Abstract: Objective We aimed to evaluate the early effectiveness and the renal safety after switching from long-term nucleos(t)ide anologues(NAs) treatment to tenofovir alafenamide fumarate(TAF) in patients with chronic HBV infection. Method We followed up consecutive chronic hepatitis B(CHB) virus infection patients with ≥12 months of prior NAs therapy who were switched to TAF 25 mg daily at the University of Hong Kong-Shenzhen Hospital from April 2019 to January 2020. Endpoints such as serum HBV DNA undetectability(HBV DNA<20U/ml), ALT normalization (upper limit of normal:male 35U/L, female 25U/L) and renal function safety were assessed at 12 weeks after switching. Renal function was evaluated by serum creatinine and estimated glomerular filtration rate (eGFR by CKD-EPI). Result Seventy-four CHB patients [(77% male, mean age (49.55±10.52)] were recruited. Serum HBV DNA undetectability rates increased from 40.54% at switching to 71.62% at 12 weeks (P<0.001). ALT normalization rates also increased from 56.76% to 74.32% after 12 weeks (P=0.038). Median serum ALT level decreased significantly from 28.90 (19.52, 42.70)U/L to 21.80 (15.20, 34.85)U/L (P=0.016). There was a small but not significant improvement in eGFR at week 12 compared to baseline. For the subgroup stage 2 chronic kidney disease (CKD) at TAF-switching, there was a significant improvement in mean eGFR after 12 weeks [(79.37±10.82)ml/(min·1.73m²) vs (72.23±9.11)ml/(min·1.73m²), P=0.017]. Conclusion Switching from prior NAs to TAF was effective for maintaining virological suppression and ALT normalization in CHB, and can lead to improvements in renal function in patients with mild chronic kidney disease.

Key words: Tenofovir alafenamide fumarate, Hepatitis B virus, Nucleos(t)ide Analogues, Entecavir, Tenofovir disoproxil fumarate