Acute effect of indacaterol plus tiotropium versus formoterol plus tiotropium on lung hyperinflation (EFINTH study) in COPD: study protocol for a randomized trial

Abstract

Introduction: Despite the wide availability of long-acting beta2-agonists and long-acting anticholinergics, isolated or in fixed-dose combinations, for maintenance treatment of chronic obstructive pulmonary disease (COPD), data of head-to-head comparative trial of different regimens of dual therapies are scarce. Indacaterol is a ultra-long-acting beta2-agonist recently launched in the Brazilian market that has been shown to significantly reduce the lung hyperinflation in COPD patients. Objective: To evaluate acute effect of indacaterol (150 mcg) plus tiotropium (5 mcg) versus formoterol (12 mcg) plus tiotropium (5 mcg) on ​​lung hyperinflation (EFINTH study) in patients with COPD. Methods: Randomized, open-label, phase IV, 2-periods, crossover trial. A total of 30 patients with moderate-to-severe COPD, symptomatic, will be recruited at a Reference Outpatient Clinic in Salvador, state of Bahia, Brazil. Spirometry and lung volumes were measured before and 5, 30, 60, 120 and 240 min after administration of dual therapy regimens. The primary outcome of this study is peak inspiratory capacity (IC). The area on the 4-h curve for IC, 1-s forced expiratory volume (FEV1) and forced vital capacity (FVC). Conclusions: This study aims to explore the effect of two dual therapy regimens on reduction of lung hyperinflation in patients with COPD and, thus, provides data for design and implementation of large-scale and long-term efficacy studies.