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The University of Southampton
Southampton Clinical Trials Unit


Trial Name

Study of mechanisms of action of omalizumab in severe asthma


Xolair (omalizumab) is an approved therapy for severe atopic asthma. However, the mechanisms of action that underlie the benefits of Xolair are not well understood.

Evidence from a large ongoing project in severe asthma (U-BIOPRED) shows that two key metabolites of prostaglandin D2 (PGD2): tetranorPGDM and 2,3-dinor-11-β-PGF2α, are elevated in the urine of severe asthmatic patients, but are not elevated in those treated with Xolair.

The purpose of this study is to use the technology of the 'omics' platforms used in U-BIOPRED (proteomics, lipidomics and breathomics) to identify biomarkers which are modulated by Xolair treatment to advance the understanding of how Xolair effects its clinical benefit.



Primary Objective: To improve understanding of the mechanisms of omalizumab by assessing the effect of 16 weeks treatment with omalizumab on urinary excretion of a key metabolite of prostaglandin 2 (PGD2), 2, 3-dinor-11-β-PGF2α and other biomarkers detected by ‘omics’ methods developed by U-BIOPRED.

Secondary Objective: To identify biomarkers which are predictive of a good clinical response, with the measurements of biomarkers being done after the first 16 weeks of treatment.

Exploratory Objective: Evaluate the value of using other clinical endpoints, either alone or in combination with measured biomarkers, to predict which participants treated with Xolair will benefit in terms of clinical improvement after 16 weeks of treatment and after 1 year of treatment.



An open label, prospective, multicentre study  




220 Patients aged 18 – 80 who have severe uncontrolled atopic asthma who have experienced two or more exacerbations in the last 12 months.

Patients who have any other active lung disease or prior treatment with Xolair or another biologic in last 4 months will NOT be eligible. Current smokers or any patient who has smoked in the past year will be ineligible but other ex-smokers will be eligible provided they meet the criteria set out in the protocol.


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