The purpose of the study is to compare the effectiveness of 3 different treatment regimens in reducing or clearing the Hepatitis B Virus in patients infected with HIV and Hepatitis B (co-infection)

A randomised multi-centre trial of tenofovir vs lamivudine vs tenofovir/lamivudine in antiretroviral naïve subjects with HIV/HBV co-infection over 48 weeks (Clinical Trial A). Plus, a 12 week viral kinetic sub-study comparing a sub-group of the patients on Clinical Trial A with a group of therapy naïve HBV mono-infected subjects (Substudy A1)

Inclusion Criteria:

• Written informed consent
• Documented HIV infection (positive serology for HIV-1 and detectable HIV-1 RNA)
• Age 18 - 70 years
• HBV DNA > 105 copies/ml
• HBsAg positive >6 months or HBsAg positive and anti HB core IgM negative
• Creatinine <= 2.0mg/dl (<= 0.2 mmol/L)
• Platelet count >= 50,000/mm
• HIV-1 antiretroviral therapy naïve
• No prior exposure to anti-HBV agents (LAM, adefovir, TDF) although prior IFN treatment allowed

Exclusion Criteria:

• HCV-RNA positive or Anti-HAV IgM positive
• Acute hepatitis (serum ALT > 1000 U/L)
• Active opportunistic infection
• Other causes of chronic liver disease identified (autoimmune hepatitis, hemochromatosis, Wilsons disease, alfa-1-antitrypsin deficiency)
• Concurrent malignancy requiring cytotoxic chemotherapy
• Decompensated or Child's C cirrhosis
• Alfa-fetoprotein (AFP) > 3X ULN (unless negative CT scan or MRI within 3 months of entry date)
• Pregnancy or lactation
• Any other condition which in the opinion of the investigator might interfere with compliance or outcome of the study