HBsAg quantification predicts off-treatment response to interferon in chronic hepatitis B patients: a retrospective study of 250 cases

BACKGROUND: For chronic hepatitis B (CHB) patients without willingness to extend the routine duration of interferon (IFN) therapy, it is important to identify patients who will benefit from treatment cessation. Hepatitis B surface antigen (HBsAg) quantification is recommended for management of IFN therapy. At present, the understanding on end-of-treatment (EOT) HBsAg level predicting post-treatment response to IFN is still finite. METHODS: A total of 2451 non-cirrhosis, HBsAg-postive patients treated with IFN-based therapy during the period from December 2010 to December 2017 at Nanfang Hospital were enrolled in this study. Serum HBsAg levels at EOT were measured to evaluate the associations between EOT HBsAg levels (Group 1, HBsAg > 0.05 and ≤ 10 IU/mL; Group 2, HBsAg > 10 and ≤ 200 IU/mL; Group 3, HBsAg > 200 IU/mL) with post-treatment HBsAg loss. Chi-squared, t-test,,Kaplan-Meier analysis, Cox regression analysis, and Multivariate Logistic regression analysis were used to analyse and evaluate differences between the there groups. RESULTS: The cumulative HBsAg loss rates 5 years after treatment in Group 1–3 were 30.4% (17/56), 9.8%(4/41) and 0%(0/153) (p < 0.001). An EOT HBsAg level of > 10 IU/mL showed relatively high negative predictive value (NPV) of up to 97.9% for HBsAg loss. Low baseline HBsAg level < 25,000 IU/mL, on-treatment HBsAg decline > 1 log10IU/mL at week 24 and EOT HBsAg level ≤ 10 IU/mL were found significantly associated with HBsAg loss. A total of 6 patients have achieved HBsAg loss at EOT and 17 patients with EOT HBsAg level ≤ 10 IU/mL have achieved post-treatment HBsAg loss. Baseline characteristics, dynamic changes of on-treatment HBsAg and duration of IFN therapy were balanced across patients with EOT or post-treatment HBsAg loss. CONCLUSION: EOT HBsAg level can serve as a monitoring indicator for IFN therapy. EOT HBsAg level ≤ 10 IU/mL was found to lead to high rate of post-treatment HBsAg loss. For patients without willingness to extend IFN treatment, off-treatment follow-up could be considered when HBsAg level decreased to ≤10 IU/mL.