Novel selective β₁-adrenoceptor antagonists for concomitant cardiovascular and respiratory disease

β-Blockers reduce mortality and improve symptoms in people with heart disease; however, current clinically available β-blockers have poor selectivity for the cardiac β₁-adrenoceptor (AR) over the lung β₂-AR. Unwanted β₂-blockade risks causing life-threatening bronchospasm and reduced efficacy of β₂-agonist emergency rescue therapy. Thus, current life-prolonging β-blockers are contraindicated in patients with both heart disease and asthma. Here, we describe NDD-713 and -825, novel highly β₁-selective neutral antagonists with good pharmaceutical properties that can potentially overcome this limitation. Radioligand binding studies and functional assays that use human receptors expressed in Chinese hamster ovary cells demonstrate that NDD-713 and -825 have nanomolar β₁-AR affinity >500-fold β₁-AR vs β₂-AR selectivity and no agonism. Studies in conscious rats demonstrate that these antagonists are orally bioavailable and cause pronounced β₁-mediated reduction of heart rate while showing no effect on β₂-mediated hindquarters vasodilatation. These compounds also have good disposition properties and show no adverse toxicologic effects. They potentially offer a truly cardioselective β-blocker therapy for the large number of patients with heart and respiratory or peripheral vascular comorbidities.-Baker, J. G., Gardiner, S. M., Woolard, J., Fromont, C., Jadhav, G. P., Mistry, S. N., Thompson, K. S. J., Kellam, B., Hill, S. J., Fischer, P. M. Novel selective β₁-adrenoceptor antagonists for concomitant cardiovascular and respiratory disease.