title: Hepatitis B surface antigen: association with sustained response to peginterferon alfa-2a in hepatitis B e antigen-positive patients.
abstract: OBJECTIVE
  Patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B, who achieve HBeAg seroconversion 6 months after completing 48 weeks of peginterferon alfa-2a therapy, have an increased chance of clearing hepatitis B surface antigen (HBsAg) during long-term treatment-free follow-up. This analysis aimed to determine whether HBsAg quantification during treatment could be used to identify posttreatment response.
  
  
  METHODS
  Patients (n = 399) treated with peginterferon alfa-2a (180 μg/week) alone or in combination with lamivudine (100 mg/day) for 48 weeks during a large, randomized study were included in this retrospective analysis. Receiver-operating characteristic analyses were used to identify baseline and on-treatment HBsAg levels associated with response (HBeAg seroconversion 6 months posttreatment).
  
  
  RESULTS
  Baseline HBsAg levels were lower in patients achieving posttreatment response than in nonresponders (3.97 and 4.21 IU/mL, respectively, p = 0.039). Two baseline HBsAg cutoff levels (5,000 and 50,000 IU/mL) provided a positive predictive value of 42% and a negative predictive value of 77%. HBsAg decline was significantly greater during and posttreatment in responders than in nonresponders (p < 0.0001). HBeAg seroconversion rates 6 months posttreatment were significantly higher in patients with HBsAg < 1,500 IU/mL at weeks 12 and 24 (56.7 and 54.4%, respectively) versus patients with HBsAg 1,500-20,000 IU/mL (32.3 and 26.1%, respectively) or HBsAg < 20,000 IU/mL (16.3 and 15.4%, respectively) (all p < 0.0001 and <0.0001).
  
  
  CONCLUSIONS
  HBsAg levels at baseline strongly associated with posttreatment response were not identified. Low HBsAg levels during peginterferon alfa-2a therapy were associated with high rates of posttreatment response. On-treatment HBsAg quantification may, therefore, help guide patient management in the future.
authors.affiliation: NKC Institute of Gastroenterology and Hepatology, Songklanagarind Hospital, Prince of Songkla University, Hat Yai, Thailand. teerha.p@psu.ac.th.
authors.forename: Teerha
authors.initials: T
authors.lastname: Piratvisuth
authors.affiliation: Service d'Hépatologie U773-CRB3, Hôpital Beaujon, University of Paris, Clichy, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Marcellin
authors.affiliation: F.Hoffmann-La Roche, Basel, Switzerland.
authors.forename: Matei
authors.initials: M
authors.lastname: Popescu
authors.affiliation: Abbott GmbH and Company, Wiesbaden-Delkenheim, Germany.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Kapprell
authors.affiliation: IST GmbH, Mannheim, Germany.
authors.forename: Vivien
authors.initials: V
authors.lastname: Rothe
authors.affiliation: Department of Infectious Diseases, Ruijin Hospital, Shanghai, China.
authors.forename: Zhi-Meng
authors.initials: ZM
authors.lastname: Lu