Boxed Warning of HBV Risk Added to Rituxanhttp://www.medpagetoday.com/PublicHealt ... eral/41864
The FDA announced today that rituximab (Rituxan) and ofatumumab (Arzerra) will now carry a boxed warning of the risk for immunosuppression-related reactivation of hepatitis B virus (HBV).
The two agents are anti-CD20-directed monoclonal antibodies used to treat chronic lymphocytic leukemia. Rituximab also is used for non-Hodgkin's lymphoma, rheumatoid arthritis, vasculitis, and other conditions.
Reactivation of HPV can occur in individuals who have previously had the infection, even if it resolved clinically, if the virus remains latent in hepatic tissue and the person subsequently becomes immunosuppressed. Liver failure and death can follow.
More than 100 possible cases of fatal HBV-associated hepatic injury associated with these agents have been identified in the FDA's Adverse Event Reporting System database.
The labeling for both rituximab and ofatumumab already contains cautions about the possibility of HBV reactivation, but further information is being added to the boxed warning for rituximab and a new boxed warning is being created for ofatumumab.
This new information includes recommendations for healthcare professionals to screen all patients before initiating treatment with rituximab or ofatumumab by measuring hepatitis B surface antigen (HBsAg) and the hepatitis B core antibody (anti-HBc).
The warnings stress that healthcare professionals should consult with hepatitis experts for advice on monitoring treatment for patients who screen positive. Monitoring should continue for several months after treatment with rituximab or ofatumumab begins, because reactivation has occurred even after treatment concludes.
Immunosuppressive treatment should be stopped in any patient who develops HBV reactivation and HBV treatment should be initiated.
Of the 109 reported cases of hepatitis B-associated injury with these agents (106 with rituximab and three with ofatumumab), 32 cases included sufficient information to be judged HBV reactivation.
In 22 of these cases, the diagnosis was based on seroconversion of HBsAg, and five also had evidence of anti-HBs positivity.
Most patients were men, and mean age was 62.
The time of reactivation in relation to exposure to the anti-CD20 monoclonal antibody ranged from 63 days after the first dose to a year after the last dose.
Healthcare professionals should discuss the risk of serious infections with all patients prior to beginning therapy, and should report any such events to the FDA's MedWatch Safety Information and Adverse Event Reporting Program.