San Francisco—The inhaled steroid prescriptions pharmacists regularly fill for asthma patients might not be as effective as previously assumed, according to a new study.

In fact, a study published in the New England Journal of Medicine and simultaneously presented at the American Thoracic Society international conference in Dallas found that among 300 patients with mild persistent asthma, inhaled steroids were no more effective than placebo in nearly three-fourths of the study patients, all over age 12 years.

Inhaled steroids—which had generally been considered the gold standard treatment—were better than placebo only for a subset of the patients who had high levels of eosinophils in their sputum, but those patients represented only about a fourth of trial participants.

“We’re intrigued by the results of this study and believe it raises questions about the way doctors manage mild persistent asthma,” said lead author Stephen Lazarus, MD, a professor of medicine at the University of California, San Francisco. “We’re not saying that steroids are unimportant for mild asthma, but our study does suggest that treatment guidelines should be re-evaluated for patients with mild persistent asthma who have low sputum eosinophils.”

The National Heart, Lung, and Blood Institute (NHLBI)–funded study points out that, in many patients with mild, persistent asthma, the percentage of eosinophils in sputum is less than 2%, which is considered low, and appropriate treatment is unknown.

To remedy that, the research team conducted a 42-week, double-blind, crossover trial, assigning 295 patients to receive the inhaled glucocorticoid mometasone, the long-acting muscarinic antagonist tiotropium or placebo. With patients categorized based on sputum eosinophil level—<2% or ≥2%—the primary outcome was defined as the response to mometasone as compared with placebo and to tiotropium as compared with placebo among patients with a low sputum eosinophil level who had a prespecified differential response to one of the trial agents.

A secondary outcome was a comparison of results in patients with a high sputum eosinophil level and those with a low level.

Results indicate that 73% of the patients had a low eosinophil level and that, of those, 59% had a differential response to a trial agent. No significant difference in the response to mometasone or tiotropium, as compared with placebo, was documented, however.

Most patients with a low eosinophil level, 57% (95% CI, 48-66) who had a differential treatment response demonstrated a better response to mometasone, and 43% (95% CI, 34-52) had a better response to placebo (P = .14).

On the other hand, 60% (95% CI, 51-68) had a better response to tiotropium versus 40% (95% CI, 32-49) who had a better response to placebo (P = .029).

Researchers emphasize that among patients with a high eosinophil level, the response to mometasone was significantly better than the response to placebo (74% vs. 26%) but the response to tiotropium was not (57% vs. 43%).

“The majority of patients with mild, persistent asthma had a low sputum eosinophil level and had no significant difference in their response to either mometasone or tiotropium as compared with placebo,” study authors conclude. “These data provide equipoise for a clinically directive trial to compare an inhaled glucocorticoid with other treatments in patients with a low eosinophil level.”

“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,” said James Kiley, PhD, director of the Division of Lung Diseases at NHLBI. He added that the research supports the value of customizing treatments for asthma patients.

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