Comparative efficacy and safety of tenofovir amibufenamide vs tenofovir alafenamide in the initial 48-week treatment of high viral load chronic hepatitis B: A single-centre retrospective study

Background/aim Tenofovir amibufenamide (TMF) employs innovative ProTide technology and a methylation strategy to enhance the lipid solubility and plasma stability of the amide bond, providing advantages over tenofovir alafenamide (TAF). Despite promising Phase III clinical trial results demonstrating its antiviral efficacy, real-world data on TMF remains scarce. This study evaluates the antiviral efficacy and safety of TMF compared to TAF as the initial treatment in patients with high viral loads of chronic hepatitis B (CHB). Methods We retrospectively collected clinical data from March 1 2022 to June 30 2022 for highly viremic CHB patients who received either TMF ( n = 58) or TAF ( n = 32) as their initial monotherapy at Beijing YouAn Hospital. To understand the efficacy and safety of TMF over 48 weeks, we compared the virological response rates and HBeAg/HBsAg serological clearance rates between TMF and TAF groups. Also, the changes in serum creatinine, eGFR and serum lipid levels were assessed. Results Baseline median HBV DNA levels were 7.85 (6.89, 8.36) IgIU/ml for TMF and 7.44 (6.89, 8.03) IgIU/ml for TAF. Median ALT levels were 102.0 (56.0, 210.0) U/L for TMF and 195.0 (73.5, 371.0) U/L for TAF, with HBeAg positivity rates of 70.7% and 75.0%, respectively. At 48 weeks, virological response rates (HBV DNA <10 IU/ml) were 43.5% (20/46) for TMF and 42.9% (12/28) for TAF ( p = 1.000). ALT normalization rates were 87.9% for TMF and 90.6% for TAF ( p = .969), and HBeAg serological clearance rates were 21.1% and 18.2%, respectively ( p = 1.000). No patients achieved HBsAg clearance. Compared with the baseline, LDL-C levels increased, while eGFR decreased, with no significant differences in serum creatinine, triglycerides and total cholesterol levels noted at week 48 for both TMF and TAF groups. Conclusion TMF demonstrates comparable antiviral efficacy to TAF when used as initial therapy in highly viremic CHB patients, with similar impacts on renal function and lipid profiles.