BACKGROUND/AIMS Tenofovir alafenamide (TAF) has emerged as a safe and effective alternative to entecavir (ETV) in the management of chronic hepatitis B (CHB). We aimed to evaluate the efficacy and safety of switching to TAF compared with maintaining ETV in patients with CHB who had achieved virologic suppression on ETV.

METHODS In this multicenter, randomized, open-label, active-controlled, noninferiority clinical trial conducted at 13 Korean centers, 196 CHB patients who had experienced virologic suppression after ≥24 weeks of ETV therapy were randomized 1:1 to switch to TAF (n=95) or continue on ETV (n=101). The primary endpoint was the proportion of patients with hepatitis B virus (HBV) DNA <29 IU/mL at week 48 (per-protocol set). Secondary endpoints included alanine aminotransferase (ALT) normalization, hepatitis B surface antigen and hepatitis B e antigen serologic responses, and safety outcomes.

RESULTS Among 188 patients in the per-protocol set (89 TAF, 99 ETV), the HBV suppression rate at week 48 was 100.0% in the TAF group and 99.0% in the ETV group (difference, 1.03%; one-sided 97.5% confidence interval, -0.96 to infinity). ALT normalization rates at week 48 were comparable between groups (55.0% in TAF vs 38.7% in ETV; p=0.26; American Association for the Study of Liver Diseases criteria). Hepatitis B e antigen seroconversion rates were also similar at week 48 (0.0% vs 12.5%; p=0.21). Safety profiles, including renal function, did not significantly differ between the two groups.

CONCLUSIONS Switching from ETV to TAF was noninferior to continuing ETV in maintaining virologic suppression, with comparable biochemical, serologic, and safety outcomes. (ClinicalTrials. gov identifier NCT06000657).