Clinical trials istradefylline, an A2AR antagonist, have taken place and it may have a beneficial effect in conjunction with commonly used anti-Parkinson’s therapies (Tao and Liang, 2015; Uchida et al., 2015; Vorovenci and Antonini, 2015), although in a later study, istradefylline was shown to enhance amyloid-β generation and γ-secretase activity (Lu et al., 2016). Here, ADORA2A is linked to Parkinson disease.