Allegheny General study finds promise in drops to treat allergies

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Mark Knochel of Ross had allergy shots as a kid and hated them.

"I don't like needles to begin with," said Mr. Knochel, 36, a family-based mental health clinician at Every Child in East Liberty. "I had to go [to the allergist] because I had to."

But after he grew up he started reaching instead for the Benadryl or some other antihistamine or over-the-counter medication to combat the annoying symptoms of his allergies: itchy and watery eyes, sneezing and itchy nose. Among his allergies are tree pollen, dog and cat dander, dust mites and, in the fall, that killer ragweed.

Then he got a chance to be in a study being conducted at Allegheny General Hospital and three other sites nationwide. It was looking at an alternative to allergy shots to build up an immunity against ragweed called sublingual immunotherapy. In the therapy, also known as SLIT, the patients put small drops of the allergen, meaning the substance to which they react, under the tongue.

As with shots, the patient slowly builds up antibodies to the allergens to ward off the allergic symptoms.

Results of the 2007 study, involving 115 subjects, were published Friday in the Journal of Allergy and Clinical Immunology. The author is David Skoner, director of Asthma and Immunology in the Department of Pediatrics at Allegheny General Hospital and one of the trial team.

The therapy does not yet have FDA approval in the United States and is considered experimental. Its use by allergists is rare, and many insurance companies won't cover the cost. But over the past 15 years it has become a widely accepted alternative to shots in Europe.

The clinical trial at Allegheny General was "double blind," which means neither the subjects nor the investigators knew who was getting a placebo and who was getting either a medium dose or a high dose of the actual ragweed allergen.

But Mr. Knochel eventually assumed he was getting the real thing because "I didn't need Benadryl as much as before. Even on a real bad day, the symptoms weren't real bad."

The formal purpose of the trial was to find a safe target maintenance dose for the drops, and that was accomplished, Dr. Skoner said.

But there were other findings and observations, as well, including the one by Mr. Knochel, Dr. Skoner said.

"The response versus the placebo was better or the same as we get with our drugs. Pretty much with all medicines we have a 10 to 15 percent improvement, but with this sub-analysis there was a bigger response than that," the doctor said.

But the study did not have anyone using shots, "so you can't say the drops are better [than shots]. We can only say they were better than ... the placebo."

Ingestion of the drops also was safe, Dr. Skoner said. "There's more risk with shots because they administer them systemically, and the drops are under the tongue. ... [Previous studies show] there are bigger odds of reaction if you get a shot."

Other advantages include less discomfort and more convenience, since the patient takes a couple weeks' or a month's supply home from the allergist's office and is responsible for taking each dose.

In addition, Dr. Skoner said, "once you're on shots you're generally committed to a three-to-five-year course. If you stop, you have to restart. You can start several weeks before a season starts [with drops] and continue through the season and then do it again next year."

Almost all of the study participants had some side effects. "The most common are local ones - mostly itching around the site of the application, in the mouth and throat," Dr. Skoner said. "We just observed it and treated through it. We might adjust the dose down a little bit."

There were 202 "adverse events," such as an asthma attack or intense injury, but only two could be proven definitely related to the drops, he added.

There were no cases of anaphylactic shock, a severe, sometimes fatal allergic reaction to allergens characterized by a sharp drop in blood pressure and breathing difficulties.

"Maybe two times a year we see anaphylaxis from shots [at Allegheny General]," Dr. Skoner said.

Because there were no shots in the study, the researchers couldn't prove definitively that drops are safer. "But if you look beyond the study, to trials published in Europe, the frequency of anaphylaxis are almost non-existent, but you do see it with shots," he added.

There were limitations to the study: Only one allergen was in the drop, and most people with allergies have multiple ones and the sample size was small.

Dr. Skoner said the study of a larger sample would be even more helpful.

"So it would be nice to see studies that involve 1,000 people to get an idea of more rare side effects that might occur."

Dr. Skoner said that shots should remain the treatment of choice with drops a good alternative.

Still, he added, that "many allergists feel threatened by [sublingual immunotherapy]," fearing that if people come in only for periodic refills of their drop supplies, there will not be enough business from patients who take shots.

Dr. Andrej A. Petrov, medical director of Allergy and Clinical Immunology at UPMC, is not among them.

"I think it's a promising therapy, one which will have its role in the future management of allergy disease." He said UPMC does not use any treatments that have not yet been approved by the FDA.


Pohla Smith: psmith@post-gazette.com or 412-263-1228.


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