Sublingual Immunotherapy

Sublingual Immunotherapy: Review

Allergy immunotherapy (AIT) relies on regular administration of treatment extracts at specified doses in order to be effective. Therefore, patient compliance is critical for allergy immunotherapy to be successful. However, recent studies suggest patient compliance with allergy immunotherapy is poorer outside of studies and diminishes over time with treatment. Studies report patients undergoing subcutaneous immunotherapy (SCIT) have noncompliance rates between 11% and 50% and patients receiving sublingual immunotherapy (SLIT) have noncompliance rates between 3% and 25%. The reasons for lack of treatment adherence and changes in compliance over the course of treatment are not well characterized.
So sublingual immunotherapy is important for allergy treatment. What is sublingual immunotherapy? Sublingual immunotherapy involves placing allergy extract under the patient's tongue for absorption rather than a subcutaneous injection. Allergen solutions for immunotherapy are often formulated with 50% glycerin to increase the persistence of allergen in the oral cavity. GREER® Aller-gcomplete® Drops from IDEXX are labeled at 20,000 PNU and are given to the patient once daily for continuous benefit. Before determining the best allergen vial composition, it is important to correlate the allergy test results with the patients' history of pruritus and patterns of exposure. Then the optimal formulation and route of administration for the individual patient can be established.

Advantages of sublingual allergy immunotherapy
1, Some owners are afraid of needle: Many people are reluctant to administer injections and are happy to have the option of an oral route of administration.
2, Sublingual allergy immunotherapy may be safer in some patients: Patients who experience adverse reactions to allergen injections should be considered excellent candidates for sublingual allergy immunotherapy.
3, Some patients respond better to sublingual allergy immunotherapy: Some patients that have failed to respond adequately to injectable immunotherapy may respond well to sublingual allergy immunotherapy.
4, A daily routine is easier for some owners: Maintenance allergen injections are usually administered every 1–3 weeks; whereas, sublingual allergy immunotherapy requires daily or, with some protocols, twice daily administration. Although this may be considered a drawback of maintenance sublingual allergy immunotherapy compared to injectable immunotherapy, daily medication may be more easily remembered by the owner, and the consequence of missing a dose is much less significant.
The option to administer allergens in a sublingual format is an exciting, safe and affordable treatment modality. Its higher safety level, ease of administration and potentially equal or better efficacy for many patients compared to conventional immunotherapy should lead to sublingual allergy immunotherapy being recommended early as a treatment option for the atopic patient.

Sublingual Immunotherapy: Reference

Leader B A et al. Immunotherapy compliance: comparison of subcutaneous versus sublingual immunotherapy[C]//International forum of allergy & rhinology. 2015.