The FDA has asked Genentech to revise the Xolair label and provide a medication guide for patients to strengthen the existing warning for anaphylaxis, a serious reaction which may include trouble breathing, chest tightness, dizziness, fainting, itching and hives. The drug Xolair, also known as omalizumab, is used to treat patients with asthma related to allergies.
The FDA said the strengthened warning includes the possibility of a patient developing anaphylaxis after any dose of Xolair, even if there was no reaction to the first dose. Also, anaphylaxis after administration of Xolair may be delayed up to 24 hours after the dose is given.
Anaphylaxis was reported following administration of Xolair in clinical trials, where cases were reported at a frequency of approximately one in a thousand patients (0.1%). However, the FDA has requested Genentech to strengthen the warning due to the nature of continued reports in the post-marketing experience, including their life-threatening potential, frequency, and the possibility for the delayed onset of anaphylaxis.