Background/aims: To determine the factors associated with virological response (VR), HBeAg loss or the emergence of adefovir (ADV)-related mutations in ADV-treated chronic hepatitis B (CHB) patients with lamivudine (LAM) resistance.
Methods: Fifty-four LAM-resistant CHB patients (46% HBeAg-positive) were treated with ADV monotherapy (n=28) or ADV plus LAM (n=26) for a mean of 30.4 months.
Results: Thirty-eight patients (70.4%) achieved VR defined as HBV-DNA levels <10(4)copies/ml within the first 12 months of treatment. Six (24%) of 25 HBeAg-positive patients exhibited HBeAg loss and 20% seroconverted to anti-HBe. Eight patients (14.8%) developed ADV-related mutations. In the multivariate analysis, female gender (HR=0.20, 95% CI: 0.05-0.76, p=0.018), HBeAg-negative (HR=0.37, 95% CI: 0.14-0.96, p=0.040) and low baseline HBV-DNA levels (HR=0.65, 95% CI: 0.45-0.95, p=0.027) were independent predictors of VR, whereas low HBV-DNA levels (HR=0.36, 95% CI: 0.11-1.20, p=0.095) and HBV-genotype D (HR=0.06, 95% CI: 0.004-0.84, p=0.037) independently predicted HBeAg loss.
Conclusions: ADV therapy suppresses viral replication in more than 70% of LAM-R patients. Factors associated with virologic response are female gender, HBeAg-negative status and low baseline serum HBV-DNA levels. Genotype D HBV infection and low baseline HBV-DNA levels independently predict HBeAg loss.