Abstract

Abediterol is a novel potent, long-acting inhaled β₂-adrenoceptor agonist in development for the treatment of asthma and chronic obstructive pulmonary disease. Abediterol shows subnanomolar affinity for the human β₂-adrenoceptor and a functional selectivity over β₁-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 β₂-adrenoceptor (E_max = 91 ± 5% of the maximal effect of isoprenaline). The potency and onset of action that abediterol shows in isolated human bronchi (EC₅₀ = 1.9 ± 0.4 nM; t_½ onset = 7–10 min) is not significantly different from that of formoterol, but its duration of action (t_½ ∼ 690 min) is similar to that of indacaterol. Nebulized abediterol inhibits acetylcholine-induced bronchoconstriction in guinea pigs in a concentration-dependent manner, with higher potency and longer duration of action (t_½ = 36 h) than salmeterol (t_½ = 6 h) and formoterol (t_½ = 4 h) and similar duration of action to indacaterol up to 48 h. In dogs, the bronchoprotective effect of abediterol is more sustained than that of salmeterol and indacaterol at doses without effects on heart rate, thus showing a greater safety margin (defined as the ratio of dose increasing heart rate by 5% and dose inhibiting bronchospasm by 50%) than salmeterol, formoterol, and indacaterol (5.6 versus 3.3, 2.2, and 0.3, respectively). In conclusion, our results suggest that abediterol has a preclinical profile for once-daily dosing in humans together with a fast onset of action and a favorable cardiovascular safety profile.