Mometasone or Tiotropium in Mild Asthma with a Low Sputum Eosinophil Level
Stephen C. Lazarus, M.D., Jerry A. Krishnan, M.D., Ph.D., Tonya S. King, Ph.D., Jason E. Lang, M.D., Kathryn V. Blake, Pharm.D., Ronina Covar, M.D., Njira Lugogo, M.D., Sally Wenzel, M.D., Vernon M. Chinchilli, Ph.D., David T. Mauger, Ph.D., Anne-Marie Dyer, M.S., Homer A. Boushey, M.D., et al., for the National Heart, Lung, and Blood Institute AsthmaNet*
Abstract
BACKGROUND
In many patients with mild, persistent asthma, the percentage of eosinophils in sputum is less than 2% (low eosinophil level). The appropriate treatment for these patients is unknown.

METHODS
In this 42-week, double-blind, crossover trial, we assigned 295 patients who were at least 12 years of age and who had mild, persistent asthma to receive mometasone (an inhaled glucocorticoid), tiotropium (a long-acting muscarinic antagonist), or placebo. The patients were categorized according to the sputum eosinophil level (<2% or ≥2%). The primary outcome was 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. The response was determined according to a hierarchical composite outcome that incorporated treatment failure, asthma control days, and the forced expiratory volume in 1 second; a two-sided P value of less than 0.025 denoted statistical significance. A secondary outcome was a comparison of results in patients with a high sputum eosinophil level and those with a low level.

RESULTS
A total of 73% of the patients had a low eosinophil level; of these patients, 59% had a differential response to a trial agent. However, there was no significant difference in the response to mometasone or tiotropium, as compared with placebo. Among the patients with a low eosinophil level who had a differential treatment response, 57% (95% confidence interval [CI], 48 to 66) had a better response to mometasone, and 43% (95% CI, 34 to 52) had a better response to placebo (P=0.14). In contrast 60% (95% CI, 51 to 68) had a better response to tiotropium, whereas 40% (95% CI, 32 to 49) had a better response to placebo (P=0.029). 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%).

CONCLUSIONS
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. These data provide equipoise for a clinically directive trial to compare an inhaled glucocorticoid with other treatments in patients with a low eosinophil level. (Funded by the National Heart, Lung, and Blood Institute; SIENA ClinicalTrials.gov number, NCT02066298.)

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Supported by the National Heart, Lung, and Blood Institute. Tiotropium and tiotropium placebo were provided by Boehringer Ingelheim. Mometasone and mometasone placebo were provided by Merck. Albuterol was provided by Teva.

Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.

This article was published on May 19, 2019, at NEJM.org.

A data sharing statement provided by the authors is available with the full text of this article at NEJM.org.

Author Affiliations
From the Division of Pulmonary and Critical Care Medicine and the Cardiovascular Research Institute (S.C.L., H.A.B., J.V.F., P.G.W.) and the Department of Pediatrics, Epidemiology, and Biostatistics (M.D.C.), University of California, San Francisco, San Francisco; the University of Illinois at Chicago (J.A.K.), the Department of Pediatrics, Rush University Medical Center (J.N.M.), Ann and Robert Lurie Children’s Hospital of Chicago (J.A.P.), and Northwestern University, Feinberg School of Medicine (L.S.) — all in Chicago; the Department of Public Health Sciences, Penn State University, Hershey (T.S.K., V.M.C., D.T.M., A.-M.D.), and the University of Pittsburgh Asthma Institute (S.W., F.H.) and Allegheny General Hospital (D.G.), Pittsburgh — all in Pennsylvania; Nemours Children’s Hospital, University of Central Florida College of Medicine, Orlando (J.E.L., K.V.B.), and Nemours Children’s Health System, Jacksonville (J.E.L., K.V.B.) — both in Florida; the Department of Pediatrics and Medicine, National Jewish Health, Denver (R.C., S.J.S., M.E.W.), and Children’s Hospital Colorado, Aurora (R.C., S.J.S., M.E.W.) — both in Colorado; Duke Allergy, Asthma, and Airway Center, Duke University School of Medicine, Durham (N.L., M.K., L.Q.), Wake Forest University School of Medicine, Winston-Salem (A.H., W.M., S.P.P.), and North Carolina Clinical Research, Raleigh (C.L.) — all in North Carolina; the Departments of Pediatrics and Medicine, Washington University in St. Louis School of Medicine, St. Louis (L.B.B., M.C.); Brigham and Women’s Hospital and Harvard Medical School (J.C.C., E.I.) and Boston Children’s Hospital (W.P.) — all in Boston; Rainbow Babies and Children’s Hospital, Cleveland (J.C., R.M., K.R.); the University of Wisconsin, Madison (L.D., D.J., R.F.L., C.A.S.); Columbia University, New York (E.D.); the Department of Pediatrics, Emory University, Atlanta (A.M.F.); and the Arizona Respiratory Center, University of Arizona, Tucson (F.D.M., W.J.M.).

Address reprint requests to Dr. Lazarus at the Division of Pulmonary and Critical Care Medicine and the Cardiovascular Research Institute, University of California, San Francisco, M-1336, 505 Parnassus Ave., San Francisco, CA 94143, or at lazma@ucsf.edu.

A complete list of the investigators in the National Heart, Lung, and Blood Institute AsthmaNet is provided in the Supplementary Appendix, available at NEJM.org.