HBV Antigen-Guided Switching Strategy From Nucleos(t)ide Analogue to Interferon: Avoid Virologic Breakthrough and Improve Functional Cure

Little is known for factors associated with virologic breakthrough (VBT) after switching from nucleos(t)ide analogue (NA) to pegylated interferon alpha (Peg-IFN-α) for patients with chronic hepatitis B (CHB). Eighty patients who received 48-week Peg-IFN-ɑ and NA combination therapy followed by Peg-IFN-ɑ monotherapy for additional 48 weeks were included in this study. HBV-related markers including HBV DNA, HBsAg, HBcrAg, HBeAg, cccDNA, and immunological biomarkers were dynamically evaluated. Twelve (15.0%) patients experienced VBT after switching to Peg-IFN-ɑ and exhibited significantly lower rates of HBsAg loss after therapy completion (0% vs. 35.3%, p = 0.014). The patients with HBcrAg≥ 5 log₁₀U/mL and HBsAg≥ 100 IU/mL had the highest risk of VBT and failed to achieve subsequent HBsAg clearance. Intrahepatic cccDNA level was significantly higher in patients with HBcrAg≥ 5 log₁₀U/mL than those with HBcrAg< 5 log₁₀U/mL. Notably, in contrast to patients with HBcrAg< 5 log₁₀U/mL or with HBsAg< 100 IU/mL who had obviously restored HBV-specific CD8⁺T cell, Tfh or B cell responses before NA cessation, those with HBcrAg≥ 5 log₁₀U/mL or with HBsAg≥ 100 IU/mL exhibited lackluster immunities before NA cessation and notable diminished immune responses thereafter. Monitoring HBcrAg and HBsAg levels, which correlated with poor immune responses during sequential Peg-IFN-ɑ strategy, may help to avoid VBT and improve functional cure of CHB.