Enzalutamide Versus Standard Androgen Deprivation Therapy for the Treatment Hormone Sensitive Prostate Cancer

This randomized phase II trial compares enzalutamide with standard androgen deprivation therapy in reducing incidence of metabolic syndrome in patients with prostate cancer that has spread to other places in the body. Metabolic syndrome is defined as changes in cholesterol, blood pressure, circulating sugar levels, and body weight. Previous studies have shown that patients with prostate cancer, who have been treated with standard medical therapy that lowers testosterone levels, have an increased risk of these changes. Hormone therapy using enzalutamide may fight prostate cancer by blocking the use of testosterone by the tumor cells instead of lowering testosterone levels. It is not yet known whether prostate cancer patients who receive enzalutamide will have reduced incidence of metabolic syndrome than patients who receive standard androgen deprivation therapy.

PRIMARY OBJECTIVES:

I. To determine the incidence of metabolic syndrome within 12 months, as defined by the Adult Treatment Panel III, in patients treated with enzalutamide compared to standard androgen deprivation therapy.

SECONDARY OBJECTIVES:

I. To determine the incidence of metabolic syndrome within 6 months, as defined by the Adult Treatment Panel III, in patients treated with enzalutamide compared to standard androgen deprivation therapy.

II. To assess bone health, as measured by a dual-energy x-ray absorptiometry (DXA) scanner.

III. To assess body composition (sarcopenic obesity), as measured by a DXA scanner.

IV. To assess quality of life (QOL), as measured by the Functional Assessment of Cancer Therapy-Prostate (FACT-P) and Sexual Health Inventory in Men (SHIM).

V. To assess time to prostate-specific antigen (PSA) progression and time to radiographic progression.

VI. To assess the incidence of developing individual risk factors, or components, which comprise metabolic syndrome.

VII. To assess the change in high-sensitivity C-reactive protein (hs-CRP) as a marker of inflammation.

VIII. To assess the safety and tolerance of enzalutamide or androgen deprivation therapy (ADT).

IX. To assess the change in physical function as measured by the Short Physical Performance Battery (SPPB).

OUTLINE: Patients are randomized to 1 of 2 treatment arms.

ARM I: Patients receive enzalutamide orally (PO) once daily (QD) for 12 months in the absence of disease progression or unacceptable toxicity.

ARM II: Patients receive standard of care ADT comprising one of the following at the discretion of the treating physician: leuprolide acetate, goserelin acetate, histrelin acetate, triptorelin, or degarelix subcutaneously (SC) or intramuscularly (IM) for 12 months in the absence of disease progression or unacceptable toxicity. Patients may also choose to undergo surgical castration as an alternative form of ADT.

After completion of study treatment, patients are followed up at 30 days.

Eligibility Criteria:
Inclusion Criteria:

* Histologically or cytologically proven adenocarcinoma of the prostate; if pathology is unavailable, the principal investigator (PI) may also make a determination of prostate cancer based on unequivocal clinic data
* Patients with advanced prostate cancer suitable for systemic treatment defined as: having metastatic disease, a biochemical relapse after primary therapy, or patients in whom primary therapy is not appropriate or feasible; patients without metastatic disease will need evaluation for local therapy and deemed inappropriate or have refused this treatment option
* Eastern Cooperative Oncology Group (ECOG) 0-2
* Age \> 18 years
* Must use a condom if having sex with a pregnant woman
* A male patient and his female partner who is of childbearing potential must use 2 acceptable methods of birth control (one of which must include a condom as a barrier method of contraception) starting at screening and continuing throughout the study period and for 3 months after final study drug administration
* Life expectancy estimated at \> 12 months
* Ability to understand and willingness to provide written informed consent document

Exclusion Criteria:

* A history of androgen deprivation therapy; patients receiving hormonal therapy in the adjuvant and/or neoadjuvant setting must have discontinued therapy at least 6 months prior to day 1 of treatment AND have a serum testosterone level \>= 50 ng/dL AND cannot have received more than 18 months of previous ADT
* A history of orchiectomy
* Previous androgen blockade (e.g. antiandrogens) in the last 3 months
* Patients already meeting the criteria for metabolic syndrome as defined by the Adult Treatment Panel III Criteria which requires 3/5 parameters encompassing glucose control, blood pressure, lipids and waist circumference; patients with 2 of the parameters at baseline will be allowed enrollment provided that one of those risk factors is hypertension (\>= 130/\>= 85 mm Hg)
* Baseline hypogonadism as defined as a testosterone \< 50 ng/dL
* PSA \< 0.5 ng/dL
* Serum vitamin D 25, hydroxy (OH) \< 12 ng/mL
* Active hepatitis C virus
* Use of corticosteroids as defined by a daily dose of prednisone (or equivalent) of 5 mg or greater for more than 1 month continuously within 3 months of screening
* Corrected calcium \> 10.6 mg/dL
* Absolute neutrophil count \< 1500/uL
* Platelet count \< 100,000/uL
* Hemoglobin \< 9 g/dL
* Total bilirubin \>= 1.5 x upper limit of normal (ULN) (unless documented Gilbert's)
* Alanine aminotransferase or aspartate aminotransferase \>= 2.5 x ULN
* Creatinine \> 2 mg/dL
* Clinically significant cardiovascular disease as evidenced by: myocardial infarction within 6 months of screening; uncontrolled angina within 3 months of screening; New York Heart Association (NYHA) class 3 or 4 congestive heart failure; clinically significant ventricular arrhythmia; Mobitz II/2nd degree/or 3rd degree heart block without a pacemaker in place; uncontrolled hypertension (HTN) (systolic \> 180 mmHg or diastolic \> 105 mmHg at screening)
* Previous exposure to enzalutamide
* Use of an investigational therapeutic within 30 days
* History of gastrointestinal disorders (medical disorders or extensive surgery) that may interfere with the absorption of the study agent
* Known or suspected brain metastasis or active leptomeningeal disease
* History of seizure or any condition that may predispose to seizure (e.g., prior cortical stroke, significant brain trauma) at any time in the past; also, history of loss of consciousness or transient ischemic attack within 12 months of day 1 visit
* Have any condition that, in the opinion of the investigator, would compromise the well-being of the subject or the study or prevent the subject from meeting or performing study requirements