Patient description: A 39-year-old man came to the clinic with cough and shortness of breath that was not relieved by his inhaler. He had these symptoms for 5 days during the past 2 weeks. He doubled his oral corticosteroids in the past week. He is a chef with a history of asthma for 3 years, suffering from frequent cough, wheezing, and shortness of breath and chest tightness. The symptoms become more bothersome within 1-2 hours of starting work every day and worsen throughout the work week. His symptoms improve within 1-2 hours outside the workplace. Spirometry was performed revealing a forced expiratory volume in the first second (FEV1) of 63% of the predicted. His past medical history is significant for seasonal allergic rhinitis in the summer. He doesn't smoke or use illicit drugs. His family history is significant for asthma in his father and sister. He currently uses inhaled corticosteroid (ICS) and fluticasone 500 mcg/salmeterol 50 mcg, one puff twice daily.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Asthma Screening Capable of giving signed informed consent Male or female subjects aged >= 18 years of age at Screening (Visit 1). A female subject is eligible to participate if she is not pregnant not breastfeeding, and at least one of the following conditions applies; Not a woman of childbearing potential (WOCBP); A WOCBP who agrees to follow the contraceptive guidance during the treatment period and for the duration of the study A diagnosis of persistent asthma for at least 12 weeks prior to Screening (Visit 1) All subjects must be using an ICS with or without LABA for at least 12 Weeks prior to Visit 1. Two populations are eligible for enrolment: Subjects maintained on a stable ICS low to medium-dose fluticasone propionate 100 to 250 mcg twice daily or equivalent for at least 4 weeks prior to Visit 1; Subjects maintained on a stable dose of an ICS/LABA low-dose combination product (e.g., 100/50 mcg twice daily or equivalent, via other combination products or via separate inhalers) for at least 4 weeks prior to Visit 1 Subjects must have a best pre-bronchodilator FEV1 of 50% of their predicted normal value. Predicted values will be based upon Global Lung Function Initiative (GLI) equations for spirometry reference values Subjects must demonstrate >=12% and 200 milliliter reversibility of FEV1 within 10 to 40 minutes following 4 inhalations of albuterol/salbutamol inhalation aerosol (or an equivalent nebulized treatment with albuterol/salbutamol solution) at Visit 1. Subjects that have documented reversibility meeting the above within the last 6 months prior to Visit 1 (Screening) will be eligible and do not need to repeat the reversibility assessment at Visit 1 (Screening). Reversibility measurements, including historical reversibility, should follow/meet the recommendations of the American Thoracic Society (ATS)/ European Respiratory Society (ERS) Task force: Standardization of Lung Function Testing All subjects must be able to replace their current short-acting bronchodilator (SABA), or other reliever strategy, with albuterol/salbutamol at Visit 1 (Screening), to be used only on an as-needed basis for the duration of the study. Each subject must be judged capable of withholding albuterol/salbutamol for at least 6 hours prior to performing spirometric evaluations Subjects must be able to read and complete the questionnaire and electronic daily diary themselves. Screening  Defined for this protocol as an asthma episode that required intubation and/or was associated with hypercapnia, respiratory arrest or hypoxic seizures within the last 5 years An asthma exacerbation requiring systemic corticosteroids within 12 weeks prior to Visit 1. Any exacerbation requiring overnight hospitalization requiring additional treatment for asthma within 6 months prior to Visit 1 Current tobacco smoker or has a smoking history of >=10 pack-years (20 cigarettes/day for 10 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, is expected to affect the subject's asthma status or the subject's ability to participate in the study Women who are pregnant or lactating or are planning on becoming pregnant during the study A subject must not have current evidence of: Atelectasis segmental or larger; Bronchopulmonary dysplasia; Chronic bronchitis; Chronic obstructive pulmonary disease (COPD) current or past diagnosis including asthma/COPD overlap; 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 participant at risk through study participation or would confound the interpretation of the efficacy 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 (t1/2) of the prior investigational study, whichever is longer of the two periods Any adverse reaction including immediate or delayed hypersensitivity to any beta2-agonist, sympathomimetic drug, or any intranasal, inhaled, or systemic corticosteroid therapy, or excipients used with fluticasone furoate/vilanterol 100/25 or fluticasone furoate 100 (i.e., drug, lactose or magnesium stearate)