Orteronel (TAK-700) is a selective inhibitor of the enzyme CYP17A1 (17α-hydroxylase/17,20-lyase), essential for androgen biosynthesis. It has been investigated for treating prostate cancer, especially metastatic castration-resistant prostate cancer (mCRPC) resistant to hormone therapies. By blocking androgen production, it suppresses cancer cell growth in research settings. Commonly studied in combination with other therapies to enhance efficacy. Reported side effects from clinical trials include fatigue, nausea, and hypertension. Used as a research chemical (≥99% purity).