Efficacy and safety of indacaterol/glycopyrronium fixed-dose combination in mild-to-moderate COPD patients symptomatic on tiotropium in Korea: Study protocol for a randomized controlled trial

Background: Long-acting bronchodilator monotherapy (long-acting β₂-agonist [LABA] or long-acting muscarinic antagonist [LAMA]) is extensively used for treatment of patients with chronic obstructive pulmonary disease (COPD) with mild-to-moderate airflow limitation. However, a substantial number of patients remain symptomatic despite treatment with a single bronchodilator, necessitating a change in therapy. Methods: This 12-week, randomized, multicenter, open-label, phase IV study aims to show that the once-daily indacaterol/glycopyrronium (IND/GLY) 110/50 μg fixed-dose LABA/LAMA combination results in an improved lung function in symptomatic patients with mild-to-moderate COPD who switch from once-daily tiotropium 18 μg. The study aims to enroll a total of 404 symptomatic patients in Korea with mild-to-moderate COPD who received tiotropium for at least 12 weeks prior to the study initiation. The primary objective of this study is to demonstrate the superiority of IND/GLY over tiotropium in terms of trough forced expiratory volume in 1 second (FEV₁) following 12 weeks of treatment. Secondary endpoints include the pre-dose trough FEV₁ after 4 weeks of treatment, transition dyspnea index (TDI) total score, COPD assessment test (CAT) total score, and rescue medication use following the 12-week treatment, and safety assessment over the 12-week treatment. Discussion: This study intends to establish the use of LABA/LAMA combination therapy in symptomatic patients with mild-to-moderate COPD by demonstrating the superiority of IND/GLY over tiotropium monotherapy. Trial registration: ClinicalTrials.gov, NCT02566031. Registered on 10 August 2015.