By Rob Goodier

November 27, 2016

NEW YORK (Reuters Health) - Immunotherapy for house dust mite allergies using sublingual tablets may improve asthma outcomes, a new analysis of three trials suggests.

"HDM (house dust mite) sublingual tablet immunotherapy improves various asthma outcomes such as inhaled corticosteroid use, exacerbations and asthma symptoms," lead author Dr. Hendrik Nolte at Merck Research Laboratories in Kenilworth, New Jersey, told Reuters Health by email.

The three trials tested dissolving tablets of freeze-dried extracts from dust mites of the species Dermatophagoides pteronyssinus and D. farinae that Merck manufactures. They can serve as an alternative to subcutaneous shots.

The first trial included 604 allergic asthma patients taking 100-800 mcg per day of inhaled corticosteroid. The patients were randomized to one, three or six immunotherapy tablets daily or a placebo. Those taking the highest dose of tablets reduced their corticosteroid use by 81 mcg per day compared to the placebo.

Analysis of a subgroup of 108 patients taking 400-800 mcg daily of budesonide found that six tablets were linked to a greater reduction of corticosteroid use by 327 mcg daily compared to placebo. That amounted to a 63% reduction from baseline, compared to a 9% drop in the placebo group after one year of treatment.

The second trial included 834 patients who took 400-1200 mcg daily of corticosteroid. They were randomized to six or 12 tablets daily or a placebo. After up to 18 months, the probability of having a first moderate or severe asthma exacerbation was 34% lower in the group taking 12 tablets daily compared with the placebo group (hazard ratio=0.66; p=0.02).

In the third trial, researchers enrolled 1,482 participants with dust mite allergies, including 460 who also had asthma. After one year, patients randomly assigned to taking 12 tablets daily saw a 19% improvement in their asthma daily symptom scores compared with the placebo group (p=0.002).

Given the similar evidence for subcutaneous immunotherapy, these findings for the tablet form are welcome but no surprise, said Dr. Janna Tuck, an allergist in private practice in Cape Girardeau, Missouri, who was not involved in the analysis.

"Once available, I think that U.S. physicians will be happy to add (sublingual immunotherapy) to our options for treating allergic rhinitis and asthma. Our patients can choose shots or tablets and choice is good," Dr. Tuck told Reuters Health.


American College of Allergy, Asthma, and Immunology Annual Meeting 2016.