Fig. 1. Linear regression analysis was performed for the measurements of %FEV₁ (A, D), %FEF₅₀ (B, E), and FeNO (C, F, I) before and during mepolizumab treatment. For Case 3, the analysis was performed for the measurements (G, H, I) before and during omalizumab treatment. Fitted lines by regression are depicted. %FEV₁, % of predicted forced expiratory volume in 1 second; %FEF₅₀, % of predicted forced expiratory flow at 50% of forced lung capacity; FeNO, fractional exhaled nitric oxide.