Hepatitis B virus reactivation in seronegative occult hepatitis B patient receiving ibrutinib therapy

Background Ibrutinib is a Bruton’s tyrosine kinase (BTK) inhibitor approved for the treatment for several mature B-cell malignancies. Reactivation of hepatitis B virus (HBV) is a well-described complication in patients with chronic HBV infection or prior HBV exposure undergoing cytotoxic or immunosuppressive chemotherapy for hematologic malignancies. This phenomenon has been frequently reported with rituximab. However, published data on the risk of HBV reactivation induced by ibrutinib are scarce. Cases of HBV reactivation in hematologic patients receiving ibrutinib therapy have recently been described, but limited only to overt hepatitis B patients or seropositive occult hepatitis B patients. Case presentation We report the first case of HBV reactivation during ibrutinib treatment in an asymptomatic 82-year-old woman with seronegative occult hepatitis B patient (i.e., negative for HBsAg, anti-HBc and anti-HBs). Four months after ibrutinib treatment, her liver function test (LFT) was deranged, with seroconversion to HBsAg positivity. Serum hepatitis B virus DNA was quantified to be 1.92 × 10 8 IU/ml. Antiviral treatment was initiated, and viral load was gradually suppressed with improvement in LFT. Conclusions Our case illustrated that in populations with a high incidence of HBV exposure, systematic screening for HBV exposure is essential prior to ibrutinib treatment, followed by serial monitoring of serologic and molecular markers of hepatitis B. There is a need for an international consensus to support the recommendation of antiviral prophylaxis against HBV reactivation in patients using ibrutinib.