Primary Biliary Cirrhosis (PBC) (cont.)
In this Article
Four immunosuppressive medications -- corticosteroids, azathioprine,
cyclosporine and methotrexate -- are discussed below.
It is noteworthy that the principal benefits of corticosteroids were seen in patients with early stages of the disease on liver biopsy. Still, these treatments did not result in a full remission or cure. Moreover, neither the size nor duration of these trials was sufficient to determine an effect on survival without liver transplantation. Accordingly, more data are needed to confirm the benefit and safety in PBC of steroids alone or in combination with UDCA. Nevertheless, these studies disproved an earlier notion that corticosteroids would cause rapid progression of the bone disease osteoporosis in patients with PBC.
Budesonide is a steroid that is more rapidly processed (metabolized) in the liver and, therefore, presumably would be less injurious to bone than other steroids. This drug was studied in selected patients with PBC who had had suboptimal (less than favorable) responses to UDCA. Unfortunately, budesonide was ineffective in this group. In fact it significantly worsened osteoporosis and did not prevent progression of the PBC. In contrast, a randomized trial comparing UDCA and placebo with a combination of budesonide and UDCA showed the combination to be more effective, while bone thinning (loss of mineral density) was comparable in the two groups. But here again, more data are needed to confirm the benefit and safety of this combination.
Azathioprine: Azathioprine (Imuran) prevents the production of new lymphocytes (white blood cells that take part in immune responses) by blocking cell division (reproduction) of the lymphocytes. The consequence of this action is to reduce the number of new inflammatory cells entering the sites of inflammation. A large study comparing the effect of azathioprine with an inactive drug (placebo) in 248 patients with PBC, however, showed no benefit. Consequently, this drug is not currently recommended for use in PBC patients outside of research protocols.
Cyclosporine: A powerful immunosuppressive drug, cyclosporine (Sandimmune, Neoral, Gengraf) is used primarily to prevent rejection of transplanted organs. The drug prevents production of an important signal required for lymphocytes to divide (reproduce) and generate inflammation. A large study of 349 PBC patients, comparing cyclosporine with an inactive drug, showed some benefit from the cyclosporine. The frequency of the side effects of high blood pressure and decreased kidney function, however, make this drug unacceptable for long-term use.
Methotrexate: Methotrexate both suppresses the immune system and prevents cells from dividing. This drug has been used successfully in severe rheumatoid arthritis and an immunologic skin disease called psoriasis. Initial limited trials in patients with PBC did not show a benefit, and serious side effects included ulcerations of the mouth, hair loss, and pneumonia. Additionally, preliminary reports of randomized, controlled trials of methotrexate therapy of PBC in Europe noted a higher than expected rate of a form of pneumonia that scars the lungs. Moreover, a recently published randomized, controlled trial of low dose methotrexate in PBC showed serious toxicity over a six-year period. Currently, a large trial in the United States comparing UDCA alone to a combination of UDCA and methotrexate is underway. At present, it is premature to recommend the use of methotrexate to treat PBC outside of clinical trials.