Wikipedia
Orteronel (TAK-700) is a non-steroidal antiandrogen that was being developed for the treatment of cancer by Takeda Pharmaceutical Company in conjunction with Millennium Pharmaceuticals. It completed two phase III clinical trials for metastatic, hormone-refractory prostate cancer but failed to extend overall survival rates, and development was voluntarily terminated as a result.
Orteronel is an androgen biosynthesis inhibitor. It selectively inhibits the enzyme CYP17A1 which is expressed in testicular, adrenal, and prostatic tumor tissues. CYP17 catalyzes two sequential reactions: (a) the conversion of pregnenolone and progesterone to their 17α-hydroxy derivatives by its 17α-hydroxylase activity, and (b) the subsequent formation of dehydroepiandrosterone (DHEA) and androstenedione, respectively, by its 17,20-lyase activity. DHEA and androstenedione are androgens and precursors of testosterone. Inhibition of CYP17 activity thus decreases circulating levels of testosterone.