2024
1622P A phase II study of the first-in-class oral innate immune activator BXCL701 with pembrolizumab in patients with metastatic castration-resistant prostate cancer (mCRPC): Long-term follow-up
Aggarwal R, Tagawa S, Monk P, Zhu X, Jones R, Linch M, Costin D, de Bono J, Karsh L, Petrylak D, Borderies P, Deshpande R, O'Neill V, Zhang J. 1622P A phase II study of the first-in-class oral innate immune activator BXCL701 with pembrolizumab in patients with metastatic castration-resistant prostate cancer (mCRPC): Long-term follow-up. Annals Of Oncology 2024, 35: s979. DOI: 10.1016/j.annonc.2024.08.1703.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerCastration-resistant prostate cancerLong-term follow-upPhase II studyII studyProstate cancerFollow-upPembrolizumabPatientsCancerARV-766, a proteolysis targeting chimera (PROTAC) androgen receptor (AR) degrader, in metastatic castration-resistant prostate cancer (mCRPC): Initial results of a phase 1/2 study.
Petrylak D, McKean M, Lang J, Gao X, Dreicer R, Geynisman D, Stewart T, Gandhi M, Appleman L, Dorff T, Chatta G, Tutrone R, De La Cerda J, Berghorn E, Gong J, Yu T, Dominy E, Chan E, Shore N. ARV-766, a proteolysis targeting chimera (PROTAC) androgen receptor (AR) degrader, in metastatic castration-resistant prostate cancer (mCRPC): Initial results of a phase 1/2 study. Journal Of Clinical Oncology 2024, 42: 5011-5011. DOI: 10.1200/jco.2024.42.16_suppl.5011.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerTreatment-related adverse eventsAR-LBD mutationsPhase 1/2 studyClinical activityProstate cancerAndrogen receptorAdverse eventsMetastatic castration-resistant prostate cancer treatmentProgressive metastatic castration-resistant prostate cancerPhase 1 dose-escalation portionDisease progressionTreatment-emergent adverse eventsCastration-resistant prostate cancerResistant to available therapiesAssociated with poor outcomesDose-limiting toxicityAndrogen deprivation therapyAdvanced prostate cancerIncreased blood creatinineWild-type ARSubgroup of patientsDose-dependent increaseDeprivation therapyPretreated patients
2023
1803P Phase I/II study of bavdegalutamide, a PROTAC androgen receptor (AR) degrader in metastatic castration-resistant prostate cancer (mCRPC): Radiographic progression-free survival (rPFS) in patients (pts) with AR ligand-binding domain (LBD) mutations
Petrylak D, Garmezy B, Shen J, Kalebasty A, Sartor O, Dreicer R, Agarwal N, Hussain M, Percent I, Heath E, Gedrich R, Yu T, Healey D, Parameswaran J, Sternberg C, Gao X. 1803P Phase I/II study of bavdegalutamide, a PROTAC androgen receptor (AR) degrader in metastatic castration-resistant prostate cancer (mCRPC): Radiographic progression-free survival (rPFS) in patients (pts) with AR ligand-binding domain (LBD) mutations. Annals Of Oncology 2023, 34: s973-s974. DOI: 10.1016/j.annonc.2023.09.2751.Peer-Reviewed Original ResearchFirst-in-class oral innate immune activator BXCL701 combined with pembrolizumab, in patients with metastatic castration-resistant prostate cancer (mCRPC) of small cell neuroendocrine (SCNC) variant: Randomized phase 2b trial.
Aggarwal R, Zhang J, Monk P, Zhu X, Costin D, Petrylak D, Borderies P, Deshpande R, Hafeez A, O'Neill V, Tagawa S. First-in-class oral innate immune activator BXCL701 combined with pembrolizumab, in patients with metastatic castration-resistant prostate cancer (mCRPC) of small cell neuroendocrine (SCNC) variant: Randomized phase 2b trial. Journal Of Clinical Oncology 2023, 41: tps5109-tps5109. DOI: 10.1200/jco.2023.41.16_suppl.tps5109.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerSerious adverse eventsPartial responsePrimary endpointPhase 2aRandomized Phase 2b TrialCastration-resistant prostate cancerOral small-molecule inhibitorPhase 2b trialPrime immune cellsRECIST 1.1 criteriaDisease control rateImmune checkpoint inhibitorsPhase 2 studyPlatinum-based chemotherapyDuration of responsePotential predictive biomarkersImmune effector cellsMeasurable diseaseNeuroendocrine variantPSA-PFSRECIST 1.1Safety populationCheckpoint inhibitorsData cutoffCombination Treatment with Sipuleucel-T and Abiraterone Acetate or Enzalutamide for Metastatic Castration-Resistant Prostate Cancer: STAMP and STRIDE Trials
Antonarakis E, Subudhi S, Pieczonka C, Karsh L, Quinn D, Hafron J, Wilfehrt H, Harmon M, Sheikh N, Shore N, Petrylak D. Combination Treatment with Sipuleucel-T and Abiraterone Acetate or Enzalutamide for Metastatic Castration-Resistant Prostate Cancer: STAMP and STRIDE Trials. Clinical Cancer Research 2023, 29: 2426-2434. PMID: 37058234, PMCID: PMC10320463, DOI: 10.1158/1078-0432.ccr-22-3832.Peer-Reviewed Original ResearchConceptsMetastatic castration-resistant prostate cancerAndrogen receptor-targeted agentsMedian overall survivalCastration-resistant prostate cancerOverall survivalNational Death IndexConcurrent administrationProstate cancerAntigen-presenting cell activationCurrent prescribing informationNew safety signalsKaplan-Meier methodologyLong-term outcomesConfidence intervalsReceptor-targeted agentsProstatic acid phosphataseAbiraterone acetateFirst infusionDeath IndexPrescribing informationHumoral responseSubsequent infusionSequential administrationSafety signalsImmune responseFirst-in-human, phase 1 study of PF-06753512, a vaccine-based immunotherapy regimen (VBIR), in non-metastatic hormone-sensitive biochemical recurrence and metastatic castration-resistant prostate cancer (mCRPC)
Autio K, Higano C, Nordquist L, Appleman L, Zhang T, Zhu X, Babiker H, Vogelzang N, Prasad S, Schweizer M, Madan R, Billotte S, Cavazos N, Bogg O, Li R, Chan K, Cho H, Kaneda M, Wang I, Zheng J, Tang S, Hollingsworth R, Kern K, Petrylak D. First-in-human, phase 1 study of PF-06753512, a vaccine-based immunotherapy regimen (VBIR), in non-metastatic hormone-sensitive biochemical recurrence and metastatic castration-resistant prostate cancer (mCRPC). Journal For ImmunoTherapy Of Cancer 2023, 11: e005702. PMID: 36948505, PMCID: PMC10040068, DOI: 10.1136/jitc-2022-005702.Peer-Reviewed Original ResearchConceptsMetastatic castration-resistant prostate cancerAndrogen deprivation therapyRadiographic progression-free survivalCastration-resistant prostate cancerPhase 1 studyBiochemical recurrenceProstate cancerImmunotherapy regimenMedian durationDose escalationMedian radiographic progression-free survivalAntigen-specific T cell responsesImmune-related adverse eventsRecommended phase 2 doseSpecific T cell responsesPhase 2 doseImmune checkpoint inhibitorsModest antitumor activityObjective response rateProgression-free survivalAntigen-specific immunityT cell responsesInfluenza-like illnessSignificant side effectsDeprivation therapyA phase 2 expansion study of ARV-766, a PROTAC androgen receptor (AR) degrader, in metastatic castration-resistant prostate cancer (mCRPC).
Petrylak D, Stewart T, Gao X, Berghorn E, Lu H, Chan E, Gedrich R, Lang J, McKean M. A phase 2 expansion study of ARV-766, a PROTAC androgen receptor (AR) degrader, in metastatic castration-resistant prostate cancer (mCRPC). Journal Of Clinical Oncology 2023, 41: tps290-tps290. DOI: 10.1200/jco.2023.41.6_suppl.tps290.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerNovel hormonal agentsCohort expansionDisease progressionEastern Cooperative Oncology Group performance status scoreOngoing androgen deprivation therapyProstate-specific antigen (PSA) declineCastration-resistant prostate cancerGonadotropin-releasing hormone analogueCohort expansion studyAndrogen deprivation therapyPerformance status scoreOverall response ratePhase 1 portionWild-type ARDeprivation therapyPrior chemotherapyCurative optionDose escalationAvailable therapiesHormonal agentsStatus scoreCurrent therapiesLigand-binding domainClinical trialsPatient-reported outcomes (PROs) in KEYNOTE-921: Pembrolizumab (pembro) plus docetaxel for patients (pts) with metastatic castration-resistant prostate cancer (mCRPC).
Petrylak D, Ratta R, Matsubara N, Korbenfeld E, Gafanov R, Mourey L, Todenhöfer T, Gurney H, Kramer G, Bergman A, Zalewski P, De Santis M, Armstrong A, Gerritsen W, Pachynski R, Saretsky T, Ghate S, Li X, Schloss C, Fizazi K. Patient-reported outcomes (PROs) in KEYNOTE-921: Pembrolizumab (pembro) plus docetaxel for patients (pts) with metastatic castration-resistant prostate cancer (mCRPC). Journal Of Clinical Oncology 2023, 41: 129-129. DOI: 10.1200/jco.2023.41.6_suppl.129.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerPatient-reported outcomesBPI-SF scoresBPI-SFTotal scoreWk 24Wk 27Castration-resistant prostate cancerPrespecified secondary end pointsEnd pointExploratory end pointsFACT-G totalPrespecified final analysisSecondary end pointsOverall improvement rateSubscale scoresMedian TTPPPain progressionData cutoffAgent therapyMedian timeAnalysis populationStudy treatmentSymptom scoresTrial armsPembrolizumab plus docetaxel for patients with metastatic castration-resistant prostate cancer (mCRPC): Randomized, double-blind, phase 3 KEYNOTE-921 study.
Petrylak D, Ratta R, Matsubara N, Korbenfeld E, Gafanov R, Mourey L, Todenhöfer T, Gurney H, Kramer G, Bergman A, Zalewski P, De Santis M, Armstrong A, Gerritsen W, Pachynski R, Byun S, Li X, Schloss C, Poehlein C, Fizazi K. Pembrolizumab plus docetaxel for patients with metastatic castration-resistant prostate cancer (mCRPC): Randomized, double-blind, phase 3 KEYNOTE-921 study. Journal Of Clinical Oncology 2023, 41: 19-19. DOI: 10.1200/jco.2023.41.6_suppl.19.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerNext-generation hormonal agentsDual primary endpointsTreatment-related AEsCycles of docetaxelPrimary endpointSecondary endpointsDocetaxel armRadiographic progression-free survivalCastration-resistant prostate cancerBlinded independent central reviewCycles of placeboData cutoff dateSafety of pembrolizumabSubsequent anticancer therapyTreatment-related deathsAndrogen deprivation therapyECOG performance statusKey secondary endpointProgression-free survivalIndependent central reviewEligible ptsDeprivation therapyRECIST 1.1Baseline characteristics
2022
Phase 1/2 study of ARV-110, an androgen receptor (AR) PROTAC degrader, in metastatic castration-resistant prostate cancer (mCRPC).
Gao X, Burris H, Vuky J, Dreicer R, Sartor A, Sternberg C, Percent I, Hussain M, Kalebasty A, Shen J, Heath E, Abesada-Terk G, Gandhi S, McKean M, Lu H, Berghorn E, Gedrich R, Chirnomas S, Vogelzang N, Petrylak D. Phase 1/2 study of ARV-110, an androgen receptor (AR) PROTAC degrader, in metastatic castration-resistant prostate cancer (mCRPC). Journal Of Clinical Oncology 2022, 40: 17-17. DOI: 10.1200/jco.2022.40.6_suppl.017.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerNovel hormonal agentsProstate-specific antigenClinical activityBetter prostate-specific antigenOngoing phase 1/2 studyCastration-resistant prostate cancerBiomarker-defined subgroupsPhase 2 dosePhase 1/2 studyWild-type ARFourth subgroupPhase 1AR alterationsRECIST responseSpecific molecular profilePrior therapyAdverse eventsAR-V7Tumor shrinkageHormonal agentsTreatment optionsClinical historyDisease progressionProstate cancerBXCL701: First-in-class oral activator of systemic innate immunity combined with pembrolizumab, in patients with metastatic castration-resistant prostate cancer (mCRPC) of adenocarcinoma phenotype—Phase 2a results.
Zhang J, Aggarwal R, Tagawa S, Linch M, Petrylak D, Costin D, De Bono J, Jones R, Karsh L, Zhu X, Borderies P, Deshpande R, O'Neill V, Monk P. BXCL701: First-in-class oral activator of systemic innate immunity combined with pembrolizumab, in patients with metastatic castration-resistant prostate cancer (mCRPC) of adenocarcinoma phenotype—Phase 2a results. Journal Of Clinical Oncology 2022, 40: 125-125. DOI: 10.1200/jco.2022.40.6_suppl.125.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerAnti-tumor activityEvaluable patientsTaxane chemotherapyPrior linesAndrogen receptorProstate cancerAdenocarcinoma cohortCastration-resistant prostate cancerOral small-molecule inhibitorEncouraging anti-tumor activityBone-only diseaseComposite response rateImmune-related AEPhase 1b/2 studyPrime immune cellsSystemic innate immunityDisease control rateAcceptable safety profileMost prostate cancersAndrogen deprivation treatmentImmune effector cellsCTC conversionMeasurable diseaseRECIST 1.1BXCL701: First-in-class oral activator of systemic innate immunity combined with pembrolizumab, in patients with metastatic castration-resistant prostate cancer (mCRPC) of small-cell neuroendocrine carcinoma (SCNC) phenotype—Phase 2a interim results.
Tagawa S, Zhang J, Monk P, Zhu X, Jones R, Linch M, Costin D, De Bono J, Karsh L, Petrylak D, Borderies P, Deshpande R, O'Neill V, Aggarwal R. BXCL701: First-in-class oral activator of systemic innate immunity combined with pembrolizumab, in patients with metastatic castration-resistant prostate cancer (mCRPC) of small-cell neuroendocrine carcinoma (SCNC) phenotype—Phase 2a interim results. Journal Of Clinical Oncology 2022, 40: 126-126. DOI: 10.1200/jco.2022.40.6_suppl.126.Peer-Reviewed Original ResearchSmall cell neuroendocrine carcinomaMetastatic castration-resistant prostate cancerEvaluable patientsAnti-tumor activityPrior linesCastration-resistant prostate cancerOral small-molecule inhibitorEncouraging anti-tumor activityBone-only diseaseComposite response rateImmune-related AEPhase 1b/2 studyPrime immune cellsSystemic innate immunityAcceptable safety profileImmune effector cellsStandard of careInterim resultsStage 1Prior chemotherapyRECIST 1.1Unconfirmed PRBID dosingCheckpoint inhibitorsMCRPC patients
2021
579MO CheckMate 9KD cohort A2 final analysis: Nivolumab (NIVO) + rucaparib for chemotherapy (CT)-naïve metastatic castration-resistant prostate cancer (mCRPC)
Petrylak D, Perez-Gracia J, Lacombe L, Bastos D, Mahammedi H, Kwan E, Zschäbitz S, Armstrong A, Pachynski R, Goh J, Burotto M, Gravis G, McCune S, Limón J, Retz M, Saad F, Amin N, Li J, Unsal-Kacmaz K, Fizazi K. 579MO CheckMate 9KD cohort A2 final analysis: Nivolumab (NIVO) + rucaparib for chemotherapy (CT)-naïve metastatic castration-resistant prostate cancer (mCRPC). Annals Of Oncology 2021, 32: s629-s630. DOI: 10.1016/j.annonc.2021.08.1092.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerCastration-resistant prostate cancerProstate cancerFinal analysisNivolumabChemotherapyRucaparibCancer610P BXCL701 - 1st-in-class oral activator of systemic innate immunity-combined with pembrolizumab, in men with metastatic castration-resistant prostate cancer (mCRPC): Phase II results
Monk P, Zhang J, Costin D, Petrylak D, Tagawa S, Karsh L, Zhu X, Linch M, Jones R, Borderies P, O'Neill V, Aggarwal R. 610P BXCL701 - 1st-in-class oral activator of systemic innate immunity-combined with pembrolizumab, in men with metastatic castration-resistant prostate cancer (mCRPC): Phase II results. Annals Of Oncology 2021, 32: s651. DOI: 10.1016/j.annonc.2021.08.1123.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerCastration-resistant prostate cancerPhase II resultsProstate cancerII resultsCancerFirst-in-human, phase I study of PF-06753512, a vaccine-based immunotherapy regimen (PrCa VBIR), in biochemical relapse (BCR) and metastatic castration-resistant prostate cancer (mCRPC).
Autio K, Higano C, Nordquist L, Appleman L, Zhang T, Zhu X, Babiker H, Vogelzang N, Prasad S, Schweizer M, Billotte S, Binder J, Cavazos N, Li R, Chan K, Cho H, Dermyer M, Hollingsworth R, Kern K, Petrylak D. First-in-human, phase I study of PF-06753512, a vaccine-based immunotherapy regimen (PrCa VBIR), in biochemical relapse (BCR) and metastatic castration-resistant prostate cancer (mCRPC). Journal Of Clinical Oncology 2021, 39: 2612-2612. DOI: 10.1200/jco.2021.39.15_suppl.2612.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerTreatment-related adverse eventsImmune checkpoint inhibitorsBiochemical relapseImmune responseCastration-resistant prostate cancerPhase INovel hormone therapyAntitumor activityManageable safety profileObjective tumor responsePD-1 antibodyAntigen-specific immunityProstate-specific membrane antigenAndrogen-sensitive diseaseReplication-deficient adenoviral vectorAnti-tumor activityStem cell antigenPC-associated antigensNoticeable antitumor activityAntibody tremelimumabExpansion doseCheckpoint inhibitorsImmunotherapy regimenAdverse eventsCheckMate 9KD cohort A1 final analysis: Nivolumab (NIVO) + rucaparib for post-chemotherapy (CT) metastatic castration-resistant prostate cancer (mCRPC).
Pachynski R, Retz M, Goh J, Burotto M, Gravis G, Castellano D, Flechon A, Zschaebitz S, Shaffer D, Limon J, Grimm M, McCune S, Amin N, Li J, Wang X, Unsal-Kacmaz K, Saad F, Petrylak D, Fizazi K. CheckMate 9KD cohort A1 final analysis: Nivolumab (NIVO) + rucaparib for post-chemotherapy (CT) metastatic castration-resistant prostate cancer (mCRPC). Journal Of Clinical Oncology 2021, 39: 5044-5044. DOI: 10.1200/jco.2021.39.15_suppl.5044.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerTreatment-related AEsObjective response rateRadiographic progression-free survivalCohorts A1Overall survivalDisease progression/unacceptable toxicityProstate-specific antigen (PSA) response rateResponse rateProgression/unacceptable toxicityCastration-resistant prostate cancerNovel hormonal therapiesSecondary efficacy resultsProgression-free survivalNew safety signalsPhase 2 trialPD-L1 upregulationPlausible therapeutic strategyPARP inhibitor treatmentMeasurable diseaseVisceral metastasesHormonal therapySecondary endpointsUnacceptable toxicityEvaluable tumorsBXCL701, first-in-class oral activator of systemic innate immunity pathway, combined with pembrolizumab (Keytruda) in men with metastatic castration-resistant prostate cancer (mCRPC).
Aggarwal R, Costin D, Zhang J, Karsh L, Healey D, Linch M, Adurthi S, Petrylak D, O'Neill V, Monk P. BXCL701, first-in-class oral activator of systemic innate immunity pathway, combined with pembrolizumab (Keytruda) in men with metastatic castration-resistant prostate cancer (mCRPC). Journal Of Clinical Oncology 2021, 39: 124-124. DOI: 10.1200/jco.2021.39.6_suppl.124.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerTotal daily doseAdverse eventsPhase 2 portionObjective responseImproved tolerabilityAnti-PD-1/PD-L1Day 1Serum IL-18 levelsCastration-resistant prostate cancerOral small-molecule inhibitorDipeptidyl peptidasePreliminary anti-tumor activityPhase 2 doseAndrogen deprivation therapyCytokine release syndromeStage IV melanomaIL-18 levelsPD-L1 expressionSignificant tumor growth inhibitionLower extremity edemaImmune effector cellsPrior clinical studiesTarget adverse eventsProstate cancer phenotypeCheckMate 9KD Arm B final analysis: Efficacy and safety of nivolumab plus docetaxel for chemotherapy-naïve metastatic castration-resistant prostate cancer.
Fizazi K, González Mella P, Castellano D, Minatta J, Rezazadeh A, Shaffer D, Vazquez Limon J, Sánchez López H, Armstrong A, Horvath L, Dzik C, Amin N, Li J, Unsal-Kacmaz K, Retz M, Saad F, Petrylak D, Pachynski R. CheckMate 9KD Arm B final analysis: Efficacy and safety of nivolumab plus docetaxel for chemotherapy-naïve metastatic castration-resistant prostate cancer. Journal Of Clinical Oncology 2021, 39: 12-12. DOI: 10.1200/jco.2021.39.6_suppl.12.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerTreatment-related AEsObjective response rateChemotherapy-naïve metastatic castration-resistant prostate cancerRadiographic progression-free survivalCastration-resistant prostate cancerMeasurable diseaseOverall survivalArm BProstate cancerMedian numberChemotherapy-naive metastatic castration-resistant prostate cancerDisease progression/unacceptable toxicityProstate-specific antigen (PSA) response rateResponse rateComparable objective response rateOngoing androgen deprivation therapyProgression/unacceptable toxicityImmune-related AESafety of nivolumabTreatment-related deathsAndrogen deprivation therapyPhase 2 trialProgression-free survivalAntitumor immune responsePhase I study of AMG 509, a STEAP1 x CD3 T-cell recruiting XmAb 2+1 immune therapy, in patients with metastatic castration-resistant prostate cancer (mCRPC).
Kelly W, Pook D, Appleman L, Waterhouse D, Horvath L, Edenfield W, Matsubara N, Danila D, Aggarwal R, Petrylak D, Sartor A, Sumey C, Adra N, Armstrong A, Cheng F, Stieglmaier J, Kouros-Mehr H, Dorff T. Phase I study of AMG 509, a STEAP1 x CD3 T-cell recruiting XmAb 2+1 immune therapy, in patients with metastatic castration-resistant prostate cancer (mCRPC). Journal Of Clinical Oncology 2021, 39: tps183-tps183. DOI: 10.1200/jco.2021.39.6_suppl.tps183.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerFirst doseImmune therapyProstate cancerECOG performance status 0Prostate-specific antigen (PSA) responseCastration-resistant prostate cancerT cell-mediated lysisDose-expansion phasePerformance status 0Phase 2 doseObjective tumor responseT effector cellsASCO Annual MeetingTotal serum testosteroneLogistic regression modelsCell surface antigensTransmembrane epithelial antigenTumor cell responseCNS metastasisLeptomeningeal diseaseRECIST 1.1Status 0Taxane regimensHormonal therapy
2020
233TiP Pembrolizumab (pembro) or placebo added to docetaxel and prednisone/prednisolone for metastatic castration-resistant prostate cancer (mCRPC) previously treated with next-generation hormonal agents (NHAs): KEYNOTE-921 phase III study
Petrylak D, Shore N, Bennamoun M, Ratta R, Piulats J, Li B, Schloss C, Fizazi K. 233TiP Pembrolizumab (pembro) or placebo added to docetaxel and prednisone/prednisolone for metastatic castration-resistant prostate cancer (mCRPC) previously treated with next-generation hormonal agents (NHAs): KEYNOTE-921 phase III study. Annals Of Oncology 2020, 31: s1332-s1333. DOI: 10.1016/j.annonc.2020.10.453.Peer-Reviewed Original ResearchMetastatic castration-resistant prostate cancerNext-generation hormonal agentsCastration-resistant prostate cancerPhase III studyIII studyHormonal agentsProstate cancerPembrolizumabPlaceboPrednisoloneCancer