Efficacy and safety of switching to tenofovir alafenamide (TAF) in virally-suppressed chronic hepatitis B patients (CHB) with renal impairment: Week 24 results
Long CW, Yi-Hsiang H, Young-Suk L, Edward JG, Hoon AS, Owen TTY, Jeong H, Josun HA, Magdy E, Chi-Yi C, Wei-Wen S, John F, Anuj G, Leland YJ, Shalini S, Belinda J, Shuyuan M, Syed-Mohammed J, and Harry LAJ. Efficacy and safety of switching to tenofovir alafenamide (TAF) in virally-suppressed chronic hepatitis B patients (CHB) with renal impairment: Week 24 results. Hepatology International 2020; 14:S35.
Introduction: TAF, a tenofovir prodrug, has demonstrated noninferior efficacy to TDF with superior bone and renal safety in virally suppressed CHB patients with eGFR (by Cockcroft-Gault; eGFRCG) ≥50 mL/min when switched from TDF. Objectives: To evaluate the efficacy and safety of switching to TAF in virally suppressed, renally-impaired, CHB patients. Methods: In this Phase 2 study, renally-impaired CHB patients taking TDF and/or other oral antivirals for ≥48 weeks and virally suppressed for ≥6 months with HBV DNA<20 IU/mL at screening were enrolled into 2 cohorts: (1) moderate-severe renal impairment (eGFRCG 15-<60 mL/min; N = 78) and (2) End Stage Renal Disease (eGFRCG<15 mL/min; N = 15) patients on chronic hemodialysis . All patients were switched to TAF 25 mg QD for 96 weeks. Co-primary endpoints were proportion with HBV DNA<20 IU/mL and adverse events (AEs)/lab abnormalities at Week 24. Secondary safety endpoints included changes in hip/ and spine bone mineral density (BMD), and in eGFRCG. Results: All patients on treatment at Week 24 maintained HBV DNA<20 IU/mL and 88% had normal ALT levels. Relative to baseline levels, switching to TAF from TDF resulted in increases in hip/spine BMD, decreases in bone turnover markers, as well as increases in eGFRCG and decreases in renal tubular markers. TAF was well tolerated with few having Grade 3 or 4 AEs. Conclusions: In renally-impaired CHB patients, including ESRD patients on hemodialysis, viral suppression was well-maintained, and the bone and renal safety were improved 24 weeks after switching from TDF to TAF.