An Overview of Hepatitis B Virus Structure Pathology and Therapeutics

The hepatitis B virus is a DNA virus belonging to the Hepadnaviridae family causing hepatitis B in humans. Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease. Treatment of Hepatitis B. The goal of treatment for chronic hepatitis B is to suppress HBV replication, prevent the progression of liver disease and thereby the development of cirrhosis, liver failure and HCC. Interferon alpha (?-IFN) is the first-line treatment option for patients without cirrhosis. Interferon has antiviral, anti-proliferative and immuno-modulatory effects. At a dose of 100 mg daily, lamivudine leads to a marked reduction or elimination of detectable HBV DNA in plasma in about 40% of HBeAg positive and 60-70% of HBeAg negative patients. Telbuvidine is a L-nucleoside analogue with potent anti-HBV activity. It is similar to lamivudine in mechanism of action and resistance profile but is more potent. However, its use is limited due to a high rate of resistance and cross-resistance with lamivudine. Emtricitabine is another L-nucleoside analogue with similar activity to that of lamivudine. Adefovir is a nucleotide analogue of deoxyadenosine monophosphate that has demonstrated efficacy in suppressing HBV DNA (20-50%) and normalizing liver function (50-70%). Entecavir is a carbocyclic analogue of 2' deoxyguanosine. It is a potent suppressor of HBV replication, resulting in loss of serum HBV DNA in 70-90%, and ALT normalization in 70-80% of patients. Tenofovir is a nucleotide analogue initially approved for the treatment of HIV. It is often used in a coformulation with emtricitabine. After 48 weeks of therapy with tenofovir, HBV DNA loss is achieved in 80-90% and ALT normalization in 70-80% of patients. Orthotopic liver transplantation is a treatment for chronic hepatitis B end-stage liver damage. However, the risk of reinfection on the graft is at least 80% with HBV presumably from extrahepatic reservoirs in the body.