• Change in Forced Expiratory Volume in 1 s(FEV-1) over 12 weeks recorded in electronic diary.
• Discontinuation due to lack of efficacy.

• Other pulmonary function tests including forced vial capacity (FVC) and peak expiratory flow rate (PEFR).
• Clinical endpoints (frequency of asthma exacerbations and patient data captured in diary including daily morning and evening PEFR).
• Serial FEV-1 area under the curve (AUC).
• Safety variable including adverse events, ECGs clinical laboratory tests and vital signs.

The purpose of this study is to compare the efficacy and safety of the fixed combination asthma drug Flutiform with its two components administered alone, fluticasone propionate and formoterol fumarate, and with placebo in adult and adolescent patients with moderate to severe asthma.

• Drug: Fluticasone propionate/Formoterol fumarate
• Other: Placebo

Ages eligible for study: 12 years and above; genders eligible for study: both; prior steroid use: steroid-requiring

Inclusion Criteria:

• History of asthma for at least 12 months.
• Documented use of inhaled corticosteroid for at least 4 weeks prior to Screening Visit Demonstrate FEV-1 of 40-80% of predicted normal values at Screening and Baseline Visit.
• Documented reversibility of 15% within 12 months of Screening visit or at Screening Visit (15% increase from pre-FEV-1 levels following albuterol inhalation or nebulized albuterol administration).
• Symptoms of Asthma during Run-in.
• Females of childbearing potential must have a negative urine pregnancy test at Screening and Baseline Visits. Females are eligible only if they are not pregnant or lactating, and are either sterile or using acceptable methods of contraception
• Must otherwise be healthy.
• Provide written informed consent. Wishes of minors must be respected.

Exclusion Criteria:

• Life-threatening asthma within past year or during Run-In Period.
• History of systemic corticosteroid medication within 3 months before Screening Visit.
• History of omalizumab use within past 6 months.
• History of leukotriene receptor antagonist use, e.g. montelukast, within past week.
• Current evidence or history of any clinically significant disease or abnormality including uncontrolled hypertension, uncontrolled coronary artery disease, congestive heart failure, myocardial infarction, or cardiac dysrhythmia.
• Upper or lower respiratory infection within 4 weeks prior to Screening visit or during Run-In Period
• Significant, non-reversible, pulmonary disease (e.g., chronic obstructive pulmonary disease [COPD], cystic fibrosis, bronchiectasis).
• Known Human Immunodeficiency Virus (HIV)-positive status.
• Smoking history equivalent to "10 pack years".
• Current smoking history within 12 months prior to Screening Visit.
• Current evidence or history of alcohol and/or substance abuse within 12 months prior to Screening visit.
• Patients who are confined in institution.