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Long-acting beta agonists not superior to tiotropium in black adults with asthma

Black adults with asthma treated with long-acting beta-agonists plus inhaled corticosteroids demonstrated no improvement in time to asthma exacerbation compared with those who received tiotropium plus inhaled corticosteroids, according to results of a randomized clinical trial.

Michael E. Wechsler, MD, MSc, of Brigham and Women’s Hospital, and colleagues sought to determine the effectiveness and safety of adding tiotropium to inhaled corticosteroids vs. adding long-acting beta agonists in the treatment of black adults with asthma. Further, the researchers examined whether there exists an association of allelic variation at the Arg16Gly locus of the beta 2-andrenergic receptor (ADRB2) gene in treatment response.

Black patients (n = 1,070) with moderate to severe asthma — who were treated at 20 centers between March 2011 and July 2013 — received either tiotropium once per day (n = 532) or long-acting beta-agonists twice per day (n = 538) in combination with inhaled corticosteroids.

The researchers recorded time to exacerbation, as well as scores on the Asthma Quality of Life Questionnaire, Asthma Control Questionnaire, Asthma Symptom Utility Index and Asthma Symptom-Free Days questionnaire.

They also recorded rates of forced expiratory volume in 1 second (FEV₁), adverse events, use of rescue medication and asthma deterioration.

Follow-up duration was 18 months with patients attending follow-up visits at 1 month, 6 months, 12 months and 18 months. During this time, patients underwent genotyping.

Researchers observed no difference in time to exacerbation between patients assigned long-acting beta-agonists compared with those assigned tiotropium (mean number of exacerbations per person-year, 0.42 vs. 0.37; rate ratio = 0.8; 95% CI, 0.73-1.11). Further, there were no changes in FEV₁ scores at 12 months (0.003 L vs. –0.018 L; difference, 0.02; 95% CI, –0.02 to 0.06) or 18 months (–0.053 L vs. –0.078 L; difference, 0.025; 95% CI, –0.045 to 0.095), Asthma Control Questionnaire scores at 18 months (change from baseline, –0.68 vs. –0.72; difference, 0.04; 95% CI, –0.18 to 0.27), or other patient-reported outcomes.

“Although we could not detect a difference in exacerbations between either combination therapy, we found that — despite combination therapy — this population experienced a high rate of exacerbations,” Wechsler and colleagues wrote. “Additional targeted interventions and further study are needed to reduce the rate of asthma exacerbations in this population.” – by Jeff Craven

Disclosure: Wechsler reports grants from the National Heart, Lung, and Blood Institute; honoraria from Merck; paid consultant roles with Genentech, Genzyme, GlaxoSmithKline, Novartis, Teva and several other pharmaceutical companies. Please see the full study for a list of all researchers’ relevant financial disclosures.