Aim of the study

While entecavir (ETV) is widely used for chronic hepatitis B (CHB) treatment, tenofovir alafenamide (TAF), which efficiently delivers the active compound to hepatocytes while maintaining lower circulating drug levels, has recently been introduced as an alternative treatment option. However, the clinical implications of switching to TAF in patients who have already achieved sustained viral suppression with ETV remain uncertain. Therefore, this study aimed to clarify the long-term efficacy and safety of switching to TAF in patients with CHB who were stable with long-term ETV treatment.

Material and methods

This prospective observational study included nucleoside analogue-naïve patients with genotype C CHB receiving long-term ETV therapy, who either continued ETV therapy (n = 31) or switched to TAF (n = 46). The primary endpoint was the longitudinal change in hepatitis B surface antigen (HBsAg) levels over 384 weeks. Secondary outcomes included changes in biochemical parameters, fibrosis marker dynamics, and renal safety indicators.

Results

After 384 weeks, no significant reduction in HBsAg levels was observed in the ETV and TAF groups (–0.575 ±0.151 and –0.531 ±0.160 log IU/ml, respectively; p = 0.675). Changes in alanine aminotransferase, Mac-2 binding protein glycosylation isomer, HB core-related antigen, and renal function indicators showed comparable trends between the groups. The urinary 2-microglobulin/creatinine ratio increased significantly only among patients who continued ETV.

Conclusions

Among patients with genotype C CHB who achieved virological suppression during prolonged ETV therapy, switching to TAF was associated with antiviral outcomes comparable to those observed with continued ETV administration. However, TAF therapy was associated with a more stable profile of renal tubular injury markers.