On February 21, 2007, the FDA announced the addition of new warnings added to the label for the asthma drug Xolair. Since being approved by the FDA in 2003, Xolair, marketed by Genentech for the treatment of asthma related to allergies, has continued to be linked to reports of anaphylaxis in users. As a result, the FDA has asked Genentech to add a black-box warning to Xolair’s label.

A black-box warning is a bolded section at the top of a prescription drug label information sheet that contains the strongest warnings of risk involved with any drug. Black-boxed warnings are required for any drug which bears the risk of serious personal injury that could lead to death. *Anaphylaxis, a serious allergic reaction that can cause tightening of the chest and obstruction of breathing airways, leading to total respiratory failure, is a serious, life-threatening event.

Anaphylaxis is a systemic allergic reaction that can involve many organs of the body besides the respiratory tract, including the stomach, heart and skin. Victims may experience dizziness, fainting, hives, itching, swelling of the mouth and throat, chest tightness, and trouble breathing. Symptoms usually occur within minutes of exposure to an allergic substance, but in rare cases a victim of anaphylaxis may not experience a reaction for up to four hours after exposure to an allergen.

In clinical studies of Xolair prior to FDA approval, patients experienced anaphylaxis at a rate of about 1 in 1,000 patients, or approximately 0.1 percent of the patient population. However, since approval of the drug, the FDA has continued to receive reports of anaphylaxis in patients on Xolair, even in patients who had no reaction to their first dose. In some cases anaphylaxis was delayed for up to 24 hours after Xolair was injected, posing a serious threat of death for Xolair patients.

The FDA reminds patients taking Xolair to always carry and know how to administer emergency self-treatment for anaphylaxis, usually given in the form of an Epi-Pen injection.

Get more information from the FDA on Xolair.

Sources: U.S. Food and Drug Administration Release #P07-25, February 21, 2007; Jennifer Corbett Dooren, “FDA Warns about Genentech Drug,” Wall Street Journal, February 22, 2007.