Off-treatment virologic relapse and outcomes of re-treatment in chronic hepatitis B patients who achieved complete viral suppression with oral nucleos(t)ide analogs

Background: The durability of off-treatment virologic responses has not been fully elucidated in chronic hepatitis B (CHB) patients who have previously achieved complete virologic suppression with nucleos(t)ide analog (NA) therapy. This study aimed to assess off-treatment virologic relapse rates and to characterize the outcomes of subsequent re-treatment in CHB patients who have discontinued oral NA following complete virologic suppression. Methods: Ninety-five CHB patients who showed complete virologic suppression were withdrawn from NAs: entecavir, lamivudine, and clevudine in 67, 15, and 13 patients, respectively. Consolidation therapy was given for 6 and 12 months for HBeAg-positive and -negative CHB, respectively, before cessation. Virologic relapse was managed with the same NA that had induced complete virologic response before discontinuation. Results: The cumulative rates of virologic relapse at 12 and 24 months were 73.8% and 87.1%, respectively. The relapse rates were independent of HBeAg positivity, HBeAg seroconversion, and type of oral NA. In a multivariate analysis, duration of oral NA therapy was the only significant predicting factor associated with off-treatment virologic relapse. Although the majority of patients regained complete virologic suppression, some patients did not respond to re-treatment with the initial NA and developed genotypic resistance. Conclusions: NA consolidation therapy for 6 and 12 months is associated with high off-treatment virologic relapse in HBeAg-positive and -negative CHB patients, respectively. Drugs with high genetic barriers to resistance should be considered as a rescue therapy for off-treatment relapse in CHB.