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

This is a Phase 1/2 study of VT-464 in chemotherapy-naïve CRPC patients who are treatment-naive or who have failed prior therapy with abiraterone and/or enzalutamide. The study will examine several parallel QD dosing regimens of VT-464 using a traditional modified "3+3" Fibonacci study design. Approximately 3 dose-levels of VT-464 will be examined in each dosing regimen that is fully enrolled.

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.