Abiraterone Acetate in Treating Patients With Metastatic Hormone-Resistant Prostate Cancer

PRIMARY OBJECTIVES:

I. To determine the magnitude of tissue testosterone suppression by abiraterone acetate in metastatic castrate-resistant prostate cancer (CRPC) (resistant to luteinizing hormone-releasing hormone [LHRH] agonist or orchiectomy ± antiandrogen) after one month of treatment to establish tissue based mechanism of action.

OUTLINE:

Patients receive abiraterone acetate orally once daily and prednisone twice daily on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed up periodically.

Inclusion criteria

• Have signed an informed consent document indicating that the subjects understands the purpose of and procedures required for the study and are willing to participate in the study
• Written authorization for use and release of health and research study information has been obtained
• Be willing/able to adhere to the prohibitions and restrictions specified in this protocol
• Able to swallow the study drug whole as a tablet
• Willing to take abiraterone acetate on an empty stomach; no food should be consumed at least two hours before and for at least one hour after the dose of abiraterone acetate is taken
• Patients who have partners of childbearing potential must be willing to use a method of birth control with adequate barrier protection as determined to be acceptable by the principal investigator and sponsor during the study and for 1 week after last dose of abiraterone acetate
• Histologically proven adenocarcinoma of the prostate
• Eastern Cooperative Oncology Group (ECOG) performance status =< 2
• Metastatic castration resistant prostate cancer as defined by serum testosterone < 50 ng/ml and one of the following:

• Prostate specific antigen (PSA) level of at least 2 ng/ml that has risen on at least 2 successive occasions at least 1 week apart
• Evaluable disease progression by modified RECIST (Response Evaluation Criteria in Solid Tumors)
• Progression of metastatic bone disease on bone scan with > 2 new lesions
• Maintenance of Lupron or antagonist unless previously treated with orchiectomy
• The presence of metastatic disease amenable to computed tomography (CT) or ultrasound guided biopsy; this may include thoracolumbar vertebral bodies, pelvis, femur or humerus, or soft tissue or nodal metastasis amenable to biopsy (excluding lung or pleural lesions)
• Patients may have received secondary hormonal manipulations (excluding prior abiraterone acetate, MDV3100 or TAK700) or up to two lines of chemotherapy; all prior therapy except Lupron must have been discontinued for more than 4 weeks before enrollment
• Serum potassium of >= 3.5 mEq/L
• Aspartate aminotransferase (AST), alanine aminotransferase (ALT) < 1.5 x upper limit of normal (ULN)
• Bilirubin levels < 1.5 x ULN
• Serum albumin of >= 3.0 g/dL
• Total bilirubin =< 1.5 x ULN
• Calculated creatinine clearance >= 60 mL/min
• Platelet count of >= 100,000/uL
• Absolute neutrophil count of > 1,500 cell/mm^3
• Hemoglobin >= 9.0 g/dL

Exclusion criteria

• Active infection or other medical condition that would make prednisone/prednisolone (corticosteroid) use contraindicated
• Patients who are currently receiving active therapy for other neoplastic disorders will not be eligible
• Patients with histologic evidence of small cell carcinoma of the prostate will not be eligible
• Known brain metastasis
• Uncontrolled hypertension (systolic blood pressure [BP] >= 160 mmHg or diastolic BP >= 95 mmHg); patients with a history of hypertension are allowed provided blood pressure is controlled by anti-hypertensive treatment
• Active or symptomatic viral hepatitis or chronic liver disease
• History of pituitary or adrenal dysfunction
• Clinically significant heart disease as evidenced by myocardial infarction, or arterial thrombotic events in the past 6 months, severe or unstable angina, or New York Heart Association (NYHA) class II-IV heart disease or cardiac ejection fraction measurement of < 50 % at baseline
• Atrial fibrillation, or other cardiac arrhythmia requiring medical therapy
• Administration of an investigational therapeutic within 30 days of screening
• Patients with dementia/psychiatric illness/social situations that would limit compliance with study requirements or would prohibit the understanding and/or giving of informed consent will not be eligible
• Patients with 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
• Patients requiring therapeutic anticoagulation (e.g., warfarin, dabigatran, heparin, or low molecular weight heparins [Lovenox, dalteparin])
• Patients with poorly controlled diabetes
• Patients with a history of gastrointestinal disorders (medical disorders or extensive surgery) that may interfere with the absorption of the study agents
• Patients with a pre-existing condition that warrants long-term corticosteroid use in excess of study dose
• Patients with known allergies, hypersensitivity, or intolerance to abiraterone acetate or prednisone or their excipients
• Child-Pugh class B or C hepatic impairment