Hepatitis B core-related antigen monitoring during peginterferon alfa treatment for HBeAg-negative chronic hepatitis B

Serum Hepatitis B core-related antigen (HBcrAg) level moderately correlates with cccDNA. We examined whether HBcrAg can add value in monitoring the effect of peginterferon (PEG-IFN) therapy for HBeAg-negative chronic hepatitis B (CHB) infection. Thus, serum HBcrAg level was measured in 133 HBeAg-negative, mainly Caucasian CHB patients, treated with 48 weeks of PEG-IFN alfa-2a. We assessed its association with response (ALT normalization & HBV DNA < 2000 IU/mL) at week 72. HBcrAg level strongly correlated with HBV DNA level (r = 0.8, P < 0.001) and weakly with qHBsAg and ALT (both r = 0.2, P = 0.01). At week 48, mean HBcrAg decline was -3.3 log U/mL. Baseline levels were comparable for patients with and without response at week 72 (5.0 vs 4.9 log U/mL, P = 0.59). HBcrAg decline at week 72 differed between patients with and without response (-2.4 vs -1.0 log U/mL, P = 0.001), but no cut-off could be determined. The pattern of decline in responders resembled that of HBV DNA, but HBcrAg decline was weaker (HBcrAg -2.5 log U/mL; HBV DNA: -4.0 log IU/mL, P < 0.001). For early identification of nonresponse, diagnostic accuracy of HBV DNA and qHBsAg decline at week 12 (AUC 0.742, CI-95% [0.0.629-0.855], P < 0.001) did not improve by adding HBcrAg decline (AUC 0.747, CI-95% [0.629-0.855] P < 0.001), nor by replacing HBV DNA decline by HBcrAg decline (AUC 0.754, CI-95% [0.641-0.867], P < 0.001). In conclusion, in Caucasian patients with HBeAg-negative CHB, decline of HBcrAg during PEG-IFN treatment was stronger in patients with treatment response. However, HBcrAg was not superior to HBV DNA and qHBsAg in predicting response during PEG-IFN treatment.