Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong.
BACKGROUND & AIMS:
Patterns of serum hepatitis B surface antigen (HBsAg) decline during nucleos(t)ide analogue (NA) therapy have not been well investigated.
We determined the cumulative serologic, virologic, and biochemical outcomes of 142 Asian CHB patients, with at least 6months exposure to other NAs, receiving tenofovir with or without lamivudine for up to 3years. Liver biochemistry, serum HBV DNA, and HBsAg levels were determined at baseline, 6months and yearly from years 1 to 3.
142, 123 (86.6%), and 70 (49.3%) CHB patients were followed up for 1, 2, and 3years, respectively. Two phases of HBsAg decline were observed. Patients with baseline HBsAg ⩾3logIU/ml, when compared to patients with baseline HBsAg <3logIU/ml, had a greater median rate of HBsAg reduction through 3years of treatment (0.155 and 0.039logIU/ml/year respectively, p<0.001). Among patients with 3years of follow-up, there was a significantly greater median rate of HBsAg reduction during the first year when compared to the second and third years (0.220, 0.136, and 0.081logIU/ml/year respectively, p<0.001). HBeAg status, HBV genotype, and concomitant lamivudine therapy were not important determinants of HBsAg kinetics (all p>0.05). The 3-year cumulative virologic suppression rate was 93.3%, with no cases of resistance detected.
Serum HBsAg levels in NA-experienced patients receiving tenofovir demonstrated a variable pattern of decline, with slower rates of reduction noted in patients with lower baseline HBsAg levels, and could explain the rarity of HBsAg seroclearance during NA therapy.