 During the Study Period, subjects will document their daily asthma symptom scores, treatment regimens, concomitant medications, PEF records, and adverse events if any. Three Clinical Visits are to be conducted, for measurement of treatment efficacy with serial spirometry at Clinical Visit 1 and 3; for monitoring safety and compliance at Clinical Visit 1, 2 and 3; and for evaluating pharmacokinetic profiles in part of the study population greater than or equal to 6 subjects per Arm using a population PK approach PPK with a sparse blood sampling regimen at Clinical Visit 3. 