Hepatitis B e antigen levels and response to peginterferon: influence of precore and basal core promoter mutants

Hepatitis B e antigen (HBeAg) levels may predict response to peginterferon (PEG-IFN) but are also influenced by presence of precore (PC) and core promoter (BCP) mutants. HBeAg was measured in 214 patients treated with PEG-IFN±lamivudine for 52weeks. Patients were classified at baseline as wildtype (WT) or non-WT (detectable PC/BCP mutants). Combined response (HBeAg loss with HBV DNA<2000IU/mL), HBeAg response (HBeAg loss with HBV DNA>2000IU/mL) or non-response was assessed at week78. Mean baseline HBeAg levels were 2.65logIU/mL in combined responders, 2.48 in non-responders and 2.24 in HBeAg responders (p=0.034). Baseline HBeAg levels were not associated with combined response after stratification by WT/non-WT. Within the PEG-IFN monotherapy group (n=104), patients with HBeAg<1logIU/mL at week24 had a higher probability of combined response (29% versus 12%, p=0.041). After stratification by WT/non-WT, WT patients with HBeAg<1logIU/mL at week24 had a probability of combined response of 78% (versus 19% in patients with >1logIU/mL, p<0.001), whereas no difference in response rates was observed in non-WT patients (p=0.848). The relationship between HBeAg levels and response to PEG-IFN depends upon the presence of PC/BCP mutants. HBeAg levels should therefore not be routinely used to select patients for PEG-IFN, nor for monitoring of therapy.