Abiraterone acetate (CAS 154229-18-2) is the 3 -acetate ester prodrug of abiraterone a steroidal inhibitor of androgen biosynthesis Abiraterone selectively and irreversibly inhibits cytochrome P450 17 -hydroxylase/17 20-lyase (CYP17) an enzyme critical for the synthesis of androgen and cortisol This inhibition occurs via covalent binding and is characterized by a reported IC50 of 72 nM Abiraterone s potency attributed to its 3-pyridyl substituent exceeds that of ketoconazole by 10- to 30-fold in CYP17 inhibition Abiraterone acetate is widely used in research exploring mechanisms and interventions for castration-resistant prostate cancer