Background: Robust data are available on the effectiveness of triple therapy to relieve symptoms, reduce exacerbation, and improve lung function in COPD patients. However, its effects on small airway remodeling have not been explored.

Objective: To investigate the effect of single-inhaler triple therapy budesonide/glycopyrrolate/formoterol fumarate metered dose inhaler (BGF MDI) using co-suspension delivery technology on small airway remodeling in patients with moderate to severe COPD by optical coherence tomography (OCT).

Methods: 15 patients were enrolled in the study. All subjects received B/G/FF (160/18/9.6?g) twice per day for 52 weeks. The primary endpoint was the change of small airway inner area (Ai) measured by OCT at the 52nd week compared to baseline. Secondary endpoints included the changes of small airway wall area percentage (Aw%), FEV1, R5-R20 and SGRQ score at the 52nd week compared to baseline.

Results: Compared to baseline, the Ai was increased (2.15±1.89 mm² vs 2.92±2.05 mm², p?0.001) and the Aw% was decreased (55.96±13.55% vs 49.69±13.47%, p?0.001) at 52th weeks. An improvement of SGRQ score (38.14±9.85 vs 24.92±6.99?p=0.04) was found at the 52nd week. FEV-1 was slightly improved (1.42±0.19 L vs 1.45±0.29 L) as well as R5-R20 (0.26±0.28 kPa/(L/s) vs 0.24±0.23 kPa/(L/s)), but the difference was not significant.

Conclusion: BGF MDI could significantly ameliorate airway remodeling and improve the quality of life in COPD patients.