SOURCE: Virchow JC, Backer V, Kuna P, et al. Efficacy of a house dust mite sublingual allergen immunotherapy tablet in adults with allergic asthma: A randomized clinical trial. JAMA 2016;316:1715-1725.
As many as half of asthmatics are sensitized to house dust mites (HDM). Decades of implementation of subcutaneous allergy desensitization have demonstrated two important facts: 1) subcutaneous desensitization can improve asthma in some patients, and 2) although serious adverse reactions to subcutaneous desensitization are rare, asthmatics are the group in which such reactions most often occur. Because of the time and effort necessary to achieve allergen desensitization, only a small minority of asthmatics currently participate in any form of allergen desensitization.
Sublingual immunotherapy is a newer format for allergen desensitization. It can be performed at home and may be preferred by patients who are avoidant of injectable desensitization, but data on asthmatic exacerbations previously has not been studied. Adult asthmatics (n = 834) were randomized to a single sublingual HDM tablet (or placebo) each morning for 18 months. Inclusion required that asthma not be well controlled on inhaled steroids (ICS) or combination inhaled products. Beginning at month 12 of the study, ICS dosing was reduced by half, and at month 15, patients discontinued ICS entirely. The primary endpoint was time to first asthma exacerbation during the ICS-withdrawal phase of the study. HDM sublingual tablets reduced the risk of moderate/severe asthma exacerbations by approximately 30% compared to placebo. HDM was well tolerated, and no serious adverse systemic events occurred. Among the minor adverse effects, oral pruritus was most commonly reported (20% of the high dose HDM treatment group vs. 3% placebo), but all reports of oral pruritus occurred at initiation of treatment onset, and all had disappeared by day five of the clinical trial. Sublingual HDM desensitization is a promising tool for asthmatic patients not well controlled on ICS.