RT Journal Article SR Electronic T1 Heterogeneity of treatment response in bronchiectasis clinical trials JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 2100777 DO 10.1183/13993003.00777-2021 A1 Oriol Sibila A1 Elena Laserna A1 Amelia Shoemark A1 Lidia Perea A1 Diana Bilton A1 Megan L. Crichton A1 Anthony De Soyza A1 Wim G. Boersma A1 Josje Altenburg A1 James D. Chalmers YR 2021 UL http://erj.ersjournals.com/content/early/2021/09/16/13993003.00777-2021.abstract AB Introduction Recent randomised clinical trials (RCTs) in Bronchiectasis have failed to reach their primary endpoints, suggesting a need to reassess how we measure treatment response. Exacerbations, quality of life (QOL) and lung function are the most common endpoints evaluated in bronchiectasis clinical trials. We aimed to determine the relationship between responses in terms of reduced exacerbations, improved symptoms and lung function in bronchiectasis.Methods We evaluated treatment response in 3 RCTs that evaluated mucoactive therapy (inhaled Mannitol), an oral anti-inflammatory/antibiotic (Azithromycin) and an inhaled antibiotic (Aztreonam). Treatment response was defined by absence of exacerbations during follow-up, an improvement of QOL above the minimum clinically important difference (MCID) and an improvement in FEV1 of ≥100 mL from baseline.Measurements and main results Cumulatively the three trials included 984 patients. Changes in FEV1, QOL and exacerbations were heterogeneous in all trials analysed. Improvements in QOL were not correlated to changes in FEV1 in the azithromycin and aztreonam trials (r=−0.17, p=0.1 and r=0.04, p=0.4) and weakly correlated in the mannitol trial (r=0.22, p<0.0001). An important placebo effect was observed in all trials, especially regarding improvements in QOL. Clinical meaningful lung function improvements were rare across all trials evaluated, suggesting that FEV1 is not a responsive measure in bronchiectasis.Conclusions Improvements in lung function, symptoms and exacerbation frequency are dissociated in bronchiectasis. FEV1 is poorly responsive and poorly correlated with other key outcome measures. Clinical parameters are poorly predictive of treatment response suggesting the need to develop biomarkers to identify respondersFootnotesThis manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.Conflict of interest: Dr. Sibila has nothing to disclose.Conflict of interest: Dr. Laserna has nothing to disclose.Conflict of interest: Dr. Shoemark has nothing to disclose.Conflict of interest: Dr. Perea has nothing to disclose.Conflict of interest: Dr. Bilton has nothing to disclose.Conflict of interest: Miss Crichton reports personal fees from Astra Zeneca, outside the submitted work; .Conflict of interest: Dr. De Soyza reports grants, personal fees and other from AstraZeneca, Bayer, Chiesi, Grifols, GSK, Insmed, Pfizer, Novartis, Medimmune, Zambon, outside the submitted work; .Conflict of interest: Dr. Boersma has nothing to disclose.Conflict of interest: Dr. Altenburg has nothing to disclose.Conflict of interest: Dr. Chalmers reports grants and personal fees from Glaxosmithkline, grants from Astrazeneca, grants from Bayer Healthcare, grants and personal fees from Grifols, personal fees from Aradigm, personal fees from Pfizer, personal fees from Napp, grants and personal fees from Boehringer-Ingelheim, grants and personal fees from Insmed, outside the submitted work; .