- Current anti-asthma therapy: All subjects must be using an ICS with or without LABA for at least 8 weeks and a stable dose for at least 4 weeks before Visit 1 (Screening and Run-in Visit). Two populations are eligible for enrolment: Subjects maintained on ICS monotherapy (Budesonide 400 mcg to 800 mcg BID or equivalent) for at least 8 weeks and a stable dose for at least 4 weeks before Visit 1 (Screening and Run-in Visit) or Subjects maintained on an ICS/LABA combination product (e.g., NEUMOTEROL 200/6 BID or 400/12 mcg BID or equivalent by other combination products or by separate inhalers) for at least 8 weeks and a stable dose for at least 4 weeks before Visit 1 (Screening and Run-in Visit). Subjects taking budesonide/formoterol as needed must switch to maintenance dosing (excluding the highest dose) with use of a SABA for symptom relief at least 8 weeks and a stable dose for at least 4 weeks before Visit 1 (Screening and Run-in Visit). NOTE: Subjects on low dose ICS monotherapy should only be enrolled, if, in the opinion of the investigator, after review of their medical history and clinical examination, they will be able to benefit from both an increase in ICS dose and the addition of LABA therapy arising from and ICS/LABA combination