Sublingual allergen immunotherapy for respiratory allergy: a systematic review

Abstract

The objective of the systematic review is to provide complete and updated information on efficacy and safety of sublingual immunotherapy (SLIT) formulations for the treatment of allergic respiratory diseases (ARDs). The literature search was conducted on PubMed database, involving double-blind, randomized clinical trials published between January 1992 and 2018, written in English, and performed in humans. The number of articles finally selected for review was 112. Data from the majority of properly controlled clinical trials demonstrate that SLIT is effective not only with short-term use (first year) but also with long-term use (up to the third year of active therapy), for treating ARDs in children and adults. Both continuous and discontinuous schemes of administration showed significant reductions in symptom and medication scores. Moreover, a SLIT-induced disease-modifying effect has been documented mainly with grass pollen extracts, since improvement is maintained during at least 2 years of follow-up after a 3-year treatment period. Additionally, allergen immunotherapy should also be considered a preventive strategy, especially for decreasing bronchial asthma incidence in children and adolescents with allergic rhinitis treated with SLIT. This therapy is also safe, producing only a few mainly local and mild-to-moderate adverse events, and usually self-limited in time. The registration and authorization of allergen SLIT preparations (grasses and house-dust mite tablets) as drugs by regulatory agencies, such as the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA), has represented a landmark in allergy immunotherapy research. Further long-term studies, specially designed with allergens other than grass pollen or house-dust mites, not only in allergic rhinoconjunctivitis but also on asthmatic subjects, as well as studies comparing different administration schedules and/or routes, are required in order to continue the progress in the modern development of this particularly promising therapy.

Diverse Mechanisms of Allergen Specific Immunotherapy

“…The SLIT-tablets have been developed for the treatment of grass pollen-induced AR and HDMinduced AR but the allergen content and dosing have not been standardized to date. The varied content among different products also affects the guidelines [15]. In addition, a limitation of SLIT tablet occurs from its ingredient which consists of only one antigen [14].…”

Allergen immunotherapy and asthma

“…Many controlled clinical trials have shown the efficacy and safety of AIT in allergic asthma for adults and children, with both findings confirmed by a recently published meta‐analysis . In particular, the impact of AIT on the treatment of asthma in children has been investigated by several randomized controlled trials with variable results due to the heterogeneity of tested products and clinical outcomes.…”

“…In particular, the impact of AIT on the treatment of asthma in children has been investigated by several randomized controlled trials with variable results due to the heterogeneity of tested products and clinical outcomes. However, a consistent reduction in combined rhinitis and asthma symptom and medication scores, as well as in rescue medication use, have been demonstrated in pediatric patients with asthma and comorbid AR treated with AIT . These clinical effects have been also demonstrated to be persistent after AIT discontinuation: A prospective study showed a reduction in the presence of asthma, number of patients using asthma medications, use of bronchodilator, and peak expiratory flow rate in asthmatic children treated with HDM SLIT after 5 years of discontinuation, compared with controls .…”

2020 Brazilian Thoracic Association recommendations for the management of asthma

“…The risk of adverse systemic reactions was found to be higher after subcutaneous administration of immunotherapy in comparison with placebo. Another meta-analysis (117) reported modest benefits of sublingual immunotherapy in patients with mild-to-moderate asthma.…”