Hepatitis B virus surface antigen levels: A guide to sustained response to peginterferon alfa‐2a in HBeAg‐negative chronic hepatitis B

We investigated the relationship between hepatitis B virus surface antigen (HBsAg) serum level decline and posttreatment response in patients with hepatitis B e antigen (HBeAg)‐negative chronic hepatitis B from a large multinational study of pegylated interferon alfa‐2a (peginterferon alfa‐2a), with or without lamivudine, versus lamivudine alone. Serum HBsAg was quantified using the Architect assay (Abbott Diagnostics) at pretreatment, end of treatment (week 48), and 6 months after the end of treatment (week 72) in sera from 386 of the 537 patients who participated in the multinational study (peginterferon alfa‐2a, 127; peginterferon alfa‐2a plus lamivudine, 137; lamivudine monotherapy, 122). Pretreatment HBsAg levels varied according to genotype, with the highest levels present in patients infected with genotypes A (median, 4.11 log10 IU/mL) and D (median, 3.85 log10 IU/mL). Significant on‐treatment decline in HBsAg was observed during treatment with peginterferon alfa‐2a (alone or combined with lamivudine; mean decline at week 48, −0.71 and −0.67 log10 IU/mL, respectively, P < 0.001), but not during treatment with lamivudine alone (−0.02 log10 IU/mL). Significantly more patients treated with peginterferon alfa‐2a (21%) or peginterferon alfa‐2a plus lamivudine (17%) achieved HBsAg levels