Short-Term Effects of Dupilumab in Eosinophilic COPD

Background/Objectives: Patients with eosinophilic chronic obstructive pulmonary disease (COPD) often remain symptomatic despite optimized triple inhaled therapy. Dupilumab is a fully human monoclonal antibody that blocks the IL-4 receptor alpha subunit, thereby inhibiting IL-4 and IL-13 signaling. Evidence from randomized trials supports dupilumab for add-on treatment of type 2-high COPD, but data referring to short-term effectiveness in clinical practice are quite limited. Methods: We conducted an observational, compassionate-use study enrolling 13 consecutive outpatients with eosinophilic COPD (blood eosinophils ≥ 300 cells/µL) receiving add-on biologic therapy with dupilumab 300 mg every two weeks. Clinical (CAT, mMRC), functional (spirometry and body plethysmography), and inflammatory parameters (blood eosinophils/basophils, fibrinogen, FeNO) were evaluated at baseline and after four weeks of treatment. Safety was monitored after injection in a clinical setting, as well as via weekly phone follow-up. Results: Participants (84.6% male; mean age 67.08 ± 11.42 years) experienced rapid and clinically meaningful improvements at four weeks. CAT score decreased from baseline 21.40 ± 6.22 to 14.00 ± 5.58 (p < 0.001) and mMRC scale from 2.90 ± 0.73 to 1.80 ± 0.63 (p < 0.0001), respectively. Pre-bronchodilator FEV₁ increased from baseline 1.35 ± 0.65 L to 1.59 ± 0.84 L (p < 0.05), and FVC from 2.36 ± 0.92 L to 2.83 ± 1.11 L (p < 0.01). A marked lung deflation was observed: indeed, residual volume declined from baseline 4.17 ± 1.98 L to 3.47 ± 2.07 L (p < 0.05), with a concomitant reduction in specific effective airway resistance (from baseline 3.15 ± 1.77 to 2.43 ± 1.44 kPa·s; p < 0.05) associated with significant increases in mid-expiratory flow (FEF_25-75: from baseline 0.62 ± 0.38 to 0.86 ± 0.71 L/s; p < 0.05) and peak expiratory flow (3.80 ± 1.40 to 4.48 ± 1.79 L/s; p < 0.01). Type 2 inflammatory biomarkers changed as follows: blood eosinophil count fell from baseline 390.0 ± 43.75 to 190.0 ± 65.47 cells/µL (p < 0.001); blood basophil number decreased from baseline 37.50 ± 13.89 to 26.25 ± 13.02 cells/µL (p < 0.001); plasma fibrinogen lowered from baseline 388.4 ± 54.81 to 334.9 ± 72.36 mg/dL (p < 0.01); FeNO levels dropped from baseline 23.95 ± 18.10 to 14.00 ± 2.04 ppb (p < 0.0001). Dupilumab was well tolerated, and no treatment-related serious adverse events or discontinuations were detected. Conclusions: Within an exploratory context of daily medical activity referring to eosinophilic COPD already treated with maximal inhaled therapy, we found relevant therapeutic effects of a four-week add-on treatment with dupilumab. In particular, our patients manifested rapid improvements in symptoms, airflow limitation, and lung hyperinflation, paralleled by significant decrements of type 2 inflammatory signatures. Such encouraging results were associated with a favorable short-term safety profile. However, larger and longer studies are necessary to corroborate these preliminary findings.