Detailed 48-week results from two large phase 3 clinical trials ( Studies 108 and 110 ) evaluating once-daily Tenofovir alafenamide ( TAF ) 25 mg in treatment-naïve and treatment-experienced adults with HBeAg-negative and HBeAg-positive chronic hepatitis B virus ( HBV ) infection, were presented during The International Liver Congress 2016.
The TAF phase 3 results have demonstrated its potential to advance the treatment of HBV, offering a similar efficacy profile to Viread with improved bone and renal safety parameters.
Both studies met their primary endpoints of non-inferiority to Viread ( Tenofovir disoproxil fumarate, TDF ) 300 mg based on the percentage of patients with HBV DNA levels below 29 IU/mL at 48 weeks of therapy.
In addition, TAF demonstrated improved renal and bone laboratory safety parameters compared to Viread.
Discontinuations due to adverse events were uncommon in both treatment arms. The most commonly reported adverse events in both studies included headache, upper respiratory tract infection, nasopharyngitis and cough, and occurred at similar rates in patients receiving either TAF or Viread.
Studies 108 and 110 are randomized, double-blind, 96-week clinical trials among 1,298 treatment-naïve and treatment-experienced patients with chronic HBV infection.
In Study 108, 425 HBeAg-negative patients were randomized 2:1 to receive TAF ( n=285 ) or Viread ( n=140 ).
In Study 110, 873 HBeAg-positive patients were randomized 2:1 to receive TAF ( n=581 ) or Viread ( n=292 ).
The primary efficacy endpoint of both studies is the proportion of subjects with plasma HBV DNA levels below 29 IU/mL.
Key secondary endpoints include change from baseline in bone mineral density at the hip and spine at week 48, and change from baseline in serum creatinine at week 48. Other secondary endpoints include alanine aminotransferases ( ALT, an enzyme that serves as a measure of liver damage ) normalization and change from baseline in eGFR at week 48. ( Xagena )
Source: Gilead, 2016