Study of TVB-2640 in Men With Metastatic Castration-Resistant Prostate Cancer

Inclusion Criteria:

• Age >18 years.

• Diagnosis of metastatic, castration resistant prostate cancer

• Potential participant must be planning to receive Enzalutamide as their first lineof therapy for castration resistant prostate cancer or have previously received upto one line of Abiraterone or an androgen receptor antagonist

• Willing to undergo a tumor biopsy prior to beginning therapy, if recent tissuesamples are not available

• Willing to undergo a tumor biopsy of at least one metastatic site or primaryprostate after ~4 weeks of therapy with both agents

• Participants without prior orchiectomy must be currently taking and willing tocontinue luteinizing hormone-releasing hormone (LHRH) analogue (agonist orantagonist) therapy until permanent discontinuation of study treatment

• Sexually active, fertile participants and their partners must agree to use medicallyaccepted methods of contraception (e.g., barrier methods, including male condom withspermicide during the course of the study and for 4 months after the last dose ofstudy treatment

• Capable of understanding and complying with the protocol requirements and must havesigned the informed consent document

Exclusion Criteria:

• Any prior cytotoxic chemotherapy for hormone sensitive prostate cancer.

• Receipt of any type of biologic, or other systemic anticancer therapy (includinginvestigational) except agents within 4 weeks before first dose of study treatment.Anti-resorptive bone agents are also allowed.

• Radiation therapy for bone metastasis within 2 weeks, any other radiation therapywithin 4 weeks before first dose of study treatment. Systemic treatment withradionuclides within 6 weeks before the first dose of study treatment. Participantswith clinically relevant ongoing complications from prior radiation therapy are noteligible.

• Known brain metastases or cranial epidural disease unless adequately treated withradiotherapy and/or surgery (including radiosurgery) and stable for at least 4 weeksprior to first dose of study treatment after radiotherapy or at least 4 weeks priorto first dose of study treatment after major surgery (e.g., removal or biopsy ofbrain metastasis). Participants must have complete wound healing from major surgeryor minor surgery before first dose of study treatment. Eligible participants must beneurologically asymptomatic and without corticosteroid treatment for neurologicalindications at the time of first dose of study treatment.

• Participants with clinically significant dry eye or corneal abnormalities

• Participants with a history of seizure

• Currently taking certain anticoagulation medications, such as coumarin agents (e.g.,warfarin), direct thrombin inhibitors (e.g., dabigatran), direct factor Xa inhibitorbetrixaban, or platelet inhibitors (e.g., clopidogrel)

• Participant has prothrombin time (PT)/INR or partial thromboplastin time (PTT) test ≥ 1.3 X the laboratory ULN within 30 days before the first dose of study treatment.

• Participants should not receive strong CYP2C8 or strong P-gp inhibitors; strongCYP3A4 or CYP2C8 inducers; and strong CYP3A4, CYP2C9 and CYP2C19 substrates whileparticipating in the trial, unless utilized with caution to treat a drug-related AEwhen no alternative is available and discussed with the Medical Monitor.

• Participant has uncontrolled, significant intercurrent or recent Cardiovasculardisorders including, but not limited to, the following conditions: i. Congestive heart failure New York Heart Association Class 3 or 4, unstable anginapectoris, serious cardiac arrhythmias.

ii. Uncontrolled hypertension defined as sustained blood pressure (BP) >140 mm Hg systolic or >90 mm Hg diastolic despite optimal antihypertensive treatment.

iii. Stroke (including transient ischemic attack [TIA]), myocardial infarction (MI), or other ischemic event, or thromboembolic event (e.g. deep venous thrombosis, pulmonary embolism) within 6 months before first dose.

• Inability to swallow tablets.

• Use of herbal products that may decrease PSA levels within 4 weeks prior toenrollment

• Previously identified allergy or hypersensitivity to components of the studytreatment formulations.

• Diagnosis of another type of cancer within 2 years before first dose of studytreatment, except for superficial skin cancers, or localized, low-grade tumorsdeemed cured and not treated with systemic therapy.

• Any serious and/or unstable pre-existing medical, psychiatric disorder or otherconditions that could interfere with participant's safety, obtaining informedconsent or compliance to the study procedures.