An Asian Study to Evaluate Efficacy and Safety of Oral Enzalutamide in Progressive Metastatic Prostate Cancer Participants

Asian Multinational Phase 3, Randomized, Double-Blind, Placebo-Controlled Efficacy and Safety Study of Oral Enzalutamide in Chemotherapy Naïve Subjects With Progressive Metastatic Prostate Cancer Who Have Failed Androgen Deprivation Therapy

Purpose of the study was to assess the effect of enzalutamide on time to Prostate Specific Antigen (PSA) progression as compared to placebo in chemotherapy naïve participants with progressive metastatic prostate cancer who have failed androgen deprivation therapy.

The study was a multinational Phase 3, randomized, double-blind, placebo-controlled efficacy and safety study of oral enzalutamide (formerly MDV3100) in asymptomatic or mildly symptomatic participants with progressive metastatic prostate cancer who have disease progression despite androgen deprivation therapy. In order to join the study, participants could not have been previously treated with cytotoxic chemotherapy. Approximately 30 Chinese participants were allocated to the pharmacokinetic (PK) cohort. Participants in the PK cohort were required to be hospitalized from Day 1 before the randomization date to at least the completion of all the assessments planned on Day 3. All participants in the PK cohort underwent blood sampling for the PK analysis. Data reported in the results section was based on data cutoff dates of 20 Sept 2015 for efficacy and safety data and 20 Jan 2016 for PK outcome measures. The study completed double-blind period and is now in the open-label 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 bone 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
• History of seizure including febrile seizure or any condition that may predispose to seizure (e.g., prior stroke, brain arteriovenous malformation, head trauma with loss of consciousness requiring hospitalization).