• Subjects who are willing and able to provide Institutional Review Board (IRB) approved written informed consent and privacy language as per national regulations.

• Men and non-pregnant women, ages 18-75 years inclusive.

• Subjects with a PBC diagnosis as demonstrated by the presence of 2 or more of the following 3 diagnostic factors:

∙ Alkaline phosphatase \> 1.5× ULN for at least 6 months

‣ Positive AMA titer or, if AMA negative or in low titer (\<1:40), positive 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 findings consistent with PBC

• Subjects who are unresponsive to UDCA and/or OCA after 6 months of treatment at a stable dose as measured by ALP \> 1.5× ULN.

• For subjects on any medication used to treat the symptoms of PBC (ex. UDCA, OCA, seladelpar), subjects must be on a stable dose for a minimum of 3 months prior to enrollment and must agree not to change their dose through study Day 60 unless reviewed by the medical monitor and approved by the site investigator.

• Subjects with ALP \> 1.5× ULN.

• Subjects with AST and ALT \< 5× ULN.

• Subjects with hemoglobin ≥ 10 g/dL.

• Subjects with total bilirubin \< 2× ULN.

⁃ Men and women of child-bearing potential (WOCBP) must agree to practice a highly effective method of contraception that may include, but is not limited to, abstinence, sex only with persons of the same sex, monogamous relationship with vasectomized partner, vasectomy, hysterectomy, bilateral tubal ligation, licensed hormonal methods, intrauterine device (IUD) beginning at the time of screening through Day 90.

⁃ Female subjects who agree not to donate ova starting at initial screening and through Day 90.

⁃ Male subjects who agree to not donate sperm starting at screening and through Day 90.