Dynamic changes of serum hepatitis B surface antigens (HBsAg) level predict HBsAg loss in hepatitis B e antigen-negative chronic hepatitis B patients treated with pegylated interferon-α-2a

Objective To investigate the predictive value of on-treatment hepatitis B surface antigens (HBsAg) levels for HBsAg loss/seroconversion in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients treated with pegylated interferon (peg-IFN)-α-2a. Methods HBeAg-negative CHB naive patients were collected from 2008 May to 2011 August in Beijing Ditan Hospital affiliated to Capital Medical University. Eligible patients had been HBsAg-positive, HBeAg-negative and with detectable hepatitis B virus (HBV) DNA for>6 months, had elevated alanine aminotransferase for>3 months, had no other liver diseases, and had been treated with peg-IFN-α-2a>3 months or had finished the treatment. All the enrolled patients were administered with peg-IFN-α-2a 180 μg/week. Serum HBV DNA, HBsAg, and anti-HBs levels were measured at baseline and every 3 months during peg-IFN-α-2a treatment. The primary efficacy of response to the treatment was HBsAg loss. Comparison between groups was conducted by chi-square test. The absolute levels of HBsAg and the decline rate of HBsAg at week 12 and week 24 were assessed using receiver operating characteristic (ROC) curve for predicting HBsAg loss at week 96 and week 120. Results A total of 81 patients were included into the data analysis. According to on-treatment HBsAg decline, patients were divided into completed response group (12 cases, 14.8%), partial response group (20 cases, 24.7%), and poor response group (49 cases, 60.5%). On week 12 of treatment, mean HBsAg decline levels in completed response and partial response groups were 0.62(0.06, 0.91) lg IU/mL and 0.19(–0.01, 0.48) lg IU/mL, respectively, which was not statistical different (Z=1.581, P=0.209). Adjusting for differences of baseline factors (calculation of the mean decline of HBsAg), completed response group and partial response group had much more pronounced decline than poor response group 0.00(–0.01, 0.14) lg IU/mL, χ2=9.00, P<0.01]. On week 24, difference of HBsAg decline among the 3 groups was statistically significant (χ2=27.72, P<0.01). The predictive ability of HBsAg cut-off level at week 24 was better than week 12 for HBsAg loss at either 96 or 120 weeks, and the differences of the area under the ROC curve were both significantly different (χ2=3.880, P=0.049 and χ2=4.412, P=0.036, respectively). Conclusion Dynamics of HBsAg level in early treatment of peg-IFN-α-2a can predict the therapeutic effect of patients with HBeAg-negative CHB. Key words: Hepatitis B, chronic; Hepatitis B surface antigens; Peg interferon α-2a; HBsAg seroconversion