WEDNESDAY, Feb. 21 (HealthDay News) -- The U.S. Food and Drug Administration has asked Genentech to add a boxed warning to the drug Xolair (omalizumab), which has been linked to anaphylaxis in patients being treated for asthma. The reactions can occur more than 24 hours after treatment, even after the first dose or in patients who did not have a reaction to the first dose.
Patients being treated with Xolair should be observed for two hours after injection, and providers should be prepared to administer treatment for anaphylaxis. Patients should also carry emergency medication and be instructed on the symptoms that would warrant self-treatment for anaphylaxis.
Xolair was approved in 2003 for treatment of patients 12 and older with a positive reaction to perennial aeroallergens and moderate to severe asthma not controlled by standard treatment. The risk of anaphylaxis is 0.1 percent and was listed on the warning label at approval. However, due to the potential severity and delayed nature of the reaction, the FDA is now strengthening the warning label.
The FDA has received 48 reports of reactions in 39,500 patients treated with Xolair between 2003 and 2005. Seventy-one percent of cases occurred in the first two hours, although 13 percent developed more than 24 hours later. There was pulmonary involvement, such as bronchospasm, in 96 percent of cases and hypotension or syncope in 13 percent of cases.
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More Information - Letter to Healthcare Professionals
