Efficacy and safety of sequential or combined therapy with tenofovir alafenamide fumarate in entecavir-treated patients with low-level viremia

Objective To investigate the efficacy of sequential tenofovir alafenamide fumarate （TAF） therapy versus the regimen of entecavir （ETV） combined with TAF in chronic hepatitis B （CHB） patients experiencing low-level viremia （LLV） after ETV therapy， as well as their impact on virologic response， liver and renal function， and blood lipid levels. Methods A total of 217 CHB patients with LLV after ETV treatment who were admitted to Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from May 2020 to December 2023 were enrolled， and according to the treatment regimen， they were divided into TAF group （180 patients receiving sequential TAF therapy） and combined group （37 patients receiving ETV+TAF therapy）. The propensity score matching （PSM） method was used to match the patients at a ratio of 1∶1， and finally 37 patients were included in each group to balance the baseline confounding factors. The two groups were compared in terms of hepatitis B virus DNA （HBV DNA） clearance rate， hepatitis B envelope antigen （HBeAg） clearance rate， liver and renal function parameters （liver stiffness measurement ［LSM］， platelet count ［PLT］， aspartate aminotransferase ［AST］， alanine aminotransferase ［ALT］， and creatinine ［Cr］）， blood lipid levels （total cholesterol ［TC］， triglyceride ［TG］， high-density lipoprotein cholesterol ［HDL-C］， and low-density lipoprotein cholesterol ［LDL-C］）， and the incidence rate of adverse reactions. The independent samples t-test was used for comparison of normally distributed continuous data between two groups， and the paired t-test was used for comparison within each group； the chi-square test was used for comparison of categorical data between groups. Results After 48 weeks of treatment， compared with the TAF group， the combined group had significantly higher HBV DNA clearance rate （86.49% vs 59.46%， χ²=6.852， P=0.009） and HBeAg clearance rate （59.46% vs 35.14%， χ²=4.391， P=0.036）. After treatment， compared with the TAF group， the combined group had significantly lower levels of LSM （7.01±1.50 kPa vs 7.90±1.68 kPa， t=2.404， P=0.019）， AST （18.02±2.28 U/L vs 21.12±2.85 U/L， t=5.166， P<0.001）， and ALT （19.85±3.86 U/L vs 22.00±3.90 U/L， t=2.383， P=0.020） and significantly higher levels of PLT ［（218.35±42.60）×109/L vs （192.82±44.13）×109/L， t=2.532， P=0.014］ and Cr （70.92±6.54 μmoL/L vs 67.60±6.13 μmoL/L， t=2.253， P=0.027）. After treatment， there was a slight increase in the level of TC in both the TAF group （5.60±0.89 mmol/L vs 5.18±0.85 mmol/L， t=2.076， P=0.041） and the combined group （5.45±0.80 mmol/L vs 5.02±0.83 mmol/L， t=2.269， P=0.026）. There was no significant difference in the incidence rate of adverse reactions between the TAF group and the combined group （21.62% vs 18.92%， χ²=0.084， P=0.772）. Conclusion For ETV-treated CHB patients experiencing LLV， compared with sequential TAF therapy， the ETV+TAF combined therapy can effectively increase virologic response rate， alleviate liver fibrosis， and improve liver function， whereas sequential TAF therapy has less impact on renal function. Sequential or combined therapy with TAF may induce a slight increase in the level of TC， which should be taken seriously in clinical practice.