Can blocking IgE-making B cells prevent asthma attacks?
Quilizumab, an antibody that targets the B cells that make IgE, lowered IgE levels by about a third but did not reduce asthma attacks or improve breathing in adults with hard-to-control allergic asthma.
Source
A randomized trial of the efficacy and safety of quilizumab in adults with inadequately controlled allergic asthma
Study at a glance
- Design
- RCT — Phase II, multinational, double-blind, placebo-controlled RCT; three quilizumab dosing regimens vs placebo (1:1:1:1) for 36 weeks plus 48 weeks of follow-up
- N
- N=578 · 578 adults randomised across four arms (433 quilizumab, 145 placebo)
- Population
- Adults aged 18-75 with allergic asthma uncontrolled despite high-dose inhaled corticosteroids plus a second controller, with at least one recent exacerbation, at sites in 14 countries
- Outcome
- Primary: annualised rate of asthma exacerbations to week 36; secondary: FEV1, symptom scores, rescue inhaler use, night awakenings; also IgE levels, biomarker subgroups and safety
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
Adults whose allergic asthma stayed uncontrolled despite high-dose inhaled steroids and a second controller were randomly assigned to one of three under-the-skin quilizumab schedules (300 mg monthly, or 150 mg or 450 mg quarterly) or placebo for 36 weeks, with patients and site staff blinded. The main outcome was the yearly rate of exacerbations needing systemic steroids or hospital care; lung function, diary symptoms and quality of life were secondary. The researchers also tested whether type 2 biomarkers (periostin, blood eosinophils, exhaled nitric oxide, IgE) picked out patients who benefited more.
What they found
Quilizumab was well tolerated and clearly active biologically, cutting total and allergen-specific IgE by 30-40% at week 36 in every dose group. However, exacerbation rates did not fall meaningfully: the best arm (300 mg monthly) showed a non-significant 19.6% reduction, and the other two arms had slightly more exacerbations than placebo. Lung function, symptoms, rescue-inhaler use and quality of life did not improve, and no biomarker subgroup showed a consistent benefit; the sponsor stopped the trial early for lack of efficacy.
The limits
What it doesn't show
The trial tested only 36 weeks of treatment in severe, uncontrolled allergic asthma, so the authors cannot say whether longer treatment or another subgroup would respond. They could not directly measure the target cells in patients, so depletion of IgE-producing B cells is inferred from falling IgE rather than shown. It was a Phase II study funded and largely authored by the manufacturer, used 90% confidence intervals and a lenient alpha typical of early-phase trials, and the earlier allergen-challenge studies that looked promising were in mild asthma, a different population.
Key terms
- IgE (immunoglobulin E)
- The antibody class that drives allergic reactions by binding allergens on mast cells and basophils.
- Membrane IgE / M1-prime segment
- A portion of IgE found only on the surface of IgE-switched B cells, which quilizumab binds to deplete those cells.
- Asthma exacerbation
- Here, a worsening of asthma symptoms that required systemic steroids for at least 3 days or hospital admission.
- FEV1
- Forced expiratory volume in one second, a standard spirometry measure of airflow and lung function.
- Biomarker-defined subgroup
- Patients grouped by a measured marker (e.g. periostin, eosinophils) to test whether they respond differently to a treatment.
- Surrogate endpoint
- A lab or physiological measure (like IgE level) used in place of a clinical outcome; changing it does not guarantee patient benefit.
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Quiz yourself
What was the main clinical result of the quilizumab trial?
Common questions
If quilizumab lowered IgE, why didn't it help?
It removed only IgE made by newly switching B cells; long-lived plasma cells and other sources keep producing IgE, and the results suggest this new local IgE production is not what drives exacerbations in this population.
How is quilizumab different from omalizumab?
Omalizumab mops up circulating IgE and lowers free IgE almost completely, whereas quilizumab targets the cells that make IgE; in similar patients omalizumab reduced exacerbations but quilizumab did not.
Why were earlier small studies misleading?
They used allergen-challenge tests in mild asthma, which may not reflect the processes that cause attacks in severe, uncontrolled asthma.
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