Environmental exposure unit simulates natural seasonal birch pollen exposures while maximizing change in allergic symptoms

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Abstract

Background

Birch pollen is a prevalent aeroallergen during the springtime allergy season. In field studies, variable allergen exposure and environmental factors can affect data quality while environmental exposure units (EEUs) deliver controlled, standardized, and reproducible allergen exposures.

Objective

To inform study design for EEU trials evaluating antiallergic therapies.

Methods

In this prospective study, 76 participants with birch allergy experienced 3 exposures to birch pollen: (1) an out-of-season EEU challenge (two 3-hour sessions on consecutive days); (2) a natural seasonal exposure; and (3) an in-season EEU challenge (3-hour exposure for 2 weeks after birch pollen season initiation).

Results

The total nasal symptom score, total ocular symptom score, and total symptom score (TSS = total nasal symptom score plus total ocular symptom score) were assessed every 30 minutes and daily during EEU and natural exposures. A high association between TSSs and day 2 of the out-of-season and in-season EEU challenges was noted, with a good association between the maximum TSS during the natural and in-season EEU challenges, and natural season and day 2 of the out-of-season EEU challenge (P < .001 for all). Participants had higher maximum change from the baseline TSS during day 2 of the out-of-season EEU challenge (12.4) vs the following: (1) first day (9.8); (2) in-season EEU challenge (8.4); and (3) natural seasonal exposure (7.6) (P < .001 for all).

Conclusion

A strong association was seen between the presence of allergy symptoms and exposure to birch pollen in the EEU (maximum change in symptom scores during day 2) and in the field. A hybrid trial design may be useful to demonstrate the clinical efficacy of novel antiallergic therapies requiring fewer participants and shorter timelines and expediting treatment availability.

Cited by (0)

Disclosures: Dr Ellis reports participating in advisory boards for ALK Abello, AstraZeneca, Aralez, Bausch Health, Circassia Ltd, GlaxoSmithKline, Johnson & Johnson, Merck, Mylan, Novartis, Pediapharm, and Pfizer; has been a speaker for ALK Abello, Aralez, AstraZeneca, Boehringer-Ingelheim, Meda, Medexus, Mylan, Merck, Novartis, Pediapharm, Pfizer, and Takeda; has received research grants through her institution from ALK Abello, AstraZeneca, Bayer LLC, Circassia Ltd, Green Cross Pharmaceuticals, GlaxoSmithKline, Sun Pharma, Merck, Novartis, Pfizer, Regeneron Pharmaceuticals, Inc., and Sanofi; and served as an independent consultant to Allergy Therapeutics, Bayer LLC, Ora Inc., and Regeneron Pharmaceuticals, Inc. in the past. Drs DeVeaux, Ramesh, Wang, Perlee, and O'Brien and Mr Langdon are employees of and stakeholders in Regeneron Pharmaceuticals, Inc. The remaining authors have no conflicts of interest to report.

Funding: This study was funded by Regeneron Pharmaceuticals, Inc., Tarrytown, New York, in accordance with Good Publication Practice guidelines.