A Phase 3, Randomized, Open-Label Study of PF-06821497 in Combination with Enzalutamide Compared with Enzalutamide or Docetaxel in Participants with Metastatic Castration Resistant Prostate Cancer Previously Treated with Abiraterone Acetate (MEVPRO-1)

The purpose of this study is to learn about the safety and effects of a compound called an EZH2 inhibitor (EZH2i) on your body when it is given in combination with a second drug, enzalutamide (an androgen receptor inhibitor currently used for treatment of CRPC). The study will explore whether the addition of the EZH2 inhibitor to enzalutamide can reverse anti-androgen resistance which may increase the effect of enzalutamide (by allowing the enzalutamide to block the production of androgens). This combination will be compared to your physician’s choice of enzalutamide or docetaxel. By giving this combination researchers want to see if the two drugs given together work better than enzalutamide by itself or docetaxel by itself. The EZH2i is an investigational drug because it is not approved for use by regulatory agencies (i.e. FDA, EMA). The combination of EZH2i and enzalutamide is therefore also considered investigational. The comparison drugs, enzalutamide alone or docetaxel, are already approved to treat castration-resistant prostate cancer.