Tenofovir alafenamide is associated with improved alanine aminotransferase and renal safety compared to tenofovir disoproxil fumarate

Tenofovir alafenamide (TAF) is a novel prodrug of tenofovir for the treatment of chronic hepatitis B (CHB) infection. We aimed to evaluate the impact of switching to TAF on alanine aminotransferase (ALT) normalization and renal safety. We also described the indications of switching to TAF. Consecutive adult CHB patients switched from tenofovir disoproxil fumarate (TDF) dominant therapy to TAF for more than 12 months were identified retrospectively. A subgroup of patients newly switched to TAF was prospectively invited to perform transient elastography examination and dual-energy X-ray absorptiometry. The time of switching to TAF was defined as baseline. Among 393 patients in the retrospective cohort, the median ALT at month 12 was significantly lower (21.0 [16.0-29.9] U/L vs. 25.0 [19.0-34.0] U/L; p < 0.001) and ALT normalization rate was higher (89.9% vs. 83.7%; p = 0.037) than those at baseline. Estimated glomerular filtration rate decreased from 12 months before baseline and then increased from baseline to month 12 significantly (69.7 +/- 22.0 ml/min/1.73 m(2) vs. 68.5 +/- 21.5 ml/min/1.73 m(2) vs. 69.2 +/- 21.5 ml/min/1.73 m(2), p = 0.002 (-12 m vs. baseline), p = 0.004 (baseline vs. 12 m)). In the prospective cohort, 103 patients switched to TAF because of age > 60 years (63.1%), bone diseases (54.4%), and renal alteration (42.7%). TAF is associated with ALT improvement and better renal safety than TDF dominant therapy in CHB patients. Most CHB patients switched to TAF because of advanced age, followed by bone disease and renal alteration.