Chronic obstructive pulmonary disease, biological agents and small molecules: where do we stand?

Chronic Obstructive Pulmonary Disease (COPD) is characterized by persistent respiratory symptoms and airflow limitation. A subset of patients exhibits eosinophilic inflammation, which has been shown to impact disease severity and exacerbation frequency. This review aims to provide an update on the role of eosinophils in COPD and the efficacy of biologics targeting inflammation. Furthermore, we will explore eosinophilia as a biomarker for COPD outcomes. The findings highlight the potential of biologics in managing COPD. We conducted a review of the English-language literature from the beginning of the databases reviewed through April 2025. In COPD there is a close interplay between inflammation, lung damage and multimorbidities, mechanisms that determine a lower efficacy of biologics. Patients currently eligible for biologics are only the subpopulation with eosinophilic airway inflammation, but biologics that target broad-acting epithelial cytokines might have a greater efficacy in a complex disease such as COPD. This is because their mechanism of action is not limited to modulation of eosinophilic inflammation alone but to multiple driver pathways. Looking forward, there is an urgent need to identify new biomarkers for better patient selection to improve the impact of biologics, which is still not yet fully satisfactory.