Risk of Hepatitis B Virus (HBV) Reactivation in Patients with Immune-Mediated Inflammatory Diseases Receiving Biologics: Focus on the Timing of Biologics after Anti-HBV Treatment

Background/Aims: Anti-hepatitis B virus (HBV) therapy is required for patients with HBV infection receiving biologics because of the high risk of HBV reactivation. However, it is unclear when to start biologics after anti-HBV treatment. We investigated the risk of HBV reactivation according to the timing of biologics initiation after anti-HBV treatment in immune-mediated inflammatory disease (IMID) patients with HBV infection. Methods: We retrospectively evaluated the incidence of HBV reactivation in IMID patients who received biologics between July 2005 and April 2020. The patients were divided into two groups (within 1-week and after 1-week) according to the timing of biologics initiation after anti-HBV treatment. The cumulative probabilities and factors associated with HBV reactivation were evaluated. Results: A total of 60 hepatitis B surface antigen-positive patients with IMID received biologics (within 1-week group, n=23 [38%]; after 1-week group, n=37 [62%]). During a median follow-up of 34 months (interquartile range, 20 to 74 months), three patients (5%) developed HBV reactivation. In univariate analysis, the timing of biologics after anti-HBV treatment was not significantly associated with the risk of HBV reactivation (hazard ratio, 0.657; 95% confidence interval, 0.059 to 7.327; p=0.733). The cumulative probabilities of HBV reactivation did not significantly differ according to the timing of biologics (p=0.731). Conclusions: The risk of HBV reactivation was not significantly associated with the timing of biologics administration after anti-HBV treatment. Thus, biologics may be initiated early in patients with IMID undergoing treatment for HBV. (Gut Liver, Published online November 29, 2021)