Factors associated with the decrease in hepatitis B surface antigen titers following interferon therapy in patients with chronic hepatitis B: Is interferon and adefovir combination therapy effective?

The purpose of antiviral therapy in chronic hepatitis B (CHB) is generally to achieve a decrease and ultimately disappearance of HBs antigen (HBsAg). Interferon (IFN) therapy of CHB appears to be less effective in Asian countries than in European countries, and the advantage of IFN and nucleotide(s) analog (NA) combination therapy has yet to be fully investigated. The present study focused on the factors associated with a decrease in HBs antigen following IFN monotherapy or IFN + NA combination therapy. A total of 35 patients with CHB who received IFN-based therapy (mean ± standard deviation age 36.7±8.5 years; 27 males and 8 females) were enrolled in this study. Of the 35 patients, 21 patients received pegylated IFN monotherapy and 14 patients received IFN and adefovir (ADV) combination therapy. We examined the factors associated with reductions in the HBsAg titer of >1.0 log IU/ml from the initial HBsAg titer to the end of treatment and to 24 weeks after treatment. Although 13 patients (37%) had a reduction in HBsAg of >1.0 IU/ml at the end of treatment, it was only maintained to 24 weeks after treatment in 7 patients (20%). The HBV core-related antigen (HBcrAg) titer before treatment was significantly higher in patients with a decrease in HBsAg at the end of treatment than in patients without a decrease in HBsAg (6.56±0.78 vs. 5.30±1.66 log IU/ml, P<0.05). Moreover, an increase in alanine aminotransferase (ALT) of >2 times from baseline occurred significantly more frequently in patients with a decrease in HBsAg (62 vs. 14%, P<0.05). The proportion of patients with a decrease in HBsAg was significantly greater in patients who received IFN monotherapy than in patients who received IFN and ADV combination therapy (43 vs. 29%, P<0.05). The present results revealed that the HBcr antigen titer before therapy and an on-treatment elevation of ALT (indicative of host instruction flare) are important factors associated with a decrease in HBsAg titers after IFN-based therapy. The efficacy of IFN and ADV combination therapy was not apparent in terms of a reduction in the HBsAg titer.