In patients with chronic obstructive pulmonary disease (COPD), therapies containing inhaled corticosteroids (ICS) and baseline blood eosinophil count are known to be associated with a lower rate of exacerbations. This study aims to effect of once-day single-inhaler triple therapy vs. double therapy in reducing exacerbations.

This randomized, phase 3, parallel-group, double-blind trial included a total of 10,355 patients with moderate-to-very-severe COPD and at least one moderate or severe exacerbation in the last year. The patients were randomly assigned in a 2:2:1 ratio to the following regiments: fluticasone furoate–umeclidinium–vilanterol (n=4,151), fluticasone furoate–vilanterol (n=4,134), and umeclidinium–vilanterol (n=2,070). The researchers modeled the blood eosinophil counts using fractional polynomials. The primary outcome of the study was the frequency of exacerbations.

The findings suggested that the reduction in the rates of moderate-severe exacerbations was associated with an increase in blood eosinophil count. The moderate-severe exacerbation ratio for triple therapy vs. double therapy was 0.88. at blood eosinophil count less than 90 and 0.56 for 310 cells or more. The findings also suggested that smoking status affected the relationship between observed efficacy and blood eosinophil count.

The research concluded that blood eosinophil counts and smoking status could affect the efficacy of triple therapy in patients with COPD with moderate-severe exacerbations.