Exception 1: Based upon the investigator's judgment that there is no inherent harm in changing the subject's current ICS/LABA therapy and the subject provides consent, subjects on inhaled Fluticasone propionate/salmeterol DPI ≥ 1000 mcg/day, or Fluticasone propionate/salmeterol HFA ≥ 880 mcg/day, or Fluticasone propionate/Formoterol ≥ 1000 mcg/day,or Beclomethasone dipropionate/Formoterol ≥ 400 mcg/day, or Budesonide/formoterol HFA ≥ 640 mcg/day, or Budesonide/formoterol DPI ≥ 800 mcg/day, or Mometasone furoate/formoterol MDI ≥ 800 mcg/day or subjects on a qualifying ICS dose plus a long-acting β2-agonists (LABA) administered via separate inhalers, may be switched to a qualifying dose of fluticasone propionate provided the subjects will not participate in the PK portion of the study.