Purpose of Review: To review current evidence on biologic therapies targeting type 2 inflammation in patients with eosinophilic COPD and respiratory comorbidities who remain uncontrolled despite optimized triple inhaled therapy. Recent Findings: Recent phase 3 trials have shown that dupilumab provides the most consistent benefit in eosinophilic COPD, reducing exacerbations and improving lung function and quality of life. Mepolizumab has shown a more limited effect, mainly on exacerbation reduction, whereas benralizumab has not demonstrated clear clinical benefit. Blood eosinophil count remains the main biomarker for treatment selection. Summary: Biologic therapies are advancing precision medicine in COPD, with dupilumab currently showing the strongest overall evidence. Careful patient selection is essential. Broader phenotyping may further improve management, as comorbidities such as chronic rhinosinusitis may contribute to symptom burden and support a multidisciplinary approach. Future studies should clarify long-term outcomes and optimal biologic selection.

Background: Airway mucus plugging is a key but long-overlooked mechanism of persistent airflow obstruction in both asthma and chronic obstructive pulmonary disease (COPD). Type 2 (T2) cytokines, particularly interleukin (IL)-4 and IL-13, drive goblet cell metaplasia, MUC5AC overexpression, and impaired mucociliary clearance, while eosinophil-derived products increase mucus viscosity and promote plug persistence. Methods: A comprehensive narrative review was conducted by searching PubMed and ClinicalTrials.gov databases from inception to February 2026. Search terms included “mucus plugs,” “mucus plugging,” “biologics,” “dupilumab,” “tezepelumab,” “mepolizumab,” “benralizumab,” “IL-4,” “IL-13,” “MUC5AC,” “quantitative CT,” “functional respiratory imaging,” “asthma,” and “COPD.” Studies were included if they reported original data or systematic evidence on mucus plug quantification, biologic-mediated changes in mucus plug scores, or imaging modalities for mucus assessment in asthma or COPD. Editorials, case reports with fewer than three patients, and studies not available in English were excluded. Two authors (P.-V.M. and A.C.) independently screened titles and abstracts; discrepancies were resolved by consensus. Randomized controlled trials, observational studies, and preclinical studies evaluating mucus plug outcomes and T2-targeted therapies were included. Reference lists of retrieved articles were hand-searched for additional relevant publications. Results: A recent systematic review identified multiple randomized controlled trials and observational studies that showed CT-assessed mucus plug scores go down with biologic therapies targeting the T2 pathway in asthma. Observational data extend this evidence to anti-IL-5/IL-5Rα agents. The VESTIGE trial provided the first functional respiratory imaging evidence of mucus plug resolution with dupilumab. In COPD, the BOREAS/NOTUS and MATINEE trials established the efficacy of dupilumab and mepolizumab in eosinophilic phenotypes; however, differences in inclusion criteria—particularly regarding FeNO thresholds and prior exacerbation burden—may explain divergent effects on lung function endpoints. Mucus plug outcomes have not been evaluated in COPD biologic trials. Quantitative imaging modalities, including HRCT mucus plug scoring, functional respiratory imaging, and hyperpolarized gas MRI, now enable objective assessment of mucus burden. Conclusions: Mucus plugging meets the definition of a treatable trait: it can be measured with CT scoring, it matters clinically, and it responds to T2 cytokine blockade. Adding mucus plug assessment to routine clinical evaluation, together with mucolytic strategies where needed, could move treatment decisions from empirical to biology-based across the asthma–COPD spectrum. Further studies are needed to confirm that mucus plug scoring works as a biomarker of treatment response in COPD and to test whether combining biologics with mucolytics improves outcomes.

Epithelial barrier damage plays a central role in the development and maintenance of allergic inflammation. Rises in the epithelial barrier permeability of airways alter tissue homeostasis and allow the penetration of allergens and other external agents. Different factors contribute to barrier impairment, such as eosinophilic infiltration and allergen protease action—eosinophilic cationic proteins’ effects and allergens’ proteolytic activity both contribute significantly to epithelial damage. In the airways, allergen proteases degrade the epithelial junctional proteins, allowing allergen penetration and its uptake by dendritic cells. This increase in allergen–immune system interaction induces the release of alarmins and the activation of type 2 inflammatory pathways, causing or worsening the main symptoms at the skin, bowel, and respiratory levels. We aim to highlight the molecular mechanisms underlying allergenic protease-induced epithelial barrier damage and the role of immune response in allergic asthma onset, maintenance, and progression. Moreover, we will explore potential clinical and radiological biomarkers of airway remodeling in allergic asthma patients.

Epithelial barrier damage plays a central role in the development and maintenance of allergic inflammation. The rise in airways epithelial barrier permeability alters the tissue homeostasis and allows the allergen and other external agents penetration. Different factors contribute to barrier impairment, such as eosinophilic infiltrate and allergens proteases action: the eosinophilic cationic proteins and the allergens' proteolytic activity have a central role in contributing to epithelial damage. In the airways, the allergens proteases degrade the epithelial junctional proteins allowing the allergen penetration and the uptake by dendritic cells. The increase in allergen-immune system interactions induce the release of the alarmins and the activation of type 2 inflammatory pathways causing, or worsening, the main symptoms at skin, bowel and respiratory levels. We aim to highlight the molecular mechanisms underlying allergenic proteases-induced epithelial barrier damage and the role of immune response in allergic asthma onset, maintenance and progression. We further will explore clinical and radiological potential biomarkers of airways remodeling in allergic asthma patients.