Relief gets sweeter

Researchers have made major advances in developing treatments for allergy and asthma sufferers.

By SUSAN ASCHOFF, Times Staff Writer
© St. Petersburg Times
published April 22, 2003

A surge in scientists' knowledge about how to target chemicals in the cells and stop the wheezing, coughing, running nose and itchy eyes that plague allergy sufferers promises a new era of breathing easier.

"It's a wonderful expansion of our knowledge," says Dr. Richard Lockey, director of the division of allergy and immunology at the University of South Florida College of Medicine and one of dozens of scientists involved in the research worldwide. "Many of these discoveries will come on the market in the next 10 years."

In clinical studies, scientists armed with genetic maps are zeroing in on more than a dozen molecules implicated in asthma and allergies.

Xolair, a drug for severe allergic asthma, could hit the market this year, pending Food and Drug Administration approval. Heralded as the first major innovation in therapy in 30 years, Xolair and similar drugs stop the body's allergic response before it starts.

Other drugs more effectively relieve symptoms. This year the FDA approved the drug Singulair in a once-a-day tablet for hay fever. In use about five years as an asthma treatment, Singulair blocks leukotrienes, substances produced by certain cells that trigger sneezing, running nose and congestion. Most oral allergy medicines block histamine.

The unprecedented advances give hope to the 1-in-5 Americans, or more than 50-million children and adults, who suffer with allergies. As many as 10 percent of Americans have chronic asthma. Florida is considered a hot spot: Warm, humid weather and a multitude of allergens, from pollen to air pollution, contribute to the state's rapidly increasing number of cases.

"Here, allergies are pretty much year-round," says Dr. Stephen Klemawesch, a specialist whose St. Petersburg practice sees hundreds of patients a week. Peak season is mid February through April.

An allergy is an abnormal response by the body's immune system to a harmless substance. Normally, the immune system reacts to a foreign microorganism or particle by producing antibodies to protect against infection. These protein antibodies bind to specific molecules, or antigens, on the invader to set off a series of reactions to fight infection. When the reaction is triggered by an everyday substance such as grass or pet dander, it is an allergy.

The number of people with allergies is on the rise worldwide. A recent study of Danish adults found that 27 percent had allergies in 1990. Eight years later, 34 percent tested positive, the Wall Street Journal reports.

No one is certain why the incidence is spiraling up. One of the most intriguing theories is the "hygiene hypothesis." Changes in standards of cleanliness and fewer childhood infections have altered the immune system, it suggests. The system, itching for a fight and designed to battle invaders, "wants to flex its muscles against something, so it picks little things, inappropriate things," Klemawesch says.

Living "dirtier" may actually be beneficial. One recent study found that children who lived with two or more dogs or cats during their first year of life were half as likely to have allergic sensitivity when they were 6 or 7 years old as children with no pets.

Treatment increasingly targets chemicals in the cells to interrupt what Lockey calls the "allergic cascade." There are histamine blockers, such as over-the-counter Claritin and prescription Zyrtec, and leukotriene blockers such as Singulair.

But the big news is a group of drugs that can block a protein called Immunoglobulin E, or IgE; the drugs stop an allergic response before it begins. The drug Xolair would be the first available to specifically target IgE molecules and prevent them from binding to a group of cells called mast cells; that binding triggers the release of histamine, leukotrienes and other chemicals that cause allergic symptoms. In clinical trials, including tests under way at USF's Asthma, Allergy and Immunology Clinical Research Unit, anti-IgE treatments injected under the skin have brought relief lasting two to four weeks.

Anti-IgE drugs also are being tested for life-threatening allergies to peanuts, found in about 1.5-million people in the United States. In a report in March in the New England Journal of Medicine, researchers found that an anti-IgE antibody raised the threshold for an allergic reaction in participants from about half a peanut to nine peanuts. Such food allergy reactions can range from nausea to death. Most of the 50 to 100 annual deaths from peanut reactions occur after a person accidentally eats the equivalent of one or two nuts, for example sometimes as innocuously as ingesting a tuna sandwich made with a knife that first spread peanut butter.

"The anti-IgE antibody could become the first preventive medicine for peanut allergies (and) help lift a cloud of fear that people with peanut allergies live under every time they eat," said research team leader Dr. Donald Leung of the National Jewish Medical and Research Center in Denver.

Treatment would be injected under the skin every two to four weeks.

Xolair, if approved, would first be given for allergic asthma in adults and children older than 12. Effective for seasonal allergies as well, the drug has an average cost of $10,000 a year that would be prohibitive in all but extreme risk cases.

"I think, over time, the price will go down and others can use it," Klemawesch says.

Many of his patients battle allergic symptoms with monthly immunotherapy injections. Physicians often combine treatments for relief.

But sufferers often fail to seek help. In a recent survey by the American College of Allergy, Asthma & Immunology, almost two-thirds said they did not see a doctor the last time their symptoms acted up. Though about half use over-the-counter medications for relief because those medications are convenient, the group says that the average person runs through five products before finding one that works. Meanwhile, the allergies interfere with sleep, outdoor activities, concentration, productivity at work and sex life.

At the center at USF, clinical studies are evaluating more than a dozen drugs for pharmaceutical companies. Lockey says that almost two dozen genes are associated with allergic responses, offering multiple targets at which researchers can aim.

"As time goes on, we should be able to select out which medicines or group of medicines would be better for an individual," he says, "and give a considerably better quality of life."

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