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Study of Pembrolizumab (MK-3475) Plus Olaparib Versus Abiraterone Acetate or Enzalutamide in Metastatic Castration-resistant Prostate Cancer (mCRPC) (MK-7339-010/KEYLYNK-010)

A Phase 3, Randomized Open-label Study of Pembrolizumab (MK-3475) Plus Olaparib Versus Abiraterone Acetate or Enzalutamide in Participants With Metastatic Castration-resistant Prostate Cancer (mCRPC) Who Are Unselected for Homologous Recombination Repair Defects and Have Failed Prior Treatment With One Next-generation Hormonal Agent (NHA) and Chemotherapy (KEYLYNK-010)

Status
Completed
Phases
Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT03834519
Acronym
KEYLYNK-010
Enrollment
793
Registered
2019-02-08
Start date
2019-05-02
Completion date
2024-01-27
Last updated
2025-05-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Prostatic Neoplasms

Keywords

Programmed Cell Death-1 (PD1, PD-1), Programmed Cell Death 1 Ligand 1 (PDL1, PD-L1), Programmed Cell Death 1 Ligand 2 (PDL2, PD-L2)

Brief summary

The purpose of this study is to assess the efficacy and safety of the combination of the polyadenosine 5'-diphosphoribose poly (ADP-ribose) polymerase (PARP) inhibitor olaparib and pembrolizumab in the treatment of participants with mCRPC who have failed to respond to either abiraterone acetate or enzalutamide (but not both) and to chemotherapy. The primary study hypotheses are that the combination of pembrolizumab plus olaparib is superior to abiraterone acetate or enzalutamide with respect to: 1. Overall Survival (OS) and 2. Radiographic progression-free survival (rPFS) per Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumors Version 1.1 as assessed by blinded independent central review (BICR) As of Amendment 06, the Data Monitoring Committee (DMC) is no longer applicable. Participants still on treatment may have the option to continue receiving study intervention or SOC if they are deriving clinical benefit, until criteria for discontinuation are met. Participants who are still on study treatment and deriving clinical benefit will no longer have tumor response assessments by BICR. However, local tumor imaging assessments should continue per standard of care (SOC) schedule. In addition, electronic patient-reported outcome (ePRO) assessments will no longer be performed and biomarker samples will no longer be collected.

Interventions

BIOLOGICALPembrolizumab

IV infusion

DRUGOlaparib

Oral tablets

DRUGAbiraterone acetate

Oral tablets

DRUGPrednisone

Oral tablets

DRUGEnzalutamide

Oral tablets or oral capsules

DRUGPrednisolone

Oral tablets

Sponsors

Merck Sharp & Dohme LLC
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
MALE
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Has histologically- or cytologically-confirmed adenocarcinoma of the prostate without small cell histology * Has prostate cancer progression while receiving androgen deprivation therapy (or post bilateral orchiectomy) within 6 months before screening * Has current evidence of metastatic disease documented by bone lesions on bone scan and/or soft tissue disease shown by computed tomography/magnetic resonance imaging (CT/MRI) * Has received prior treatment with abiraterone acetate OR enzalutamide, but not both * Have disease that progressed during or after treatment with abiraterone acetate for either metastatic hormone-sensitive prostate cancer (mHSPC) or mCRP or enzalutamide for mCRPC for at least 8 weeks (at least 14 weeks for participants with bone progression) * Participants that received abiraterone acetate for mHSPC may not have received abiraterone acetate or enzalutamide for mCRPC * Have received docetaxel chemotherapy regimen for metastatic castration-resistant prostate cancer (mCRPC) and have had progressive disease during or after treatment with docetaxel * Has ongoing androgen deprivation with serum testosterone \<50 ng/dL (\<2.0 nM) * If receiving bone resorptive therapy, including but not limited to bisphosphonates or denosumab, must have been receiving stable doses before randomization * Must agree to refrain from donating sperm during the intervention period and for at least the time needed to eliminate each study intervention after the last dose of study intervention PLUS be abstinent from heterosexual intercourse OR must agree to use contraception unless confirmed to be azoospermic * Contraception use by men should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. If the contraception requirements in the local label for any of the study interventions is more stringent than the requirement above, the local label requirements are to be followed. * Has provided tumor tissue from a fresh core or excisional biopsy (obtained within 12 months of screening) from soft tissue not previously irradiated. Samples from tumors progressing at a prior site of radiation are allowed. Participants with bone-only or bone-predominant disease may provide a bone biopsy sample * Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 assessed within 7 days of randomization

Exclusion criteria

* Has a known additional malignancy that is progressing or has required active treatment in the last 3 years * Has an active autoimmune disease that has required systemic treatment in the past 2 years * Has a history of (noninfectious) pneumonitis requiring steroids, or has current pneumonitis * Has known active human immunodeficiency virus (HIV), hepatitis B virus (e.g., hepatitis B surface antigen reactive) or hepatitis C virus (HCV) infection (e.g., HCV RNA \[qualitative\] is detected) * Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis * Has a history of seizure or any condition that may predispose to seizure * Has a history of loss of consciousness within 12 months of screening * Has myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) or has features suggestive of MDS/AML * Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy * Has (≥Grade 3) hypersensitivity to pembrolizumab and/or any of its excipients * Has known hypersensitivity to the components or excipients in olaparib, abiraterone acetate, prednisone or prednisolone, or enzalutamide * Has symptomatic congestive heart failure (New York Heart Association Class III or IV heart disease) * Has received an anticancer monoclonal antibody (mAb) before randomization * Has received prior treatment with olaparib or any other PARP inhibitor * Has received prior treatment with apalutamide or darolutamide * Has received prior treatment with enzalutamide or apalutamide for metastatic hormone-sensitive prostate cancer * Has used herbal products that may have hormonal anti-prostate cancer activity and/or are known to decrease PSA (e.g., saw palmetto) before the date of randomization * Has received prior treatment with radium or other therapeutic radiopharmaceuticals for prostate cancer * Has received prior treatment with an anti-PD-1, anti-PD-L1, or anti PD-L2 agent, or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., CTLA-4, OX-40, or CD137) * Is currently receiving either strong or moderate inhibitors of cytochrome P450 \[CYP\] (CYP3A4) that cannot be discontinued for the duration of the study * Has received a previous allogenic bone marrow transplant or double umbilical cord transplantation (dUCBT) or a solid organ transplant * Has received a live vaccine within 30 days prior to the date of randomization * Is currently participating in or has participated in a study of an investigational agent, or has used an investigational device, within 4 weeks before the date of randomization * Has a bone superscan * Is expecting to father children within the projected duration of the study, starting with the screening visit through 90 days after the last dose of study intervention

Design outcomes

Primary

MeasureTime frameDescription
Overall Survival (OS)Up to ~31 monthsOverall survival (OS) is defined as the time from randomization to death due to any cause. The nonparametric Kaplan-Meier method was used to estimate the survival curves.
Radiographic Progression-Free Survival (rPFS)Up to ~26 monthsrPFS is defined as the time from randomization to the first documented progressive disease (PD) per PCWG-modified RECIST 1.1 based on BICR or death due to any cause, whichever occurred first. Per PCWG-modified RECIST 1.1, PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also have demonstrated an absolute increase of ≥5 mm. The appearance of one or more new lesions or ≥2 new bone lesions was also considered PD. PCWG-modified RECIST is similar to RECIST 1.1 with the exception that a confirmation assessment of PD (\>4 weeks after the initial PD) is required for participants who remain on treatment following a documented PD per RECIST 1.1 and PCWG rules include new bone lesions. The rPFS per PCWG-modified RECIST as assessed by BICR for all participants is presented. The nonparametric Kaplan-Meier method was used to estimate the survival curves.

Secondary

MeasureTime frameDescription
Duration of Response (DOR)Up to ~26 monthsDOR is defined as the time from first documented evidence of CR or PR until progressive disease (PD) or death. Per PCWG-modified RECIST 1.1, PD is defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. The appearance of ≥ 2 new bone lesions is also considered PD. DOR as assessed by BICR is presented.
Time to Prostate-Specific Antigen (PSA) ProgressionUp to ~31 monthsTime to PSA progression is defined as the time from randomization to PSA progression. PSA progression date is defined as the date of: 1\) ≥25% increase and ≥2 ng/mL above the nadir, confirmed by a second value ≥3 weeks later if there is PSA decline from baseline, OR 2) ≥25% increase and ≥2 ng/mL increase from baseline beyond 12 weeks if there is no PSA decline from baseline. The nonparametric Kaplan-Meier method was used to estimate the survival curves.
Time to First Symptomatic Skeletal-Related Event (SSRE)Up to ~31 monthsSSRE is defined as the time from randomization to the first symptomatic skeletal-related event, defined as whichever occurs first: * First use of external-beam radiation therapy (EBRT) to prevent or relieve skeletal symptoms; * Occurrence of new symptomatic pathologic bone fracture (vertebral or nonvertebral); * Occurrence of spinal cord compression; or * Tumor-related orthopedic surgical intervention
Time to Initiation of the First Subsequent Anticancer Therapy (TFST)Up to ~26 monthsTFST is the time from randomization to initiation of the first subsequent anticancer therapy defined as the first anti-cancer treatment not part of the study arm for a given participant, or death, whichever occurs first. The nonparametric Kaplan-Meier method was used to estimate the survival curves.
Time to Pain Progression (TTPP)Up to ~31 monthsTTPP is defined as the time from randomization to pain progression as determined by Item 3 of the Brief Pain Inventory Short Form (BPI-SF) and by the Analgesic Quantification Algorithm (AQA) score. Pain progression is defined as: 1. For participants who are asymptomatic at baseline, a ≥2-point change from baseline in the average (4-7 days) BPI-SF item 3 score at 2 consecutive visits OR initiation of opioid use for pain 2. For participants who are symptomatic at baseline (average BPI-SF Item 3 score \>0 and/or currently taking opioids), a ≥2-point change from baseline in the average BPI-SF Item 3 score 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 higher) OR any increase in opioid use at 2 consecutive follow-up visits. Participants who had more than 2 consecutive visits that were not evaluable for pain progression were censored at the last evaluable assessment.
Number of Participants Who Experience an Adverse Event (AE)Up to ~55 monthsAn AE is defined as any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants who experienced an adverse event are presented.
Number of Participants Who Discontinue Study Treatment Due to an Adverse Event (AE)Up to ~1461 DaysAn AE is defined as any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants who discontinue study treatment due to an AE are presented.
Time to Radiographic Soft Tissue ProgressionUp to ~31 monthsTime to radiographic soft tissue progression is defined as the time from randomization to radiographic soft tissue progression per soft tissue rule of PCWG-modified RECIST 1.1. Progression is defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. The appearance of one or more new lesions is also considered progression. Time to radiographic soft tissue progression as assessed by BICR is presented.
Objective Response Rate (ORR)Up to ~31 monthsORR is defined as the percentage of participants with Complete Response (CR: disappearance of all target lesions per RECIST 1.1 and no evidence of disease (NED) bone scan) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions per RECIST 1.1 and Non-PD, non-evaluable (NE), or NED bone scan or CR with non-PD or NE bone scan.) The percentage of participants who experienced CR or PR as assessed by BICR is presented.

Countries

Argentina, Australia, Austria, Brazil, Canada, Chile, France, Germany, Ireland, Israel, Italy, Japan, Netherlands, New Zealand, Russia, South Korea, Spain, Taiwan, United Kingdom, United States

Participant flow

Pre-assignment details

Participants randomized to the next-generation hormonal agent monotherapy (NHA) arm received one of two NHA treatments, per protocol.

Participants by arm

ArmCount
Pembrolizumab + Olaparib
Participants received olaparib 600 mg as two 150 mg oral tablets twice daily (BID) continuously until progression PLUS on Day 1 of each 21-day cycle, pembrolizumab 200 mg by intravenous (IV) infusion for up to 35 cycles (approximately 2 years).
529
Next-generation Hormonal Agent Monotherapy (NHA)
Participants received a single NHA of either abiraterone acetate (participants previously treated with enzalutamide) 1000 mg as two 500 mg or four 250 mg oral tablets once daily (QD) PLUS prednisone or prednisolone 10 mg as one 5 mg tablet BID until progression OR participants received enzalutamide (participants previously treated with abiraterone acetate) 160 mg as four 40 mg oral tablets or capsules OR two 80 mg tablets QD until progression.
264
Total793

Withdrawals & dropouts

PeriodReasonFG000FG001
Overall StudyDeath368174
Overall StudyLost to Follow-up21
Overall StudyPhysician Decision51
Overall StudySponsor decision14980
Overall StudyWithdrawal by Subject58

Baseline characteristics

CharacteristicPembrolizumab + OlaparibNext-generation Hormonal Agent Monotherapy (NHA)Total
Age, Continuous69.9 Years
STANDARD_DEVIATION 7.4
69.1 Years
STANDARD_DEVIATION 7.3
69.6 Years
STANDARD_DEVIATION 7.4
Ethnicity (NIH/OMB)
Hispanic or Latino
71 Participants32 Participants103 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
441 Participants219 Participants660 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
17 Participants13 Participants30 Participants
Measurable Response Evaluation Criteria in Solid Tumors Version 1.1 Disease Status at Baseline
RECIST Measurable: No
285 Participants145 Participants430 Participants
Measurable Response Evaluation Criteria in Solid Tumors Version 1.1 Disease Status at Baseline
RECIST Measurable: Yes
244 Participants119 Participants363 Participants
Prior Use of NHA Treatment
Abiraterone and Enzalutamide
0 Participants1 Participants1 Participants
Prior Use of NHA Treatment
Abiraterone only
289 Participants143 Participants432 Participants
Prior Use of NHA Treatment
Enzalutamide only
240 Participants120 Participants360 Participants
Race (NIH/OMB)
American Indian or Alaska Native
1 Participants0 Participants1 Participants
Race (NIH/OMB)
Asian
102 Participants59 Participants161 Participants
Race (NIH/OMB)
Black or African American
1 Participants4 Participants5 Participants
Race (NIH/OMB)
More than one race
1 Participants0 Participants1 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
1 Participants1 Participants2 Participants
Race (NIH/OMB)
Unknown or Not Reported
4 Participants1 Participants5 Participants
Race (NIH/OMB)
White
419 Participants199 Participants618 Participants
Sex: Female, Male
Female
0 Participants0 Participants0 Participants
Sex: Female, Male
Male
529 Participants264 Participants793 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
372 / 529178 / 264
other
Total, other adverse events
495 / 526215 / 256
serious
Total, serious adverse events
179 / 52659 / 256

Outcome results

Primary

Overall Survival (OS)

Overall survival (OS) is defined as the time from randomization to death due to any cause. The nonparametric Kaplan-Meier method was used to estimate the survival curves.

Time frame: Up to ~31 months

Population: All randomized participants.

ArmMeasureValue (MEDIAN)
Pembrolizumab + OlaparibOverall Survival (OS)15.8 Months
Next-generation Hormonal Agent Monotherapy (NHA)Overall Survival (OS)14.6 Months
Comparison: Treatment difference in survival assessed by the stratified log-rank test stratified by measurable disease status and prior NHA treatment.p-value: 0.261695% CI: [0.77, 1.14]Log Rank
Primary

Radiographic Progression-Free Survival (rPFS)

rPFS is defined as the time from randomization to the first documented progressive disease (PD) per PCWG-modified RECIST 1.1 based on BICR or death due to any cause, whichever occurred first. Per PCWG-modified RECIST 1.1, PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also have demonstrated an absolute increase of ≥5 mm. The appearance of one or more new lesions or ≥2 new bone lesions was also considered PD. PCWG-modified RECIST is similar to RECIST 1.1 with the exception that a confirmation assessment of PD (\>4 weeks after the initial PD) is required for participants who remain on treatment following a documented PD per RECIST 1.1 and PCWG rules include new bone lesions. The rPFS per PCWG-modified RECIST as assessed by BICR for all participants is presented. The nonparametric Kaplan-Meier method was used to estimate the survival curves.

Time frame: Up to ~26 months

Population: All randomized participants.

ArmMeasureValue (MEDIAN)
Pembrolizumab + OlaparibRadiographic Progression-Free Survival (rPFS)4.4 Months
Next-generation Hormonal Agent Monotherapy (NHA)Radiographic Progression-Free Survival (rPFS)4.2 Months
Comparison: Treatment difference in rPFS assessed by the stratified log-rank test stratified by measurable disease status and prior NHA treatment.p-value: 0.554495% CI: [0.82, 1.25]Log Rank
Secondary

Duration of Response (DOR)

DOR is defined as the time from first documented evidence of CR or PR until progressive disease (PD) or death. Per PCWG-modified RECIST 1.1, PD is defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. The appearance of ≥ 2 new bone lesions is also considered PD. DOR as assessed by BICR is presented.

Time frame: Up to ~26 months

Population: All randomized participants who experience a confirmed CR or PR and had measurable disease at baseline.

ArmMeasureValue (MEDIAN)
Pembrolizumab + OlaparibDuration of Response (DOR)8.1 Months
Next-generation Hormonal Agent Monotherapy (NHA)Duration of Response (DOR)8.5 Months
Secondary

Number of Participants Who Discontinue Study Treatment Due to an Adverse Event (AE)

An AE is defined as any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants who discontinue study treatment due to an AE are presented.

Time frame: Up to ~1461 Days

Population: All randomized participants who received at least 1 dose of study intervention.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Pembrolizumab + OlaparibNumber of Participants Who Discontinue Study Treatment Due to an Adverse Event (AE)90 Participants
Next-generation Hormonal Agent Monotherapy (NHA)Number of Participants Who Discontinue Study Treatment Due to an Adverse Event (AE)11 Participants
Secondary

Number of Participants Who Experience an Adverse Event (AE)

An AE is defined as any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. The number of participants who experienced an adverse event are presented.

Time frame: Up to ~55 months

Population: All randomized participants who received at least 1 dose of study intervention.

ArmMeasureValue (COUNT_OF_PARTICIPANTS)
Pembrolizumab + OlaparibNumber of Participants Who Experience an Adverse Event (AE)518 Participants
Next-generation Hormonal Agent Monotherapy (NHA)Number of Participants Who Experience an Adverse Event (AE)238 Participants
Secondary

Objective Response Rate (ORR)

ORR is defined as the percentage of participants with Complete Response (CR: disappearance of all target lesions per RECIST 1.1 and no evidence of disease (NED) bone scan) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions per RECIST 1.1 and Non-PD, non-evaluable (NE), or NED bone scan or CR with non-PD or NE bone scan.) The percentage of participants who experienced CR or PR as assessed by BICR is presented.

Time frame: Up to ~31 months

Population: All randomized participants who had measurable disease at baseline.

ArmMeasureValue (NUMBER)
Pembrolizumab + OlaparibObjective Response Rate (ORR)16.8 Percentage of Participants
Next-generation Hormonal Agent Monotherapy (NHA)Objective Response Rate (ORR)5.9 Percentage of Participants
95% CI: [4, 17.1]
Secondary

Time to First Symptomatic Skeletal-Related Event (SSRE)

SSRE is defined as the time from randomization to the first symptomatic skeletal-related event, defined as whichever occurs first: * First use of external-beam radiation therapy (EBRT) to prevent or relieve skeletal symptoms; * Occurrence of new symptomatic pathologic bone fracture (vertebral or nonvertebral); * Occurrence of spinal cord compression; or * Tumor-related orthopedic surgical intervention

Time frame: Up to ~31 months

Population: All randomized participants.

ArmMeasureValue (MEDIAN)
Pembrolizumab + OlaparibTime to First Symptomatic Skeletal-Related Event (SSRE)NA Months
Next-generation Hormonal Agent Monotherapy (NHA)Time to First Symptomatic Skeletal-Related Event (SSRE)NA Months
95% CI: [0.38, 0.78]
Secondary

Time to Initiation of the First Subsequent Anticancer Therapy (TFST)

TFST is the time from randomization to initiation of the first subsequent anticancer therapy defined as the first anti-cancer treatment not part of the study arm for a given participant, or death, whichever occurs first. The nonparametric Kaplan-Meier method was used to estimate the survival curves.

Time frame: Up to ~26 months

Population: All randomized participants.

ArmMeasureValue (MEDIAN)
Pembrolizumab + OlaparibTime to Initiation of the First Subsequent Anticancer Therapy (TFST)7.2 Months
Next-generation Hormonal Agent Monotherapy (NHA)Time to Initiation of the First Subsequent Anticancer Therapy (TFST)5.7 Months
95% CI: [0.71, 1.03]
Secondary

Time to Pain Progression (TTPP)

TTPP is defined as the time from randomization to pain progression as determined by Item 3 of the Brief Pain Inventory Short Form (BPI-SF) and by the Analgesic Quantification Algorithm (AQA) score. Pain progression is defined as: 1. For participants who are asymptomatic at baseline, a ≥2-point change from baseline in the average (4-7 days) BPI-SF item 3 score at 2 consecutive visits OR initiation of opioid use for pain 2. For participants who are symptomatic at baseline (average BPI-SF Item 3 score \>0 and/or currently taking opioids), a ≥2-point change from baseline in the average BPI-SF Item 3 score 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 higher) OR any increase in opioid use at 2 consecutive follow-up visits. Participants who had more than 2 consecutive visits that were not evaluable for pain progression were censored at the last evaluable assessment.

Time frame: Up to ~31 months

Population: All participants who have at least 1 assessment available and have received at least 1 dose of study intervention.

ArmMeasureValue (MEDIAN)
Pembrolizumab + OlaparibTime to Pain Progression (TTPP)13.5 Months
Next-generation Hormonal Agent Monotherapy (NHA)Time to Pain Progression (TTPP)12.0 Months
p-value: 0.364395% CI: [0.72, 1.26]Log Rank
Secondary

Time to Prostate-Specific Antigen (PSA) Progression

Time to PSA progression is defined as the time from randomization to PSA progression. PSA progression date is defined as the date of: 1\) ≥25% increase and ≥2 ng/mL above the nadir, confirmed by a second value ≥3 weeks later if there is PSA decline from baseline, OR 2) ≥25% increase and ≥2 ng/mL increase from baseline beyond 12 weeks if there is no PSA decline from baseline. The nonparametric Kaplan-Meier method was used to estimate the survival curves.

Time frame: Up to ~31 months

Population: All randomized participants.

ArmMeasureValue (MEDIAN)
Pembrolizumab + OlaparibTime to Prostate-Specific Antigen (PSA) Progression3.3 Months
Next-generation Hormonal Agent Monotherapy (NHA)Time to Prostate-Specific Antigen (PSA) Progression3.5 Months
95% CI: [0.89, 1.38]
Secondary

Time to Radiographic Soft Tissue Progression

Time to radiographic soft tissue progression is defined as the time from randomization to radiographic soft tissue progression per soft tissue rule of PCWG-modified RECIST 1.1. Progression is defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. The appearance of one or more new lesions is also considered progression. Time to radiographic soft tissue progression as assessed by BICR is presented.

Time frame: Up to ~31 months

Population: All randomized participants.

ArmMeasureValue (MEDIAN)
Pembrolizumab + OlaparibTime to Radiographic Soft Tissue Progression10.3 Months
Next-generation Hormonal Agent Monotherapy (NHA)Time to Radiographic Soft Tissue Progression6.4 Months
95% CI: [0.62, 1]

Source: ClinicalTrials.gov · Data processed: Feb 19, 2026