Abstract
BACKGROUND AND AIMS: Chronic hepatitis B (CHB) patients rarely achieve hepatitis B surface antigen (HBsAg) loss with nucleoside/nucleotide analog therapy. METHODS: In this retrospective study, it was evaluated that the rate of HBsAg loss in the HBe antigen negative (HBeAg(-)) patients (n=101) treated with entecavir (ETV) for ≥24 weeks followed by switching to (n=22) or adding on (n=26) pegylated interferon (PEG-IFN), and continuing ETV (n=53). RESULTS: HBsAg clearance rate at week 48 was 9% (2/22), 15% (4/26), and 0% (0/53) (P<0.05), in switch-to or add-on, or ETV monotherapy CHB patients, respectively. HBsAg reduction at week 48 was 1.182, 0.6614, or 0.056 log IU/mL, in switch-to, add-on, and ETV patients, respectively (P<0.001). The response rate (HBsAg reduction >1 log IU/mL at week 48) in the switch-to, add-on, and ETV monotherapy CHB patients was 60%, 40%, and 2%, respectively (P<0.001). In the switch-to and add-on patients, HBsAg reduction and clearance were associated with HBsAg titers at week 0 and HBsAg reduction at week 24. Furthermore, HBsAg reduction at week 24 was associated with the response rate at week 48 in the switch-to and add-on patients, showing that the area under the receiver operating characteristic curve was 0.904. Positive predictive value and negative predictive value for response rate was 70% and 100% with cut-off value 0.2 log IU/mL, respectively. CONCLUSION: In summary, we demonstrated that PEG-IFN enhanced HBsAg loss in HBeAg(-) CHB patients. High HBsAg clearance was achieved in the patients with HBsAg titers at baseline <1,000 IU/mL and HBsAg reduction >0.2 log IU/mL.