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.