Efficacy of 3 years of adefovir monotherapy in chronic hepatitis B patients with lamivudine resistance

AIM: To study the effect of rescue monotherapy with adefovir (ADV) in patients with chronic hepatitis B (CHB) who developed drug resistance to lamivudine (LAM).METHODS: A total of 76 treated CHB patients with resistance to LAM were enrolled in the present study. The patients’ baseline characteristics, such as age, gender, blood tests and hepatitis B virus (HBV) DNA were collected; therapy duration and the response of each patient were also recorded. ADV monotherapy was set as the observation group A. Twenty-four patients with LAM resistance, who were set as group B, accepted combined therapy with LAM + ADV. Patients were followed up at 0, 12, 24, 52, 104 and 156 wk. Hepatitis B surface antigen status, hepatitis B e antigen (HBeAg)/anti-HBe status, HBV DNA level and biochemical indexes were monitored. Sequencer of HBV polymerase gene was performed on the ABI 3730 automated sequencer. If no desired effects had been achieved during the course of treatment, patients’ choices were also taken into account. The control group was tested at the same time.RESULTS: In the two groups, 27 cases developed viral breakthrough after LAM treatment response. The remaining 49 cases underwent biochemical rebound accompanied by rtM204I/V or rtL180M mutation. In group A, 52 cases finished 156 wk of ADV monotherapy; of whom, 36 cases were HBeAg positive and 16 HBeAg negative. In patients whose baseline HBV DNAs were 10³-10⁵ copies/mL, 88.8% of patients’ HBV DNAs were lower than the lower test limit (10³ copies/mL) after 12 to 156 wk of ADV treatment. In patients whose baseline HBV DNAs were ≥ 10⁶ copies/mL, 41.1%-47.0% of patients’ HBV DNAs were lower than the lower test limit after the same course of ADV therapy (χ² were 4.35-5.4, 41.1%-47.0% vs 88.8% group 10³-10⁵ copies/mL, P < 0.01). In group A, seroconversion of HBeAg developed in 8 of 36 cases (22.2%). In group B, 24 cases finished 156 wk of LAM + ADV; of whom, 17 cases were HBeAg positive and 7 HBeAg negative. In patients whose baseline HBV DNAs were 10³-10⁵ copies /mL, 81.8% of patients’ HBV DNAs were lower than the lower test limit (10³ copies/mL) after 12 to 156 wk of treatment. In the patients whose baseline HBV DNAs were ≥ 10⁶ copies/mL, 46.1%-53.8% of patients’ HBV DNAs were lower than the lower test limit after the same course of LAM + ADV therapy (χ² were 4.1-5.0, 46.1%-53.8% vs 81.8% group 10³-10⁵ copies/mL, P < 0.05-0.01). In group B, 4 of 17 cases (23.5%) developed seroconversion of HBeAg. Treatment outcomes in groups A and B were comparable.CONCLUSION: In both group A and B, the ratios of virological response have similar efficacy in patients with lower baseline HBV DNAs.