The MUSIC trial: harmonising our understanding of inhaled corticosteroids and the COPD airway microbiome

COPD is projected to affect more than 600 million people by 2050 [1] and contributes to approximately 5% of global deaths annually [2]. Acute exacerbations of COPD (AECOPD) are associated with accelerated loss of lung function, decreased quality of life, increased risk of cardiovascular events and mortality. In addition to the use of long-acting β₂-agonist (LABA) and long-acting muscarinic antagonist (LAMA) inhaled medications, the 2025 Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines advocate for the addition of inhaled corticosteroids (ICS) to form "triple inhaled therapy" (i.e. LABA+LAMA+ICS) in high-risk COPD patients with blood eosinophil counts of ≥100 cells per μL, as this serves as a predictive biomarker for clinical response to ICS therapy [3].