Tiotropium improves asthma symptoms as well as salmeterol

Tiotropium bromide and salmeterol caused similar improvements in asthma symptoms when added to an inhaled glucocorticoid, according to a new NIH trial.

The three-way, double-blind, triple-dummy crossover trial included 210 adults with asthma. The effectiveness of adding tiotropium (which is currently approved for chronic obstructive pulmonary disease, but not asthma) was compared to doubling the dose of inhaled glucocorticoid or adding salmeterol. Compared to the doubled glucocorticoid, tiotropium increased morning peak expiratory flow (PEF) by 25.8 liters per minute (P<0.001), and was also superior in evening peak expiratory flow, proportion of asthma-control days, prebronchodialotor forced expiratory volume in one second (FEV₁) and daily symptom scores. Tiotropium was noninferior to salmeterol on all of the study's outcomes, and did significantly better on prebronchodilator FEV₁ (a difference of 0.11 liters, P=0.003).

Because the study was short (14 weeks) and included a small number of patients, it wasn't possible to examine the rate of asthma exacerbations or long-term safety issues, the study authors cautioned. The findings should not be considered clinically directive until additional studies with greater statistical power are conducted, according to the authors. The study was published in the Sept. 23 New England Journal of Medicine.

However, some clinicians have already begun substituting tiotropium for salmeterol and other long-acting beta-antagonists in patients who remain symptomatic on low doses of inhaled glucocorticoids, an accompanying editorial noted. This study provides encouraging results for such patients, although more data are needed to determine whether tiotropium and possibly other long-acting anticholinergic agents are effective and safe alternatives. Several other trials are currently exploring this possibility, the editorialist said.