Objective To analyze clinical courses and rescue therapies of adefovir-resistant chronic hepatitis B patients who had lamivudine resistance before and then changed to take adefovir dipivoxil. Methods 15 patients resistant to lamivudine were retrospectively analyzed, who had virological breakthrough after adefovir dipivoxil monotherapy and were treated with rescue therapy.Adefovir-resistant mutations were detected by direct sequencing of the HBV polymerase gene. Results 15 patients with former lamivudine resistance were treated with adefovir dipivoxil monotherapy for a median of 16 months, and 14 patients were found adefovir-resistant mutations at rtA181T/V and(or) rtN236T, only 1 patient was found multi-mutations at rtM204I + rtL180M + rtA181T. Rescue therapies were given to all the 15 patients after drug resistance. Among the 7 patients treated with lamivudine in combination with adefovir for 3 months,whose HBV DNA levels decreased (2.2±0.6)lg copy/mL on average, 5 patients achieved HBV DNA undetectable after 6 months combinative therapy. The HBV DNA levels of the 3 patients treated with entecavir decreased 2.8～3.5 lg copy/mL within 6 months treatment. Conclusion These preliminary data suggest the combination of lamivudine and adeforvir dipivoxil may be an effective rescue therapy for adefovir-resistant patients who have former lamivudine resistance.

Objective To analyze the clinical features and mutation patterns of HBV polymerase gene in patients with chronic hepatitis B(CHB) after the emergence of drug-resistance during Lamivudine(LAM) therapy.Methods LAM-resistant mutations were detected by direct sequencing of the HBV polymerase gene in hospitalized patients and outpatients of CHB with LAM-resistance in Changhai Hospital from Dec.2005 to Dec.2007.Clinical features after the emergence of LAM-resistant mutations were retrospectively analyzed.Results Two hundred and fifteen patients with CHB were diagnosed as LAM-resistant.Among them 192 patients were found to have LAM-resistant-associated mutations in the HBV polymerase gene.The mean value of serum HBV DNA was 6.25?1.31(log10copies/ml),the mean value of alanine aminotransferase(ALT) was 75U/L(ranged 19-821 U/L).ALT elevation and hepatitis recrudescence were found in 139 among 192(72.4%) patients.99.0%(190/192) patients had YMDD mutations.Four major mutation patterns of LAM-resistant HBV were identified as rtM204I(33.9%),rtL180M+rtM204V(26.0%),rtL180M+rtM204I(21.9%) and rtV173L+rtL180M+rtM204V(11.5%).The rtM204V mutation was accompanied more frequently by the rtL180M mutation compared with the rtM204I mutation(P0.05).Conclusions YMDD is the major mutation pattern of HBV polymerase gene after emergence of LAM-resistance.The mutation patterns of HBV polymerase gene are possibly not related to the clinical severity of CHB patients during LAM therapy.

Objective To evaluate the efficacy and safety of adefovir dipivoxil(ADV) monotherapy and ADV lamivudine(LAM) combined therapy for patients with LAM-resistant chronic hepatitis B.Methods 124 chronic hepatitis B patients with LAM-resistant mutations were enrolled in the present study.74 patients were treated with ADV combined with LAM therapy,and other 50 patients subjected to ADV monotherapy.There were no differences between the two groups in patients' baseline characteristics.Sequencing of the HBV polymerase gene was performed to determine LAM and ADV mutations occurred at baseline or during therapy.All patients were monitored with clinical examinations and routine laboratory tests during the therapy.Results The reduced logarithmic values of serum HBV DNA after 12-week and 24-week treatment were 1.99?0.64 and 2.61?0.80 in ADV group,obviously lower compared with those in ADV+LAM group(2.55?0.74 and 3.19?0.82,respectively,P