Liver diseases due to hepatitis B reactivation are serious causes of morbidity and mortality in hepatitis B infected patients treated with chemotherapy. We have previously shown that with pre-emptive use of lamivudine, one can drastically reduce liver-related morbidity and mortality in such patients. However, due to the development of hepatitis B virus resistance to lamivudine, some of these hepatitis B infected patients still develop hepatitis. This is a research study aiming to compare the use of adefovir dipivoxil to lamivudine in hepatitis B infected patients treated with chemotherapy. Both of these drugs have been approved for the treatment of the hepatitis B infection in the United States, European Union and Hong Kong.

All patients who were recruited in this study will receive study medication, either lamivudine 100 mg daily or adefovir dipivoxil 10 mg daily to cover the entire period of chemotherapy for 72 weeks. All patients will be follow-up for an additional 24 weeks thereafter. Altogether, 70 subjects will be recruited from Queen Mary Hospital, Hong Kong SAR.

This is an open-label study, which means that the patients and the study doctor will know which treatment the subjects are assigned into. If a subject decides to take part in the study and is found eligible, he/she will be randomly (like flipping of coin) assigned to one of the following dose groups:

Lamivudine (100 mg) tablet Adefovir dipivoxil (10 mg) tablet

Inclusion Criteria:

• HBsAg+, nucleoside/nucleotide analogue naïve, malignant disease for iv chemotherapy

Exclusion Criteria:

• HCV+ HDV+