Inclusion criteria:

1. Male or female subjects at least 12 years or older (females less than one year post-menopausal must have a negative serum or urine pregnancy test recorded at the screening visit prior to the first dose of study medication, be non-lactating, and willing to use adequate and highly effective methods of contraception throughout the study if they are sexually active. A highly effective method of birth control is defined as those which result in a low failure rate (i.e. less than 1% per year) when used consistently and correctly such as sterilization, implants, injectables, combined oral contraceptives, some IUDs (Intrauterine Device, hormonal), sexual abstinence or vasectomised partner).
2. Known history of mild to moderate-severe persistent, reversible asthma for ≥ 6 months prior to the screening visit.

3. Demonstrate a FEV1 of ≥40% to ≤85% for predicted normal values (Quanjer et al, 19931) during the screening phase following appropriate withholding of asthma medications (if applicable).

   • No β2-agonist use on day of screening.
   • No use of inhaled combination asthma therapy on day of screening.
   • Inhaled corticosteroids are allowed on day of screening.
4. Documented reversibility of ≥15% in FEV1 in the screening phase.
5. Demonstrate satisfactory technique in the use of the study medications.
6. Willing and able to enter information in the diary and attend all study visits.
7. Willing and able to substitute study medication for their pre study prescribed asthma medication for the duration of the study.
8. Written informed consent obtained

Exclusion criteria:

1. Near fatal or life-threatening (including intubation) asthma within the past year.
2. Hospitalization or an emergency visit for asthma within the past year.
3. History of systemic (oral or parenteral) corticosteroid medication within 1 month before the Screening Visit.
4. History of omalizumab use within the past 6 months.
5. History of leukotriene receptor antagonist use, e.g. montelukast, or theophylline within the past week.
6. Current evidence or history of any clinically significant disease or abnormality including uncontrolled coronary artery disease, congestive heart failure, myocardial infarction, or cardiac dysrhythmia. 'Clinically significant' is defined as any disease that, in the opinion of the Investigator, would put the patient at risk through study participation, or which would affect the outcome of the study.
7. In the investigators opinion a clinically significant upper or lower respiratory infection within 4 weeks prior to the Screening Visit.
8. Significant, non-reversible, active pulmonary disease (e.g., chronic obstructive pulmonary disease (COPD), cystic fibrosis, bronchiectasis, tuberculosis).
9. Known Human Immunodeficiency Virus (HIV)-positive status.
10. A smoking history equivalent to "10 pack years" (i.e., at least 1 pack of 20 cigarettes /day for 10 years or 10 packs/day for 1 year, etc.).
11. Current smoking history within 12 months prior to the Screening Visit.
12. Current evidence or history of alcohol and/or substance abuse within 12 months prior to the Screening Visit.
13. Subjects who have taken B-blocking agents, tricyclic antidepressants, monoamine oxidase inhibitors, astemizole (Hismanal), quinidine type antiarrhythmics, or potent CYP 3A4 inhibitors such as ketoconazole within the past week.
14. Current use of medications that will have an effect on bronchospasm and/or pulmonary function.
15. Current evidence or history of hypersensitivity or idiosyncratic reaction to test medications or components.
16. Receipt of an investigational drug within 30 days of the Screening Visit (12 weeks if an oral or injectable steroid).
17. Current participation in a clinical study