Purpose: Recently, there have been reports of hepatitis B virus (HBV) reactivation after rituximab combination chemotherapy in hepatitis B surface antigen (HBsAg) -negative patients with B-cell lymphoma. In this prospective study, the frequency of and risk factors for HBV reactivation in patients who were receiving rituximab chemotherapy were examined.
Patients and methods: A total of 314 HBsAg-negative patients with diffuse large B-cell lymphoma were treated with rituximab chemotherapy. Antibody to hepatitis B surface antigen (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc) tests were performed in all patients. In patients who were positive for anti-HBs and/or anti-HBc, serum HBV-DNA was measured.
Results: Of the 314 patients, 51 (16.2%) were HBV carriers. HBV reactivation occurred during or after rituximab chemotherapy in six patients (12%). All six patients who developed HBV reactivation were anti-HBc positive, and three of them were also anti-HBs positive. In these six patients, the pretreatment anti-HBs titer was low. Entecavir administration was started when serum HBV DNA became positive, and serum HBV-DNA became negative within 1 to 3 weeks. Rituximab chemotherapy was then continued. Risk factors for HBV reactivation were being male and having a low anti-HBs titer.
Conclusion: HBV reactivation occurred in some patients who had been anti-HBs negative or had a low anti-HBs level. In addition, HBV reactivation occurred at an early stage of rituximab chemotherapy, but rituximab chemotherapy could be continued after entecavir administration reduced the serum HBV-DNA level. Entecavir (BMS 200495) prophylaxis was not performed when rituximab chemotherapy was started, and it was thought that entecavir could be started when serum HBV-DNA increased.