['asthma']
['fluticasone furoate/vilanterol 100/25 mcg via ellipta inhaler', 'placebo inhalation powders via ellipta inhaler', 'fluticasone propionate/salmeterol 250/50 mcg via accuhaler/diskus inhaler', 'placebo inhalation powder via accuhaler/diskus inhaler', 'fluticasone propionate 250 mcg via accuhaler/diskus inhaler']

        Inclusion Criteria

          -  Subjects must give their signed and dated written informed consent to participate
             prior to commencing any study related activities.

          -  Subjects must be outpatients >=12 years of age at Visit 1 who have had a diagnosis of
             asthma, as defined by the National Institutes of Health, for at least 12 weeks prior
             to Visit 1 (Note: Countries with local restrictions prohibiting enrollment of
             adolescents will enroll subjects >=18 years of age only).

          -  Subjects may be male or an eligible female. An eligible female is defined as having
             non-childbearing potential or having childbearing potential and a negative urine
             pregnancy test at Screening and agrees to use an acceptable method of birth control
             consistently and correctly.

          -  Subjects must have a FEV1 of >=80% of the predicted normal value.

          -  Subjects are eligible if they have received mid dose ICS plus LABA (equivalent to
             FP/salmeterol 250/50 twice daily or an equivalent combination via separate inhalers)
             for at least the 12 weeks immediately preceding Visit 1.

          -  All subjects must be able to replace their current SABA treatment with
             albuterol/salbutamol aerosol inhaler at Visit 1 for use, as needed, for the duration
             of the study. Subjects must be able to withhold albuterol/salbutamol for at least 6
             hours prior to study visits.

          -  If in the opinion of the investigator the subject's asthma is well controlled.
             Exclusion Criteria

          -  History of Life-Threatening Asthma, defined for this protocol as an asthma episode
             that required intubation and/or associated with hypercapnea, respiratory arrest or
             hypoxic seizures within the last 5 years.

          -  Culture-documented or suspected bacterial or viral infection of the upper or lower
             respiratory tract, sinus or middle ear that is not resolved within 4 weeks of Visit 1
             and led to a change in asthma management or in the opinion of the Investigator,
             expected to affect the subject's asthma status or the subject's ability to participate
             in the study.

          -  Any asthma exacerbation requiring oral corticosteroids within 12 weeks of Visit 1 or
             resulting in an overnight hospitalization requiring additional treatment for asthma
             within 6 months prior to Visit 1.

          -  A subject must not have current evidence of Atlectasis, Bronchopulmonary dysplasia,
             Chronic bronchitis, Chronic obstructive pulmonary disease, Pneumonia, Pneumothorax,
             Interstitial lung disease, or any evidence of concurrent respiratory disease other
             than asthma

          -  A subject must not have any clinically significant, uncontrolled condition or disease
             state that, in the opinion of the investigator, would put the safety of the subject at
             risk through study participation or would confound the interpretation of the results
             if the condition/disease exacerbated during the study.

          -  A subject must not have used any investigational drug within 30 days prior to Visit 1
             or within five half-lives (t½) of the prior investigational study, whichever is longer
             of the two.

          -  Any adverse reaction including immediate or delayed hypersensitivity to any
             beta2-agonist, sympathomimetic drug, or any intranasal, inhaled, or systemic
             corticosteroid therapy. Known or suspected sensitivity to the constituents of RELVAR™
             ELLIPTA inhaler, SERETIDE™ ACCUHALER/DISKUS inhaler or FP 250.

          -  History of severe milk protein allergy.

          -  Administration of prescription or non-prescription medication that would significantly
             affect the course of asthma, or interact with study drug.

          -  A subject must not be using or require the use of immunosuppressive medications during
             the study.

          -  A subject will not be eligible if he/she or his/her parent or legal guardian has any
             infirmity, disability, disease, or geographical location which seems likely (in the
             opinion of the Investigator) to impair compliance with any aspect of this study
             protocol, including visit schedule and completion of the daily diaries.

          -  Current tobacco smoker or has a smoking history of 10 pack-years (20 cigarettes/day
             for 10 years). A subject may not have used inhaled tobacco products or inhaled
             marijuana within the past 3 months (e.g., cigarettes, cigars, electronic cigarettes,
             or pipe tobacco).

          -  A subject will not be eligible for this study if he/she is an immediate family member
             of the participating investigator, sub-investigator, study coordinator, or employee of
             the participating investigator.
      