OPRM1 and congestive heart failure: To date, the diseases with the most clinical data in support of the development of biased drugs are: the use of ß-adrenergic receptors (ßAR) and angiotensin AT1 receptor ligands in congestive heart failure (CHF) (Barrese and Taglialatela, 2013; Lymperopoulos and Aukszi, 2017); μ-opioid receptor (μOR) ligands in the management of pain; and to a lesser extent, possibly ß2AR ligands in asthma (Dickey et al., 2010; Forkuo et al., 2016; Joshi et al., 2017; Nguyen et al., 2017).