Table 1.

Various cytochrome P450 (CYP) 17 inhibitors and their mechanisms of action.

CYP17 inhibitors	Mechanism of action
Abiraterone and D4A	Inhibition of 17α hydroxylase and 17,20 lyase; 17β hydroxysteroid dehydrogenase and steroid 5α reductase; AR antagonism
Orteronel (TAK-700)	Selective inhibition of 17,20 lyase over 17α hydroxylase
Viamet (VT-464)	Selective inhibition of 17,20 lyase over 17α hydroxylase; AR antagonism
Galeterone (TOK-001)	17α hydroxylase and 17,20 lyase inhibition; AR antagonism; downregulation of AR protein expression
CFG920	Dual CYP17/CYP11B2 inhibitor

AR, androgen receptor.