RESUMO
<p><b>BACKGROUND</b>Lamivudine is the first L-nucleoside analogue approved for the treatment of the patients with chronic hepatitis B (CHB) for over 10 years. The aim of this study was to evaluate the virologic responses at weeks 12 and 24 for the prediction of therapeutic effect and virologic breakthrough after 2 years of lamivudine treatment in the patients with CHB.</p><p><b>METHODS</b>A retrospective study was conducted with 255 hepatitis B e antigen (HBeAg) positive and 122 HBeAg-negative CHB patients treated with lamivudine (100 mg, daily) and duration of treatment was 6 to 72 months. The levels of serum hepatitis B virus (HBV)-DNA at weeks 12 and 24 were evaluated for the predictive value of therapeutic effect and drug resistance after 2 years of lamivudine treatment.</p><p><b>RESULTS</b>HBeAg seroconversion was closely correlated with levels of serum HBV DNA at week 12 (P = 0.000, OR = 0.394) and 24 (P = 0.019, OR = 0.442), while virologic breakthrough was more correlated with baseline levels of serum HBV DNA (P = 0.019, OR = 1.484) and at week 12 (P = 0.049, OR = 1.398) and 24 (P = 0.012, OR = 2.025). At year 2, the virologic response at week 24 was more sensitive compared with week 12 when it was used to predict the efficacy and virologic breakthrough, but was less specific compared with those at week 12. There were no significant differences in terms of predicting positive and negative values of HBV DNA between week 12 and 24 for efficacy and drug resistance at year 2 in both HBeAg positive and HBeAg negative patients.</p><p><b>CONCLUSION</b>Level of serum HBV DNA at 24-week is a proper predictor for the therapeutic effect and virologic breakthrough at year 2 of lamivudine treatment.</p>