The gold-standard treatment is no more effective than placebo for patients with mild persistent asthma, say researchers from the Steroids in Eosinophil Negative Asthma (SIENA) study, funded by the National Heart, Lung, and Blood Institute.
The researchers divided 295 participants into groups based on low- or high-sputum eosinophil levels and assigned them randomly to each of 3 treatment groups for 12-week periods: inhaled steroids (mometasone), a long-acting muscarinic antagonist (LAMA) (tiotropium), or placebo.
Surprisingly, 221 participants—nearly 73%—were classified as having low-sputum eosinophils (< 2%), a much higher frequency than the researchers expected. And of those, the number who responded better to steroids was no different from the number responding to placebo. Of the Eos-low group, 60% had better symptom control with LAMA; 40% had better symptom control with placebo.
By contrast, patients classified as “Eos-high” were nearly 3 times as likely to respond to inhaled steroids compared with placebo.
Other research has indicated that about half the population with mild persistent asthma have < 2% sputum eosinophils and are not likely to respond well to steroids. But laboratory tests to measure sputum eosinophils are not routinely used in most clinics, the researchers say.
The difference between the groups is not large enough to conclude that patients are more likely to do better on LAMA drugs, the researchers say, but their study highlights the need to look for alternatives to inhaled steroids for patients with mild asthma.
The research underscores the value of customizing treatments to help people with asthma, said James Kiley, PhD, director of the Division of Lung Diseases at NHLBI. “This study adds to a growing body of evidence that different patients with mild asthma should be treated differently, perhaps using biomarkers like sputum eosinophils to select which drugs should be used—a precision medicine approach.”