S1014 Abiraterone Acetate in Treating Patients With Prostate Cancer Who Have Undergone Initial Hormone Therapy

DISEASE CHARACTERISTICS: * Histologically or cytologically proven diagnosis of adenocarcinoma of the prostate * Metastatic (M1) disease as evidenced by soft tissue and/or bony metastases at the time of initiation of androgen-deprivation therapy (ADT) * Must have at least one of the following: * Visceral disease (liver, lung, other viscera) * Bone metastases to sites in either the axial (spine, pelvis, ribs, or skull) and/or the appendicular (clavicle, humerus, or femur) skeleton * Distant lymph node disease (e.g., above the aortic bifurcation, etc.) * No small cell or neuroendocrine prostate cancer * Patients must be receiving ADT (e.g., gonadotropin-releasing hormone \[GNRH\] antagonist, with or without antiandrogen) prior to entering this study * Degarelix, a FDA-approved GNRH antagonist, is an acceptable form of ADT * Bilateral surgical orchiectomy is also acceptable * Suboptimal response to ADT induction as defined by the following criteria: * Declining PSA (current PSA is less than the PSA prior to starting ADT) that fails to reach 4 ng/mL or below despite continuous ADT * PSA of \> 4 ng/mL must be observed between 6-12 months after the initiation of ADT * Documentation of failure to achieve this PSA of ≤ 4 ng/mL must be within 28 days of registration * The PSA must be obtained after any applicable antiandrogen washout period * If the PSA is declining or stable (defined as a PSA rise ≤ 0.1 ng/mL from nadir) and the patient is on an antiandrogen, they must remain on the antiandrogen * Patients with stable or declining PSA who have had previous antiandrogen exposure, but are not taking an antiandrogen at the time of registration, must wait at least 6 weeks from the last antiandrogen dose before registration and still demonstrate a stable or falling PSA which is \> 4 ng/mL by month 12, in order to be eligible * If the PSA is rising and they are on an antiandrogen, formal antiandrogen washout must be performed (4 weeks for flutamide and 6 weeks for bicalutamide and nilutamide with no evidence of a falling PSA after washout) * No patients with radiographic progression when compared to available imaging studies performed prior to starting the GNRH agonist/antagonist therapy * Patients who have measurable disease must have radiographic assessment (at least an abdominal/pelvic CT scan) within 28 days prior to registration * Non-measurable disease must be assessed (i.e., bone scan) within 42 days prior to registration * No patients with a history of brain metastases or who currently have treated or untreated brain metastases * Patients with clinical evidence of brain metastases must have a brain CT scan or MRI negative for metastatic disease within 56 days prior to registration PATIENT CHARACTERISTICS: * Zubrod performance status 0-2 * ANC ≥ 1,500/μL * Platelet count ≥ 100,000/μL * Hemoglobin ≥ 10 g/dL * Serum creatinine ≤ 1.5 times the upper limit of normal (ULN) OR creatinine clearance ≥ 60 mL/min * Bilirubin ≤ 1.5 times ULN (unless documented Gilbert disease) * AST and ALT \< 1.5 times ULN * Potassium ≥ 3.5 mmol/L * Patient must have a testosterone value of \< 50 ng/dL obtained within 28 days prior to registration * Patients must have controlled blood pressure defined as systolic blood pressure \< 160 mm Hg and diastolic blood pressure \< 95 mm Hg * Patients with a history of hypertension are eligible provided blood pressure is controlled by anti-hypertensive treatment * Patients who have partners of child-bearing potential must be willing to use a method of birth control with adequate barrier protection during the study and for 1 week after the last study drug administration * Must be able to take oral medication without crushing, dissolving, or chewing tablets * Patients must not have a history of gastrointestinal disorders (medical disorders or extensive surgery) that may interfere with the absorption of abiraterone acetate * No other prior malignancy is allowed except for any of the following: * Adequately treated basal cell or squamous cell skin cancer * Adequately treated stage I or II cancer from which the patient is currently in complete remission * Any other cancer from which the patient has been disease-free for 5 years * No patients with active or symptomatic viral hepatitis or chronic liver disease * No moderate (Child-Pugh B) or severe (Child-Pugh C) hepatic impairment * No history of NYHA class III or IV heart failure * Patients must have LVEF ≥ 50% * No known allergies, hypersensitivity, or intolerance to abiraterone acetate, prednisone, or their excipients PRIOR CONCURRENT THERAPY: * See Disease Characteristics * Patients with a history of prior neoadjuvant or adjuvant GNRH agonist/antagonist therapy (related to previous surgery or radiation) are eligible provided they finished this therapy at least two years prior to registration * Prior enrollment to SWOG-S0925 (either arm) is not exclusionary * At least 6 weeks since prior and no concurrent finasteride or dutasteride * At least 28 days since prior radiotherapy or surgery and recovered * At least 4 weeks since prior investigational products * At least 4 weeks since prior flutamide (6 weeks for bicalutamide and nilutamide) with no evidence of a falling PSA * No other concurrent oral antiandrogen * No prior or concurrent cytotoxic chemotherapy or radiopharmaceuticals for prostate cancer * No prior or concurrent ketoconazole for the treatment of prostate cancer * Not requiring more than 10 mg a day of prednisone for another medical indication * Not planning to receive any concurrent cytotoxic chemotherapy, immunotherapy, surgery, or radiotherapy during protocol treatment * No concurrent hormonal-acting agents, including diethylstilbestrol/DES, aldosterone, PC-SPES, or spironolactone * No concurrent antifungal medication (e.g., fluconazole or itraconazole) * No medications that alter cardiac conduction * No prior Provenge (sipuleucel-T)