[Entecavir - options and obstacles of an effective treatment for chronic hepatitis B]

Abstract

The level of HBV-DNA is a crucial determinant of the progression to liver cirrhosis or hepatocellular carcinoma. Thus the effective suppression of HBV-DNA below the limit of detection of high sensitive assays is a major aim of treatment. This aim will be achieved in almost all patients with current available direct antiviral drugs. However, the development of drug resistance remains a main challenge for the future. Entecavir has a good profile regarding both antiviral efficacy and resistance profile in the treatment of previously untreated patients. After five year on Entecavir more than 90 % of HBe-Ag positive patients had achieved HBV-DNA below 300 copies/ml and resistance developed in only about 1 %. However, patients in whom there had been previous resistance to lamivudine have lower treatment responses and higher resistance rates because only one or two additional mutations in the HBV-polymerase gene are required for the development of entecavir resistance in contrast to three mutations required in treatment naïve patients. In summary, Entecavir adds a new milestone in the treatment of chronic hepatitis B.