Original Research

Umeclidinium/vilanterol as step-up therapy from tiotropium in patients with moderate COPD: a randomized, parallel-group, 12-week study

Kerwin EM, Kalberg CJ, Galkin DV, Zhu C, Church A, Riley JH, Fahy WA

International Journal of Chronic Obstructive Pulmonary Disease 2017, 12:745-755

Published Date: 24 February 2017