House Dust Mite SLIT Tablet Well Tolerated in Children With Allergic Asthma

A phase 3 study showed that the standard quality (SQ) house dust mite sublingual immunotherapy (SLIT) tablet was well tolerated in children aged 5 – 7 years with house dust mite allergic asthma.1

In children, house dust mite sensitization increases the risk of developing allergic asthma. Allergen immunotherapy for house dust mite allergic asthma has shown promise in adults, but there is a lack of evidence for this treatment in children.

Graham Roberts, from the David Hide Asthma and Allergy Centre, St Mary's Hospital, and colleagues conducted MT-11, a phase 3, randomized, double-blind, placebo-controlled trial, to assess the efficacy and safety of the SQ house dust mite SLIT tablet in children aged 5 – 17 years with house dust mite allergic asthma. The primary endpoint was the yearly rate of clinically relevant asthma exacerbations.

The study included 533 children with a recent history of asthma exacerbations despite receiving inhaled corticosteroids or long-acting beta-agonists. Children were randomized to receive daily SQ house dust mite SLIT-tablet or placebo for 24 – 30 months.

As a result of the COVID-19 pandemic, asthma exacerbations occurred far less frequently than anticipated, which contributed to the study not meeting its primary endpoint. The annual rate ratio for clinically relevant asthma exacerbations was 0.89 (95% CI, 0.60–1.30), suggesting a benefit with the house dust mite SLIT tablet but not a clear advantage over placebo. The study observed changes in the house dust mite-specific IgE, IgG4, and IgE-BF in the SLIT arm but not the placebo arm.

“The overall annualized rate of asthma exacerbations was low in both groups (0.21 with the SQ HDM SLIT-tablet and 0.18 with placebo), which could largely be attributed to the approximately 67% decrease in asthma exacerbation rate during the COVID-19 pandemic compared to the pre-pandemic rate,” the team wrote.

Before the pandemic, the placebo group in MT-11 experienced an exacerbation rate of 0.39, much lower than the 1.4 rate the study had expected. This expectation was based on an earlier study by Lanier and colleagues, which enrolled children with inadequately controlled asthma despite medium- or high-dose inhaled corticosteroids, with or without other controller therapy.2 However, the rate actually observed in the MT-11 trial is closer to what later pediatric trials reported, where placebo groups had yearly exacerbation rates between 0.43 and 0.87.1

“This observation indicates that management of asthma symptoms in children has generally improved since the completion of the Lanier et al. trial, potentially due to reduced outdoor pollution, changes in healthcare utilization, and improved asthma self-management,” investigators added.1 “There were considerably lower levels of respiratory tract infections during the COVID-19 pandemic, due to imposed social distancing measures and restricted social interaction.”

Like dust mites, viral respiratory infections are another trigger for asthma exacerbations in children. Other explanations that may explain why asthma exacerbations went down during the pandemic include children being more likely to go to the hospital for asthma or wheezing and being more likely to adhere to asthma controller medication due to increased awareness of health risks associated with asthma and COVID-19.1

Despite these findings, the trial showed the house dust mite SLIT tablet was well tolerated over the 2 years, with most treatment-related adverse events mild or moderate in severity. Under 2% of participants discontinued due to treatment-related adverse events. The most common treatment-related adverse events were local application site reactions, including oral pruritus, throat irritation, ear pruritus, and upper abdominal pain. Investigators observed no increased incidence of asthma-related events, no anaphylaxis, and no adrenaline use in the house dust mite SLIT-tablet arm.1

“The findings from the MT-11 and MT-12 trials provide important safety data to support decision-making for [house dust mite allergen immunotherapy] use in a pediatric population with [house dust mite] respiratory allergy,” investigators wrote.1

References

1. Roberts G, Just J, Nolte H, Hels OH, Emeryk A, Vidal C. SQ House Dust Mite Sublingual Immunotherapy Tablet in Children With Allergic Asthma: A Randomised Phase III Trial. Allergy. 2025;80(12):3401-3411. doi:10.1111/all.70073

2. Lanier B, Bridges T, Kulus M, Taylor AF, Berhane I, Vidaurre CF. Omalizumab for the treatment of exacerbations in children with inadequately controlled allergic (IgE-mediated) asthma. J Allergy Clin Immunol. 2009;124(6):1210-1216. doi:10.1016/j.jaci.2009.09.021