Efficacy and Safety of CHF 5993 100/6/12.5 μg HFA-152a pMDI in Patients With Asthma Uncontrolled on Medium Doses of Inhaled Corticosteroids in Combination With Long-acting ß2-agonists

Inclusion Criteria: * Subjects must meet all of the following inclusion criteria to be eligible for enrolment into the study: 1. Subjects must provide written informed consent prior to any study-related procedures; 2. Subjects must be male or female Chinese aged ≥18 and ≤75 years; 3. Subjects must have a documented history of asthma for at least 1 year and asthma must have been diagnosed before the subject's age of 40; 4. Subjects must have uncontrolled asthma, receiving double therapy only on medium doses of ICS in combination with LABA at a stable dose for at least 4 weeks prior to screening; 5. Subjects must have a pre-bronchodilator FEV1 \<80% of their predicted normal value, after appropriate wash out from bronchodilators at the screening visit. 6. Subjects must have a positive response to a reversibility test at screening. 7. Subjects must have uncontrolled asthma evidenced by a score at the ACQ-7 ≥1.5 (this criterion must be met at screening and at randomisation). Exclusion Criteria: * Subjects meeting any of the following criteria will be excluded from study enrolment: 1. Subjects who have a history of near fatal asthma or of a past hospitalisation for status asthmaticus or severe asthma exacerbation which, in the judgement of the Investigator, may place the subject at undue risk; 2. Subjects who have undergone hospitalisation, emergency room visit or use of systemic corticosteroids for an asthma exacerbation in the 4 weeks prior to the screening visit or during the run-in period; 3. Subjects with any asthma exacerbation or respiratory tract infection in the 4 weeks prior to the screening visit or during run-in period; 4. Subjects with any change in dose, schedule or formulation of the combination ICS+LABA in the 4 weeks prior to the screening visit; 5. Subjects who have used systemic corticosteroid medication in the 4 weeks prior to screening or slow-release corticosteroids in the 12 weeks prior to screening; 6. Subjects who have a history of a diagnosis of chronic obstructive pulmonary disease (COPD) (according to the Global Initiative for Chronic Obstructive Lung Disease \[GOLD\] document), cystic fibrosis, bronchiectasis or alpha- 1 antitrypsin deficiency or any other significant lung disease which may interfere with study evaluations; 7. Subjects who are current smokers; ex-smokers with total cumulative exposure ≥10 pack-years; having stopped smoking 1 year or less prior to the screening visit; 8. Subjects who are treated with monoclonal antibodies (e.g., anti-immunoglobulin (Ig)E or anti-IgG antibodies) or biological drugs; 9. Subjects who have received an investigational drug within 2 months or six half-lives (whichever is greater) prior to the screening visit, or have been previously randomised in this study, or are currently participating in another clinical study.