Blood eosinophil counts as a guide for COPD treatment strategies

A major goal of chronic obstructive pulmonary disease (COPD) care is prevention of exacerbations. 1 Global Initiative for Chronic Obstructive Lung Disease, Global strategy for the diagnosis, management and prevention of chronic obstructive lung disease. http://www.goldcopd.com (accessed Dec 12, 2017). Google Scholar To achieve this goal, the main pharmacological treatment options are long-acting antimuscarinic agents (LAMAs) alone or combined with long-acting β2 agonists (LABAs), or inhaled corticosteroids in combination with LABAs. 1 Global Initiative for Chronic Obstructive Lung Disease, Global strategy for the diagnosis, management and prevention of chronic obstructive lung disease. http://www.goldcopd.com (accessed Dec 12, 2017). Google Scholar A crucial and much debated issue is how to identify the best option for each patient based on his or her characteristics, which represents the fundamental goal of personalised medicine. 2 Woodruff PG Agusti A Roche N Singh D Martinez FJ Current concepts in targeting chronic obstructive pulmonary disease pharmacotherapy: making progress towards personalised management. Lancet. 2015; 385: 1789-1798 Summary Full Text Full Text PDF PubMed Scopus (176) Google Scholar Blood eosinophil counts could be a useful predictor of response to some pharmacological agents, although the stability of blood eosinophil-defined COPD subtypes is unclear, 3 Casanova C Celli BR de-Torres JP et al. Prevalence of persistent blood eosinophilia: relation to outcomes in patients with COPD. Eur Respir J. 2017; 50 Crossref Scopus (100) Google Scholar , 4 Bafadhel M Pavord ID Russell REK Eosinophils in COPD: just another biomarker?. Lancet Respir Med. 2017; 5: 747-759 Summary Full Text Full Text PDF PubMed Scopus (133) Google Scholar , 5 Gibson PG Variability of blood eosinophils as a biomarker in asthma and COPD. Respirology. 2018; 23: 12-13 Crossref PubMed Scopus (26) Google Scholar as well as to what extent they reflect airway eosinophilic inflammation 6 Negewo NA McDonald VM Baines KJ et al. Peripheral blood eosinophils: a surrogate marker for airway eosinophilia in stable COPD. Int J Chron Obstruct Pulmon Dis. 2016; 11: 1495-1504 Crossref PubMed Scopus (114) Google Scholar , 7 Hastie AT Martinez FJ Curtis JL et al. Association of sputum and blood eosinophil concentrations with clinical measures of COPD severity: an analysis of the SPIROMICS cohort. Lancet Respir Med. 2017; 5: 956-967 Summary Full Text Full Text PDF PubMed Scopus (158) Google Scholar and predict future exacerbations. 3 Casanova C Celli BR de-Torres JP et al. Prevalence of persistent blood eosinophilia: relation to outcomes in patients with COPD. Eur Respir J. 2017; 50 Crossref Scopus (100) Google Scholar , 8 Kim VL Coombs NA Staples KJ et al. Impact and associations of eosinophilic inflammation in COPD: analysis of the AERIS cohort. Eur Respir J. 2017; 50 Crossref Scopus (60) Google Scholar , 9 Zysman M Deslee G Caillaud D et al. Relationship between blood eosinophils, clinical characteristics, and mortality in patients with COPD. Int J Chron Obstruct Pulmon Dis. 2017; 12: 1819-1824 Crossref PubMed Scopus (61) Google Scholar One of the most convincing demonstrations of the role of eosinophils in COPD pathophysiology (at least in some patients) and of their potential as treatment guides comes from the effect of selective anti-eosinophil drugs–ie, anti-IL-5 monoclonal antibodies that reduce exacerbation rates in patients with COPD, an effect that appears more prominent in patients with higher blood eosinophil counts. 10 Pavord ID Chanez P Criner GJ et al. Mepolizumab for eosinophilic chronic obstructive pulmonary disease. N Engl J Med. 2017; 377: 1613-1629 Crossref PubMed Scopus (327) Google Scholar , 11 Brightling CE Bleecker ER Panettieri RA et al. Benralizumab for chronic obstructive pulmonary disease and sputum eosinophilia: a randomised, double-blind, placebo-controlled, phase 2a study. Lancet Respir Med. 2014; 2: 891-901 Summary Full Text Full Text PDF PubMed Scopus (226) Google Scholar Additionally, recently reviewed studies suggest that blood eosinophil counts could also be used to predict response to inhaled corticosteroids. 4 Bafadhel M Pavord ID Russell REK Eosinophils in COPD: just another biomarker?. Lancet Respir Med. 2017; 5: 747-759 Summary Full Text Full Text PDF PubMed Scopus (133) Google Scholar Predictors of exacerbation risk and response to budesonide in patients with chronic obstructive pulmonary disease: a post-hoc analysis of three randomised trialsIn patients with COPD treated with formoterol, blood eosinophil count predicts exacerbation risk and the clinical response to ICS. Full-Text PDF