BAY-298 is an orally active and selective luteinizing hormone receptor (LH-R) antagonist with IC50s of 96 nM, 23 nM, and 78 nM for hLH (human LH), rLH (rat LH), and cLH (cynomolgus monkey LH), respectively. It is the first nanomolar hLH-R antagonist that reduces sex hormone levels in vivo [1].

LH (rat):46nM , LH (human):185 nM , LH (cynomolgus monkey):78 nM

BAY-298 administered orally at dosages ranging from 4.5 to 72 mg/kg/day over a period of 8 days, leads to a dose-dependent reduction in serum estradiol levels in proestrus in intact female rats. Additionally, when administered to female and male Wistar rats either intravenously (iv) at a dosage of 0.5 mg/kg or orally (po) at 2 mg/kg, BAY-298 exhibits half-lives of 31 hours and 33 hours, respectively, for iv and po routes. The maximum serum concentrations (Cmax) achieved are 0.28 kg/L for iv and 0.066 kg/L for po administration.