The purpose of this study is to evaluate the efficacy, based on prostate-specific antigen (PSA) progression, of abiraterone acetate in participants with metastatic (spread of cancer cells from one part of the body to another) castration (any action, surgical, chemical, or otherwise, by which a male loses the functions of the testes) resistant prostate cancer (cancer in prostrate; a gland that makes fluid that aids movement of sperm) (mCRPC), chemo-naive (treatment of cancer is not done using drugs), who received a prior diethylstilbestrol therapy (DES).
This is a Phase 2, multinational (when medical research study takes place in more than one country), multicenter (when more than one hospital or medical school team work on a medical research study), open-label (all people know the identity of the intervention), and single arm study to determine benefits of abiraterone acetate and low-dose prednisone to androgen deprivation therapy (ADT) in mCRPC participants who failed to prior DES therapy. The study will consist of a Screening Phase of up to 28 days before enrollment; a PSA Evaluation Phase; and a Follow-up Phase of up to 24 months. Each cycle of abiraterone therapy will be of 28 days. Participants will receive 1000 milligram (mg) abiraterone acetate orally once daily plus prednisone 5 mg orally once daily plus stable regimen of ADT (luteinizing hormone-releasing hormone \[LHRH\] agonists) as per Investigator's discretion. Treatment will continue until PSA progression, clinical progression, consent withdrawal, or the occurrence of unacceptable toxicity. Efficacy will primarily be assessed by time to PSA progression. Participants' safety will be monitored throughout the study.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
46
Participants will receive abiraterone acetate 1000 mg (4\*250 mg tablets) orally once daily until PSA progression, clinical progression, consent withdrawal, or the occurrence of unacceptable toxicity.
Participants will prednisone 5 mg orally once daily from Day 1 of Cycle 1 and continues until PSA progression, clinical progression, consent withdrawal, or the occurrence of unacceptable toxicity.
Participants will remain on a stable regimen of ADT, that is, luteinizing hormone-releasing hormone (LHRH) agonists including leuprolide acetate and goserelin acetate as per Investigator's discretion.
Unnamed facility
Porto Alegre, Brazil
Unnamed facility
Rio de Janeiro, Brazil
Unnamed facility
Santo André, Brazil
Unnamed facility
São Paulo, Brazil
Time to Prostate-specific Antigen (PSA) Progression
Time to PSA progression was calculated from date of enrollment to the date of first documentation of PSA progression. As per Prostate Cancer Clinical Trials Working Group (PCWG2) criteria, PSA progression was defined as greater than or equal to (\>=) 25 percent (%) and \>=2 nanogram/milliliter (ng/mL) after 12 weeks (in case of no decline in PSA from Baseline), or first PSA increase that is \>=25% and \>=2 ng/mL above the nadir, and which was confirmed by a second value 3 or more weeks later (in case of decline of PSA from Baseline).
Time frame: Up to 2 years
Percentage of Participants Who Achieved Prostate-Specific Antigen (PSA) Response
The PSA response according to Prostate Specific Antigen Working Group 3 criteria was defined as at least 50% decrease in PSA level from Baseline.
Time frame: Week 12 to any time up to 2 years
Overall Survival
Overall survival was defined as the time from date of the first dose of abiraterone acetate to the date of death due to any cause. For participants who did not die until the time of analysis, survival time was censored at the time of last contact alive.
Time frame: Up to 4 years
Percentage of Participants With Pain Progression as Assessed by Brief Pain Inventory - Short Form (BPI-SF) - Pain Severity Score
The BPI-SF is a publicly available instrument to assess the pain and includes severity and interference scores. BPI-SF is an 11-item self-report questionnaire that is designed to assess the severity and impact of pain on daily functions of a participant. Pain severity score is a mean value for BPI-SF questions 3, 4, 5 and 6 (questions inquiring about the extent of pain, where the extent is ranked from 0 \[no pain\] to 10 \[pain as bad as you can imagine\]). Pain severity progression was defined as an increase in score of 30% or greater from baseline without decrease in analgesic use.
Time frame: Up to 2 years
Percentage of Participants With Pain Progression as Assessed by Brief Pain Inventory - Short Form (BPI-SF) - Pain Interference Score
The BPI-SF is a publicly available instrument to assess the pain and includes severity and interference scores. BPI-SF is an 11-item self-report questionnaire that is designed to assess the severity and impact of pain on daily functions of a participant. Pain interference score is mean value for the 7 BPI-SF questions (questions inquiring about the extent of interference with activities by pain) where the extent is ranked from 0 (does not interfere) to 10 (completely interferes). Pain interference progression was defined as an increase in score of 50% or greater from baseline without decrease in analgesic use.
Time frame: Up to 2 years
Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)
An AE is any untoward medical occurrence in a participant who will receive study drug without regard to possibility of causal relationship. An SAE is an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; or congenital anomaly.
Time frame: Up to 4 years
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