How immunotherapy can cut long-term asthma medication use

Asthma affects more than 6 million children, and avoidance can be a tough preventive strategy for kids to manage. A new research review is investigating how much immunotherapy can help.

Currently, pharmacology and avoidance are the top treatments and preventive strategies for asthma, but the new study investigates the efficacy of allergen immunotherapy.¹ There are only 4 sublingual allergen immunotherapy tablets approved by the US Food and Drug Administration (FDA), according to the report, and they combat allergies to dust mites, 2 different grasses, and ragweed. Allergen immunotherapy also can be offered subcutaneously, the researchers say, and the goal of this type of treatment is to build tolerance to certain allergens that may induce an asthma attack.

“The goal of allergen immunotherapy (AIT) is to induce allergen-specific immune tolerance, and it is the only allergic disease-modifying therapy available,” says Jessica Rice, DO, lead author of the review and an assistant professor of Pediatrics at Johns Hopkins University School of Medicine, Baltimore, Maryland.

Researchers from this review and several others were tasked with summarizing and updating the current evidence for the efficacy and safety of immunotherapy to inform asthma guidelines. The manuscript was published in the May 2018 issue of Pediatrics. The report reviewed 40 studies-11 sublingual immunotherapy trials and 17 subcutaneous immunotherapy trials plus several other nonrandomized controlled studies involving both routes.

There was some evidence that subcutaneous immunotherapy could improve asthma-related quality of life and forced expiratory volumes, as well as reducing long-term medication use. However, symptoms were not graded on a validated scale across the studies, making an accurate comparison difficult, and there was insufficient evidence on the benefits of immunotherapy in terms of overall asthma symptoms and healthcare usage.

The majority of subcutaneous and sublingual allergen immunotherapy trials have focused on a single allergen-the house dust mite-in monosensitized patients, and so it’s possible that results may not be generalizable to patients with allergic asthma who are polysensitized, patients treated with multiple allergens, or patients treated with a different inhalant allergen immunotherapy, Rice says. Also, most of the trials included children and adolescents with mild-to-moderate persistent asthma, she adds. 

“Patients with severe, uncontrolled asthma are at increased risk for systemic reactions, therefore asthma immunotherapy should not be initiated unless asthma symptoms are stable,” Rice says. She adds that although immunotherapy was effective in reducing long-term medication use, it may not be effective in reducing the use of rescue medications or hospitalizations due to exacerbations.

“While we found moderate-strength evidence that subcutaneous immunotherapy reduces long-term asthma controller medication use, there was otherwise low or insufficient evidence that asthma immunotherapy decreases the use of quick-relief medication and systemic corticosteroids or healthcare utilization events,” Rice says.

The study notes that local and systemic adverse reactions, including anaphylaxis, occurred with both the subcutaneous and sublingual therapies, and clinicians are advised to monitor patients after initiating therapy.

“Per the practice guidelines, asthma immunotherapy should be administered in a setting that can monitor for and manage adverse reactions, and patients should be monitored for 30 minutes after therapy-this includes the first dose of sublingual immunotherapy,” the study notes. “After the first dose, sublingual immunotherapy can be administered at home. Patients administering sublingual immunotherapy at home should, however, be instructed on how to manage adverse reactions and situations when sublingual immunotherapy should be held.”

Patients with severe symptoms or poorly controlled asthma should not be treated with immunotherapy, the study cautions.

The research team suggests that future studies focus on the use of multiple-allergen immunotherapy in children who are polysensitized, as well as to study the effect of immunotherapy on asthma symptoms using a validated scale so that symptoms may be better compared across studies.

References:

1. Rice JL, Diette GB, Suarez-Cuervo C, et al. Allergen-specific immunotherapy in the treatment of pediatric asthma: a systematic review. Pediatrics. 2018;141(5):e20173833.