This is a pharmacokinetic comparison of CHF 1535 50/6 NEXT DPI versus the free combination of Beclomethasone DPI and Formoterol DPI in children (5 to 11 years old) of a formulation already approved in adults.

Pharmacokinetic study in asthmatic children 5 to 11 years old treated with either a fixed combination of beclomethasone 50 ug/unit dose plus formoterol fumarate 6 ug/unit dose via the NEXT DPI dry powder inhaler or a free combination of Beclomethasone 100 ug DPI and Formoterol 6 ug DPI according to a cross-over design.

Inclusion Criteria:

1. Male/Female children aged 5 -11y
2. Written informed consent obtained by parents/legal representative (according to local regulation) and by the minor (age and local regulation permitting).
3. Children with stable asthma
4. Children with asthma on regular treatment with ICS or using short-acting inhaled beta2-agonists as reliever to control asthma symptoms
5. Forced expiratory volume in one second (FEV1) > 70% of predicted values (% pred) after withholding beta2-agonists treatment for a minimum of 4 h prior to each study treatment.
6. A cooperative attitude and ability to be trained about the proper use of DPI and compliant to study procedures.

Exclusion Criteria:

1. Past or present diagnoses of cardiovascular, renal or liver disease
2. Known hypersensitivity to the active treatments
3. Exacerbation of asthma symptoms within the previous 4 weeks
4. Inability to perform the required breathing technique and blood sampling
5. Hospitalization due to exacerbation of asthma within 1 month prior to screening (visit 1)
6. Lower respiratory tract infection within 1 month prior to screening (visit 1)
7. Disease (other than asthma) which might influence the outcome of the study
8. Obesity, i.e. > 97% weight percentile by local standards