CLINICAL VALIDATION OF THE SPECIALIZED PARTICULATE CONTROL ENVIRONMENTAL EXPOSURE UNIT (SPAC-EEU) FOR CAT DANDER EXPOSURE

Introduction

The Specialized Particulate Control Environmental Exposure Unit (SPaC-EEU) is a controlled allergen challenge facility that has recently undergone a successful technical validation for cat dander exposure, specifically Felis domesticus 1 (Fel d 1). We subsequently performed a clinical validation with cat-allergic and non-allergic participants.

Methods

Recruited participants attended a screening visit where eligibility was assessed. Successfully screened cat-allergic and non-allergic participants subsequently attended one of two 3-hour cat dander exposure sessions in the SPaC-EEU. Fel d 1 concentrations were determined using a Fel d 1-specific ELISA. Participants recorded symptom scores at 18 timepoints, between baseline and 24 hours post-onset of allergen exposure.

Results

Forty-five participants completed this study, 31 cat-allergics and 15 non-allergics. Twenty-five participants attended first session (median Fel d 1=36.1 ng/m³) and 21 participants attended second session (median Fel d 1=102.0 ng/m³). Total nasal symptom scores (TNSS) for allergic participants in both sessions were not significantly different (p<0.05) at any timepoint, hence results were combined. Allergic participants had significantly increased (p<0.01) TNSS at all timepoints, from 15 minutes to 24 hours post-exposure, compared to non-allergics. Peak nasal inspiratory flow as percent change from baseline was significantly decreased (p<0.05) for allergics compared to non-allergics from 1.0 to 2.5 hours. No clinically significant safety outcomes were reported in either session.

Conclusion

The SPaC-EEU can safely produce clinically relevant and meaningful nasal symptoms in only cat-allergic participants. We have proven that this facility is an effective and reliable clinical model for cat allergen-induced allergic rhinitis.