Efficacy of adefovir dipivoxil in the treatment of lamivudine-resistant hepatitis B virus genotype C infection

Background and Aims: Adefovir dipivoxil (ADV) is a nucleotide analogue that is known to be effective for lamivudine-resistant hepatitis B virus (HBV) mutants as well as wild-type HBV. The aim of this study is to assess the efficacy of ADV against lamivudine-resistant genotype C HBV mutants. Methods: Thirty-five patients with breakthrough hepatitis due to lamivudine-resistant HBV received ADV 10 mg daily with discontinuation of lamivudine. Quantitative HBV DNA, HBeAg, liver function test including alanine aminotransferase (ALT) was checked every 4–12 weeks to evaluate the efficacy of ADV. Results: ADV was administered for a median of 48 weeks (range: 24–120 weeks). The rate of serum HBV DNA loss was 68.6%, 80.0%, 84.0%, and 88.2% at weeks 12, 24, 36, and 48, respectively. The rate of serum HBeAg seroconversion was 8.3% and 14.3% at weeks 24 and 48, respectively. The rate of serum ALT normalization at week 48 was 70.6%. Within 32 weeks after stopping ADV therapy, serum HBV DNA levels increased to a median of 378.9 pg/ml in 88.9% of patients, who were treated for a median of 40 weeks. Moreover, in some patients, the ALT level increased to more than five times the upper limit of normal. Conclusions: Administration of ADV is an effective option for the treatment of patients with lamivudine-resistant genotype C HBV infection.