Citing reports of severe, potentially fatal allergic reactions, the U.S. Food and Drug Administration (FDA) has issued a new warning about omalizumab, an asthma drug marketed by Genentech as Xolair. The agency has requested a “black box” warning be added to the product’s label reflecting the risk of anaphylaxis.

Xolair was approved by the FDA in 2003 to treat patients with allergy-related asthma. It was previously believed that the risk of anaphylaxis was most severe within two hours of receiving the injection. However, the FDA decided to issue its latest warning after receiving reports that serious allergic reactions can develop up to 24 hours after being administered the drug, and even longer in some cases.

“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, FDA has now requested that Genentech, Inc., add the boxed warning and strengthen the existing warning,” the alert 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. Health care providers should be prepared to manage life-threatening anaphylaxis following Xolair administration and observe patients for at least two hours after an injection. Following administration of Xolair, patients should also carry and know how to initiate emergency self-treatment for anaphylaxis.”

Symptoms of anaphylaxis include difficulty breathing, tightness in the chest, dizziness, fainting, itching and hives, and swelling of the mouth and throat. The FDA noted that they have received reports from approximately 39,500 patients who’ve been treated with Xolair and that “at least 0.1 percent” of those people suffered anaphylaxis following treatment, which would translate to about 40 instances of anaphylaxis among that cohort. In other words, about one of every thousand patients who take Xolair have had severe allergic reactions.

This entry was posted on Thursday, February 22nd, 2007 at 4:45 pm and is filed under Legal News, Health Concerns.