Azathioprine in primary biliary cirrhosis: a preliminary report of an international trial.

The effects of azathioprine on the course of primary biliary cirrhosis were studied prospectively in a multinational, double-blind randomized clinical trial involving 236 patients, of which 124 received azathioprine and 112 placebo. No significant effects were seen on survival, clinical course, hepatic histologic features, hepatic tests, or immunologic abnormalities after a median follow-up period of 18 mo, but most of the trends observed were in favor of azathioprine. The results obtained so far indicate that the effect of azathioprine as a single treatment is limited and probably of little clinical importance, but more years of follow-up will be needed to provide a definite conclusion.