Randomised, Double-Blind, Placebo-Controlled, Parallel Group Study to Assess the Efficacy (Bronchodilation) and Safety of 4 Weeks of Treatment of Orally Inhaled BI 1744 CL (4 Doses) Delivered by the Respimat® Inhaler in Patients With Asthma

Inclusion Criteria:

1. All patients must sign an informed consent consistent with ICH-GCP guidelines prior to participation in the trial, which includes medication washout and restrictions

2. Male or female patients, 18 years of age or older

3. Diagnosis of asthma (GINA)

4. Pre-bronchodilator FEV1 greater than or equal to 60% predicted and \<90% predicted (ECSC);

5. Increase in FEV1 greater than or equal to 12% and 200 ml 15 minutes after 400µg salbutamol (albuterol) at Visit 1

6. Patient must have been taking Inhaled Corticosteroids for at least 12 weeks prior to screening, and must have been receiving a stable low/moderate dose for at least 6 weeks prior to screening.

7. Patients must be able to perform technically acceptable pulmonary function tests and PEF measurements, and must be able to maintain records (Patient Daily e-Diary) during the study period as required in the protocol

8. Patients must be able to inhale medication in a competent manner from the Respimat® inhaler and from a metered dose inhaler (MDI).

Exclusion Criteria:

1. Patients with a smoking history of more than 10 pack years

2. Patients with any of the following conditions: a diagnosis of thyrotoxicosis, a diagnosis of paroxysmal tachycardia (\>100 beats per minute), a marked baseline prolongation of QT/QTc interval (e.g., repeated demonstration of a QTc interval \>450 ms), a history of additional risk factors for Torsade de Pointes (TdP) (e.g., heart failure, hypokalemia, family history of Long QT Syndrome)

3. Patients with any of the following conditions: a history of myocardial infarction within 1 year of screening visit (Visit 1), a diagnosis of clinically relevant cardiac arrhythmia, a history of cor pulmonale, known active tuberculosis, a malignancy for which patient has undergone resection, radiation therapy or chemotherapy within last five years (patients with treated basal cell carcinoma are allowed), a history of life-threatening pulmonary obstruction, a history of cystic fibrosis, clinically evident bronchiectasis, a history of significant alcohol or drug abuse

4. Patients who have undergone thoracotomy with pulmonary resection

5. Patients who have taken an investigational drug within one month or six half lives (whichever is greater) prior to Screening Visit (Visit 1)

6. Pregnant or nursing women

7. Women of childbearing potential not using a highly effective method of birth control. Female patients will be considered to be of childbearing potential unless surgically sterilised by hysterectomy or bilateral tubal ligation, or post-menopausal for at least 2 years

8. Patients who have previously been randomized in this study or are currently participating in another study

9. Patients who are unable to comply with pulmonary medication restrictions prior to randomization