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Ozone can cause acute airway inflammation in both asthmatics and normal volunteers. However, in asthmatics ozone can cause episodes of worsening of asthma. We want to learn if chronic allergic response, known as "IgE-induced airway inflammation" is what causes the increased inflammation in response to ozone. To do this we will examine the response to ozone in a group of asthmatics treated with omalizumab, a medicine available and approved for use in people with asthma, or a placebo control. The placebo for this study is inert physiologic saline ("salt water") which contains no omalizumab. Both the omalizumab and the placebo will be administered as an injection under the skin. Omalizumab, also called Xolair, is a humanized monoclonal antibody, which means that it originally was produced in mice, then genetically engineered to look more like human than mouse antibody. Omalizumab inactivates IgE, a protein our own immune systems make as part of allergic reactions. The purpose of this study is to test the hypothesis that omalizumab, by blocking this aspect of allergic reactions, will decrease the number of inflammatory cells in the airway after ozone challenge. We also hypothesize that omalizumab will decrease the effects of ozone on changes in lung function, mucociliary clearance (a measure of how quickly mucus clears form the airway) and airway reactivity. Airway reactivity is a measure of how sensitive the airways are to a medication used to diagnose asthma, called methacholine. We will examine these as additional information we can learn during the course of the study. This is a blinded study, meaning that neither you nor the researchers know if you get the active drug or placebo, but that information can be obtained if needed. The placebo is an injection of inert physiological saline ("salt water") which contains no omalizumab.
Full description
Week 0: Training and baseline studies day MCC (Dr. Bennett and MCC technician); blood draw for baseline studies, urine pregnancy test if applicable, treadmill training, spirometry, exercise testing with minute ventilation measurement, and sputum induction for baseline studies (SC)
Randomization of cohorts for study (SC):
Week 1: Visit for injection of omalizumab vs. placebo (injections carried out by CEMALB nurse; MD immediately available in facility) (see below for dosing of omalizumab); phlebotomy for baseline CBC with platelets; urine pregnancy test if applicable
Week 3: Visit for injection of omalizumab vs. placebo; urine pregnancy test if applicable
Week 5: Visit for injection of omalizumab vs. placebo (CEMALB nurse); urine pregnancy test if applicable
Week 7: Visit for injection of omalizumab vs. placebo; urine pregnancy test if applicable
Week 9: Visit for injection of omalizumab vs. placebo; urine pregnancy test if applicable
Week 11: Visit for injection of omalizumab vs. placebo, phlebotomy for CBC and platelets; urine pregnancy test if applicable
Randomization of chamber exposure order (for each cohort) (SC):
Week 13: EXPOSURE PROCEDURES-SESSION 1
Day 1 (Pre-exposure):
Day 2 (Exposure to Air or 0.4 ppm Ozone for 2 hours):
Day 3 (followup gamma scan)
THREE WEEK WAITING PERIOD (+/- 1 WEEK)
Week 16: EXPOSURE PROCEDURES-SESSION 2
Similar to Session 1 except with opposite (air or ozone) exposure regimen.
Study Discontinuation Visit (5-10 days after last exposure) History, spirometry (SC), medical evaluation if needed (Investigator MD)
Dosages of ozone and omalizumab
Ozone:The 0.4 ppm ozone exposures will be conducted in an ozone exposure chamber. Each subject will be exposed to ozone for 2 hours. During exposures, subjects will perform four 15 minute bouts of moderate exercise (minute ventilation or VE = 30 40 L/min) on a treadmill, each separated by 15 minutes of seated rest. Minute ventilation is measured for 2-3 minutes after about 4 minutes of exercise during the first exercise period, and again at about 12 minutes of exercise. It is then measured at about 12 minutes into each exercise period.
Omalizumab: Dosing for omalizumab will be consistent with doses approved for use in moderate or severe allergic asthma. The only exception to its indicated use is that we will be examining its effect in mild (rather than moderate or severe) allergic asthmatics, a group we have recruited for ozone challenge. IgE within the following ranges and body weights for subcutaneous omalizumab dosing:
Subjects for whom the IgE level and weight indicate that no dose will be given will be excluded from the study.
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Data sourced from clinicaltrials.gov
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