BACKGROUND: Few studies have assessed the safety and efficacy of potential asthma medications in children younger than 5 years. We descriptively assessed the safety and efficacy of tiotropium, a long-acting anticholinergic drug, in children aged 1-5 years with persistent asthmatic symptoms.

METHODS: This exploratory 12-week, randomised, double-blind, placebo-controlled, parallel-group, phase 2/3, regulatory multicentre trial was done at 32 hospitals, clinics, and clinical research units in 11 countries in Asia, Europe, and North America. Children aged 1-5 years with at least a 6-month history of persistent asthmatic symptoms and a need for inhaled corticosteroids were eligible. Patients were randomly allocated using an interactive voice or web-based response system to receive once-daily tiotropium 2·5 μg, tiotropium 5 μg, or placebo as an add-on to inhaled corticosteroids with or without additional controller medication. Patients and investigators were masked to study group assignment. Tiotropium was given via the Respimat inhaler once daily as two puffs of 1·25 μg in the 2·5 μg group, two puffs of 2·5 μg in the 5 μg group, or two puffs of placebo. The primary outcomes were safety, which was assessed by comparing adverse events between the tiotropium and placebo groups, and efficacy, which was measured as the change in weekly mean combined daytime asthma symptom score from baseline to week 12. Statistical analyses of treatment effects were exploratory; although endpoints were defined, they were used for descriptive analyses only. The safety and primary analyses were done in all patients who received at least one dose of their assigned treatment. This study is registered with ClinicalTrials.gov (NCT01634113), and is completed.

FINDINGS: Between July 26, 2012, and Dec 4, 2014, 102 children were randomly assigned to the three treatment groups (36 to receive tiotropium 2·5 μg, 32 to receive tiotropium 5 μg, and 34 to receive placebo). 101 children completed the study and were included in the analyses. The changes in adjusted weekly mean combined daytime asthma symptom scores between baseline and week 12 were not significantly different between any of the groups. The adjusted mean difference between the tiotropium 2·5 μg group and placebo group was -0·080 (95% CI -0·312 to 0·152) and the difference between tiotropium 5 μg and placebo group was -0·048 (-0·292 to 0·195). Adverse events were less frequent with tiotropium treatment than with placebo (20 [56%] of 36 children with tiotropium 2·5 μg, 18 [58%] of 31 with tiotropium 5 μg, and 25 [74%] of 34 with placebo), although no formal statistical comparison between groups was performed. A greater proportion of children reported asthma exacerbations as adverse events in the placebo group (ten [29%] of 34) than in the tiotropium groups (five [14%] of 36 in the 2·5 μg group and two [6%] of 31 in the 5 μg group). Serious adverse events were reported in three patients (all of whom received placebo); no adverse events led to discontinuation of treatment or death.

INTERPRETATION: To our knowledge, our small study is the first to assess the safety and efficacy of tiotropium in children aged 1-5 years with persistent asthmatic symptoms. Tolerability of tiotropium was similar to that of placebo, which is consistent with previous findings in older populations. Although mean daytime asthma symptom scores were not significantly different between groups, tiotropium showed the potential to reduce asthma exacerbation risk compared with placebo. The findings of the study are limited by the small sample size and descriptive statistical analyses. Additional well powered trials are needed to further assess the safety and efficacy of tiotropium in young children.

FUNDING: Boehringer Ingelheim.