Tacrolimus (FK 506), a treatment for primary sclerosing cholangitis: results of an open-label preliminary trial.

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disease of the liver that is characterized by progressive cholestasis and the development of secondary biliary cirrhosis. There is no widely recognized therapy for this disease, although anti-inflammatory agents (steroids), immunosuppressive agents (methotrexate), anti-fibrotics (colchicine), and choleretic agents (ursodeoxycholic acid) have been used in various small series. In the present study, Tacrolimus (FK 506), a new and powerful immunosuppressive macrolide antibiotic, has been used to treat 10 patients with PSC. Each subject had a liver biopsy, ERCP with visualization of the intra- and extrahepatic biliary tree, and a panel of hematological, serological, and biochemical laboratory tests before the initiation of the FK 506 therapy. The FK 506 was administered orally at 12-h intervals and was monitored by serial plasma FK 506 trough levels. After 360 days of treatment, the median serum bilirubin level was reduced by 75%, and the serum alkaline phosphatase was reduced by 70%. Moreover, the serum ALT and AST levels were reduced by 80 and 86%, respectively. No change in the serum level of BUN and creatinine levels occurred as a consequence of the FK 506 treatment. These data demonstrate that: 1) FK 506 can be used to treat PSC; 2) the response to FK 506 by patients with PSC is rapid; and, 3) no adverse effect on the serum BUN and creatinine levels was observed. It is anticipated that FK 506 will become an important agent for the treatment of patients with PSC because of its powerful immunosuppressive activity.