A Phase 2 Study to Evaluate Safety and Efficacy of Abiraterone Acetate in Male Participants With Prostate Cancer

• Testosterone Concentration in Prostate Tissue [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  Testosterone is a potent androgen (a hormone that promotes the development and maintenance of male characteristics) and major product secreted by cells in the testis and produced in the adrenal glands and by prostate cancers. Abiraterone acetate affects sources of testosterone in the body (ie, adrendal gland and prostate tumor). Testosterone concentration was measured in prostate tissues after exposure to study treatments at Week 12.
  
  
• Dihydrotestosterone (DHT) Concentration in Prostate Tissue [ Time Frame: Week 12 ] [ Designated as safety issue: No ]
  The DHT is a potent androgenic metabolite of testosterone and the concentration of DHT was measured in prostate tissues after exposure to study treatments at Week 12.
  
  

• Testosterone and Dihydrotestosterone (DHT) Concentration in Prostate Tissue [ Time Frame: Week 24 ] [ Designated as safety issue: No ]
  Testosterone is a potent androgen (a hormone that promotes the development and maintenance of male characteristics) and major product secreted by cells in the testis and produced in the adrenal glands and by prostate cancers. Dihydrotestosterone (DHT) is a potent androgenic metabolite of testosterone. Testosterone and DHT concentration was measured in prostate tissues after exposure to study treatments at Week 24.
  
  
• Androstenedione and Dehydroepiandrosterone (DHEA) Concentrations in Prostate Tissue [ Time Frame: Week 12 and 24 ] [ Designated as safety issue: No ]
  Androstenedione is a steroid (a group of polycyclic compounds closely related biochemically to terpenes, for example, cholesterol, numerous hormones), that is produced in the testis, ovary and the adrenal cortex, and depending on the tissue type, androstenedione can serve as a precursor to testosterone, estrone and estradiol. The DHEA is a major steroid produced by the adrenal cortex. It is also produced in small quantities in the testis and the ovary. Androstenedione and DHEA concentration was measured in prostate tissues at Week 12 and 24.
  
  
• Serum Levels of Androgens [ Time Frame: Week 12 and 24 ] [ Designated as safety issue: No ]
  Serum concentrations of testosterone, DHT, androsterone, DHEA, DHEA-Sulfate, DHEA-Glucuronide and delta-4-androstenedione were measured at Weeks 12 and 24.
  
  
• Percentage of Participants With Prostate-specific Antigen (PSA) Response [ Time Frame: Weeks 12 and 24 ] [ Designated as safety issue: No ]
  The PSA response was evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST) criterion which is, percentage of participants with PSA less than or equal to 0.2 nanogram/milliliter at Weeks 12 and 24 after androgen deprivation.
  
  
• Percentage of Participants With Pathologic Complete Response (CR) [ Time Frame: Week 24 ] [ Designated as safety issue: No ]
  Complete response is defined as a disappearance of all target lesions and was assessed by the Response Evaluation Criteria in Solid Tumors (RECIST) criterion.
  
  
• Number of Participants With Tumor Expression of Androgen Receptor (AR) Regulated Genes at Week 24 [ Time Frame: Week 24 ] [ Designated as safety issue: No ]
  Tumor expression of AR regulated genes determined by real-time polymerase chain reaction (RT PCR). PCR is an in vitro method for producing large amounts of specific deoxyribonucleic acid (DNA) or ribonucleic acid fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). RT PCR is a method used for detecting the amplified DNA products from the PCR as they accumulate instead of at the end of the reaction.
  
  
• Correlation Between Molecular and Protein Expression With Intracellular Androgen Levels and Pathologic Response to Study Treatment [ Time Frame: Week 24 ] [ Designated as safety issue: No ]
  Molecular and protein expression was correlated with intracellular androgen levels and pathologic response to study treatment.
  
  

This is an open-label (all people know the identity of the intervention), randomized (the study drug is assigned by chance), and multi-center (conducted in more than one center) study of abiraterone in male participants with prostate cancer. The duration of study will be approximately 24-32 weeks per participant. The study consists of 4 parts: Screening (that is, 30 days before study commences on Day 1); Treatment (abiraterone acetate 1000 milligram per day or leuprolide acetate as 22.5 milligram intramuscular injection [injection of a substance into a muscle] or prednisone 5 mg once daily); Prostatectomy (Week 24); and Follow-up ( 4-8 weeks after prostatectomy). Participants will receive either abiraterone, leuprolide and prednisone for 24 weeks (that is, Group 1) or leuprolide once every 12 weeks up to Week 24 then abiraterone and prednisone from Week 13 to 24 (that is, Group 2). All the eligible participants will be randomly assigned to 1 of the 2 treatment groups. Efficacy will be evaluated primarily through the concentrations of testosterone and dihydrotestosterone from prostate tissues at Week 12. Participants' safety will be monitored throughout the study.