Outcomes of Cessation of Nucleos(t)ide Analog Administration on Hepatitis B Virus Reactivation after Allogeneic Hematopoietic Stem Cell Transplantation: A Nationwide Retrospective Study

Monitoring of hepatitis B virus (HBV)-DNA and HBV-DNA-guided preemptive therapy using nucleos(t)ide analogs (NAs) are recommended to prevent the development of hepatitis due to HBV reactivation after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in recipients with resolved HBV infection. However, little is known about the appropriate duration of NA treatment and the effect of NA cessation on the recurrence of HBV reactivation. This study aimed to clarify the consequences of NA cessation in allo-HSCT recipients with resolved HBV infection who experienced HBV reactivation following transplantation. We retrospectively reviewed the clinical records of recipients with resolved HBV infection (hepatitis B surface antigen [HBsAg]-negative, anti-HBc-positive) before allo-HSCT who had been diagnosed with HBV reactivation (HBsAg-positive and/or HBV-DNA detectable) after allo-HSCT between January 2010 and December 2020. A total of 72 patients from 16 institutions were registered (median age, 60 years; age range, 27 to 73 years; 42 males and 30 females). The day of initial HBV reactivation ranged from day 10 to day 3034 after allo-HSCT (median, 513 days). Anti-HBs were lost in >80% of the patients at the time of HBV reactivation. All 72 patients received preemptive NAs, and no fatal HBV reactivation-related hepatitis was observed. HBV-DNA without hepatitis was continuously detected in 5 patients during the follow-up period. Administration of NAs was discontinued in 24 of 72 patients (33%) by physician decision. Second HBV reactivation occurred in 11 of the 24 patients (46%) in whom administration of NAs was discontinued. The duration of NA treatment did not differ significantly between patients with or without second HBV reactivation. The frequency of further HBV reactivation tended to be lower in patients with an anti-HBs titer of >10 mIU/mL at the time of NA cessation. Multiple reactivations of HBV after NA cessation was common in patients with HBV reactivation who underwent allo-HSCT despite the long duration of NAs. Careful monitoring of HBV-DNA is important even after the discontinuation of NAs in the case with HBV reactivation after allo-HSCT, because multiple reactivations could occur. Active immunization by HB vaccine might be effective for suppressing further HBV reactivation after cessation of NAs.