IMAAGEN: Impact of Abiraterone Acetate in Prostate-Specific Antigen

The purpose of this study is to show that abiraterone acetate plus prednisone added to the current standard of care, gonadotropin-releasing hormone (GnRH) decreases prostate specific antigen (PSA) and prolongs the time until it is evident that the cancer has grown. Additionally, safety information about abiraterone acetate in combination with prednisone will be collected. This will include looking at what side effects occur, how often they occur, and for how long they last.

This is a Phase 2, prospective, multicenter, open-label, single-arm study of abiraterone acetate plus prednisone in men with non-metastatic, castration-resistant prostate cancer (CRPC) who have a rising PSA despite castrate levels of testosterone. The study consists of Screening Phase (up to 4 weeks), Core Study Treatment Phase (comprised of six 28-day cycles), a Pre-metastatic Disease Follow-up Phase, an Optional Drug Holiday Phase; and a 30-day Safety Follow-up Visit. Each treatment cycle will last 28 days. Participating participants will receive study agents (Abiraterone acetate 1000 mg/day plus prednisone 5 mg/day, orally) continually during the study. If the partcipants elects to participate in the Optional Drug Holiday Phase, participants will discontinue abiraterone acetate plus prednisone and ADT. Participants will have the option to return to study medication during the first year of the Optional Drug Holiday Phase if there is evidence of rising PSA but no metastasis based on study imaging. If participants do no elect to participate, they will continue with the core study treatment as per protocol. The study will end when all participated participants have disease progression or end of the 2-year period (if participants participated in the Optional Drug Holiday Phase). Participants will be required to return to the study site 30 days after receiving the last dose of abiraterone acetate for safety follow-up.

Eligibility Criteria:
Major Inclusion Criteria:

* Be a male \>= 18 years of age
* Have adenocarcinoma of the prostate
* Currently receiving continuous treatment with Gonadotropin-releasing hormone (GnRH) monotherapy for at least 6 months before or have undergone surgical removal of the testicles
* Serum testosterone of \< 50 ng/dL(\< 2.0 nM)
* Have rising PSA defined as a PSA of \>= 10 ng/mL obtained at screening or PSADT of ≤ 10 months with the first of the 3 consecutive PSA values used to calculate PSADT ≥ 2.0 ng/mL
* Have an Eastern Cooperative Oncology Group (ECOG) performance status less than or equal to 2
* Be capable of swallowing study agents whole as a tablet
* Be willing/able to adhere to the prohibitions and restrictions specified in this protocol

Major Exclusion Criteria:

* Have prior or current evidence of local disease progression or metastatic disease as defined by modified response evaluation criteria in solid tumors (RECIST) criteria
* Have received chemotherapy for treatment of castrate-resistant prostate cancer; however, if a patient received chemotherapy in an adjuvant setting, prior to having CRPC, for castrate-sensitive prostate cancer, the patient is still eligible
* Are currently receiving any antiandrogen therapy (eg, bicalutamide, flutamide, or nilutamide).
* If previously treated with antiandrogen therapy, there must be documentation of at least 2 consecutive rising PSA values at least 2 weeks apart obtained prior to screening
* If previously treated with flutamide, at least 1 of the PSA values must be obtained 4 weeks or more after flutamide discontinuation.
* If previously treated with bicalutamide or nilutamide, at least 1 of the PSA values must be obtained 6 weeks or more after antiandrogen discontinuation
* Have previously received agents having any CYP17 inhibitory activity for the treatment of prostate cancer, such as ketoconazole
* Have previously received aminoglutethimide
* Have an active infection or other medical condition that would contraindicate prednisone use
* Have uncontrolled hypertension
* Have active hepatitis or chronic liver disease
* Have clinically significant heart disease
* Have poorly controlled diabetes
* Have received an investigational therapeutic within 30 days of screening
* Have partners of childbearing potential and are not 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.
* Individuals with a history of a non-prostate malignancy are ineligible for this study with the following exceptions. Individuals with a history of other malignancies are eligible if they have been disease-free for at least 3 years and are deemed by the investigator to be at low risk for recurrence of that malignancy. Individuals with the following cancers are eligible if diagnosed and treated within the past 3 years: basal cell or squamous cell carcinoma of the skin