An Efficacy and Safety Study of Fluticasone Furoate/Vilanterol 100/25 Microgram (mcg) Inhalation Powder, Fluticasone Propionate/Salmeterol 250/50 mcg Inhalation Powder, and Fluticasone Propionate 250 mcg Inhalation Powder in Adults and Adolescents With Persistent Asthma

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.