A Study of IDN-6556 in Subjects With NAFLD and Raised Transaminases

This is a double-blind, randomized study to evaluate the effects of IDN-6556 on serum
transaminases and pharmacodynamics of IDN-6556 in subjects with non-alcoholic fatty liver
disease with elevated alanine aminotransferase.

Inclusion Criteria:

- Male or female subjects of minimum adult legal age (according to local laws for
signing the informed consent document), able to provide written informed consent, and
understand and comply with the requirements of the study

- Diagnosis of non-alcoholic fatty liver disease (NAFLD) as evidenced by imaging or
other diagnostic assessments

- Alanine aminotransferase (ALT) levels ≥1.5 x ULN on at least two occasions, seven or
more days apart, during the Screening period

- alpha-fetoprotein (AFP) ≤ 100 ng/mL

- Hemoglobin ≥10 g/dL, a platelet count ≥ 100 x 109/L, and a white blood cell count ≥
3.0 x 109/L

- If on metformin, sulfonylureas, statins, or fibrates, subjects must be on a stable
dose of these drugs for at least three months prior to Screening and during the study

Exclusion Criteria:

- Known infection with HIV, HCV, or HBV

- Decompensated or severe liver disease as evidenced by one or more of the following:

1. Confirmed cirrhosis or suspicion of cirrhosis

2. Esophageal varices

3. Ascites

4. Suspicion of portal hypertension

5. Hospitalization for liver disease within 60 days of screening

6. Bilirubin >2 x ULN, or ALT or AST > 10 x ULN

- Inflammatory bowel disease

- Diagnosed or suspected systemic lupus erythematosus (SLE) and/or rheumatoid arthritis
(RA)

- Hepatocellular carcinoma (HCC) at entry into the study

- History of or active non-liver malignancies other than curatively treated skin cancer
(basal cell or squamous cell carcinomas)

- Significant systemic or major illness other than liver disease, including coronary
artery disease, cerebrovascular disease, pulmonary disease, renal insufficiency,
and/or serious psychiatric disease, that, in the opinion of the Investigator would
preclude the subject from participating in and completing the study

- History or presence of alcohol abuse, defined as consumption of more than 210 mL of
alcohol per week (the equivalent of 14 4-ounce glasses of wine or 14 12-ounce
cans/bottles of beer or wine coolers), or other substance abuse within the prior two
years