Potent, orally active and non-peptide gonadotropin-releasing hormone (GnRH, LHRH) receptor antagonist (IC50 values are 0.2, 4.0 and 60 nM for human, monkey and rat GnRH receptors respectively). Inhibits LH release in vitro (IC50 = 100 nM) and reduces plasma LH concentration in castrated male cynomolgus monkeys.