Inclusion Criteria:

• Patients will be enrolled for screening at Visit 1 into the run-in period if they meet all the following criteria:
• Clinical diagnosis of moderate persistent asthma for at least 6 months, according to GINA revised version 2005 guidelines 1 and considering current treatment;
• Forced expiratory volume (FEV1) or peak expiratory flow rate (PEFR) ≥ 80% of the predicted normal value;
• Treated with fluticasone 1000 mcg + salmeterol 100 mcg daily for at least 4 weeks at a stable dose;
• Reporting no nocturnal symptoms or awakenings, no exacerbations, no limitations of activities, symptoms in ≤2 days and use of rescue medication ≤2 days per week, in the last 4 weeks;
• Exhibiting a co-operative attitude and ability to be trained to correctly use the study devices and to complete the diary cards.

At the end of run in period (Week 8+0; Visit 3), patients will be recruited into the treatment period and randomized to treatment if they meet the following criterion:

• Asthma is controlled 1 in each of the last 4 weeks of run-in (no nocturnal symptoms or awakenings; no exacerbations; no limitations of activities; symptoms in ≤2 days; use of rescue medication ≤2 days; morning PEF ≥80% of predicted in every day) confirmed by reviewing the diary cards.

Exclusion Criteria:

• Inability to carry out pulmonary function testing;
• Diagnosis of Chronic Obstructive Pulmonary Disease (COPD) as defined by the NHLBI/WHO's GOLD guidelines;
• Current smokers or recent (less than one year) ex-smokers with a smoking history of ≥10 pack/years;
• History of near fatal asthma;
• Evidence of symptomatic infection of the airways in the previous 8 weeks;
• Three or more courses of oral corticosteroids or hospitalisation due to asthma during the previous 6 months;
• Patients treated with anticholinergics and antihistamines during the previous 2 weeks, with topical or intranasal corticosteroids and leukotriene antagonists during the previous 4 weeks;
• History or current evidence of heart failure, coronary artery disease, myocardial infarction, severe hypertension, cardiac arrhythmias;
• Diabetes mellitus;
• PTCA or CABG during the previous six months;
• Patients with an abnormal QTc interval value in the ECG test, defined as >450 msec in males or > 470 msec in females;
• Other haemodynamic relevant rhythm disturbances (including atrial flutter or atrial fibrillation with ventricular response, bradycardia (≤55 bpm), evidence of atrial-ventricular (AV) block on ECG of more than 1st degree;
• Clinically significant or unstable concurrent diseases: uncontrolled hyperthyroidism, significant hepatic impairment, poorly controlled pulmonary (tuberculosis, active mycotic infection of the lung), gastrointestinal (e.g. active peptic ulcer), neurological or haematological autoimmune diseases;
• Cancer or any chronic diseases with prognosis <2 years;
• History of alcohol or drug abuse;
• Patients treated with monoamine oxidase inhibitors, tricyclic antidepressants or beta-blockers as regular use;
• Allergy, sensitivity or intolerance to study drugs and/or study drug formulation ingredients;
• Patients who received any investigational new drug within the last 12 weeks;

At the end of run in period (Week 8+0; Visit 3), patients will not be randomized to treatment if they do not completely meet the definition of "controlled asthma". These subjects will be considered screening failures and will not count against the planned number to be recruited.