Immunotherapy Tablets For Dust Mite Allergy Reduce Asthma Risk

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.