Tiotropium bromide is an effective add-on maintenance therapy for patients with asthma who remain symptomatic on medium-dose inhaled corticosteroids, improving asthma control and forced expiratory volume in 1 second (FEV₁) irrespective of patient characteristics, according to study results published in Respiratory Medicine.
Many patients with asthma remain symptomatic despite available therapies. To determine whether the safety and efficacy of tiotropium bromide differ by patients’ baseline characteristics, researchers conducted subgroup analyses of data from 2 replicate phase 3 randomized double-blind placebo-controlled parallel-group studies (MezzoTinA-asthma; ClinicalTrials.gov Identifier: NCT01172808 and NCT01172821) of once-daily soft-mist inhaler tiotropium bromide 5 μg and 2.5 μg as add-on therapy to inhaled corticosteroids. Subgroup analyses were performed based on categories of age, sex, smoking status, race, ethnicity, age at asthma onset, disease duration, predicted FEV1, FEV1 reversibility at screening, and medication use. End points included change in peak FEV₁ response (0-3 hours after dose), trough FEV₁ response, 7-question Asthma Control Questionnaire responder rate, and risk for severe asthma exacerbation over the 24-week treatment period.
Disease characteristics and baseline demographics were balanced between the placebo (n=523) and treatment groups (tiotropium bromide 5 μg: n=517; tiotropium bromide 2.5 μg: n=519). After 24 weeks of treatment, peak FEV₁ and trough FEV₁ responses were significantly improved with tiotropium bromide compared with placebo. Subgroup analyses revealed that these lung function improvements were independent of baseline characteristics.
Significant improvements in the 7-question Asthma Control Questionnaire responder rate were observed after week 24 with tiotropium bromide 5 μg and 2.5 μg compared with placebo (odds ratio, 1.32 [95% CI, 1.02-1.71; P =.035] and 1.33 [95% CI, 1.03-1.72; P =.031], respectively). These improvements were not significantly influenced by baseline characteristics.
Compared with placebo, time to first severe asthma exacerbation was reduced with tiotropium bromide, with overall hazard ratios of 0.5 (95% CI, 0.30-0.84) for the 2.5-μg dose and 0.72 (95% CI, 0.45-1.14) for the 5-μg dose. This reduction was largely independent of baseline characteristics. Rates of adverse events and serious adverse events were similar between treatment groups.
The study investigators concluded that their results “suggest that once-daily tiotropium [bromide] as add-on to [inhaled corticosteroids] provides a beneficial treatment option for patients with asthma who remain symptomatic despite medium-dose [inhaled corticosteroids], regardless of baseline characteristics.”
Disclosure: This study was supported by Boehringer Ingelheim. Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Casale TB, Aalbers R, Bleecker ER, et al. Tiotropium Respimat® add-on therapy to inhaled corticosteroids in patients with symptomatic asthma improves clinical outcomes regardless of baseline characteristics. Respir Med. 2019;158:97-109.