ADORA3 and asthma: Two inhaled, selective AR ligands with anti-inflammatory actions, i.e., A2AAR agonist UK432097 16 (for COPD) and mixed A2AAR agonist/A3AR antagonist GW328267X 17 (for asthma and allergic rhinitis) failed to show efficacy in clinical trials, but there were complicating pharmacokinetic factors (Mantell et al., 2010).