title: Patterns of hepatitis B surface antigen decline and HBV DNA suppression in Asian treatment-experienced chronic hepatitis B patients after three years of tenofovir treatment.
abstract: OBJECTIVE
  Patterns of serum hepatitis B surface antigen (HBsAg) decline during nucleos(t)ide analogue (NA) therapy have not been well investigated.
  
  
  METHODS
  We determined the cumulative serologic, virologic, and biochemical outcomes of 142 Asian CHB patients, with at least 6 months exposure to other NAs, receiving tenofovir with or without lamivudine for up to 3 years. Liver biochemistry, serum HBV DNA, and HBsAg levels were determined at baseline, 6 months and yearly from years 1 to 3.
  
  
  RESULTS
  142, 123 (86.6%), and 70 (49.3%) CHB patients were followed up for 1, 2, and 3 years, respectively. Two phases of HBsAg decline were observed. Patients with baseline HBsAg ≥3 log IU/ml, when compared to patients with baseline HBsAg < 3 log IU/ml, had a greater median rate of HBsAg reduction through 3 years of treatment (0.155 and 0.039 log IU/ml/year respectively, p < 0.001). Among patients with 3 years 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 0.081 log IU/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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong.
authors.forename: Wai-Kay
authors.initials: WK
authors.lastname: Seto
authors.forename: Kevin
authors.initials: K
authors.lastname: Liu
authors.forename: Danny Ka-Ho
authors.initials: DK
authors.lastname: Wong
authors.forename: James
authors.initials: J
authors.lastname: Fung
authors.forename: Fung-Yu
authors.initials: FY
authors.lastname: Huang
authors.forename: Ivan Fan-Ngai
authors.initials: IF
authors.lastname: Hung
authors.forename: Ching-Lung
authors.initials: CL
authors.lastname: Lai
authors.forename: Man-Fung
authors.initials: MF
authors.lastname: Yuen
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000627:therapeutic use*; D044466:Asian People; D004279:DNA, Viral / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000235:genetics; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology*; D006723:Hong Kong; D006801:Humans; D007700:Kinetics; D019259:Lamivudine / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000627:therapeutic use*; D000068698:Tenofovir; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D063065:Organophosphonates; D019259:Lamivudine; C053001:adefovir; D000068698:Tenofovir; D000225:Adenine
keywords: ALT; CHB; HBV; HBeAg; HBsAg; Nucleoside analogue; Nucleotide analogue; Surface antigen; TDF; Tenofovir; alanine aminotransferase; anti-HBs; antibody to the hepatitis B surface antigen; chronic hepatitis B; hepatitis B e antigen; hepatitis B surface antigen; hepatitis B virus; tenofovir disoproxil fumarate