Change in FEV1. (a) Change from pre-dose in FEV1 (L) measured at baseline; (b) Change from pre-dose in FEV1 (L) measured at week 12. FEV1, forced expiratory volume in the first second; BDP/FF, beclomethasone dipropionate/formoterol fumarate; FP/S, fluticasone propionate/salmeterol. p < 0.001 at each time point compared to baseline pre-dose for both treatments and at each visit. ***p < 0.001 between treatments.