Tenofovir Alafenamide in HBV Related Decompensated Liver

TAF is a new prodrug of tenofovir, specifically designed to achieve higher intracellular active drug concentration allowing for dosing of only 25 mg once daily and thus can potentially lower the already relatively low risk of renal toxicity and bone loss with TDF. However, such renal and bone complications with TDF may become more pronounced in decompensated CHB patients10. In the phase 3 trials11, 12, TAF had demonstrated a compatible antiviral effect (noninferior efficacy), and a higher rate of alanine aminotransferase (ALT) normalization to TDF. TAF also demonstrated an improved renal function and less bone loss compared to TDF. Therefore, TAF was approved as the first line therapy for CHB patients with compensated liver function. The lack of data regarding TAF therapy in decompensated CHB patients raised the concern of safety and efficacy of TAF in this group of patients. A small, single arm Phase 2 switch study (GS-US-320-4035; Study 4035; NCT03180619) which has enrolled 31 subjects with CPT scores ≥7, either at time of screening or by history, who were virally suppressed on TDF and/or other oral antiviral agents is currently underway with favorable safety and efficacy results through 48 weeks.\[Lim YS, Lin CY, Heo J, et al. EASL 2020, poster SAT442.\] While Gilead Study 4035 will continue through 96 weeks of treatment, additional data in this population are thus needed, particularly in CHB patients who have decompensated liver disease and are not being treated and are viremic. Herein, we conduct the present study and aim to investigate the safety and efficacy of TAF in CHB patients with hepatic decompensation.