A Trial of IDN-6556 in Post Orthotopic Liver Transplant for Chronic HCV

There are data to suggest that with eradication of the HCV virus, improvements in liver
fibrosis can be seen in the post-transplant population. However, amelioration of inflammatory
activity, and deceleration of fibrosis progression is a gradual process over the course of
many years. This placebo-controlled study is designed to evaluate the effects of IDN-6556,
compared to placebo, on markers of apoptosis and inflammation, and liver histology.

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
able to understand and willing to comply with the requirements of the study

- History of orthotopic liver transplantation for HCV-induced liver disease

- Diagnosis of HCV infection (HCV-RNA detectable in serum) and liver fibrosis and/or
incomplete cirrhosis status post liver transplantation, and achieved a sustained
virologic response (SVR) with anti-viral HCV treatment within 18 months of Day 1

- Liver fibrosis on liver histology as read by central histopathologist of Ishak F2 to
F6 within three months of Day 1 (Up to 15 subjects with an Ishak score of F6 can be
enrolled)

- Willingness to utilize two reliable forms of contraception (for both males and females
of childbearing potential) from Screening to one month after the last dose of study
drug

Exclusion Criteria:

- Known infection with hepatitis B virus (HBV) and/or human immunodeficiency virus (HIV)

- History of renal transplant and/or severe renal impairment defined as eGFR (estimated
glomerular filtration rate) of less than 30 mL/min/1.73 m2

- Evidence of tumor burden >Milan criteria, or evidence of micro- or macrovascular
invasion in explanted liver

- Hepatocellular carcinoma (HCC) at entry into the study

- Concurrent sirolimus (rapamycin) use

- History or presence of clinically concerning cardiac arrhythmias, or prolongation of
Screening (pre-treatment) QT or QTc interval of > 480 milliseconds (msec)

- Subjects with diagnosed or suspected systemic lupus erythematosus (SLE) and/or
rheumatoid arthritis (RA)

- If female: known pregnancy, positive urine or serum pregnancy test, or
lactating/breastfeeding