BackgroundAG NPP709 (Synatura®) has been demonstrated to be efficacious in decreasing cough and sputum in patients with acute upper respiratory infection and chronic inflammatory bronchitis. The aim of this study was to evaluate the efficacy of AG NPP709 in patients with chronic bronchitis type chronic obstructive pulmonary disease (COPD).MethodsThis was a prospective, open-label, single-arm clinical trial (NCT03623282). Chronic bronchitis type COPD patients aged >40 years were enrolled. The primary endpoint was improvement on the CAT scores between the baseline visit and week 12. The secondary endpoints were the effect of AG NPP709 on the pulmonary function and systemic inflammation, as indexed by CRP, fibrinogen, IL-6, TNF-α and IL-33 levels.ResultsThirty patients were enrolled. All patients were male, and their mean age was 71.93±7.93 years. The mean post-bronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio was 58.63±11.40, and FEV1 (%) was 75.93±20.42. The mean total CAT score was 14.77±7.14. Of these patients, 26 were followed up after 3 months. A significant improvement was observed in the total CAT score (from 14.38±6.62 to 12.73±6.60, P=0.005). Fibrinogen level decreased significantly (P=0.013). No serious adverse events occurred.ConclusionsAG NPP709 improved the quality of life, as represented by the CAT score, in patients with chronic bronchitis type COPD, and significantly reduced fibrinogen levels. These results suggest that AG NPP709 is efficacious and safe in patients with chronic bronchitis type COPD.