Association Between Level of Hepatitis D Virus RNA at Week 24 of Pegylated Interferon Therapy and Outcome.

BACKGROUND & AIMS: Interferon is the only effective treatment for chronic hepatitis D virus (HDV) infection. No rules have been set for stopping treatment based on viral kinetics. We analyzed data from an international study of hepatitis D treatment to identify factors associated with outcomes of pegylated interferon treatment, with and without adefovir.

METHODS: We analyzed data from the Hep-Net-International Delta Hepatitis Intervention Trial on 50 patients with compensated liver disease who tested positive for anti-HDV and HDV RNA. Subjects received pegylated interferon α 2a, with adefovir or placebo, or only adefovir, for 48 weeks. Twenty-four weeks after treatment ended, 41 patients were evaluated for levels of HDV RNA and DNA, liver enzymes, and hepatitis B surface antigen (HBsAg); liver biopsy specimens were analyzed for fibrosis. Response to therapy was defined as end-of-treatment response or post-treatment week 24 virologic response. In both cases virologic response was associated with undetectable HDV RNA levels. Patients with less than a 1 log decrease in HDV RNA at the end of treatment were considered null responders.

RESULTS: Based on univariate and multivariate analysis, the level of HDV RNA at week 24 of treatment was associated more strongly with response to therapy than other factors analyzed. The level of HBsAg at week 24 of treatment was associated with a response to therapy only in univariate analysis. Lack of HDV RNA at week 24 of treatment, or end of treatment, identified responders with positive predicted values of 71% and 100%, respectively. At 24 weeks after treatment, a decrease in HDV RNA level of less than 1 log, combined with no decrease in HBsAg level, identified null responders with a positive predictive value of 83%. A decrease in HDV RNA level of more than 2 log at week 24 of treatment identified null responders with a negative predictive value of 95%.

CONCLUSIONS: Based on an analysis of data from a large clinical trial, the level of HDV RNA at week 24 of treatment with pegylated interferon, with or without adefovir for 48 weeks, can identify patients who will test negative for HDV RNA 24 weeks after the end of treatment. This information can be used to help physicians manage patients receiving therapy for chronic hepatitis D.