Immunotherapy Tablets For Dust Mite Allergy Reduce Asthma Risk

Apr 26, 2016
Originally published on May 2, 2016 7:04 am

Immunotherapy tablets are starting to edge out shots as a treatment for allergies. And it looks like the pills can help reduce the frequency of asthma attacks, too.

Scientists reported Tuesday that immunotherapy tablets for dust mite allergy reduced the risk of an attack in people with moderate to severe asthma. The results were published in JAMA, the journal of the American Medical Association.

Allergies are a big trigger of asthma, and allergy to dust mites, tiny insects that live in homes, is the most common allergic asthma trigger.

The 693 people who completed the study had asthma that wasn't well controlled by inhaled corticosteroids. Half of the participants took a pill made of dust-mite allergen daily, letting it dissolve under the tongue. The immunotherapy tablet significantly reduced the risk of a moderate or severe asthma attack.

It's the first time sublingual immunotherapy tablets (often referred to as SLIT) have been tested as an asthma treatment, according to Dr. J. Christian Virchow, a professor of pulmonology at the University of Rostock in Germany and lead author of the study.

"It's the first large-scale study and I should be modest, but I think it's a bit of a milestone," Virchow told Shots. Earlier studies didn't look specifically at how immunotherapy shots affected asthma, he says. Rather they studied allergic rhinitis and then sifted out the people with asthma after the fact.

Allergy shots that inject an allergen extract under the skin have long been used to treat asthma, allergies and eczema, but they're a pain in many ways. So patients and doctors have been eager to see if the tablets could work as well to tame the runaway immune response that causes allergic symptoms.

In 2014, the Food and Drug Administration approved Oralair for grass allergies. It was the first sublingual allergy immunotherapy tablet approved for use in the United States. It then approved Grastek, also for grass allergies, and Ragwitek, for, you guessed it, ragweed.

The tablets typically are to be taken daily for three years, with protection from symptoms continuing after that. They're about as effective as allergy shots, and less likely to prompt anaphylactic shock. The risk of a rare life-threatening reaction is one big reason that allergy shots are given at a doctor's office.

None of the participants in the study had serious side effects. Some had local side effects like swelling of the lips and tongue or an itchy throat.

The dust mite tablets for asthma haven't been tested in children, but Virchow says he thinks the treatment might actually work better for them than for adults. The people in the study had had asthma for a mean of 13 years, he says, and may not have responded as well as a child who was recently diagnosed. "But we need to have a study in children."

"More research needs to be done" is a cliche of biomedicine, but here's a case where it's really true, according to an editorial that accompanies this study. Most people with allergies are allergic to more than one substance. As more sublingual allergen tablets are tested and approved, patients should be able to tailor their allergy or asthma treatment in a way that's been impossible before.

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RACHEL MARTIN, HOST:

And those of you out there who dread spring because of all the pollen in the air, listen up. There's a new approach to treating allergies, and NPR's Nancy Shute has details.

NANCY SHUTE, BYLINE: For years, Kathy Baker went to the doctor for shots every three weeks. It kept her hay fever under control. Then she started getting these welts on her arms.

KATHY BAKER: Lumpiness in my arms at the sites of the injections because I had been getting injections for so long.

SHUTE: She'd had it.

BAKER: I thought, this is ridiculous. We have to try something else.

SHUTE: Then she found a doctor who was using the same thing that's in the allergy shots but in a different way. She told Baker to put them in her mouth.

BAKER: You take one, two or three drops underneath your tongue. Hold it there for, you know, a minute, and then swallow it. And then you're good to go.

SHUTE: It's important to note that this liquid method has not been approved by the Food and Drug Administration. But the FDA has approved a similar approach, tablets you stick under your tongue. So far, the tablets are only for grass and ragweed allergy.

But the pills are also being tested at a treatment for asthma. A study published in JAMA found that taking tablets for dust mite allergen helped reduce the risk of an asthma attack. Robert Wood is head of allergy at Johns Hopkins Children's Center.

ROBERT WOOD: The impact that it had was not just reducing symptoms on kind of a day-to-day basis, but also the more significant symptoms that we refer to as an asthma exacerbation, the kind of thing that would lead you to come to the hospital for an emergency room visit or even a hospitalization.

SHUTE: Wood and other researchers are testing this kind of oral therapy for food allergies like peanut. Peanut allergy can be deadly, and there aren't any treatments for it. When researchers tried giving people shots for peanut allergies years ago, some people had dangerous reactions.

WOOD: It really told us right off the bat that we were not going to be able to inject people with food allergy to what they're allergic to.

SHUTE: So now they're trying three different ways to expose people to tiny bits of peanut.

WOOD: One of which is truly oral immunotherapy, where you're actually eating small and gradually increasing amounts of the food you are allergic to. The second is sublingual, where you are - again, it's being delivered in smaller amounts under the tongue. Then the third is using it delivered by a patch, where you're really wearing the food on your skin rather than taking it inside your body.

SHUTE: Tablets and patches to treat food allergies are not going to be available for a while because it will take years to test the treatments to make sure they're truly safe. But tablets for less serious allergies like hay fever may be on the market soon. Nancy Shute, NPR News. Transcript provided by NPR, Copyright NPR.