Study to Evaluate the Effects of Two Doses of MBX-8025 in Subjects With Primary Biliary Cirrhosis (PBC)

Primary:

To evaluate the effect of MBX-8025 on Alkaline Phosphatase (AP) levels

Secondary:

To evaluate the safety and tolerability of MBX-8025 in subjects with Primary Biliary
Cirrhosis (PBC) To evaluate the effects of MBX-8025 on Primary Biliary Cirrhosis (PBC)
response criteria To evaluate the effects of MBX-8025 on other markers of liver function,
lipids, pruritus and Quality of Life (QoL)

Exploratory:

To evaluate the effect of MBX-8025 on liver imaging and other biochemical markers that may be
relevant to the pathophysiology of PBC or the mechanism of action of the drug

Inclusion Criteria:

1. Must have given written informed consent (signed and dated) and any authorizations
required by local law

2. 18 to 75 years old (inclusive)

3. Male or female with a diagnosis of PBC, by at least two of the following criteria:

- History of AP above ULN for at least six months

- Positive Anti-Mitochondrial Antibodies (AMA) titers (>1/40 on immunofluorescence
or M2 positive by enzyme linked immunosorbent assay (ELISA) or positive
PBC-specific antinuclear antibodies

- Documented liver biopsy result consistent with PBC

4. On a stable and recommended dose of UDCA for the past twelve months

5. AP ≥ 1.67 × ULN

6. For females of reproductive potential, use of at least one barrier contraceptive and a
second effective birth control method during the study and for at least two weeks
after the last dose. For male subjects, use of appropriate contraception (e.g.,
condoms), so their female partners of reproductive potential do not become pregnant
during the study and for at least two weeks after the last dose

Exclusion Criteria:

1. A medical condition, other than PBC, that in the investigator's opinion would preclude
full participation in the study or confound its results (e.g., cancer on active
treatment)

2. AST or ALT > 3 × ULN

3. Total bilirubin > 2 × ULN

4. Auto-immune hepatitis

5. Primary sclerosing cholangitis

6. Known history of alpha-1-Antitrypsin deficiency

7. Known history of chronic viral hepatitis

8. Creatine kinase above ULN

9. Serum creatinine above ULN

10. For females, pregnancy or breast-feeding

11. Use of colchicine, methotrexate, azathioprine, or systemic steroids in the two months
preceding screening

12. Current use of fibrates, including fenofibrates, or simvastatin

13. Use of an experimental treatment for PBC

14. Use of experimental or unapproved immunosuppressant

15. Any other condition(s) that would compromise the safety of the subject or compromise
the quality of the clinical study, as judged by the Investigator