Efficacy and safety of tenofovir disoproxil fumarate (TDF) in hepatitis B virus (HBV) monoinfection: longitudinal analysis of a UK cohort

Aim: Current clinical recommendations suggest treating chronic hepatitis B virus (HBV) infection in a minority of cases, but more data are needed to determine the benefits and risks of Tenofovir disoproxil fumarate (TDF) therapy. We aimed to assess the impact of TDF on liver disease, and the risk of nephrotoxicity. Method: We studied a longitudinal UK chronic HBV (CHB) cohort attending out-patient clinics between 2005 and 2018, analysing data for 206 ethnically diverse adults (60 on TDF, 146 untreated), with median follow-up 3.3+/-2.8 years. Results: Patients prescribed TDF were older (39 vs. 35 years, p=0.004) with a male excess (63% vs. 47%, p=0.04) compared to untreated patients. Reflecting treatment eligibility criteria, at baseline, treated patients were more likely to have elevated ALT (p<0.001), higher HBV DNA viral load (VL) (p<0.001), and higher elastography scores (p=0.002), but with no difference in renal function (p=0.6). In the TDF group, VL declined significantly between baseline and subsequent time points (all p<0.0001) with VL suppressed in 94% at three years, while in the untreated group viraemia was unchanged from baseline. In the TDF group, ALT and elastography scores normalised during treatment and by three years were equivalent to those in the untreated group. Progression of liver fibrosis did not occur in the TDF group but arose in 7.4% of untreated patients, although this difference was non-significant. There was no significant difference in renal impairment during follow-up between two groups. Conclusion: TDF may have long-term benefits for a wider pool of the CHB population.