Effectiveness of entecavir vs tenofovir disoproxil fumarate for functional cure of chronic hepatitis B in an international cohort

Introduction: Both entecavir (ETV) and tenofovir disoproxil fumarate (TDF) are first-line therapies for chronic hepatitis B (CHB), but their comparative effectiveness with regards to hepatitis B surface antigen (HBsAg) seroclearance remains unclear. Methods: This international multicenter cohort study enrolled 7697 treatment-naïve CHB patients (median age 50 years; male 66.75%) initiated on either ETV (n = 5430) or TDF (n = 2267) without baseline malignancy or immunosuppression from 23 centers across 10 countries or regions. Patients were observed for HBsAg seroclearance until death, loss to follow-up, or treatment discontinuation or switching. The incidences of HBsAg seroclearance were adjusted for competing mortality and compared between ETV and TDF cohorts with inverse probability of treatment weighting (IPTW) and also by multivariable regression analysis. Results: The study population was followed up for a median duration of 56.1 months with 36,929 11 person-years of observation. HBsAg seroclearance occurred in 70 ETV-treated and 21 TDF-treated patients, yielding 8-year cumulative incidence of 1.69% (95% confidence interval [CI] 1.32–2.17) for ETV and 1.34% (95% CI 0.85–2.10%), for TDF (p = 0.58). In the IPTW analysis with the two study cohorts more balanced in background covariates, the age-adjusted hazard ratio (HR) of TDF versus ETV for HBsAg seroclearance was 0.91 (95% CI 0.50–1.64; p = 0.75). Furthermore, there was no significant difference between the two medications in the multivariable competing risk regression model (adjusted sub-distributional HR 0.92 for TDF vs. ETV; 95% CI 0.56–1.53; p = 0.76). Conclusions: ETV and TDF did not differ significantly in the incidence of HBsAg seroclearance, which rarely occurred with either regimen.