- Receiving treatment with lamivudine with confirmation of HBV reverse transcriptase mutation(s) known to confer resistance to lamivudine (rtM204I/V with or without rtL180M) by central laboratory assessment prior to randomization; adefovir dipivoxil treatment of ≤ 48 weeks at the time of screening (inclusive of combination adefovir dipivoxil + lamivudine at entry) was allowed