Quantitation of hepatitis B surface antigen (HBsAg) is an increasingly popular method to determine the treatment response in chronic hepatitis B (CHB) patients. The clinical value of HBsAg level measurement during rescue therapy for lamivudine (LMV)-resistant CHB patients have not been evaluated to date. Therefore, this study investigated the correlation between HBsAg level and treatment response in LMV-resistant CHB patients treated with adefovir (ADV) add-on therapy.

LMV-resistant CHB patients treated with LMV-ADV combination therapy for over 2 years were included. HBsAg levels were measured at 6 month intervals until 1 year, and annually thereafter. Treatment response was assessed by determining the virological response (VR, undetectable HBV DNA levels) during treatment.

Fifty patients were included, of which 40 showed a VR. HBsAg levels were not different significantly at baseline (4.0 vs. 3.6 Log10 IU/mL, P=0.072). However, the HBsAg level decreased after 6 months of treatment in patients with a VR and became different significantly between the groups thereafter (3.9 vs. 3.3 at 6 months, P=0.002; 3.8 vs. 3.2 at 1 year, P=0.004; 3.9 vs. 3.2 at 2 years, P=0.008; 3.7 vs. 3.1 at 3 years, P =0.020).

The HBsAg level at 6 months after treatment can help predict treatment response.

Quantification of the hepatitis B surface antigen (HBsAg) is increasingly used to determine the treatment response in patients with chronic hepatitis B (CHB). However, there are limited data about the clinical implications of Quantification of HBsAg long-term nucleoside analogue treatment for CHB. We investigated the clinical correlation between HBsAg level and clinical course in patients with CHB who are treated long-term with nucleoside analogues.

Patients with CHB who started lamivudine or entecavir monotherapy before June 2007 were enrolled. HBsAg was quantified at baseline, at 6 months, and at 1, 2, 3, 4, and 5 years of treatment. We compared data between the groups according to the presence or absence of a virological response (VR) and resistance.

Forty-eight patients were analyzed. There was no definite reduction in HBsAg level during the early period of treatment; differences in HBsAg levels between baseline and each time point were significant only at 5 years (P=0.028). In a subgroup analysis, this difference was significant only in non-resistant patients at 5 years (P=0.041).

There was no definite decrease in the HBsAg level during the early period of nucleoside analogue treatment, with long-term treatment being required to observe a significant reduction.