Background and aims: BRII-179, a novel therapeutic vaccine comprised of PreS1, PreS2 and S hepatitis B virus (HBV) surface antigens that can induce functional HBV specific B-cell and T-cell immune responses is currently under evaluation in a randomized, double-blind, placebo-controlled phase 2a study in China. In the previous interim analyses, BRII-179 as an add-on therapy in patients with chronic hepatitis B (CHB) receiving Peginterferon alfa (PEG) and nucleos (t)ide reverse transcriptase inhibitors (NRTI) therapy improved HBsAg loss at end-of-treatment (EOT) (Primary end point, 26.3% vs. 19.3% in full analysis set [FAS]) and the numerical difference maintained through 24-week post EOT. Besides, HBsAb ≥10 IU/L was strongly associated with sustained HBsAg loss at 12 weeks and 24 weeks post EOT.