A Safety and Efficacy Study of Oral MDV3100 in Chemotherapy-Naive Patients With Progressive Metastatic Prostate Cancer

Randomized, Double Blind Treatment Period:

Inclusion Criteria:

Histologically confirmed adenocarcinoma of the prostate without neuroendocrine differentiation or small cell features
Ongoing androgen deprivation therapy with a GnRH analogue or bilateral orchiectomy
Progressive disease despite androgen deprivation therapy as defined by rising PSA levels or progressive soft tissue or bony disease
No prior treatment with cytotoxic chemotherapy
Asymptomatic or mildly symptomatic from prostate cancer

Exclusion Criteria:

Severe concurrent disease, infection, or co-morbidity that, in the judgment of the Investigator, would make the patient inappropriate for enrollment
Known or suspected brain metastasis or active leptomeningeal disease
History of another malignancy within the previous 5 years other than curatively treated non-melanomatous skin cancer

Open-Label Treatment Period:

The following inclusion criteria apply to patients receiving enzalutamide or placebo during double-blind treatment.

Eligible patients must meet all inclusion criteria.

Received randomized double-blind treatment in PREVAIL;
Open-label day 1 visit is within 6 months after this amendment is approved and becomes effective at the study site;
Is willing to maintain androgen deprivation therapy with a gonadotropin-releasing hormone (GnRH) agonist/antagonist or has had a bilateral orchiectomy;

The exclusion criteria apply only to patients starting new treatment with enzalutamide after receiving placebo as randomized treatment. Each patient must not meet any of the following criteria:

Has taken commercially available enzalutamide (Xtandi);
Severe concurrent disease, infection, or co-morbidity that, in the judgment of the Investigator, would make the patient inappropriate for enrollment
Known or suspected brain metastasis or active leptomeningeal disease