Tiotropium Respimat Efficacy and Safety in Asthma: Relationship to Age.

BACKGROUND: Data are limited on the differential response to long-acting bronchodilators in older versus younger adults with asthma. OBJECTIVE: To determine whether the response to tiotropium Respimat differed in older versus younger patients with asthma. METHODS: Post hoc analyses of 4 randomized, double-blind, placebo-controlled studies in adults with asthma were carried out. Two studies compared tiotropium Respimat 5 µg once daily with placebo, both added to high-dose inhaled corticosteroid (ICS) plus long-acting ß2-agonist (ie, severe asthma). The other 2 evaluated tiotropium Respimat 2.5 or 5 µg once daily, salmeterol 50 µg twice daily, or placebo, all added to medium-dose ICS (moderate asthma). Data were analyzed in 2 pools: (1) severe and (2) moderate asthma. Efficacy end points: trough and peak FEV1; trough forced vital capacity; Asthma Control Questionnaire total score and responder percentage, all at week 24. One set of analyses was performed with age as a continuous covariate; the second was conducted in categories less than 40, 40 to 60, and more than 60 years, with treatment-by-age subgroup interaction P values obtained. Safety was analyzed in age categories. RESULTS: Across the age categories, treatment-by-age subgroup interaction P values for trough FEV1 were .13 and .77 for patients with severe and moderate asthma, respectively, not indicating significant impact of age on overall treatment effect, with this observation replicated in the 2 continuum analyses. The other end points (including safety) were also not impacted by age. CONCLUSIONS: Once-daily tiotropium Respimat add-on to ICS or ICS/long-acting ß2-agonist therapy was effective and well tolerated in patients with asthma independent of age.