Response to Correspondence ALL-2023-01107 “Short-course subcutaneous treatment with PQ Grass strongly improves symptom and medication scores in grass allergy”P.J. de Kam1, S. Zielen2, J.A. Bernstein3, U. Berger4, M. Berger5, M. Cuevas6, D. Cypcar7, A. Fuhr-Horst8, W.A. Greisner9, M. Jandl10, S. Laßmann11, M. Worm12, J. Matz13, E. Sher14, C. Smith15, G.C. Steven16, R. Mösges17,18, M.H. Shamji19,20, L. DuBuske21, F. Borghese1, K. Oluwayi1, T. Zwingers1, M. Seybold1, O. Armfield1, M.D. Heath1, S.J. Hewings1, M.F. Kramer1, M.A. Skinner1Allergy Therapeutics plc, Worthing, United KingdomChildren and Adolescents Dept., Allergology, Pulmonology & Cystic fibrosis, Goethe University, Frankfurt, GermanyBernstein Clinical Research Center, LLC, Cincinnati, OH, United States of AmericaAerobiology and Pollen Research Unit, Dept. Oto-Rhino-Laryngology, Medical University Vienna, Vienna, Austria.Wiener Gesundheitsverbund, Hospital Hietzing, Department of Otorhinolaryngology, Vienna, AustriaClinic and Polyclinic of Otorhinolaryngology, University Clinic Carl Gustav Carus, TU Dresden, GermanyAllergy Partners of Western North Carolina, Asheville, NC, United States of AmericaENT Research- Institut für klinische Studien, Essen, GermanyBluegrass Allergy Research, Lexington, KY, United States of AmericaHamburger Institut für Therapieforschung GmbH, Hamburg, GermanyStudienzentrum Dr. Sabine Laßmann, Saalfeld, GermanyUniversitätsmedizin Berlin, Department of Dermatology and Allergy - Charite Campus Mitte, Berlin, GermanyChesapeake Clinical Research, Inc. White Marsh, MD, United States of AmericaAllergy Partners of New Jersey, Ocean, NJ, United States of AmericaCertified Research Associates, Cortland, NY, United States of AmericaAllergy Asthma & Sinus Center, S.C., Greenfield, WI, United States of AmericaIMSB (Institute of Computational Biology and Medical Statistics), University at Cologne, Cologne, GermanyClinCompetence, Cologne, GermanyImmunomodulation and Tolerance Group, Allergy and Clinical Immunology, Department of National Heart and Lung Institute, Imperial College London, London, United KingdomAsthma UK Centre in Allergic Mechanisms of Asthma, Imperial College London, London, United KingdomDivision of Allergy and Immunology, Department of Internal Medicine, George Washington University Hospital, Washington, DC, United States of America

CORRIGENDUMDate: 09 Feb 2024Manuscript number: ALL-2023-01229.R1Title of Article: Response to Correspondence ALL-2023-01107 “Short-course subcutaneous treatment with PQ Grass strongly improves symptom and medication scores in grass allergy”Authors: P.J. de Kam1, S. Zielen2, J.A. Bernstein3, U. Berger4, M. Berger5, M. Cuevas6, D. Cypcar7, A. Fuhr-Horst8, W.A. Greisner9, M. Jandl10, S. Laßmann11, M. Worm12, J. Matz13, E. Sher14, C. Smith15, G.C. Steven16, R. Mösges17,18, M.H. Shamji19,20, L. DuBuske21, F. Borghese1, K. Oluwayi1, T. Zwingers1, M. Seybold1, O. Armfield1, M.D. Heath1, S.J. Hewings1, M.F. Kramer1, M.A. Skinner1Allergy Therapeutics plc, Worthing, United KingdomChildren and Adolescents Dept., Allergology, Pulmonology & Cystic fibrosis, Goethe University, Frankfurt, GermanyBernstein Clinical Research Center, LLC, Cincinnati, OH, United States of AmericaUniversity of Innsbruck, Department of Botany, Innsbruck, AustriaWiener Gesundheitsverbund, Hospital Hietzing, Department of Otorhinolaryngology, Vienna, AustriaClinic and Polyclinic of Otorhinolaryngology, University Clinic Carl Gustav Carus, TU Dresden, GermanyAllergy Partners of Western North Carolina, Asheville, NC, United States of AmericaENT Research- Institut für klinische Studien, Essen, GermanyBluegrass Allergy Research, Lexington, KY, United States of AmericaHamburger Institut für Therapieforschung GmbH, Hamburg, GermanyStudienzentrum Dr. Sabine Laßmann, Saalfeld, GermanyUniversitätsmedizin Berlin, Department of Dermatology and Allergy - Charite Campus Mitte, Berlin, GermanyChesapeake Clinical Research, Inc. White Marsh, MD, United States of AmericaAllergy Partners of New Jersey, Ocean, NJ, United States of AmericaCertified Research Associates, Cortland, NY, United States of AmericaAllergy Asthma & Sinus Center, S.C., Greenfield, WI, United States of AmericaIMSB (Institute of Computational Biology and Medical Statistics), University at Cologne, Cologne, GermanyClinCompetence, Cologne, GermanyImmunomodulation and Tolerance Group, Allergy and Clinical Immunology, Department of National Heart and Lung Institute, Imperial College London, London, United KingdomAsthma UK Centre in Allergic Mechanisms of Asthma, Imperial College London, London, United KingdomDivision of Allergy and Immunology, Department of Internal Medicine, George Washington University Hospital, Washington, DC, United States of AmericaName of the Corresponding Author: Pieter-Jan De Kam

Background: In preschoolers, performing an acceptable spirometry and measuring bronchodilator response (BDR) is challenging; impulse oscillometry (IOS) may be an alternative to spirometry. However, there is still no consensus in standardization of BDR for IOS in young children. Objective: The objective of the study was to identify optimal thresholds to define a positive BDR test with IOS. Methods: Young infants aged 3 to 6 years with suspected asthma were evaluated in a real life setting with both IOS and spirometry pre- and post-BDR. The BDR was defined as positive when the change of FEV1 was ≥12% and/or ≥200 mL. Results: Among 72 patients (age 4.98 ± 0.94 years; 64% boys), 36 (age 5.15 ± 0.99 years; 64% boys) were selected for the subsequent analysis according to ATS / ERS quality criteria of measurements. The spirometric BDR was found positive in seven subjects (19.4%). In IOS, the mean decrease in R5 and AX was 19.86% ± 10.04 and 44% ± 22.10, and the mean increase in X5 was 23.28% ± 17.82, respectively. A decrease in R5 of 25.7% (AUC 0.77, p = 0.03) and an increase in X5 of 25.7% (AUC 0.75, p = 0.04) showed the best combination of sensitivity and specificity to detect an increase of FEV1 ≥12% and/or ≥200 mL. Conclusion: The IOS may present a valid alternative to spirometry to measure BDR in preschool children. We are considering a decrease of 26% in R5 and an increase of 26% in X5 as diagnostic threshold for BDR.