Comparison of Peg-INF plus TDF versus TDF Monotherapy in Indeterminate-phase Chronic Hepatitis B Patients with High HBsAg levels, HBeAg-negative status, and Normal ALT Levels.

BACKGROUND AND AIMS: Chronic hepatitis B patients with baseline hepatitis B surface antigen (HBsAg) <1500 IU/mL are considered as the favorable population for achieving functional cure. This trial aimed to explore a treatment strategy to help the unfavorable population characterized by high HBsAg levels (>3000 IU/mL), hepatitis B e antigen-negative status, and normal alanine transaminase levels in the indeterminate phase (HBeIP), transition to the favorable group. METHODS: In this investigator-initiated, open-label clinical trial, we randomly assigned participants aged 18 to 60 years with HBeIP characteristics to receive either tenofovir disoproxil fumarate (TDF) monotherapy (monotherapy group) or pegylated interferon alfa-2b (Peg-IFNα-2b) plus TDF (combination group). The primary endpoints were the HBsAg loss rate and the proportion of participants with HBsAg <1,500 IU/mL through week 96. RESULTS: From May 2021 to November 2023, we enrolled 263 participants, with 131 randomly assigned to the combination group and 132 to the monotherapy group. In the primary analysis, none of the 132 participants (0%) in the monotherapy group achieved HBsAg loss, compared with 10 of 131 (7.6%) in the combination group (P = 0.001). Through week 96, 48.9% (64/131) of participants in the combination group achieved HBsAg <1,500 IU/mL, and a reduction in HBsAg level greater than 1 log10 IU/mL between baseline and week 24 was an independent predictor of this endpoint (Odds Ratio = 16.957, 95% Confidence Interval: 3.002-95.797, P = 0.001). In contrast, only two participants (1.5%) in the monotherapy group achieved HBsAg <1,500 IU/mL. CONCLUSIONS: Compared with TDF monotherapy, combination therapy with Peg-IFNα-2b and TDF significantly improved both HBsAg <1,500 IU/mL and HBsAg loss rates in HBeIP patients.