The preclinical pharmacological profile of vilanterol using radioligand binding and cAMP studies in recombinant assays as well as human and guinea pig tissue systems to characterize β(2)-AR binding and functional properties.?Vilanterol displayed a subnanomolar affinity for the β(2)-AR that was comparable with that of salmeterol but higher than olodaterol, formoterol, and indacaterol.?In cAMP functional activity studies, vilanterol demonstrated similar selectivity as salmeterol for β(2)- over β(1)-AR and β(3)-AR, but a significantly improved selectivity profile than formoterol and indacaterol.?Vilanterol also showed a level of intrinsic efficacy that was comparable to indacaterol but significantly greater than that of salmeterol.