The primary objective of this study is to measure efficacy of saruparib + physician's choice of ARPI compared with placebo + ARPI in men with metastatic hormone-sensitive prostate cancer (mHSPC) who have previously received docetaxel chemotherapy or a prostate-specific membrane antigen (PSMA)-directed lutetium-177 radioligand therapy with no evidence of disease progression and PSA ≥ 0.2 ng/mL.

Inclusion Criteria:

• Participant must be ≥ 18 at the time of signing the informed consent.

• Histologically documented diagnosis of prostate adenocarcinoma that is de novo or recurrent and hormone-sensitive.

• Metastatic disease confirmed prior to initiation of previous treatment with docetaxel or Lu-PSMA-containing regimens for mHSPC.

• Previous treatment with docetaxel (IV, Q3w)- or Lu-PSMA (IV, Q6w) with last dose within past 6 months.

• Participants must have the following:

  • Must be receiving ADT with a GnRH analogue or has undergone bilateral orchiectomy.
  • Had no evidence of disease progression
  • Had all toxicities related to docetaxel- or Lu-PSMA-containing treatment (except for alopecia and peripheral neuropathy) resolved to CTCAE Grade 1 or lower.

• PSA ≥ 0.2 ng/mL within 14 days prior to randomization.

• Serum testosterone < 1.7 nmol/L or 50 ng/dL.

• Palliative radiotherapy for symptoms management will be permitted and is to be completed at least 4 weeks prior to randomization for wide field radiation therapy and at least 2 weeks prior to randomization for limited field radiation therapy.

• Provision of a FFPE tumor tissue sample and a blood sample (for ctDNA).

• Confirmed HRRm, HRD and PTEN status.

• Adequate organ and bone marrow function.

• Minimum life expectancy of 6 months.

• Male, assigned at birth, inclusive of all gender identities.

• Contraceptive use by participants or participant partners should be consistent with local regulations.

• Capable of giving signed informed consent.

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Exclusion Criteria:

• Hypersensitivity to saruparib, ARPI or any excipients of these products or any contraindication or restriction based on the local label.
• Any history of persisting (> 2 weeks) severe cytopenia due to any cause (eg, ANC< 0.5 × 10^9/L or platelets < 50 × 10^9/L)
• Any known predisposition to bleeding (eg, active peptic ulceration, recent [within6 months] hemorrhagic stroke, proliferative diabetic retinopathy.
• Spinal cord compression or brain metastases unless asymptomatic and stable.
• History of MDS/AML or with features suggestive of MDS/AML
• History of another primary malignancy, with some exceptions.
• Any chronic gastrointestinal diseases or conditions including inability to swallow the formulated product that would preclude adequate absorption of any study drug.
• History of seizure or predispose to seizure, including any history of loss of consciousness or transient ischemic attack within 12 months of enrolment.
• Serious, uncontrolled medical disorder, non-malignant systemic disease or active, uncontrolled infection.
• Major surgical procedure or significant traumatic injury within 4 weeks of the first dose or an anticipated need for major surgery during the study.
• Switched ARPI agent in previous treatment for mHSPC due to disease progression. Note: if the ARPI agent was switched due to any reason other than disease progression and switch was prior to ICF signature, participants will be eligible.
• Any prior treatment with a PARPi or platinum chemotherapy.
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Qualified researchers can request access to anonymized individual patient-level data from AstraZeneca group of companies sponsored clinical trials via the request portal Vivli.org. All requests will be evaluated as per the AZ disclosure commitment: https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

Yes, indicates that AZ are accepting requests for IPD, but this does not mean all requests will be shared.

AstraZeneca will meet or exceed data availability as per the commitments made to the EFPIA PhRMA Data Sharing Principles. For details of our timelines, please rerefer to our disclosure commitment at https://astrazenecagrouptrials.pharmacm.com/ST/Submission/Disclosure.

When a request has been approved AstraZeneca will provide access to the anonymized individual patient-level data via secure research environment Vivli.org. Signed Data Usage Agreement (non-negotiable contract for data accessors) must be in place before accessing requested information.

Double-blind