Abiraterone inhibits the CYP17A enzyme, which is a critical enzyme in androgen biosynthesis. Abiraterone has regulatory approval in metastatic castration-resistant prostate cancer (mCRPC) in both chemotherapy-naïve and in the post-docetaxel setting based upon results from two randomized phase III studies. Abiraterone is also proven to extend survival in the metastatic, hormone-naïve population based on two phase III studies. Abiraterone is a castrating agent, but, other than a small first in human study, all clinical studies have been done in conjunction with gonadotropin-releasing hormone (GnRH) analogues. Maintaining castrate level of serum testosterone is critical in the treatment of metastatic prostate cancer. It is unknown if GnRH analogues must be continued to maintain castrate levels of serum testosterone in patients treated with abiraterone.
