[Interdisciplinary aspects of and new drugs for chronic hepatitis B].

Hepatitis B virus infection is a significant health problem worldwide. The prevalence of HBsAg positivity is about 0.5-0.7% in Hungary. Liver cirrhosis and/or hepatocellular carcinoma develops in 15-40% of chronic hepatitis B virus infected patients without treatment. The ultimate goal of treatment would be to clear the virus from the infected subject; however, in practice, we can usually achieve long term suppression of viral replicaton with consequent prevention of the progression of liver disease, and reduction of the risk of the development of liver cirrhosis and hepatocellular carcinoma. Currently, there are two different treatment strategies for patients with chronic hepatitis B virus infection: therapy of finite duration with interferon or long-term treatment with nucleot(s)ide analogues. Entecavir and tenofovir are the two most effective nucleot(s)ide analogues with high barrier to resistance, thus, they can be confidently used as first-line treatments. Lamivudine engenders very high rates of resistance; adefovir is less efficacious than entecavir or tenofovir, and also engendering higher rates of resistance, thus none of them are recommended for initiation of a new treatment. Tenofovir is the treatment option in cases with lamivudine resistance, because entecavir has an unfavourable resistance-profile in this group of patients. Interferon is contraindicated during pregnancy. Should treatment of chronic hepatitis B virus infection be necessary during pregnancy, tenofovir, listed by the FDA as pregnancy category B drug, is to be preferred. Nucleot(s)ide analogues may be used to reduce the risk of intra-uterine and perinatal transmission of hepatitis B virus, which may occur in a proportion of newborns from highly viremic mothers, despite active and passive immunization. Similarly, tenofovir is recommended in the last trimester of pregnancy for women with high viremia. The risk of reactivation of chronic hepatitis B virus infection is high in HBsAg positive patients, and in patients with occult hepatitis B virus infection during and after chemotherapy or immunosuppressive treatment, including biological response modifiers (particularly related to rituximab therapy). Therefore, all candidates for these treatments should be screened for HBsAg and anti-HBc. Pre-emptive nucleot(s)ide analogues therapy should be initiated in patients with HBsAg positivity, and patients with occult hepatitis B virus infection. The role of general practitioners and occupational health physicians in the identification and the prevention of hepatitis B virus infection is stressed. Issues of high risk population groups, candidacy for vaccination, and methodology of active and passive immunisation are also reviewed in this paper.