Omalizumab-associated anaphylactic reactions reported between January 2007 and June 2008

Allergic reactions to omalizumab continue to be reported. Some patients not labeled as having anaphylaxis have multisystem allergic reactions consistent with anaphylaxis, raising questions about the adequacy of the Food and Drug Administration categorizations. The characteristics of these patient reports point toward a spectrum of systemic allergic reactions associated with omalizumab use.