849), respectively.

The optimal cut-off HBsAg level and HBsAg reduction to predict HBsAg seroclearance were <200 IU/mL (sensitivity, 84.2%; specificity, 73.4%) and 0.5 log IU/mL/year (sensitivity, 62.8%; specificity, 88.7%), respectively. For patients with HBsAg levels ≥200 IU/mL, an annual 0.5-log reduction was highly predictive of subsequent HBsAg seroclearance (AUROC, 0.867; 95% CI: 0.778-0.956). Conclusion: To conclude, serum HBsAg <200 IU/mL and 0.5-log reduction in HBsAg were predictive of HBsAg seroclearance within 3 years of follow-up. These parameters may serve as good indicators for the consideration of treatment duration and cessation for chronic hepatitis B. (HEPATOLOGY 2012;56:812–819) Seroclearance of the hepatitis B surface antigen (HBsAg) during the natural history of chronic hepatitis 17-AAG chemical structure B (CHB) is associated with favorable long-term Veliparib mouse outcomes,1, 2 although the development of hepatocellular carcinoma (HCC) remains possible.3-5 The incidence of HBsAg seroclearance ranges between 0.5% and 2.26% per year.3, 5, 6 HBsAg seroclearance is the ultimate treatment

endpoint for CHB, but occurs only infrequently after pegylated interferon (Peg-IFN)7 or nucleoside analog therapy.8-10 The recent development of serum HBsAg quantification has provided an additional tool in monitoring both treated and untreated CHB patients.11 Serum HBsAg titers were initially proposed as a surrogate marker for hepatitis B virus (HBV) covalently

closed circular DNA. But, a recent study found such a correlation to exist only in hepatitis B e antigen (HBeAg)-positive, and not in HBeAg-negative, disease.12 Several recent studies have highlighted the differences in HBsAg titers throughout the natural history of CHB, but are limited by their cross-sectional nature.13, 14 A recent longitudinal study demonstrated the variations in HBsAg levels in different disease phases of CHB. A serum HBsAg reduction of more than 1 log reflects improved immune control and increases the probability Thymidylate synthase of HBsAg seroclearance.15 Two recent studies from Asia followed up 390 and 103 HBeAg-negative patients, respectively, and found a HBsAg level of <100 IU/mL predictive of eventual HBsAg seroclearance.16, 17 These longitudinal studies, however, were all limited by the very small number of patients with HBsAg seroclearance (n < 20). Another recent study consisting of 46 patients with HBsAg seroclearance suggested the optimal level to predict HBsAg seroclearance to be HBsAg <200 IU/mL.18 However, the relationship between HBsAg and HBV DNA preceding HBsAg seroclearance and the possible combined use of both markers in predicting HBsAg seroclearance have not been studied. The value of serum HBV DNA levels in predicting HBsAg seroclearance remains controversial.