Impact of switching to tenofovir alafenamide fumarate in patients with entecavir-treated chronic hepatitis B.

Abstract

Tenofovir alafenamide (TAF), a new tenofovir prodrug, has been developed to circumvent the less favorable safety profile of tenofovir disoproxil fumarate (TDF). We investigated reductions in hepatitis B surface antigen (HBsAg) levels in patients with HBV infection who received continuous entecavir (ETV) monotherapy or sequential therapy with ETV and TAF. This retrospective cohort study included 286 patients who were divided into two groups: continuous ETV monotherapy (ETV group, n = 168) and sequential therapy with ETV and TAF (ETV-TAF group, n = 108). Factors associated with a 90% reduction in HBsAg levels were analyzed by a Cox proportional hazards model using a time-dependent covariate in both groups. In the multivariate Cox proportional hazards model, the ETV-TAF group [adjusted hazard ratio (aHR) 2.750; 95% confidence interval (CI), 1.265-3.405; P = 0.0038] and BMI ≤ 25.0 kg/m2 (aHR 0.520, 95% CI, 0.308-0.875; P = 0.0139) demonstrated a 90% reduction in HBsAg levels. HBsAg levels of patients in the TAF phase in the ETV-TAF group showed greater yearly percent reductions than those in the ETV group and those in the ETV phase in the ETV-TAF group (P = 0.0361 and P = 0.0022, respectively, Steel-Dwass test). HBsAg levels decreased more rapidly after patients switched from ETV to TAF. Switching to TAF may be an effective treatment option to reduce HBsAg levels.