Relugolix & EnzalutamideRelugolix + Enzalutamide Study in High-Risk Prostate Cancer

Inclusion Criteria:

1. Capable of giving signed informed consent;
2. Patients must be ≥18 years of age at the time of signing the informed consent form.
3. Men with a diagnosis of adenocarcinoma of the prostate pathologically proven diagnosis with the following:

• Locally advanced high-risk prostate defined as i. PSA >20 ng/mL or ISUP grade 4/5 (Gleason score >7) or cT2c or ii. Any PSA, any ISUP grade, cT3-4 or cN+ (locally advanced)
4. Have normal organ and bone marrow function measured at the screening visit including

• Platelets ≥100 × 103/microliter (μL);
• Hemoglobin ≥ 10.0 grams/dL;
• Leukocytes (WBC) ≥ 3 × 103/μL;
• Absolute neutrophil count ≥1.5 × 103/μL;
• Serum AST and ALT ≤2.5 × upper limit of normal (ULN);
• Total bilirubin ≤1.5 ×ULN (unless values are consistent with Gilbert's syndrome for which the total bilirubin must be < 3x ULN);
• Serum creatinine ≤ 1.5 × ULN; OR Measured or calculated creatinine clearance ≥30 mL/min for participant with creatinine levels >1.5 × institutional ULN

5. Eastern Cooperative Oncology Group (ECOG) performance status 0-2.
6. The participant has, in the opinion of the investigator, a life expectancy of at least 6 months.
7. Male patients must be willing to use contraception during treatment and for 3 months after the last dose of study treatment when having sexual intercourse with a pregnant woman or with a woman of childbearing potential. Female partners of male patients should also use a highly effective form of contraception if they are of childbearing potential.

Exclusion Criteria:

1. History of major adverse cardiac event, including myocardial infarction, new congestive heart failure (CHF) or CHF exacerbation, or stroke, within the past 6 months.
2. Patients who are receiving any other investigational agents.
3. Patients with distant metastatic cancer will be excluded from the study as intermittent hormonal therapy is not standard of care treatment for this population.
4. Active secondary malignancies requiring treatment
5. History of allergic reactions attributed to compounds of similar chemical or biologic composition to any of study drugs
6. Participants with uncontrolled intercurrent illness.
7. Participant is unable to swallow pills.
8. Not a candidate for surgical or radiation therapy