3123 Pollen Exposure in a Mobile Exposure Chamber: Comparing Real-Life Symptoms with Exposure Symptoms

Friday, 16 October 2015
Hall D1 Foyer (Floor 3) (Coex Convention Center)

Karl-Christian Bergmann, MD , Allergy-Centre-CharitÚ, Berlin, Germany

Torsten Sehlinger , Bluestone Technology Gmbh, Woerrstadt, Woerrstadt, Germany

Georg B÷lke , Department of Dermatology and Allergy, CharitÚ - Universtaetsmedizin Berlin, Berlin, Germany

Uwe Berger, MBA , Aerobiology and Pollen Information Research Unit, Medical University of Vienna, Vienna, Austria

Torsten Zuberbier, Prof. Dr. med. Dr. h.c. , Allergy-Centre-CharitÚ, CharitÚ-Universitaetsmedizin Berlin, Berlin, Germany

Rationale:As required by the EMA and the US FDA for pivotal trials involving allergen immunotherapy (AIT) products, clinical efficacy assessment is currently based on DBPC field studies with natural allergen exposure. Problems with the field studies include the variability of allergen exposure in different trial sites, the uncertainty of time exposure and confounding environmental factors. A novel mobile Allergen exposure chamber was designed to operate with stable and reproducible allergen exposure under standardized environmental conditions. To be accepted as an appropriate alternative to natural allergen exposure for clinical trials the clinical validation of the Exposure Chamber must document that the symptoms provoked in the chamber reflect the kind and severity of symptoms in real-life.

Methods:To determine the pollen-induced allergic nasal, eye and bronchial symptoms and their severity in real life we used data from patients suffering on rhinitis reported by using an electronic “patient hay-fever diary” (PHD) since 2009-2011 in a public app (Pollen App 3.0). For each organ and their symptoms a severity score of from 0 – 3 is possible, resulting in a total symptom score (TSS) of 12. Also, comparisons of symptoms with pollen concentration in their surrounding leading to a “symptom load index” (SLI) were used to define the severity of “real-life symptomatology” in pollen allergic patients. In the chamber birch and grass pollen allergic adults were exposed to different birch and grass pollen loads (4.000 to 8.000) for 90 – 240 min outside the pollen seasons. Spirometry, FeNO and nasal secretion was measured before and after exposure.  Nasal, conjunctival and bronchial symptoms were recorded each 10 min, peak-flow and peak nasal inspiratory flow every 30 min.

Results: Using > 60.500 data sets from >1.600 PHD users the mean TSS for 2009 to 2011 in Germany was calculated with 3.0 to 5.4 for birch seasons and 3.9 to 4.4 for grass seasons. The SLI (TSS) was calculated on a total of 293,098 data entries ranging for birch season from 4.5 to 5.6 and for grass season from 3.4 to 4.7 points. The repeated exposures with birch and grass pollen with 4000 – 8000 grains/m3 elicited reproducible symptoms on all 3 organs and significant differences between placebo and verum pollen exposure. Generally, the symptoms started to occur after 10 min and reached a plateau following 70 - 90 min of continuous exposure. The TSS for birch pollen reached an average of 5.8 and for grass 6.5 points.

Conclusions: Exposures with birch and grass pollen in the mobile exposure chamber allow to induce clinical symptoms in the same kind and severity in patients with allergic rhinitis due to pollen experience in real-life. Therefore, they are an alternative to natural allergen exposure.