Sublingual grass and ragweed immunotherapy: Clinical considerations—a PRACTALL consensus report

In early 2014, the Food and Drug Administration approved three sublingual allergen immunotherapy (SLIT) products for use in the United States: a 5-grass tablet, a timothy grass tablet, and a ragweed tablet. The approval was based on multicenter clinical trials with large patient populations and supported by decades of real-life use in Europe. Li et al. have provided a consensus report of the experts of the American Academy of Allergy, Asthma and Immunology (AAAAI) and European Academy of Allergy and Clinical Immunology (EAACI) for the prescribing clinician (J Allergy Clin Immunol 2016; 137(2): 369-376).

The decision to use SLIT depends on practical considerations, cost, convenience, and patient preference. Within the current therapeutic options for allergic rhinitis, SLIT offers a therapy that can be self-administered at home and has the potential to permanently alter the course of allergic disease. In addition to those patients who prefer a disease-modifying approach, SLIT may work well for those with disease that does not respond to standard pharmacotherapy. While preliminary studies suggest it has a beneficial effect on asthma, asthma alone is not a clinical indication.

There is currently insufficient evidence to make a meaningful comparison between SLIT and subcutaneous immunotherapy (SCIT), but the current data suggests both routes reduce symptom scores and rescue medication use. Systemic reviews and meta-analyses suggest the clinical effect size may be greater for SCIT than SLIT, but the findings are not definitive. There have also been no head-to-head comparisons of SLIT with as-needed medications such as second generation antihistamine or nasal corticosteroids, but indirect comparisons suggest SLIT’s efficacy can be as good as SCIT. An important addition is that SLIT can provide sustained benefits for up to two years after discontinuation of three years of treatment as previously observed for SCIT.

The most common adverse events associated with SLIT are local reactions, such as gastrointestinal symptoms, which affect up to 75% of patients. Most occur shortly after treatment initiation and cease without medical intervention. Patients often also experience irritation in the lips, tongue, or throat. The incidence rate of fatal and near-fatal systemic reactions is low, likely lower than that of SCIT; and severe anaphylaxis is rare. Data from three large, pivotal European trials have indicated SLIT is efficacious and safe for children. Evidence also suggests that in children with allergic rhinitis, SLIT may decrease the rate of future asthma development.