Abstract: ObjectiveTo evaluate hepatitis B virus （HBV） mutations and its impact on antiviral effects in chronic hepatitis B（CHB） patients with mutants resistant to lamivudine or adefovir.Methods142 nucleos（t）ide-naive CHB patients treated with lamivudine were switched to lamivudine plus adefovir（n=72） or entecavir plus adefovir （n=70） because of lamivudine resistance and 72 nucleos（t）ide-naive CHB patients treated with adefovir were switched to adefovir plus lamivudine （n=36） or adefovir plus entecavir （n=36） after resistance occurred. HBV DNA polymerase reverse transcriptase mutations were analyzed before and after 48 weeks of rescue therapy.ResultsAmong CHB patients with lamivudine resistance,mutation patterns were mainly M204V and IL180M, with a frequency of 98.6%（140/142） and 56.3%（80/142）,respectively;Undetectable serum HBV DNA were noted in 86.1% of patients in lamivudine and adefovir treatment group,and 97.1% of patients in entecavir and adefovir treatment group（P>0.05）;Among CHB patients with adefovir resistance,A181V and N236T mutation rates were 63.9%（46/72） and 52.8%（38/72）,respectively;Undetectable serum HBV DNA were found in 52.8%（19/36） of patients in adefovir and lamivudine treatment group,significantly lower than that [77.8% （28/36）,x²=4.963,P<0.05] of patients in adefovir and entecavir treatment group.ConclusionsAddition of adefovir dipivoxil to lamivudine is effective rescue therapy in patients with rtM204 mutation resistance to lamivudine,but in patients with rtA181 mutation resistance to adefovir dipivoxil,the addition of entecavir is superior to lamivudine.

Key words: Hepatitis B, Lamivudine, Adefovir, Drug resistance, Rescue therapy