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.