Tenofovir discontinuation after long-term viral suppression in HBeAg negative chronic hepatitis B. Can HBsAg levels be useful?

Background: Recent studies have shown that antiviral treatment discontinuation is safe and associated with virologic remission in HBeAg-negative patients. However, the period of viral suppression and follow-up in these studies was relatively short.

Objectives: To investigate whether continuous viral suppression with tenofovir disoproxil fumarate for more than 7 years is associated with HBsAg loss and sustained response after treatment discontinuation and receiving a full course of hepatitis B vaccination.

Study Design: Patients with HBeAg-negative chronic HBV infection and more than 7 years of persistent viral suppression with tenofovir therapy were selected for treatment discontinuation and HBV vaccination. Follow-up with monthly ALT, HBV-DNA, and HBsAg determinations lasted 72 weeks. In patients with viral relapse, the viral quasispecies in the overlapping reverse transcriptase and small surface protein regions was analysed by ultra-deep pyrosequencing.

Results: Eight of 17 HBeAg-negative patients accepted tenofovir discontinuation: 5 patients achieved sustained response (persistent HBV-DNA levels <2000IU/mL and normal ALT) despite an initial virologic relapse, one lost HBsAg, and two needed re-treatment. All patients with an on-treatment HBsAg level decline >5000IU/mL achieved sustained response. Patients with HBsAg level <100IU/mL during an ALT flare after antiviral discontinuation achieved sustained response. Significant changes were seen in the composition of the HBV quasispecies, and half the patients showed changes in HBV genotype.

Conclusions: Even though the majority of patients presented an initial relapse with selection of HBV variants, most achieved sustained response. Changes in HBsAg levels on and off treatment may be useful for predicting the likelihood of virologic remission.