Allergic Asthma, Allergy, Allergy to House Dust
Conditions
Keywords
Allergy, Asthma, House dust mite
Brief summary
This is a randomized, double blind, cross-over study designed to determine the concentration of airborne house dust mite allergen inducing bronchial response in asthmatic subjects allergic to mite, during allergen exposures in the Alyatec environmental exposure chamber (EEC). The study was also designed to validate the specificity of the asthmatic reaction induced by exposure to airborne house dust mite allergen in Alyatec EEC.
Interventions
OTHERExposure to placebo in EEC
Patients are exposed to placebo (saline solution) in the EEC for 4h maximum
OTHERExposure to three concentrations of HDM allergen in EEC
Patients are exposed to different concentrations of airborne HDM allergen (Der p1) in the EEC for 4h maximum
OTHERExposure to a single concentration of HDM allergen in EEC
Patients are exposed to a single concentration of airborne HDM allergen (Der p1) in the EEC for 4h maximum
Sponsors
Alyatec
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Intervention model description
Randomized, double blind, cross-over study including two study groups
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
No
Inclusion criteria
* Subjects having signed the informed consent * Subjects affiliated to a social security scheme * Positive metacholine test * FEV1 value \> 70% of theoretical FEV1 value * Asthma Control Test (ACT) ≥ 20/25 in 4 weeks prior to EEC exposure Group A: * Mild allergic asthma to HDM (GINA 1 or 2) with associated rhinitis and/or conjunctivitis. * Positive skin prick-test to Dpt and Df (wheal diameter \>5 mm compared to the negative control) * Specific immunoglobulin E (IgE) for Dpt and Df \> 0.7 kU/L Group B: * Mild allergic asthma (GINA 1 or 2) not sensitized to HDM with associated rhinitis and/or conjunctivitis. * Negative skin prick-test and specific IgE for Dpt and Df. * Positive skin prick-test and specific IgE for another allergen.
Exclusion criteria
* Uncontrolled asthma * Asthma Control Test (ACT) \< 20/25 in 4 weeks prior to EEC exposure * Use of oral corticosteroids in the 4 weeks preceding inclusion in the study * Use of biotherapy in the 4 months preceding inclusion in the study * Existence of a severe obstructive syndrome with FEV1 \<70% of the theoretical value * Obstruction triggered by spirometric evaluations * Hospitalization for asthma or exacerbation in the last 4 weeks * History of Acute Severe Asthma requiring hospitalization in intensive care or intubation * Desensitization to dust mite allergens in the last 5 years * Sensitization to allergens in the indoor environment (cat allergens or molds) with obvious exposure to these allergens * Active tobacco: plus 10 cigarettes / day and tobacco history of +10 PA * Uncontrolled systemic arterial hypertension * Recent myocardial infarction (\<3 months) * Recent stroke (\<3 months) * Known arterial aneurysm * Epilepsy under treatment * Progressive tumor pathology * Chronic renal pathology * Hypersensitivity to one of the excipients used * Subjects who participated in another clinical study in the three months prior to inclusion
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Determine the concentration of HDM allergen (in ng/m3 of Der p1) necessary to induce a bronchial response in at least 60% of asthmatic subjects allergic to HDM | 10 hours: 4 hours of exposure in the EEC then 6 hours post-exposure. | The bronchial response is evaluated by measuring FEV1 value during EEC exposure. Early asthmatic response (EAR) occurs when a 20% drop in FEV1 is detected during the exposure compared to the pre-exposure FEV1. Late bronchial response (LAR) occurs when a 15% drop in FEV1 or 20% drop in peak flow is detected 1 to 6h after the EAR. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Evaluate the safety of allergenic exposure in EEC | 28 hours: 4 hours of exposure in EEC then 24 hours post-exposure | Safety is assessed with clinical evaluations performed during the 4h of exposure in the EEC |
| Evaluate the metrology of the EEC | 4 hours of exposure in EEC | The metrology is assessed with the measure of allergen concentration and particules diameter thanks to sensors in the chamber. |
| Evaluate the specificity of the bronchial response | 4 hours of exposure in EEC | The specificity of the bronchial response is assessed with the HDM exposure in the EEC of asthmatic subjects non allergic to HDM. |
| Evaluate the effect of the exposure on rhinitis symptoms | 28 hours: 4 hours of exposure in EEC then 24 hours post-exposure | The effect of the exposure on the rhinitis response is assessed with Total Nasal Symptom Score (TNSS). The TNSS was obtained from the sum of all four individual symptom scores, with a total possible score ranging from 0 (no symptoms) to 12 (maximum symptom intensity). |
| Evaluate the effect of the exposure on conjunctivitis symptoms | 28 hours: 4 hours of exposure in EEC then 24 hours post-exposure | The effect of the exposure on the conjunctivitis response is assessed with Total Ocular Symptom Score (TOSS). The TOSS was obtained from the sum of all four individual symptom scores, with a total possible score ranging from 0 (no symptoms) to 12 (maximum symptom intensity). |
Countries
France
Outcome results
None listed