[New developments in therapy of chronic hepatitis B. When are nucleoside analogs indicated?]

Nucleoside analogues are promising agents for the treatment of chronic hepatitis B infection (HBV-DNA-positive by hybridization assay). The drug being studied most intensively is Lamivudine (Zeffix) which has recently been approved in Germany. When given orally once daily (100 mg) Lamivudine is well-tolerated and suppresses HBV-DNA to undetectable levels in the majority of patients. Since relapse is frequent when medication is stopped long-term treatment (at least until seroconversion of HBeAg) is warranted. Indications for lamivudine monotherapy are patients with chronic hepatitis B in which interferon (IFN) is contraindicated or patients who did not respond to a previous course of interferon. Further indications are the HBV-DNA-positive cirrhosis prior to liver transplantation (OLT) and the HBV-reinfection after OLT. The main problem of long-term monotherapy with lamivudine is viral resistance. The clinical impact of the resistant mutants is often not clear. Withdrawal or even continuation of the medication may be acceptable approaches. Other nucleoside analogues like Entecavir or Adefovir are currently being tested in clinical studies. Famciclovir was investigated preferably in patients with decompensated liver disease or HBV-reinfection after OLT. Because of conflicting results the drug should only be used under study conditions. In IFN-naive patients with chronic hepatitis B (and compensated liver disease) alpha-interferon is still the first-line therapy. With a standard course of interferon 30-40% of the patients become seronegative for HBeAg as compared with 16-17% when treated with lamivudine for twelve months. Combination of lamivudine and interferon is not more effective than IFN alone. In the future combined antiviral treatment is likely to replace monotherapy.