Benralizumab attenuates airway eosinophilia in prednisone-dependent asthma

[...]our findings indicate that targeting IL-5Rα+ cells interferes with and attenuates IL-5–driven eosinophilopoietic processes that may contribute to persistent airway eosinophilia in patients with severe, prednisone-dependent asthma. Nonadherent MNCs were immunostained for flow cytometry and cultured for 14-day semisolid methylcellulose colony-forming assay as detailed below.Sputum induction and processing Sputum was induced and processed using the method described by Pizzichini et al.E3 Cytospins were prepared from the pelleted cells on glass slides and stained with Diff-Quik (American Scientific Products, McGaw Park, Ill) for differential counts, enumerated by an observer blinded to the treatment period.Eosinophil colony-forming assay Methylcellulose culture assays were conducted as previously described.E4Fluorescence immunocytochemistry for EoP cells Nonadherent MNCs from blood- and sputum-extracted cells were stained for EoP cells and ILC2 enumerations with antibodies to surface markers Lin-eFluor450, FcεR1-eFluor450, CD45-AmCyan, ST2-PE, IL7Rα (CD127)-PE-CF594, CD34-allophycocyanin (PE-Cy7), and CD125 (IL-5Rα)-phycoerythrin (APC) or relevant isotype controls (BD Bioscience, ON, Canada). Because of the small sample size, drug treatment regimens (Q4W, n = 4 and every 8 weeks, first 3 doses Q4W, n = 6) were combined and compared with placebo (n = 7). Characteristic Benralizumab (n = 11) Placebo (n = 7) Age (y) 46.4 ± 9.4 58 ± 10.2 Sex Male 9 (82) 1 (14) Female 2 (18) 6 (86) Body mass index (kg/m2) 32.6 (27.2-43.5) 29.2 (26.2-47.8) Duration of asthma (y) 12.6 ± 15.4 10.5 ± 9.4 Oral corticosteroid dosage (prednisone equivalent; mg/d) 10 (7.5-40) 10 (10-25) Inhaled corticosteroid dosage (fluticasone equivalent; μg/d) 1625 (1000-3000) 1625 (1000-3125) Long-acting β2-agonist 11 (100) 7 (100) Leukotriene-receptor antagonist 4 (36) 1 (14) FEV1 before bronchodilation Absolute (L) 2.28 ± 0.49 1.85 ± 0.36 % of predicted normal value 60.1 ± 9.9 69.2 ± 3.9 FVC (L) 3.76 ± 0.87 2.58 ± 0.51 FEV1/FVC 62 ± 10 72 ± 3 FEV1 reversibility 10.1 ± 3.3 11.5 ± 3.4 Smoking history Current 0 0 Ex-smoker 1 (9) 2 (29) Never smoker 10 (91) 5 (71) Cigarette pack-years 3.75 (3.75-3.75) 6.9 (5.80-8.00) Comorbidities Hypertension 4 (36) 4 (57) Hyperlipidemia 1 (9) 3 (43) Statin use 0 (0) 3 (43) Blood eosinophils (cells/μL) 440 (210-780) 370 (290-670) Table E1 Demographic and clinical characteristics of patients at baseline EDN and IL-5 concentrations Benralizumab V6 Benralizumab V14 Pl