A randomised, double-blind, four-way, crossover trial comparing the 24-h FEV1 profile for once-daily versus twice-daily treatment with olodaterol, a novel long-acting β2-agonist, in patients with chronic obstructive pulmonary disease.

A randomised, double-blind, four-way, crossover trial comparing the 24-h FEV1 profile for once-daily versus twice-daily treatment with olodaterol, a novel long-acting β2-agonist, in patients with chronic obstructive pulmonary disease.