In this study, a significantly higher proportion of TDF-treated patients at week 48 achieved the primary end-point, compared with those treated with ADV (66% vs 12% in HBeAg-positive; and 71% vs 49% in HBeAg-negative; P < 0.001). At the end of treatment, 76% and 93% of the patients in the TDF group had HBV DNA levels of < 80 IU/mL,

compared with 13% and 63% of patients in the ADV group in both HBeAg-positive and HBeAg-negative patients, respectively (P < 0.001). Notably, 3% of HBeAg-positive patients treated with TDF lost HBsAg while no patients in the ADV-treated group encountered HBsAg loss. The drug resistance rate was 0% for TDF at weeks 48 and 72. The purpose of viral load measurement is BMN-673 very important during antiviral treatment. First, PD0325901 ic50 it can measure the magnitude of viral load suppression, and second, it can detect viral breakthrough as early as possible.31 An on-treatment adjustment algorithm or the so-called ‘roadmap’ for NA therapy was proposed by several international experienced hepatologists in 2007 and was updated in 2008.32 Briefly, the serum HBV DNA

levels can be assessed at week 12 to check the initial antiviral response. If the serum HBV DNA levels declined less than 1 log10 IU/mL after antiviral agent therapy, it is called a ‘primary treatment failure,’ which is an indication to change treatment regimen at an early stage. The next early predictor of efficacy should be done at week 24 of therapy. This measurement is considered essential in the management of both HBeAg-positive and HBeAg-negative patients. This is because it was found to be the main predictor of subsequent treatment efficacy in terms of HBeAg seroconversion in HBeAg-positive patients, and of subsequent resistance. Notably, the

incidence of drug resistance in ETV or TDF therapy is too low to identify using any on-treatment predictors to date. At week 24, the declined serum HBV DNA levels should Adenosine triphosphate further be categorized as complete (< 60 IU/mL), partial (60 to 2000 IU/mL), or inadequate (≧ 2000 IU/mL). In the face of suboptimal responses, further management strategies using LAM, Ldt or ADV are then based on the status of the virological response at week 12 and 24 as shown in Figure 1. Furthermore, periodical monitoring of HBV DNA levels should be done every 3–6 months to confirm adequate viral suppression and to detect viral breakthrough early. Once virological breakthrough has occurred, the recommendation is to use add-on therapy with a drug without cross-resistance. For patients with LAM resistance, ADV add-on therapy is highly effective at restoring viral suppression and preventing the emergence of resistance to ADV.33 Add-on therapy with TDF might be an even more attractive option for these patients.