Therapeutic applications of ET antagonists include the treatment of pulmonary artery hypertension, where dual ETA/ETB antagonists have been used in the clinic since 2002 (Rubin et al., 2002; Kohan et al., 2011; Mazzuca and Khalil, 2012), while the ETB agonist IRL1620 may be useful for enhancing chemotherapeutic delivery and has recently entered phase II clinical trials (Maguire and Davenport, 2014). Here, EDNRB is linked to pulmonary arterial hypertension.