Gilead Sciences announced that Studies 108 and 110 evaluating the use of once-daily tenofovir alafenamide (TAF) 25mg in treatment-nave and treatment-experienced adults with HBeAg-negative and HbeAg-positive hepatitis B virus (HBV) infection met their primary objectives.
Both randomized, double-blind, 96-week studies showed that TAF was non-inferior to Viread (tenofovir disoproxil fumarate [TDF]) based on the percent of patients with HBV DNA <29 IU/mL at 48 weeks of therapy. TAF also showed improved renal and bone laboratory safety parameters compared to Viread.
In Study 108 (n=425), 94% of patients receiving TAF and 92.9% receiving of patients receiving Viread achieved HBV DNA <29 IU/mL at Week 48. In Study 110 (n=873), 63.9% of patients receiving TAF and 66.8% of patients receiving Viread achieved HBV DNA <29 IU/mL at Week 48. In both studies, TAF demonstrated a statistically significant increase in ALT normalization relative to the Viread arms when using the AASLD criteria. ALT normalization was not statistically significant when using the central laboratory cut-off value.
The TAF regimen showed improved changes in bone and renal laboratory parameters compared to Viread. In both studies, patients receiving TAF experienced a significantly smaller mean percentage decrease from baseline in hip and spine bone mineral density at Week 48 (P<0.001) vs. patients receiving Viread. Also, smaller in increases in serum creatinine were seen in patients receiving TAF in Study 110. Median change in eGFR from baseline to Week 48 was more favorable in the TAF arms in both studies (P<0.01).