Chronic hepatitis C (non-A, non-B hepatitis) is a common and often progressive viral liver disease. To assess the efficacy of therapy with the antiviral agent interferon alfa, we randomly assigned 166 patients with chronic hepatitis C to treatment with either 3 million or 1 million units of recombinant interferon alfa three times weekly for 24 weeks, or to no treatment.

The probability of normalization or near normalization of the serum alanine aminotransferase levels after six months of interferon therapy was 46 percent in patients treated with 3 million units of interferon (P <0.001) and 28 percent in those treated with 1 million units (P <0.02), but only 8 percent in untreated patients. The serum alanine aminotransferase level became completely normal in 22 of the 26 patients (85 percent) who responded to treatment with 3 million units of interferon and 9 of the 16 patients (56 percent) who responded to treatment with 1 million units. The patients who received 3 million units of interferon had histologic improvement because of the regression of lobular and periportal inflammation. Relapse within six months after the completion of treatment occurred in 51 percent of the patients treated with 3 million units of interferon and 44 percent of those treated with 1 million units.

We conclude that a 24-week course of interferon therapy is effective in controlling disease activity in many patients with hepatitis C, although relapse after the cessation of treatment is common.

Infection with the hepatitis C virus may result in chronic liver disease for which no effective therapy is now available. We studied the effects of recombinant human interferon alfa in a prospective, randomized, double-blind, placebo-controlled trial in patients with well-documented chronic hepatitis C. Forty-one patients were enrolled in the trial, 37 of whom were later found to have antibody to hepatitis C virus. Twentyone patients received interferon alfa (2 million units) subcutaneously three times weekly for six months, and 20 received placebo.

The mean serum aminotransferase levels and the histologic features of the liver improved significantly in the patients treated with interferon but not in the patients given placebo. Ten patients treated with interferon (48 percent) had a complete response, defined as a decline in mean serum aminotransferase levels to the normal range during therapy; three others had a decrease in mean aminotransferase levels of more than 50 percent. After treatment ended, however, serum aminotransferases usually returned to pretreatment levels; 6 to 12 months after the discontinuation of interferon therapy, only two patients (10 percent) still had normal values.

We conclude that interferon alfa therapy is beneficial in reducing disease activity in chronic hepatitis C; however, the beneficial responses are often transient.