibody with the presence of hepatitis C virus ribonucleic acid; subjects with active hepatitis B (HBV) infection (hepatitis B surface antigen [HbsAg] positive) will be excluded. A subject with resolved hepatitis A at least 3 months prior to the Screening Visit can be screened.
  • Primary sclerosing cholangitis and secondary sclerosing cholangitis (eg, due to cholangiolithiasis, ischemia, telangiectasia, vasculitis, infectious diseases)
  • Alcoholic liver disease
  • History of definite autoimmune hepatitis or PBC/autoimmune hepatitis overlap, defined as both of the following: 1) IgG >2 × ULN and/or positive anti-smooth muscle antibodies, 2) liver histology revealing moderate or severe periportal or periseptal inflammation
  • Nonalcoholic steatohepatitis (NASH)
  • Gilbert's Syndrome
  • Alpha-1-antitrypsin deficiency, cystic fibrosis, Wilson's disease, hemochromatosis based on historically established diagnosis
  • Drug-induced liver injury (DILI) as defined by typical exposure and history
  • Known condition that involves bile duct obstruction or cholestasis other than PBC, eg, vascular diseases (eg, Budd-Chiari syndrome, sinusoidal obstruction syndrome, congestive hepatopathy), congenital conditions (ductal plate malformations, Caroli syndrome, congenital liver fibrosis), idiopathic ductopenia
  • Hepatocellular carcinoma

• Participant meets any other exclusion criteria outlined in the Clinical Study Protocol.