A phase II/III, randomised, double-blind, placebo-controlled, parallel group trial to evaluate safety and efficacy of tiotropium inhalation solution (2.5 µg and 5 µg) administered once daily in the afternoon via Respimat® Inhaler for 12 weeks in patients 1 to 5 years old with persistent asthma

1. All patients' parents (or legally accepted caregivers) must sign and date an informed consent consistent with ICH-GCP guidelines and local legislation prior to participation in the trial. Where appropriate, participants should assent to enroll in the study.
2. Male or female outpatients between 1 and 5 years of age.
3. By a physician documented (at least 6 month) history of persistent asthma symptoms,
including (but not limited to) wheezing, cough, and/or shortness of breath.
4. For patients aged 5 years and capable of performing technically acceptable PFTs: documented impaired lungfunction.
5. All patients must have been on maintenance treatment with an inhaled corticosteroid
at a stable dose, either as mono treatment or in combination with another controller
medication, for at least 4 weeks before Visit 1.
6. All patients must be symptomatic (partly controlled) as defined by the GINA guideline for children aged 5 years and younger in the week prior to Visit 1 (screening) and in the week prior to randomisation (Visit 2).
7. Patients must be able to inhale from the Respimat® inhaler (with or without spacer).
8. Patients and parents/guardians must be able to perform all trial related procedures correctly, including diligently filling out the Paediatric Asthma Caregiver Diary.
9. Parents/guardians must be literate and either one or both (depending on local requirements) must be able to accompany their child to the clinic for all visits.

1. Patients with a significant disease other than asthma. A significant disease is defined as a disease which, in the opinion of the investigator, may (i) put the patient at risk because of participation in the trial, or (ii) influence the results of the trial, or (iii) cause concern regarding the patient's ability to participate in the trial.
2. Patients with clinically relevant abnormal screening haematology or blood chemistry will be excluded if the abnormality defines a significant disease as defined in exclusion criterion 1.
3. Patients with a history of congenital or acquired heart disease, or patients who have been hospitalised for cardiac syncope or failure during the past year.
4. Patients with any unstable or life-threatening cardiac arrhythmia (in the opinion of the investigator), including cardiac arrhythmia requiring intervention (e.g. pacemaker implantation) or a change in drug therapy within the past year.
5. Patients with a malignancy for which the patient has undergone resection, radiation therapy or chemotherapy.
6. Patients with clinically significant lung diseases other than asthma, such as, but not limited to, the following diagnoses: cystic fibrosis, vascular ring or sling, tracheo(broncho)malacia, or bronchopulmonary dysplasia.
7. Alternative causes (other causes than asthma) that can lead to respiratory symptoms of wheeze, cough and shortness of breath, such as , but not limited to, transient viral infection, primary immunodeficiency, congenital heart disease, parasitic disease, vocal cord dysfunction and foreign body aspiration.
8. Patients with known active tuberculosis.
9. Patients who have undergone thoracotomy with pulmonary resection. 10. Patients who are currently in a pulmonary rehabilitation program or have completed a pulmonary rehabilitation program in the 6 weeks prior to the screening visit (Visit 1).
11. Patients with known hypersensitivity to anticholinergic drugs, BAC, EDTA or any other components of the tiotropium inhalation solution.
12. Patients who are unable to comply with pulmonary medication restrictions prior to Visit 1 and/or prior to Visit 2.
13. Patients with any acute asthma exacerbation or respiratory tract infection in the four weeks prior to Visit 1.
14. Patients who have previously been randomised in this study or are currently participating in another study.
15. Patients requiring salbutamol/albuterol as asthma rescue medication (6 or more puffs by MDI or three or more nebulized treatments per day on more than two consecutive days) during the screening period.
16. Patients with known narrow-angle glaucoma, or any other disease where anticholinergic treatment would be medically contraindicated (in the opinion of the investigator).
17. Patients with moderate to severe renal impairment, as defined by a creatinine clearance <50 mL/min/1.73 m2 BSA, as tiotropium is a predominantly renally excreted drug. Creatinine clearance will be calculated according to Schwartz Formula.