Anti-Immunoglobulin E (Omalizumab/Xolair) for chronic asthma in adults and children

Walker S, Monteil M, Phelan K, Lasserson TJ, Walters EH

Published Online:

October 8, 2008

Allergic people produce Immunoglobulin E (IgE) when exposed to environmental allergens, and IgE binds to mast cells in the airways. Acute exposure to the allergen causes mast cells to release chemicals (such as histamine) causing itching, sneezing, blocked nose, wheezing, shortness of breath and cough. This review of trials found that anti-IgE, a treatment developed to remove IgE from the circulation, led to a reduction, and in some cases, withdrawal of regular inhaled steroid use and a reduction in asthma exacerbations. Compared with placebo, effects were relatively modest. Side effects were few and mild-moderate in the short term; longer term evaluation is needed. Patient and physician assessment of the effectiveness of therapy were positive.

Abstract (click to read)

Background:

Omalizumab is a recombinant humanised monoclonal antibody directed against immunoglobulin E (anti-IgE) to inhibit the immune system's response to allergen exposure. Omalizumab is directed against the binding site of IgE for its high affinity Fc receptor. It prevents free serum IgE from attaching to mast cells and other effector cells and prevents IgE mediated inflammatory changes.

Objectives:

To determine the efficacy of anti-IgE compared with placebo in patients with allergic asthma

Search strategy:

We searched the Cochrane Airways Group Asthma trials register for potentially relevant studies (February 2006).

Selection criteria:

Randomised controlled trials examining anti-IgE administered in any manner for any duration. Trials with co-interventions were included as long as they were the same in each arm.

Data collection and analysis:

Two reviewers independently assessed study quality and extracted and entered data. Three modes of administration were identified from the published literature (inhaled, intravenous and subcutaneous injection). Subgroup analysis was performed by asthma severity. Data were extracted from published and unpublished sources.

Main results:

Fourteen trials (15 group comparisons) were included in the review, contributing a total of 3143 mild to severe allergic asthmatic participants with high levels of IgE. Treatment with intravenous and subcutaneous Omalizumab significantly reduced free IgE compared with placebo. Omalizumab led to a significant reduction in inhaled steroid (ICS) consumption compared with placebo (-119 mcg/day (95% CI -154 to -83, three trials)). There were significant increases in the number of participants who were able to reduce ICS by over 50% (odds ratio (OR) 2.50, 95% confidence interval (CI) 2.02 to 3.10 (four trials)); or completely withdraw their daily ICS intake (OR 2.50 (95%CI 2.00 to 3.13; four trials)). Participants treated with Omalizumab were less likely to suffer an asthma exacerbation with treatment as an adjunct to ICS (OR 0.52, 95%CI 0.41 to 0.65, five trials), or as an ICS tapering agent (OR 0.47, 95% CI 0.37 to 0.60, four trials).

Authors' conclusions:

Omalizumab was significantly more effective than placebo at increasing the numbers of patients who were able to reduce or withdraw their inhaled steroids, but the clinical value of the reduction in steroid consumption has be considered in the light of the high cost of Omalizumab. The impressive placebo effects observed in control groups bring into question the true effect of Omalizumab. Omalizumab was effective in reducing asthma exacerbations as an adjunctive therapy to inhaled steroids, and during steroid tapering phases of clinical trials. Omalizumab was generally well tolerated, although there were more injection site reactions with Omalizumab. Patient and physician assessments of the drug were positive. Further assessment in paediatric populations is necessary, as is direct double-dummy comparison with ICS.

This record should be cited as:

Walker S, Monteil M, Phelan K, Lasserson TJ, Walters EH. Anti-IgE for chronic asthma in adults and children. Cochrane Database of Systematic Reviews 2006, Issue 2. Art. No.: CD003559. DOI: 10.1002/14651858.CD003559.pub3

Assessed as up to date:

February 21, 2006

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Primary Review Group:

Airways Group

Asthma topics:

Treating with Medications > Steroids > Steroid sparing agents

Health topics:

Lungs & airways > Asthma (chronic) > Other medications

Lungs & airways > Asthma (chronic) > Steroid-sparing

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Anti-Immunoglobulin E (Omalizumab/Xolair) for chronic asthma in adults and children

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