By summer, allergy sufferers may see a generation of medicines introduced that attack allergic reactions at their source.
The Food and Drug Administration is considering approval of omalizumab, which would be sold under the trade name Xolair, for treatment of moderate to severe cases of allergic asthma. Xolair is designed to block actions of immunoglobin E, or IgE, the underlying trigger of a variety of allergic diseases.
Unlike sprays and pills that treat symptoms of allergic reactions, Xolair can stop the allergic reaction itself. It has shown promise in reducing symptoms of hay fever and suppressing potentially deadly reactions to peanuts or other allergens.
"There will be many of these types of therapies that will be in development over the next several years," said Dr. Thomas B. Casale, director of clinical research at Creighton University School of Medicine in Omaha, Neb. "Our way of treating allergic diseases and asthma will change dramatically."
The goal is to develop allergy medicines that intervene early in the chain reaction that causes allergic disease. Most hay fever drugs on the market target chemicals released late in the allergic reaction, and nasal steroid sprays used by asthmatics reduce the inflammation that results from exposure to allergens.
Xolair has a different target. People who are allergic produce the antibody IgE when exposed to allergens such as ragweed or cat hair. IgE then attaches to mast cells, which release histamines and other chemicals that cause allergic symptoms.
Xolair - jointly developed by Genentech, Novartis and Tanox - is not a drug in the traditional sense but a monoclonal antibody that attaches to IgE antibodies, preventing them from triggering mast cell reactions.
Trial results for Xolair have been favorable. Last week, a federal panel unanimously supported use of the drug for cutting wheezing and shortness of breath in patients whose current medicine does not control these symptoms, making FDA approval all but certain.
In tests, Xolair not only reduced the severity of asthma attacks but the need to take other asthma medications. Studies have shown Xolair also may reduce symptoms of allergic rhinutis, or hay fever. And a study of people with severe allergies to peanuts showed that those treated with a closely related antibody developed by Tanox could eat more peanuts before showing an allergic reaction.
