Treatment of delta hepatitis.

Hepatitis delta virus (HDV) is a defective RNA virus that depends on hepatitis B virus (HBV) for its lifecycle. Treatment of chronic HDV infection is difficult as it does not have an enzymatic function as a target, such as polymerases and proteases of HBV and hepatitis C virus. Recently, it has been suggested that farnesyl transferase could be an enzymatic target. Currently, interferon is the only agent against HDV infection. Virological response has risen to 20-47% with pegylated interferon. Monotherapy of nucleos(t)ide analogs are ineffective against the HDV infection, but adefovir and pegylated interferon combination therapy have had some advantages for reduction of HBV surface antigen (HBsAg) levels. Recent studies suggest that measuring HBsAg levels during treatment could be more meaningful than HDV RNA negativity to predict virological response. Prenylation inhibitors that can affect the interactions between the large HDV antigen and HBsAg in the HDV virion are expected treatments for HDV infection. More studies are needed to understand the molecular mechanisms of HDV to manage the disease.