Inclusion Criteria:

• Clinical diagnosis of moderate to severe persistent asthma for at least 6 months, according to GINA revised version 2002 guidelines (11):

  • Forced expiratory volume (FEV1) or peak expiratory flow rate (PEFR) ³ 50% and £ 80% of the predicted normal;
  • Asthma not adequately controlled with the current therapies, defined as presence of daily asthma symptoms > once a week and night-time asthma symptoms > twice a month, and daily use of short-acting β2-agonists. These findings are to be based on recent medical history and are to be confirmed in the 2-week run-in period.
• Treatment with inhaled corticosteroids at a daily dose ≤ 1000 μg of BDP or equivalent. The daily dose of inhaled corticosteroids taken at visit 1 will be assessed taking into account the following ratios between the doses of the different steroids: fluticasone propionate : BDP CFC = 1 : 2; budesonide : BDP CFC = 4 : 5; flunisolide : BDP CFC = 1 : 1. The ratios between inhaled steroids are irrespective of the formulations (i.e. spray aerosol or powder) used. When BDP is given in the new extra-fine HFA-134a formulation (as QVAR®, 3M Healthcare), the ratio with BDP CFC is set as 2 : 5. Therefore, the maximum allowed daily dose of inhaled corticosteroids at study entry will be: budesonide 800 μg, fluticasone propionate 500 μg, flunisolide 1000 μg, BDP 1000 mg, BDP HFA extra-fine 400 μg.
• Positive response to the reversibility test in the screening visit, defined as an increase of at least 12% (or, alternatively, of 200mL) from baseline value in the measurement of FEV1 30 minutes following 2 puffs (2 ´ 100 µg) of inhaled salbutamol administered via pMDI. The reversibility test can be avoided in patients having a documented positive response in the previous 6 months.
• A co-operative attitude and ability to be trained to correctly use the metered dose inhalers and to complete the diary cards.
• Written informed consent obtained.
• At the end of the 2-week run-in period, the presence of daily asthma symptoms (of at least mild intensity) and nighttime asthma symptom (of at least mild intensity) > once a week, as well as of daily use of relief salbutamol is to be confirmed by reviewing the diary cards for run-in.

Exclusion Criteria:

• Inability to carry out pulmonary function testing;
• Diagnosis of Chronic Obstructive Pulmonary Disease (COPD) as defined by the National Heart Lung and Blood Institute/World Health Organisation (NHLBI/WHO) Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines (30);
• History of near fatal asthma;
• Evidence of severe asthma exacerbation or 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 long-acting β2-agonists, anticholinergics and antihistamines during the previous 2 weeks, with topical or intranasal corticosteroids and leukotriene antagonists during the previous 4 weeks;
• Patients who have changed their dose of inhaled corticosteroids during the previous 4 weeks, or treatment with inhaled corticosteroids at a daily dose > 1000 μg of BDP or equivalent (except for extra-fine formulations, see inclusion criteria);
• Current smokers or recent (less than one year) ex-smokers, defined as smoking at least 10 cigarettes/day;
• History or current evidence of heart failure, coronary artery disease, myocardial infarction, severe hypertension, cardiac arrhythmias;
• Diabetes mellitus;
• Percutaneous transluminal coronary angioplasty (PTCA) or coronary artery by-pass graft (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;
• Pregnant or lactating females or females at risk of pregnancy, i.e. those not demonstrating adequate contraception (i.e. barrier methods, intrauterine devices, hormonal treatment or sterilization). A pregnancy test is to be carried out in women of a fertile age.
• 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 unlikely to comply with the protocol or unable to understand the nature, scope and possible consequences of the study;
• Patients who received any investigational new drug within the last 12 weeks;
• Patients who have been previously enrolled in this study;
• At the end of the run-in period, patients will not be admitted to the treatment period in the case of an increase of PEFR (L/sec) measured at the clinics at the end of the run-in period ³ 15% in respect of values measured at the start of the run-in period;
• Patients with asthma exacerbations during the run-in period will also be excluded from the study.