Hepatitis B Virus Reactivation in Patients Receiving Bruton Tyrosine Kinase Inhibitors

Background: Bruton tyrosine kinase (BTK) inhibitors are used to treat B-cell hematologic malignancies. Ibrutinib has been associated with hepatitis B virus (HBV) reactivation. We sought to identify patients with hematologic malignancies who developed HBV reactivation after receiving first-generation (ibrutinib) or second-generation (acalabrutinib and zanubrutinib) BTK inhibitors. Methods: We retrospectively studied all consecutive patients with hematologic malignancies with past HBV infection (HBV surface antigen [HBsAg] negative and hepatitis B core antibody [anti-HBc] positive) or chronic HBV infection (HBsAg positive and anti-HBc positive) treated with BTK inhibitors at our institution from November 1, 2015, through November 1, 2022. Results: Of 82 patients initially identified, 53 were excluded (11 because of false-positive anti-HBc results, and 42 because they were receiving anti-HBV prophylaxis owing to recent receipt of anti-CD20 monoclonal antibodies). The 29 remaining patients were further analyzed and 3 (10%; 2/28 with past and 1/1 with chronic HBV infection) were found to have HBV reactivation. One patient received ibrutinib, and 2 received acalabrutinib. All developed HBV-associated hepatitis requiring anti-HBV therapy and survived. One patient continued receiving acalarutinib. Among the patients with past HBV infection, 13 received ibrutinib and 1 (8%) had HBV reactivation; 14 received acalabrutinib and 1 (7%) had HBV reactivation (P = 1.0). Conclusions: HBV reactivation risk is intermediate in patients with past HBV infection who receive BTK inhibitors. For patients with past HBV infection who received BTK inhibitors, data are insufficient to recommend universal anti-HBV prophylaxis, but monitoring for HBV reactivation is warranted.