Late Hepatitis B reactivation after treatment with rituximab

There is a large reservoir of individuals with past hepatitis B virus (HBV) infection that are in risk for HBV reactivation when immunosuppressed. On the setting of hematologic malignancy, the malignancy itself and currently used treatments, especially anti-CD20 agents, have risk of HBV reactivation. Antiviral prophylaxis is recommended by some international societies. We present a case of HBV reactivation more than 12 months after stopping rituximab containing treatment and 6 months of antiviral prophylaxis with entecavir, in a patient with HBV functional cure. The patient was restarted on antivirals and again obtain functional cure. The antiviral was stopped 1 year after seroconversion and the patient followed for another year without evidence of new reactivation. Most literature supports the use of antiviral prophylaxis in patients treated with rituximab. However, there are still conflicting indications and no consensus regarding the duration of prophylaxis. This clinical case and review of the literature supports a longer prophylaxis duration (more than 18 months after finishing rituximab treatments) instead of standard 12 months prophylaxis.