Abediterol, also known as LAS100977, is a novel potent, long-acting inhaled β(2)-adrenoceptor agonist in development for the treatment of asthma and chronic obstructive pulmonary disease. Abediterol shows subnanomolar affinity for the human β(2)-adrenoceptor and a functional selectivity over β(1)-adrenoceptors higher than that of formoterol and indacaterol in both a cellular model with overexpressed human receptors and isolated guinea pig tissue. Abediterol is a full agonist at the human β(2)-adrenoceptor (E(max) = 91 ± 5% of the maximal effect of isoprenaline). The potency and onset of action that abediterol shows in isolated human bronchi (EC(50) = 1.9 ± 0.4 nM; t½ onset = 7-10 min) is not significantly different from that of formoterol, but its duration of action (t½ ∼ 690 min) is similar to that of indacaterol.