A Study to Evaluate Once-Daily Oral VT-464 in Patients With Castration-Resistant Prostate Cancer

Key Inclusion Criteria: * Patients must have documented histological or cytological evidence of adenocarcinoma of the prostate. * Patients must have a minimum serum PSA level of \>2 ng/ml that is rising based on the Prostate Cancer Working Group 2 criteria. * Patients must have castrate levels of testosterone (\<50 ng/dl \[1.74 nmol/l\]). * Patients must have undergone orchiectomy, or have been on LHRH agonists or antagonists, for at least 3 months prior to study entry. Patients on LHRH agonists/antagonists must remain on these agents for the duration of the study. * Patients must have an ECOG Performance Score of 0 or 1. Key Exclusion Criteria: * Patients who have received prior cytotoxic chemotherapy for castration-resistant prostate cancer unless enrolled in a previous chemotherapy cohort. * Patients who have received second-line antihormonal therapy, including ketoconazole, aminoglutethimide, or high-dose estrogen within 30 days of study entry. * Patients who have completed sipuleucel-T (Provenge ®) treatment within 30 days of study entry. * Patients who have received TOK-001 (Galeterone®) or any other investigational product directed towards the androgen receptor or androgen biosynthesis. * Patients who have received antiandrogens such as flutamide (EULEXIN®), bicalutamide (CASODEX®), or nilutamide (NILANDRON®) for \> 3 months must be off treatment for 6 weeks and demonstrate a continued rise in PSA after withdrawal. Patients on antiandrogens for \< 3 months must be off medication for 2 weeks. Patients on 5 alpha reductase inhibitors such as finasteride (PROSCAR®, PROPECIA®), or dutasteride (AVODART®) must stop medication at least 3 months from study entry. * Patients who require pharmacological or replacement doses of systemic corticosteroids or who have received systemic corticosteroids within 30 days of study entry; use of topical, inhaled or ophthalmic steroids is permitted. * Patients who have received palliative radiotherapy within 4 weeks of study entry. * Patients with a history within the last 3 years of another invasive malignancy.