HBsAg Clearance in Inactive Chronic HBsAg Carriers After Interferon Treated

• HBsAg loss/seroconversion [ Time Frame: HBsAg level was lower than 0.05IU/mL after 96 weeks treatment ] [ Designated as safety issue: Yes ]
  HBsAg loss was defined as HBsAg levels <0.05 IU/mL. Anti-HBs was measured using Architect i2000 kit,and anti-HBs >10 mIU/L was considered positive.
  
  

Drug: Pegylated interferon alfa-2a
patients were given peginterferon alfa-2a (40KD) (Pegasys®; Roche, Basel, Switzerland)180 µg by subcutaneous injection once weekly for 120 weeks
Other Name: Pegasys®; Roche, Basel, Switzerland

Chronic HBV inactive carriers were enrolled in the out-patient department of Beijing Ditan Hospital. All of them were HBsAg positive and anti-HBs negative for more than 6 months with persistent undetectable HBV DNA and normal ALT levels measured at 3-6 monthly intervals during the preceding 2 years as well as with serum HBsAg levels ≤100 IU/mL determined on two occasions during the month prior to treatment. All patients did not have other liver diseases and contraindications for interferon therapy.

After giving informed consent, patients were treated with weekly subcutaneous injections of peginterferon alpha-2a 180 µg. The use of other immune suppressive or regulatory drugs and other antiviral drugs was prohibited during the course of the study.

In this study, the only parameter to assessing the treatment response was HBsAg level change. Treatment endpoint was HBsAg loss(＜0.05 IU/mL) and anti-HBs positive(＞10 mIU/mL) defined as seroconversion.

Depending on the decline of HBsAg level, treatment was either continued for a prolonged period until the endpoint was achieved, or terminated in case of nonresponse. Treatment was proceeded if HBsAg level continued to decline until HBsAg seroconversion was achieved and the anti-HBs level was above 200 mIU/ml. If the patients were not willing to extend treatment, the therapy was ended at the time of HBsAg loss, or stopped without further decline of HBsAg levels on three months treatment.

Liver function parameters, including ALT, aspartate aminotransferase (AST), albumin (ALB) and total bilirubin (Tbil) were examined using an automated biochemical analyzer. Peripheral blood neutrophil and platelet count were detected before treatment, and monitored during treatment with one to three month intervals, and base on the test results to adjust the next checking time. Quantitative HBV DNA testing was conducted using a commercially available real-time fluorescence quantitative PCR kit. HBsAg levels were quantified with Architect i2000 HBsAg quantitative assay (Abbott Laboratories) kit.

The main efficacy endpoints were HBsAg loss and seroconversion.