Authors: Wechsler ME et al., JAMA 2015 Oct 27; 314:1720
Tiotropium is not inferior to long-acting β-agonists for add-on asthma therapy.
National asthma guidelines recommend long-acting β-agonists (LABAs) for patients whose asthma is not controlled by low-dose inhaled corticosteroids (ICS; J Allergy Clin Immunol 2007; 120:5 Suppl:S94); however, LABAs might be associated with risk for severe asthma exacerbations. In SMART, black patients who used salmeterol were more likely to suffer asthma-related deaths than were white salmeterol recipients (NEJM JW Gen Med Mar 1 2006 and Chest 2006; 129:15); black patients have a higher incidence of β2-adrenergic–receptor polymorphisms that are associated with impaired response to β-agonists.
Now, in an open-label U.S. primary care study, 1070 black patients with moderate-to-severe asthma were randomized to once-daily tiotropium (a long-acting anticholinergic) or twice-daily LABA (salmeterol or formoterol) in addition to their current ICS doses. At 18 months, no difference was noted between the groups in the primary outcome of time to first exacerbation; lung function, symptoms scores, and adverse events were similar between groups. The subgroup of patients with polymorphisms that are presumed to be associated with impaired responses to β-agonists and who were treated with LABAs experienced no excess severe exacerbations.
Comment
Three conclusions can be drawn from this study. First, LABAs are safe add-on therapy in black patients, and β2-adrenergic–receptor polymorphisms do not result in excess risk for exacerbations in patients treated with ICS/LABA combinations. Second, tiotropium was not inferior to LABAs and, although asthma guidelines do not espouse tiotropium yet, it is an attractive option for patients whose asthma is not controlled with ICS monotherapy. Third, these findings highlight the need for better asthma therapies for black patients generally, because 29 asthma-related hospitalizations and 2 asthma-related deaths occurred during follow-up. |
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