Abstract: Objective The aim of this study was to investigate the antiviral efficacy of tenofovir alafenamide (TAF) in the re-treatment of patients with chronic hepatitis B (CHB) and low-level viremia (LLV) after entecavir (ETV) treatment. Methods 101 patients with CHB were recruited in our hospital between January 2018 and December 2022, and the enrollment included ETV-treated for longer than 48 weeks and LLV was confirmed by serum HBV DNA load detection. 50 patients toke oral ETV continuously for 48 weeks, and other 51 patients switched to TAF re-treatment for 48 weeks. Serum creatinine (sCr), β₂ microglobulin (β2-G) levels and estimated glomerular filtration rate (eGFR) were routinely detected, and the liver stiffness measurement (LSM) was measured by transient elastography. The complete virological response (CVR) was defined as serum HBV DNA negative, and less than 20 IU/mL quantitatively. Results At the end of 48 weeks, the CVR in the TAF-treated patients was 98.0%, much higher than 24.0%(P<0.05) in ETV-treated patients, while there were no significant differences as respect to serum HBeAg negative rates (17.7% vs. 4.0%, P>0.05) and serum ALT normalization rates (96.1% vs. 98.0, P>0.05) in two groups; serum ALT, AST levels and the LSM in patients receiving TAF were (37.7±5.3)U/L, (34.8±5.7)U/L and (7.1±1.0)kPa, all not significantly different compared to [(36.2±4.8)U/L, (35.2±5.3)U/L and (7.8±1.1)kPa, respectively, P>0.05] in patients taking ETV; serum Cr and β₂-MG levels were (70.4±6.5)μmol/L and (1.3±0.3)mg/L, both significantly lower than [(78.5±6.9)μmol/L and (1.6±0.2)mg/L, P<0.05], while the eGFR was (105.9±17.3)mL/min/1.73 m², much higher than [(98.0±16.7)mL/min/1.73 m², P<0.05] in ETV-treated patients. Conclusion We recommend the CHB patients with LLV after ETV treatment switch to TAF therapy, which could elevate virological response rate, and warrants further clinical investigation.

Key words: Hepatitis B, Entecavir, Low-level viremia, Tenofovir alafenamide, Re-treatment, Complete virological response