Study of Abatacept (Orencia) to Treat Primary Biliary Cirrhosis

This is an open label, active treatment trial to assess the efficacy and safety of abatacept
in subject with PBC who have had an incomplete biochemical response to UDCA. In this trial,
20 subjects with PBC who have had an incomplete biochemical response to UDCA will be assigned
to treatment with weekly subcutaneous injections of 125 mg of abatacept. The treatment phase
of the study will last 24 weeks with an off-treatment follow up at Week 36.

Inclusion criteria include:

- Confirmed diagnosis of PBC

- Alkaline phosphatase > 1.67 times the upper limit of normal after 6 months of treatment
with UDCA

Inclusion Criteria:

- Confirmed PBC diagnosis based upon at least 2 of 3 criteria

1. Anti-mitochondrial antibody (AMA) titer > 1:40

2. Alkaline phosphatase > 1.5 times the upper limit of normal for at least 6 months

3. Liver biopsy findings consistent with PBC

- Incomplete response to UDCA defined by an alkaline phosphatase > 1.67 X the upper
limit of normal after 6 months of UDCA at a minimum dose of 13 mg/kg/d

- Taking a stable dose of UDCA for at least 3 months prior to Day 0

- aspartate aminotransferase (AST) and alanine aminotransferase ALT < 5 times the upper
limit of normal

Exclusion Criteria:

- Presence of concomitant liver diseases including viral hepatitis, primary sclerosing
cholangitis, alcoholic liver disease, Wilson's disease, hemochromatosis, or Gilbert's
syndrome.

- Prior liver transplantation

- Decompensated liver disease

- Use of immunosuppressants within 6 months of Day 0

- Use of biologic agents within 12 months of Day 0