Abstract: Objective Adefovir dipivoxil(ADV) is effective in treatment of lamivudine(LAM)resistant chronic hepatitis B(CHB). However, the effect of ADV monotherapy on telbivudine(LdT)resistant CHB needs to be elucidated. The aim of this study was to observe the efficacy and resistance of ADV monotherapy in LdT-resistant patients. Methods Thirteen LDT-resistant CHB patients(10 HBeAg positive patients and 3 HBeAg negative patients) were treated with 10 mg ADV once daily at least 48 weeks, follow-up was performed every 12 weeks and virological, serological and biochemical responses were explored. Virological response was defined as HBV DNA <300 copies/mL. Results The baseline median HBV DNA was 3.9×10⁹ copies/mL. Viral load was decreased 3.77, 4.28 and 5.31 lg copies/mL at 12, 24 and 48 weeks and dropped persistently with the therapy continuation. Biochemical response(ALT) was obtained after virological response. There was no serological response and ADV resistance after 96 week treatment with ADV. Conclusion Switching to ADV monotherapy in LdT-resistant patients with CHB can reduce HBV DNA rapidly and effectively. No ADV resistance was found during up to 96 weeks treatment.

Key words: adefovir dipivoxil, telbivudine, resistance, chronic hepatitis B