HBsAg and HBcrAg as predictors of HBeAg seroconversion in HBeAg-positive patients treated with nucleos(t)ide analogues.

HBeAg seroconversion marks an important spontaneous change and treatment end-point for HBeAg-positive patients and is a pre-requisite for HBsAg loss or functional cure. In this retrospective analysis, we aimed to identify predictors of seroconversion using serum quantitative HBsAg and HBcrAg, in HBeAg-positive patients treated with nucleos(t)ide analogues (NA). Data and samples from 118 HBeAg-positive adults (genotypes A-G) started on NA between Jan 2005 and Sept 2016 were retrospectively analysed at several time-points. The predictive power of on-treatment levels of HBsAg and HBcrAg was determined using receiver operating curve (ROC) analysis and cut-off values determined by maximized Youden's index. About 36.4% of patients achieved HBeAg seroconversion after a median of 39 months' treatment. On treatment kinetics of HBV DNA, HBsAg and HBcrAg differed between HBeAg seroconverters and nonseroconverters. A combination of HBsAg and HBcrAg had the greatest predictive value for HBeAg seroconversion: at 6 months, HBsAg of 3.9 log10  IU/mL and HBcrAg of 5.7 log10 U/mL had a sensitivity of 71.4%, specificity of 79.5%, positive predictive value (PPV) of 65.2% and negative predictive value (NPV) of 83.8%, with AUROC of 0.769 (0.668, 0.869; 95%CI), and at 12 months, HBsAg 3.8 log10  IU/mL and HBcrAg 5.5 log10 U/mL had a sensitivity of 73.7%, specificity of 79.5%, PPV of 63.6% and NPV of 86.1%, with AUROC 0.807 (0.713, 0.901; 95% CI). In conclusion, our results may be used to identify patients who are unlikely to achieve treatment end-points, which will be important as the future management of chronic hepatitis B looks to therapies that offer functional cure.