Seviteronel (VT-464) is a 17,20-lyase selective inhibitor of CYP17A1, which plays key roles in adrenal and intratumoral de novo biosynthesis of androgens. The inhibition of 17,20-lyase activity by seviteronel (VT-464) is enough to reduce androgen levels, and its preserving of 17alpha-hydroxylase activity largely avoids interference with the production of other steroidal hormones. Seviteronel (VT-464) also has shown AR-antagonist activity independent of CYP17 enzyme inhibition. It is currently in phase 2 clinical trials as a therapeutic for castration-resistant prostate cancer patients.