Study on Olaparib Plus Abiraterone as First-line Therapy in Men With Metastatic Castration-resistant Prostate Cancer

• ClinicalTrials.gov Identifier: NCT03732820
• Recruitment Status: Active, not recruiting
• First Posted: November 7, 2018
• Results First Posted: June 15, 2023
• Last Update Posted: February 28, 2024
• Sponsor: AstraZeneca
• Collaborator: Merck Sharp & Dohme LLC
• Information provided by (Responsible Party): AstraZeneca

Tracking Information

• First Submitted Date: September 28, 2018
• First Posted Date: November 7, 2018
• Results First Submitted Date: July 29, 2022
• Results First Posted Date: June 15, 2023
• Last Update Posted Date: February 28, 2024
• Actual Study Start Date: October 31, 2018
• Actual Primary Completion Date: July 30, 2021 (Final data collection date for primary outcome measure)

Current Primary Outcome Measures (submitted: May 22, 2023)

Number of Participants With Radiological Progression Free Survival (rPFS) Event by Investigator Assessment [ Time Frame: Assessed from date of randomisation to data cut off (DCO1): 30Jul2021 (Approx. 2 years 9 months) ]

An rPFS event is defined as progression determined by Response Evaluation Criteria in Solid Tumours version 1.1 [RECIST 1.1] and/or Prostate Cancer Working Group 3 [PCWG-3] or death (by any cause in the absence of progression), regardless of whether the patient withdraws from randomised therapy or receives another anticancer therapy prior to progression. Per RECIST v1.1, progression is defined as the sum of TLs has a 20% and absolute ≥ 5mm increase from nadir, and/or unequivocal progression in any non target lesions, and/or any new lesion identified. Per PCWG3, progression on a bone scan is defined as 2 or more new lesions observed from the first visit after baseline compared to baseline, or from all other visits compared to first visit after baseline. A confirmatory scan is required.

Original Primary Outcome Measures (submitted: November 5, 2018)

Radiological progression free survival (rPFS) [ Time Frame: From date of randomization to study completion (up to 4 years) ]

Radiological progression free survival (rPFS) - defined as the time from randomisation to

1. radiographic progression, assessed by investigator per Response Evaluation Criteria in Solid Tumours (RECIST) 1.1 (soft tissue) and Prostate Cancer Working Group-3 (PCWG-3) criteria (bone), or
2. death from any cause, whichever occurs first

Current Secondary Outcome Measures (submitted: December 5, 2023)

• Number of Participants With Overall Survival (OS) Event [ Time Frame: Assessed from date of randomisation to data cut off (DCO3): 12Oct2022 (Approx. 3 years 11 months). DCO3 is the final data cut-off for the OS analysis and therefore no further updates will be made. ]
  An OS event is defined as death by any cause, regardless of whether the patient withdraws from randomised therapy or receives another anticancer therapy.
• Number of Participants With Time to First Subsequent Anticancer Therapy or Death (TFST) Event [ Time Frame: Assessed from date of randomisation to data cut off (DCO3): 12Oct2022 (Approx. 3 years 11 months) ]
  A TFST (excluding radiotherapy) event is defined as the start of the first subsequent anticancer therapy after discontinuation of randomised treatment or death from any cause.
• Number of Participants With Time to Pain Progression (TTPP) Event [ Time Frame: Assessed from date of randomisation to data cut off (DCO3): 12Oct2022 (Approx. 3 years 11 months) ]
  A TTPP event is defined as pain progression based on the Brief Pain Inventory-Short Form (BPI-SF) Item 3 (range 0-10, a higher score indicates worse pain) and opiate analgesic use (Analgesic quantification algorithm [AQA] score, range 0-7, a higher score indicates increased opioid use). For patients who are asymptomatic at baseline (average worst pain score of 0 and not taking opioids): A ≥2 point change from baseline in average (4-7 days) worst pain score observed at 2 consecutive visits or initiation of opioid use; For patients who are symptomatic at baseline (average worst pain score >0 and/or receiving opioids): A ≥2 point change from baseline in average (4-7 days) worst pain score observed at 2 consecutive visits and an average worst pain score ≥4, and no decrease in average opioid use (≥1-point decrease in AQA score from a starting value of ≥2), or increase in opioid use (≥1-point increase, or ≥2-point increase if the starting value is 0) at 2 consecutive follow-up visits.
• Number of Participants With Opiate Use [ Time Frame: Assessed from date of randomisation to data cut off (DCO3): 12Oct2022 (Approx. 3 years 11 months) ]
  An event for opiate use is defined as the first opiate use for cancer related pain.
• Number of Participants With First Symptomatic Skeletal Related Event (SSRE) [ Time Frame: Assessed from date of randomisation to data cut off (DCO3): 12Oct2022 (Approx. 3 years 11 months) ]
  An SSRE event is defined as the first sympomatic skeletal-related event defined by

  • Use of radiation therapy to prevent or relieve skeletal symptoms.
  • Occurrence of new symptomatic pathological bone fractures (vertebral or non-vertebral).
• Number of Participants With Second Progression or Death (PFS2) Event [ Time Frame: Assessed from date of randomisation to data cut off (DCO3): 12Oct2022 (Approx. 3 years 11 months) ]
  An event for PFS2 is defined as the second progression on next-line anticancer therapy or death, whichever occurs earlier.
• Brief Pain Inventory-Short Form (BPI-SF) [ Time Frame: Assessed from date of randomisation to data cut off (DCO3): 12Oct2022 (Approx. 3 years 11 months) ]
  The BPI-SF is a validated, 15-item domain-specific instrument designed to assess the severity of pain and the impact/interference of pain on daily functions. BPI-SF worst pain, pain severity and pain interference score changes can be a minimum of -10 and a maximum of 10. A negative change from baseline value indicates improvement.
• Functional Assessment of Cancer Therapy- Prostate Cancer (FACT-P) [ Time Frame: Assessed from date of randomisation to data cut off (DCO3): 12Oct2022 (Approx. 3 years 11 months) ]
  Functional Assessment of Cancer Therapy-Prostate Cancer (FACT-P) total score and Functional Assessment of Cancer Therapy-General (FACT-G) total score. Total FACT-P score is the sum of Physical Well-being (PWB), Social Well-being (SWB), Emotional Well-being (EWB), Functional Well-being (FWB) and Prostate cancer subscale (PCS). FACT-P total score change from baseline values can be a minimum of -156 and a maximum of 156. A positive value indicates improvement. FACT-G total score is the sum of PWB, SWB, EWB and FWB. FACT-G Total score change from baseline values can be a minimum of -108 and a maximum of 108. A positive value indicates improvement.

Original Secondary Outcome Measures (submitted: November 5, 2018)

• Time to first subsequent anticancer therapy or death (TFST) [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  Time from randomisation to the earlier of the first subsequent anticancer therapy start date following study treatment discontinuation or death from any cause
• Time to pain progression (TTPP) [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  Time to pain progression (TTPP) is defined as the time from randomisation to pain progression based on the Brief Pain Inventory-Short Form (BPI-SF) Item 3 "worst pain in 24 hours" and opiate analgesic use (analgesic quantification algorithm [AQA] score)
• Overall survival (OS) [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  Time from randomisation to death from any cause
• Time to opiate use [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  Time from randomisation to the first opiate use for cancer-related pain
• Time to a Symptomatic Skeletal-Related Event (SSRE) [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  A Symptomatic Skeletal-Related Event (SSRE) is defined as use of radiation therapy to bone in order to prevent or relieve skeletal complications, occurrence of new symptomatic pathological bone fractures (vertebral or non-vertebral, resulting from minimal or no trauma), occurrence of radiologically confirmed spinal cord compression or a tumour-related orthopaedic surgical intervention.
• Circulating Tumour Cells (CTC) conversion [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  Proportion of patients who achieve a decline in the number of Circulating Tumour Cells (CTCs) from ≥5 cells/7.5 mL at baseline to <5 cells/7.5 mL at any time post baseline in whole blood (Circulating Tumour Cells (CTC) conversion rate)
• Time to second progression or death (PFS2) [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  Time from randomisation to second progression or clinical progression or death
• Brief Pain Inventory-Short Form (BPI-SF) [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  To assess progression in pain severity domain, change in pain interference domain, and pain palliation
• Functional Assessment of Cancer Therapy- Prostate Cancer (FACT-P) [ Time Frame: From date of randomization to study completion (up to 4 years) ]
  Functional Assessment of Cancer Therapy- Prostate Cancer (FACT-P) total score, Functional Assessment of Cancer Therapy- General (FACT-G) total score, trial outcome index, functional well-being, physical well-being, prostate cancer subscale, and Functional Assessment of Cancer Therapy (FACT) Advanced Prostate Symptom Index-6 (FAPSI-6)
• Homologous Recombination Repair (HRR) gene status [ Time Frame: At baseline ]
  Tumour and blood samples for mutations in Breast Cancer 1 gene (BRCA1), or Breast Cancer 2 gene (BRCA2), Ataxia-telangiectasia mutated (ATM) and 12 other Homologous Recombination Repair (HRR) genes will be evaluated.
• Maximum plasma concentration at steady state [Cmax,ss] [ Time Frame: Week 5 from 45 min before the first olaparib dose, up to 9 hours post dose ]
  To characterize the steady state Pharmacokinetics (PK) of olaparib, in the presence of abiraterone.
• Time to maximum plasma concentration at steady state (Cmax,ss) [tmax,ss] [ Time Frame: Week 5 from 45 min before the first olaparib dose, up to 9 hours post dose ]
  To characterize the steady state Pharmacokinetics (PK) of olaparib, in the presence of abiraterone.
• Minimum plasma concentration at steady state [Cmin,ss] [ Time Frame: Week 5 from 45 min before the first olaparib dose, up to 9 hours post dose ]
  To characterize the steady state Pharmacokinetics (PK) of olaparib, in the presence of abiraterone.
• Partial area under the concentration-time curve in 0-8 h [AUC0-8]) [ Time Frame: Week 5 from 45 min before the first olaparib dose, up to 9 hours post dose ]
  To characterize the steady state Pharmacokinetics (PK) of olaparib, in the presence of abiraterone.
• Maximum plasma concentration at steady state [Cmax,ss] [ Time Frame: Week 5 from 45 min before the abiraterone dose, up to 9 hours post dose ]
  To characterize the steady state Pharmacokinetics (PK) of abiraterone and its active metabolite Δ4-abiraterone, in the presence and absence of olaparib.
• Time to maximum plasma concentration at steady state (Cmax,ss) [tmax,ss] [ Time Frame: Week 5 from 45 min before the abiraterone dose, up to 9 hours post dose ]
  To characterize the steady state Pharmacokinetics (PK) of abiraterone and its active metabolite Δ4-abiraterone, in the presence and absence of olaparib.
• Minimum plasma concentration at steady state [Cmin,ss] [ Time Frame: Week 5 from 45 min before the abiraterone dose, up to 9 hours post dose ]
  To characterize the steady state Pharmacokinetics (PK) of abiraterone and its active metabolite Δ4-abiraterone, in the presence and absence of olaparib.
• Partial area under the concentration-time curve [AUC0-8]) [ Time Frame: Week 5 from 45 min before the abiraterone dose, up to 9 hours post dose ]
  To characterize the steady state Pharmacokinetics (PK) of abiraterone and its active metabolite Δ4-abiraterone, in the presence and absence of olaparib.
• Number of adverse events [ Time Frame: From the time of signature of informed consent throughout the treatment period (up to 4 years plus 30 days) ]
  Percentage of patients with any adverse event (AE), adverse event (AE) leading to study drug discontinuation, adverse event (AE) leading to death, serious adverse event (SAE), adverse event (AE) related to study drug, serious adverse event (SAE) related to study drug
• Vital signs-blood pressure [ Time Frame: From the time of signature of informed consent throughout the treatment period (up to 4 years plus 30 days) ]
  To assess systolic and diastolic blood pressure as variable of safety and tolerability of the combination of olaparib and arbiraterone vs placebo and arbiraterone
• Vital signs-pulse rate [ Time Frame: From the time of signature of informed consent throughout the treatment period (up to 4 years) ]
  To assess pulse rate as variable of safety and tolerability of the combination of olaparib and arbiraterone vs placebo and arbiraterone
• Vital signs-body temperature [ Time Frame: From the time of signature of informed consent throughout the treatment period (up to 4 years) ]
  To assess body temperature as variable of safety and tolerability of the combination of olaparib and arbiraterone vs placebo and arbiraterone
• ECG [ Time Frame: From the time of signature of informed consent throughout the treatment period (up to 4 years) ]
  To assess 12 lead resting ECG as variable of safety and tolerability of the combination of olaparib and arbiraterone vs placebo and arbiraterone. According to Clinical Study Protocol all ECGs should be assessed by the investigator as to whether they are clinically significantly abnormal / not clinically significantly abnormal.
• Change in Albumin (g/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Albumin recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Alkaline phosphatase (U/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Alkaline phosphatase recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Aspartate aminotransferase (U/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Aspartate aminotrasnferase recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Amylase (U/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Amylase recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Alanine aminotransferase (U/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Alanine aminotransferase recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Total bilirubin (μmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Total bilirubin recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Direct bilirubin [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Direct bilirubin recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Calcium (mmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Calcium recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Chloride (mmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Chloride recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Creatinine (μmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Creatinine recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Gamma glutamyltransferase (U/L) [ Time Frame: At screening only ]
  Data for Gamma glutamyltransferase recorded in the eCRF will be listed and summarized by treatment group.
• Change in Fasting gucose (mmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Fasting glucose recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Lactate dehydrogenase (U/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Lactate dehydrogenase recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Magnesium (mmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Magnesium recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Potassium (mmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Potassium recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Phosphorus ((mmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Phosphorus will be recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Sodium (mmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Sodium recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Carbon dioxide (mEq/L ) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Carbon dioxide recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Total protein (g/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for protein recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Urea or blood urea nitrogen, depending on the local practice (mmol/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for urea or urea nitrogen recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in absolute neutrophil count (/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for absolute neutrophil recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in absolute lymphocyte count (/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for absolute lymphocyte recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in haemoglobin (g/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for haemoglobin recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in platelet count with differential (/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for platelet count with differential recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in total white blood cell count with differential(/L) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for WBC count recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in red blood cell count (/l) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for RBC count recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Haematocrit (%) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for Haematocrit recorded in the eCRF will be listed and summarized by treatment group and visit.
• Change in Mean Cell Volume (fL) [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for MCV count recorded in the eCRF will be listed and summarized by treatment group and visit.
• Urinalysis:change in blood [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for blood testing recorded in the eCRF will be listed and summarized by treatment group and visit.
• Urinalysis: Change in protein [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for urine protein recorded in the eCRF will be listed and summarized by treatment group and visit.
• Urinalysis: change in glucose [ Time Frame: At scheduled visits from screening to 30 days after last dose of study medication ]
  Data for urine glucose recorded in the eCRF will be listed and summarized by treatment group and visit.

• Current Other Pre-specified Outcome Measures: Not Provided
• Original Other Pre-specified Outcome Measures: Not Provided

Descriptive Information

• Brief Title: Study on Olaparib Plus Abiraterone as First-line Therapy in Men With Metastatic Castration-resistant Prostate Cancer
• Official Title: A Randomised, Double-blind, Placebo-controlled, Multicentre Phase III Study of Olaparib Plus Abiraterone Relative to Placebo Plus Abiraterone as First-line Therapy in Men With Metastatic Castration-resistant Prostate Cancer (PROpel Study)
• Brief Summary: The purpose of this study is to evaluate the efficacy and safety (including evaluating side effects) of combination of olaparib and abiraterone versus placebo and abiraterone in patients with metastatic castration-resistant prostate cancer (mCRPC) who have received no prior cytotoxic chemotherapy or new hormonal agents (NHAs) at metastatic castration-resistant prostate cancer (mCRPC) stage.

Detailed Description

PROpel is a phase III study evaluating the efficacy, safety, and tolerability of olaparib versus placebo when given in addition to abiraterone to patients with metastatic castration-resistant prostate cancer (mCRPC) who have not received prior chemotherapy or new hormonal agents (NHAs) for metastatic castration-resistant prostate cancer (mCRPC) (first-line setting).

Approximately 720 patients globally were planned to be randomized in PROpel in a 1:1 ratio to treatment with either olaparib and abiraterone or placebo and abiraterone. Enrolment had completed with a total of 796 patients randomised. Following the completion of global enrolment, the China cohort will randomise approximately 108 additional patients at sites in China, also in a 1:1 ratio.

Patients will receive oral treatment with olaparib 300 mg twice daily + abiraterone 1000 mg once daily or placebo twice daily + abiraterone 1000 mg once daily. Patients in both treatment groups will also receive either prednisone or prednisolone 5 mg twice daily.

• Study Type: Interventional
• Study Phase: Phase 3
• Study Design: Allocation: Randomized; Intervention Model: Parallel Assignment; Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor); Primary Purpose: Treatment
• Condition: Metastatic Castration-resistant Prostate Cancer

Intervention

• Drug: olaparib
  300 mg (2 x 150 milligrams (mg) tablets) twice daily
  Other Name: Lynparza
• Drug: abiraterone acetate
  1000 milligrams (mg) once daily
  Other Name: Zytiga

Study Arms

• Experimental: olaparib plus abiraterone

  Olaparib is available as a film-coated tablet containing 100 milligrams (mg) or 150 milligrams (mg) of olaparib. Subjects will be administered olaparib orally at a dose of 300 milligrams (mg) twice daily (bid). The initial dosage of 300 milligrams (mg) twice daily will be composed of 2 x 150 milligrams (mg) tablets per dose. The 100 milligrams (mg) and 150 milligrams (mg) tablets will be used to manage dose reductions during the study.

  Abiraterone acetate with prednisone or prednisolone will be sourced locally as commercially available materials. Subjects will be administered abiraterone orally at a dose of 1000 milligrams (mg) once daily, in combination with prednisone or prednisolone 5 milligrams (mg) administered orally twice daily.

  Interventions:

  • Drug: olaparib
  • Drug: abiraterone acetate
• Placebo Comparator: placebo plus abiraterone

  Placebo to match olaparib is available as a film-coated tablet in 100 milligrams (mg) or 150 milligrams (mg). Subjects will be administered placebo orally at a dose of 300 milligrams (mg) twice daily (bid). The initial dosage of 300 milligrams (mg) twice daily will be composed of 2 x 150 milligrams (mg) tablets per dose. The 100 milligrams (mg) and 150 milligrams (mg) tablets will be used to manage dose reductions during the study.

  Abiraterone acetate with prednisone or prednisolone will be sourced locally as commercially available materials. Subjects will be administered abiraterone orally at a dose of 1000 milligrams (mg) once daily, in combination with prednisone or prednisolone 5 milligrams (mg) administered orally twice daily.

  Intervention: Drug: abiraterone acetate

• Publications *: Not Provided

Recruitment Information

• Recruitment Status: Active, not recruiting
• Actual Enrollment (submitted: February 2, 2024): 895
• Original Estimated Enrollment (submitted: November 5, 2018): 720
• Estimated Study Completion Date: April 28, 2026
• Actual Primary Completion Date: July 30, 2021 (Final data collection date for primary outcome measure)

Eligibility Criteria

Inclusion Criteria:

1. Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form and in the study protocol.
2. Provision of signed and dated, written informed consent form prior to any mandatory study specific procedures, sampling, and analyses.

3. For inclusion in i) the optional exploratory genetic research and ii) the optional biomarker research, patients must fulfill the following criteria:

   • Provision of informed consent for genetic research prior to collection of sample.
   • Provision of informed consent for biomarker research prior to collection of sample.

   If a patient declines to participate in the optional exploratory genetic research or the optional biomarker research, there will be no penalty or loss of benefit to the patient. The patient will not be excluded from other aspects of the study.

4. Patients must be ≥18 years of age (or ≥19 years of age in South Korea) at the time of signing the informed consent form. For patients enrolled in Japan who are <20 years of age, written informed consent should be obtained from the patient and from his legally acceptable representative.
5. Histologically or cytologically confirmed prostate adenocarcinoma.
6. Metastatic status defined as at least 1 documented metastatic lesion on either a bone scan or a computed tomography(CT)/ magnetic resonance imaging (MRI) scan.
7. First-line metastatic castration-resistant prostate cancer (mCRPC).
8. Ongoing androgen deprivation with gonadotropin-releasing hormone analogue or bilateral orchiectomy, with serum testosterone <50 nanograms per decilitre (ng/dL) (<2.0 nanomoles per litre (nmol/L)) within 28 days before randomisation. Patients receiving androgen deprivation therapy (ADT) at study entry should continue to do so throughout the study.
9. Candidate for abiraterone therapy with documented evidence of progressive disease.
10. Patients must have normal organ and bone marrow function measured within 28 days prior to administration of study treatment.
11. Eastern Cooperative Oncology Group (ECOG) performance status 0-1, with no deterioration over the previous 2 weeks.
12. The participant has, in the opinion of the investigator, a life expectancy of at least 6 months.
13. Prior to randomisation, sites must confirm availability of either an archival formalin fixed, paraffin embedded (FFPE) tumour tissue sample, or a new biopsy taken during the screening window, which meets the minimum pathology and sample requirements in order to enable homologous recombination repair (HRR) status subgroup analysis of the primary endpoint radiographic progression-free survival (rPFS). If there is not written confirmation of the availability of tumour tissue prior to randomisation, the patient is not eligible for the study.
14. Male patients must use a condom during treatment and for 3 months after the last dose of olaparib+abiraterone when having sexual intercourse with a pregnant woman or with a woman of childbearing potential. Female partners of male patients should also use a highly effective form of contraception if they are of childbearing potential.

Exclusion Criteria:

1. Has a known additional malignancy that has had progression or has required active treatment in the last 5 years.
2. Patients with myelodysplastic syndrome (MDS)/ acute myeloid leukaemia (AML) or with features suggestive of yelodysplastic syndrome (MDS)/ acute myeloid leukaemia (AML).
3. Clinically significant cardiovascular disease Association Class II-IV heart failure or cardiac ejection fraction measurement of <50% during screening as assessed by echocardiography or multigated acquisition scan.
4. Planned or scheduled cardiac surgery or percutaneous coronary intervention procedure.
5. Prior revascularisation procedure (significant coronary, carotid, or peripheral artery stenosis).
6. Uncontrolled hypertension (systolic blood pressure (BP) ≥160 millimeters of mercury (mmHg) or diastolic blood pressure (BP) ≥95 millimeters of mercury (mmHg)).
7. History of uncontrolled pituitary or adrenal dysfunction.
8. Active infection or other medical condition that would make prednisone/prednisolone use contraindicated.
9. Any chronic medical condition requiring a systemic dose of corticosteroid >10 milligrams (mg) prednisone/prednisolone per day.
10. Patients who are considered a poor medical risk due to a serious, uncontrolled medical disorder, non-malignant systemic disease or active, uncontrolled infection.
11. Persistent toxicities (Common Terminology Criteria for Adverse Events [CTCAEs] grade >2) caused by previous cancer therapy, excluding alopecia.
12. Patients with brain metastases. A scan to confirm the absence of brain metastases is not required.
13. Patients with spinal cord compression are excluded unless they are considered to have received definitive treatment for this and have evidence of clinically stable disease for 4 weeks.
14. Patients who are unevaluable for both bone and soft tissue progression
15. Patients who are unable to swallow orally administered medication and patients with gastrointestinal disorders likely to interfere with absorption of the study medication.
16. Immunocompromised patients
17. Patients with known active hepatitis infection (ie, hepatitis B or C).
18. Any previous treatment with Polyadenosine 5'diphosphoribose [poly (ADP ribose)] polymerase (PARP) inhibitor, including olaparib.
19. Patients receiving any systemic chemotherapy or radiotherapy (except for palliative reasons) within 3 weeks prior to study treatment. Patients who receive palliative radiotherapy need to stop radiotherapy 1 week before randomisation.
20. Any previous exposure to a Cytochrome P450 (CYP) 17 (17α-hydroxylase/C17,20-lyase) inhibitor (eg, abiraterone, orteronel).
21. Concomitant use of known strong Cytochrome P450 (CYP) 3A inhibitors (eg, itraconazole, telithromycin, clarithromycin, protease inhibitors boosted with ritonavir or cobicistat, indinavir, saquinavir, nelfinavir, boceprevir, telaprevir) or moderate CYP3A inhibitors (eg, ciprofloxacin, erythromycin, diltiazem, fluconazole, verapamil). The required washout period prior to starting study treatment is 2 weeks.
22. Concomitant use of known strong Cytochrome P450 (CYP) 3A inducers (eg, phenobarbital, enzalutamide, phenytoin, rifampicin, rifabutin, rifapentine, carbamazepine, nevirapine or St John's wort) or moderate Cytochrome P450 (CYP) 3A inducers (eg, bosentan, efavirenz or modafinil). The required period prior to starting study treatment is 5 weeks for phenobarbital and enzalutamide and 3 weeks for other agents.
23. Major surgery within 2 weeks of starting study treatment and patients must have recovered from any effects of any major surgery.
24. Previous allogenic bone marrow transplant or double umbilical cord blood transplantation (dUCBT).
25. Participation in another clinical study with an investigational product or investigational medical devices within 1 month of randomisation.
26. History of hypersensitivity to olaparib or abiraterone, any of the excipients of olaparib or abiraterone, or drugs with a similar chemical structure or class to olaparib or abiraterone.
27. Involvement in the planning and/or conduct of the study (applies to both AstraZeneca and Merck staff and/or staff at the study site).
28. Judgment by the investigator that the patient should not participate in the study if the patient is unlikely to comply with study procedures, restrictions and requirements.
29. Previous randomisation in the present study.

Sex/Gender

• Sexes Eligible for Study: Male

• Ages: 18 Years to 99 Years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Contacts: Contact information is only displayed when the study is recruiting subjects
• Listed Location Countries: Australia, Belgium, Brazil, Canada, Chile, Czechia, France, Germany, Italy, Japan, Korea, Republic of, Netherlands, Slovakia, Spain, Turkey, United Kingdom, United States
• Removed Location Countries: China

Administrative Information

• NCT Number: NCT03732820
• Other Study ID Numbers: D081SC00001; 2018-002011-10 ( EudraCT Number )
• Has Data Monitoring Committee: Yes

U.S. FDA-regulated Product

• Studies a U.S. FDA-regulated Drug Product: Yes
• Studies a U.S. FDA-regulated Device Product: No

• IPD Sharing Statement: Not Provided
• Current Responsible Party: AstraZeneca
• Original Responsible Party: Same as current
• Current Study Sponsor: AstraZeneca
• Original Study Sponsor: Same as current
• Collaborators: Merck Sharp & Dohme LLC

Investigators

• Principal Investigator: Fred Saad, MD; University of Montreal Hospital Center
• Principal Investigator: Noel Clarke, M.D.; Christie Hospital Foundation Trust

• PRS Account: AstraZeneca
• Verification Date: February 2024