Treatment Effect of the Tree Pollen SLIT-Tablet on Allergic Rhinoconjunctivitis During Oak Pollen Season.

Abstract

BACKGROUND\nBirch, alder, hazel, and oak are members of the birch homologous group based on cross-reactivity toward the birch pollen allergen Bet v 1. Theoretically, allergy to these tree pollens may be treated by immunotherapy with one representative allergen extract.\n\n\nOBJECTIVE\nTo evaluate post-hoc whether treatment of birch pollen-induced allergic rhinoconjunctivitis with a standardized tree sublingual immunotherapy (SLIT)-tablet containing birch pollen extract reduces symptoms and symptom-relieving medication use during the oak pollen season (OPS).\n\n\nMETHODS\nIn a randomized, multinational, double-blind trial (EudraCT-2015-004821-15), 634 participants (12-65 years) received daily tree SLIT-tablet (12 SQ-Bet) or placebo before and during tree pollen season (alder/hazel plus birch pollen season [BPS]). Symptom-relieving medication was allowed. The primary endpoint was the average total combined score (TCS; sum of rhinoconjunctivitis daily symptom score [DSS] and daily medication score [DMS]) during BPS. Outcomes during the OPS (excluding overlapping BPS days) were analyzed post-hoc.\n\n\nRESULTS\nRelative improvements in average TCS, DSS, and DMS with the tree SLIT-tablet versus placebo during the OPS were 25%, 22%, and 32%, respectively (all p<0.001). Significant correlations were observed between birch and oak sIgE at baseline (r=0.86) and between birch and oak IgG4 after treatment (r=0.72). Oak sIgE and IgG4 kinetics in response to tree SLIT-tablet treatment were similar to birch.\n\n\nCONCLUSIONS\nThe tree SLIT-tablet leads to significant improvement of rhinoconjunctivitis outcomes during the OPS, supporting the clinical relevance of immunologic cross-reactivity towards birch and oak allergens.