Immunological Mechanisms of Oralair® in Patients With Seasonal Allergic Rhinitis

Immunological Mechanisms of Oralair® (5 Grass Mix Sublingual Allergen Immunotherapy Tablet) in Patients With Seasonal Allergic Rhinitis

Allergic diseases represent a major health issue worldwide and epidemiological studies in Melbourne, Australia, have reported a high prevalence of rhinitis (hayfever) and atopy (genetic tendency to make allergy antibody) in Asian and Caucasian subjects. Mainstay treatment of allergic rhinitis is allergen avoidance and pharmacotherapy for symptom relief. Allergen immunotherapy offers the advantages of specific treatment with long lasting efficacy, and can modify the course of disease. However, use of this treatment is restricted by the high risk of adverse events especially in asthmatics. Other, better tolerated, routes of allergen administration than the current conventional subcutaneous route (SCIT) have been investigated including the sublingual route (SLIT) and recently sublingual tablets for pollen allergy immunotherapy became available. The tablets are safe and easy to use and contain pollen extracts from 5 of the most common allergy-causing European grasses but include ryegrass (Lolium perenne), the major seasonal pollen for allergy in Melbourne and south-eastern Australia. The immunological mechanisms of sublingual immunotherapy are not fully understood. The investigators propose conducting a longitudinal open label study to investigate the immunological changes that occur with the 5 grass pollen sublingual immunotherapy tablet (Oralair®) in a cohort of Chinese and non-Chinese background subjects. The investigators will investigate the induction of relevant T cell regulatory immune mechanisms and changes in serum allergen-specific immunoglobulin (Ig) E and IgG4. Immunoregulatory cytokine synthesis and T cell phenotype (Bio-plex and flow cytometry) will be examined. This project will provide important fundamental knowledge on which to inform decisions for the greater application of this treatment for subjects with moderate and severe allergic rhinitis.

A sublingual allergen immunotherapy tablet (Oralair) containing: 300 index of reactivity (IR) of 5 grass pollen allergen extracts:perennial ryegrass (Lolium perenne), meadow grass (Poa pratensis), timothy grass (Phleum pratense), cocksfoot (Dactylis glomerata) and sweet vernal grass (Anthoxanthum odoratum) in an open label fashion administered for 4 months prior to the pollen season.

Change in Quality of Life assessed by an Allergic Rhinitis Quality of Life Questionnaire at 4, 8 and 12 months

Inclusion Criteria: Subjects of Chinese heritage or non-Chinese heritage Clinical diagnosis of moderate to severe seasonal allergic rhinitis Ryegrass-specific IgE : CAP-Pharmacia score > 1 Exclusion Criteria: Ongoing immunotherapy or previous immunotherapy (within last 5 years) Continuous oral corticosteroids Moderate, severe or unstable asthma Standard contraindications for allergen immunotherapy Ongoing treatment with β-blockers Immunodeficiency diseases Malignancy Significant inflammatory condition or disease in the oral cavity

Head of Allergy, Asthma and Clinical Immunology Service, Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital

Senior Clinical Fellow, Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital

O'Hehir RE, Varese NP, Deckert K, Zubrinich CM, van Zelm MC, Rolland JM, Hew M. Epidemic Thunderstorm Asthma Protection with Five-Grass Pollen Tablet Sublingual Immunotherapy: A Clinical Trial. Am J Respir Crit Care Med. 2018 Jul 1;198(1):126-128. doi: 10.1164/rccm.201711-2337LE. No abstract available.