To demonstrate that CHF 1535 via NEXT DPI (beclomethasone dipropionate + formoterol fumarate 100 + 6 μg), 1 inhalation or 2 inhalations twice daily, for 12 weeks is non-inferior to the corresponding dose of CHF 1535 via HFA-134a "extrafine" pMDI in terms of pulmonary function in moderate to severe symptomatic asthmatic patients aged ≥ 12 years under treatment with inhaled corticosteroids

Inclusion Criteria:

• Written informed consent
• Outpatients of both sexes, aged > 12 years
• Moderate to severe symptomatic asthma
• Forced expiratory volume in the first second (FEV1) > 40% and < 80% of the predicted normal values
• Reversibility test
• "Partly controlled" asthma (GINA revised 2006)
• Patients free of long-acting beta2-agonists (LABAs) treatment
• Under inhaled corticosteroids (ICS) treatment
• A minimum inspiratory flow ≥ 40 L/min 10.
• Non-smokers or ex smokers
• Asthma Control Questionnaire ACQ score ≥ 1.5

Exclusion Criteria:

• Pregnant or nursing (lactating) women
• Women of child-bearing potential, UNLESS they are menopausal or have acceptable methods of contraception
• Significant seasonal variation in asthma or asthma occurring only during episodic exposure to an allergen or a chemical sensitizer
• History of near fatal asthma
• Occurrence of asthma exacerbations or respiratory tract infections in the 6 weeks preceding the screening visit
• Diagnosis COPD
• History of cystic fibrosis, bronchiectasis or alpha-1 antitrypsin deficiency
• Diagnosis of restrictive lung disease
• Patients treated with oral or parenteral corticosteroids in the previous 2 months (3 months for parenteral depot corticosteroids)
• Intolerance or contra-indication to treatment with beta2-agonists and/or inhaled corticosteroids
• Allergy to any component of the study treatments
• Any change in the dose, schedule, formulation or product of an inhaled corticosteroid in the 4 weeks prior to screening visit
• Significant medical history of and/or treatments for cardiac, renal, neurological, hepatic, endocrine diseases, or any laboratory abnormality ;
• Patients with abnormal QTc