Lack of effect of Grastek® on birch pollen-induced allergic rhinoconjunctivitis in the Environmental Exposure Unit

Publication date: Available online 9 February 2018
Source:Annals of Allergy, Asthma & Immunology
Author(s): Anne K. Ellis, Mark W. Tenn, Lisa M. Steacy, Daniel E. Adams, Andrew G. Day, Terry J. Walker, Hendrik Nolte
BackgroundGrastek® is a standardized sublingual immunotherapy tablet(SLIT-T) approved for the treatment of grass pollen-induced allergic rhinitis(AR) and conjunctivitis. Many grass-allergic patients are also co-sensitized to birch pollen. Whether Grastek® can confer symptomatic benefits for birch pollen-induced AR symptoms is unknown.ObjectiveTo evaluate the treatment effect of Grastek® for birch pollen-induced AR in participants sensitized to both grass and birch pollen using the Environmental Exposure Unit(EEU).MethodsPhase IV, randomized, double-blind, placebo-controlled, parallel-group study enrolling participants aged 18-65 years allergic to both timothy grass and birch pollen. Following a baseline EEU birch pollen challenge where a minimum Total Nasal Symptom Score(TNSS) of 6/12 was required for enrollment, participants were randomized to receive Grastek® or placebo taken once daily for 4 months. No confirmatory grass pollen challenge was performed. The primary endpoint was the change in TNSS averaged from assessments from hours 2 to 5 during the post-treatment birch pollen challenge(PTC) compared to baseline. Secondary/exploratory endpoints included temporally identical changes in Total Ocular Symptom Score(TOSS), Total Rhinoconjunctivitis Symptom Score(TRSS), and individual symptom scores.ResultsThe difference in TNSS reduction following 4 months of therapy between the Grastek® and placebo group was not significant(P=0.83). Reductions in TOSS(P=0.19) and TRSS(P=0.67) were also comparable between groups. Findings between groups for individual symptom scores were similar(all P>0.4) except watery eyes where symptom reduction was slightly better in the placebo arm(P=0.014). Grastek® was well tolerated and no serious AEs occurred.ConclusionA by-stander effect of grass SLIT-T on birch pollen-induced AR symptoms was not detected. Symptomatic benefits of grass SLIT-T are likely allergen specific.



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