Safety Study of Continued Enzalutamide Treatment In Prostate Cancer Patients

• Drug: Enzalutamide
  
  160 mg by mouth once daily
  Other Names:
  

  • MDV3100
  • Xtandi
• Drug: Abiraterone
  
  1000 mg by mouth once daily
  Other Names:
  

  • Abiraterone acetate
  • Zytiga
• Drug: Placebo for Enzalutamide
  
  Sugar pill manufactured to mimic Enzalutamide 40 mg capsule
• Drug: Prednisone
  
  5 mg by mouth twice daily
  Other Name: prednisolone

• Experimental: Enzalutamide & Abiraterone/prednisone
  
  Enzalutamide (160 mg) administered as four 40-mg capsules by mouth once daily in combination with abiraterone (1000 mg) administered as four 250-mg tablets by mouth once daily and prednisone (10 mg) administered as one 5-mg tablet by mouth twice daily
  Interventions:
  

  • Drug: Enzalutamide
  • Drug: Abiraterone
  • Drug: Prednisone
• Active Comparator: Enzalutamide placebo & Abiraterone/prednisone
  
  Enzalutamide placebo (placebo) capsules (identical in appearance to enzalutamide) administered as 4 capsules by mouth once daily in combination with abiraterone (1000 mg) administered as four 250-mg tablets by mouth once daily and prednisone (10 mg) administered as one 5-mg tablet by mouth twice daily.
  Interventions:
  

  • Drug: Abiraterone
  • Drug: Placebo for Enzalutamide
  • Drug: Prednisone

Inclusion Criteria:

• Men with metastatic castration-resistant prostate cancer
• Progressive disease on androgen deprivation therapy
• Patients must agree to continue androgen deprivation therapy with a GnRH agonist/antagonist throughout the study or have had a prior bilateral orchiectomy
• ECOG performance score ? 1
• Estimated life expectancy of ? 12 months

Exclusion Criteria:

• Prior cytotoxic chemotherapy, aminoglutethimide, ketoconazole, abiraterone, or enzalutamide for the treatment of prostate cancer
• Prior participation in a clinical trial of an investigational agent that inhibits the androgen receptor or androgen synthesis (unless the treatment was placebo)
• History of brain metastasis, active leptomeningeal disease or seizure
• Severe cardiovascular or hepatic disease
• Pituitary or adrenal dysfunction

• Astellas Pharma Inc
• Medivation, Inc.