2 The technology

2.1 Entecavir (Baraclude, Bristol-Myers Squibb) is an oral nucleoside analogue. It works by inhibiting the viral DNA polymerase responsible for hepatitis B virus (HBV) replication. Entecavir has a marketing authorisation in the UK for the treatment of chronic HBV infection in adults with compensated liver disease and evidence of active viral replication, persistently elevated serum alanine aminotransferase (ALT) levels and histological evidence of active inflammation and/or fibrosis. For further information, see the summary of product characteristics.

2.2 Adverse events associated with the use of nucleoside analogues include lactic acidosis and severe hepatomegaly with steatosis. Additional adverse events reported for entecavir include headache, fatigue, dizziness and nausea. For full details of side effects and contraindications, see the summary of product characteristics.

2.3 The acquisition costs of entecavir (excluding VAT; 'British national formulary' edition 55) are £378.00 for a 30-tablet pack (500 micrograms), £378.00 for a 30-tablet pack (1 mg) and £441.00 for a 210-ml pack (50 micrograms/ml) of the oral solution. Costs may vary in different settings because of negotiated procurement discounts. The optimal treatment duration is currently unknown. For people who have not previously received treatment with antiviral drugs for chronic hepatitis B, the recommended dose is 500 micrograms once daily. For people taking lamivudine who have evidence of viraemia or lamivudine resistance, the recommended dose is 1 mg, once daily. Dose reductions are required for people with renal impairment.