Use of adefovir in the treatment of the chronic hepatitis B virus infection with resistance to lamivudine.

Current therapies for the treatment of chronic hepatitis B virus (HBV) infection do not eliminate viral replication once therapy is stopped, resulting in a rapid rebound of viremia in a majority of patients. Prolonged therapy results in emergence of resistant virus, which is a major clinical concern. The appearance of resistant HBV is associated with decreased seroconversion rates as well as worse liver histology. Adefovir dipivoxil, a nucleotide analogue with potent antiviral activity against HBV and human immunodeficiency virus (HIV), has shown in vivo and in vitro to have activity against lamivudine-resistant HBV. We present a series of 6 patients with chronic HBV infection and lamivudine-resistant HBV treated with adefovir dipivoxil. The viremia decreased in all patients; in 4 of them, serum HBV DNA was negative by chain reaction (PCR) in a mean period of 10 months from beginning of treatment. Resistance to adefovir after 12 months of treatment has not been detected. Alanine aminotransferase (ALT) levels decreased in all patients and, at this moment, 5 of 6 patients present normal levels. There were no toxic side effects due to adefovir treatment. The data confirm that adefovir treatment has efficacy against HBV lamivudine-resistant forms.