The aim of this study is to determine the efficacy of Rowenta® "Intense Pure Air XL" air cleaner on the early and late bronchial response, in cat-allergic asthmatic patients during an allergen exposure in ALYATEC environmental chamber (EEC)
A monocentric, double-blind, placebo-controlled, cross-over study conducted outside of the pollen season. The study lasts 3 months for each patient, which includes a screening period, two exposure visits in the Alyatec Environmental Exposure Chamber (EEC) with active or placebo air cleaners, and a follow-up visit. Patients with early asthmatic reaction during baseline exposure are randomly allocated to one of two sequences: active air cleaners /placebo or placebo/active air cleaners. Randomization is balanced (1:1) between the two sequences. There is a 3-week wash-out period between the two exposures.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
24
Cat allergen is nebulized in the EEC. When the concentration is stable, air cleaners are switched on. The number of air cleaners placed in the EEC is defined according to the volume of the EEC and the air renewal. Patients are exposed to cat allergen in the presence of active air cleaners in the EEC
Cat allergen is nebulized in the EEC. When the concentration is stable, placebo air cleaners are switched on. The placebo effect is obtained thanks to the removal of air cleaners filters prior to the exposure. The number of placebo air cleaners placed in the EEC is defined according to the volume of the EEC and the air renewal. Patients are exposed to cat allergen in the presence of placebo air cleaners in the EEC.
Alyatec
Strasbourg, Bas-Rhin, France
Frequency of early asthmatic response
In subjects exposed in the EEC to an average cat allergen concentration of 40 ng/m3 (Feld1) in presence of an active air cleaner compared to a placebo. Early asthmatic response is defined by a drop of at least 20% compared to baseline FEV1.
Time frame: Week 9
Frequency of late asthmatic response
Late asthmatic response is defined by a 15% drop of FEV1 compared to baseline FEV1 between 1h and 6h after the end of the allergen exposure.
Time frame: Week 9
Severity of early and/or late asthmatic response
Evaluated by the maximum percentage of drop in FEV1. It was measured in subjects exposed to cat allergen with active air cleaners compared to placebo air cleaners.
Time frame: Week 9
Difference of asthma symptoms during exposure to cat allergen with active air cleaners versus placebo.
The intensity of asthma symptoms is assessed using the visual analogue scale (VAS). The VAS is based on one question which allows to evaluate the symptoms on a scale from 0 to 10. 0 means no symptoms (best condition) and 10 means high symptoms (worse condition).
Time frame: Week 9
Difference of rhinitis symptoms during exposure to cat allergen with active air cleaners versus placebo.
The intensity of rhinitis symptoms is assessed using the TNSS (Total Nasal Symptom Score) nasal self-assessment questionnaire. The score of the TNSS varies from 0 (no symptoms) to 12 (high symptoms).
Time frame: Week 9
Difference of rhinitis symptoms during exposure to cat allergen with active air cleaners versus placebo.
The intensity of rhinitis symptoms is assessed using the visual analogue scale (VAS). The VAS is based on one question which allows to evaluate the symptoms on a scale from 0 to 10. 0 means no symptoms (best condition) and 10 means high symptoms (worse condition). A difference of 23 mm between two assessments done before and after exposure is considered as clinically significant.
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Time frame: Week 9
Difference of conjunctivitis symptoms during exposure to cat allergen with active air cleaners versus placebo.
The intensity of conjunctivitis symptoms is assessed using the TOSS (Total Ocular Symptom Score) conjunctival self-assessment questionnaire. It varies between 0 (no symptoms) and 6 (high symptoms).
Time frame: Week 9
Difference of conjunctivitis symptoms during exposure to cat allergen with active air cleaners versus placebo.
The intensity of conjunctivitis symptoms is assessed using the visual analogue scale (conjunctivitis VAS). The VAS is based on one question which allows to evaluate the symptoms on a scale from 0 (no symptoms) to 10 (high symptoms).
Time frame: Week 9
Difference of conjunctivitis symptoms during exposure to cat allergen with active air cleaners versus placebo.
The intensity of conjunctivitis symptoms is assessed using Abelson's Score. Abelson's score varies from 0 (no symptoms) to 13 (higher symptoms). A positive conjunctival response is defined by Albelson's Score evaluated by physician above or equal to 5 during allergen exposure.
Time frame: Week 9