ralaniten acetate

Ralaniten acetate (EPI-506) is a first-in-class, orally available small molecule nonsteroidal antiandrogen developed by ESSA Pharmaceuticals for the treatment of metastatic castration-resistant prostate cancer (mCRPC)[1][2][3]. It acts as an inhibitor of the N-terminal domain (NTD) of the androgen receptor (AR), a mechanism that allows it to block AR signaling—including from AR splice variants implicated in resistance to current androgen receptor pathway inhibitors such as enzalutamide and abiraterone[1][3][5][6]. EPI-506 is a prodrug of ralaniten (EPI-002), one of four stereoisomers derived from EPI-001, itself a bisphenol A derivative[1]. Clinical trials showed some PSA declines at higher doses but also revealed poor oral bioavailability and high metabolism, leading to discontinuation in favor of next-generation compounds with improved potency and tolerability[1][3][8].

Other names

ralaniten triacetateEPI-002 (active metabolite)bisphenol A derivative