Substudy 01A: Safety and Efficacy of Opevesostat (MK-5684)-Based Treatment Combinations or Opevesostat Alone in Participants With Metastatic Castration-resistant Prostate Cancer (mCRPC) (MK-5684-01A)

May 21, 2026 updated by: Merck Sharp & Dohme LLC

MK-5684-01A Substudy: A Phase 1/2 Umbrella Substudy of MK-5684-U01 Master Protocol to Evaluate the Safety and Efficacy of MK-5684-based Treatment Combinations or MK-5684 Alone in Participants With Metastatic Castration-resistant Prostate Cancer (mCRPC)

Substudy 01A is part of a larger research study that is testing experimental treatments for metastatic castration-resistant prostate cancer (mCRPC). The larger study is the umbrella study (U01).

The goal of substudy 01A is to evaluate the safety and efficacy of opevesostat-based treatment combinations, or as a single agent, in participants with mCRPC.

This substudy will have two phases: a safety lead-in phase and an efficacy phase. The safety lead-in phase will be used to evaluate the safety and tolerability, and to establish a recommended Phase 2 dose (RP2D) for the opevesostat-based treatment combinations. There will be no hypothesis testing in this study.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

220

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Australia
    • New South Wales
      • Macquarie University, New South Wales, Australia, 2109
        • Recruiting
        • Macquarie University-MQ Health Clinical Trials Unit ( Site 0108)
        • Contact:
          • Study Coordinator
          • Phone Number: +61402856430
    • Queensland
      • Greenslopes, Queensland, Australia, 4120
        • Recruiting
        • Gallipoli Medical Research Ltd-GMRF CTU ( Site 0107)
        • Contact:
          • Study Coordinator
          • Phone Number: +61 7 33947284
    • Victoria
      • Melbourne, Victoria, Australia, 3000
        • Recruiting
        • Peter MacCallum Cancer Centre-Parkville Cancer Clinical Trials Unit (PCCTU) ( Site 0110)
        • Contact:
          • Study Coordinator
          • Phone Number: +61385595000
  • Canada
    • Quebec
      • Montreal, Quebec, Canada, H3T 1E2
        • Recruiting
        • Jewish General Hospital ( Site 0206)
        • Contact:
          • Study Coordinator
          • Phone Number: 514-340-8222
      • Montreal, Quebec, Canada, H2X 3E4
        • Recruiting
        • Centre Hospitalier de l'Université de Montréal ( Site 0200)
        • Contact:
          • Study Coordinator
          • Phone Number: 5148908000x27466
      • Québec, Quebec, Canada, G1J 1Z4
        • Recruiting
        • Centre intégré de cancérologie du CHU de Québec Université Laval, Hôpital de l'Enfant-Jésus ( Site 0207)
        • Contact:
          • Study Coordinator
          • Phone Number: 418-691- 5225
  • Chile
    • Biobio
      • Temuco, Biobio, Chile, 4810218
        • Active, not recruiting
        • CIDO SpA-Oncology ( Site 0302)
    • Maule Region
      • Talca, Maule Region, Chile, 3465584
        • Recruiting
        • Clinica Universidad Catolica del Maule-Oncology ( Site 0304)
        • Contact:
          • Study Coordinator
          • Phone Number: +56947532700
    • Region M. de Santiago
      • Santiago, Region M. de Santiago, Chile, 8420383
        • Recruiting
        • Bradfordhill ( Site 0300)
        • Contact:
          • Study Coordinator
          • Phone Number: +56229490970
      • Santiago, Region M. de Santiago, Chile, 832000
        • Recruiting
        • Pontificia Universidad Catolica de Chile ( Site 0303)
        • Contact:
          • Study Coordinator
          • Phone Number: +56934331806
      • Santiago, Region M. de Santiago, Chile, 7500921
        • Active, not recruiting
        • FALP ( Site 0301)
  • Colombia
    • Bogota D.C.
      • Bogotá, Bogota D.C., Colombia, 110131
        • Recruiting
        • FUNDACION CTIC CENTRO DE TRATAMIENTO E INVESTIGACION SOBRE CANCER LUIS CARLOS SARMIENTO ANGULO ( Site 0406)
        • Contact:
          • Study Coordinator
          • Phone Number: +573147968518
      • Bogotá, Bogota D.C., Colombia, 111321
        • Recruiting
        • Clinica Colsanitas S.A, Sede Clínica Universitaria Colombia ( Site 0402)
        • Contact:
          • Study Coordinator
          • Phone Number: 573103469453
    • Cesar Department
      • Valledupar, Cesar Department, Colombia, 200001
        • Recruiting
        • Sociedad De Oncología y Hematología Del Cesar SAS-Oncology ( Site 0400)
        • Contact:
          • Study Coordinator
          • Phone Number: 57 3128385292
    • Departamento de Córdoba
      • Montería, Departamento de Córdoba, Colombia, 230002
        • Recruiting
        • IMAT S.A.S ( Site 0404)
        • Contact:
          • Study Coordinator
          • Phone Number: 605 3135342052
    • Valle del Cauca Department
      • Cali, Valle del Cauca Department, Colombia, 760032
        • Recruiting
        • Fundación Valle del Lili-Oncology CIC ( Site 0403)
        • Contact:
          • Study Coordinator
          • Phone Number: +576023319090 - 4022
  • Denmark
    • Capital Region
      • Copenhagen, Capital Region, Denmark, 2730
        • Recruiting
        • Herlev and Gentofte Hospital ( Site 0501)
        • Contact:
          • Study Coordinator
          • Phone Number: 38 68 94 38
    • North Denmark
      • Aalborg, North Denmark, Denmark, 9000
        • Recruiting
        • Aalborg Universitetshospital, Syd ( Site 0503)
        • Contact:
          • Study Coordinator
          • Phone Number: 97660000
  • Finland
    • Pohjanmaa
      • Vaasa, Pohjanmaa, Finland, 65130
        • Recruiting
        • Vaasan Keskussairaala ( Site 0603)
        • Contact:
          • Study Coordinator
          • Phone Number: 0035862136981
    • Uusimaa
      • Helsinki, Uusimaa, Finland, 00029
        • Recruiting
        • Helsinki University Hospital - Comprehensive Cancer Center (HYKS - Syöpäkeskus) ( Site 0604)
        • Contact:
          • Study Coordinator
          • Phone Number: 0035894711
      • Helsinki, Uusimaa, Finland, 00180
        • Recruiting
        • Docrates Syöpäsairaala ( Site 0602)
        • Contact:
          • Study Coordinator
          • Phone Number: 00358505001869
  • France
      • Paris, France, 75015
        • Recruiting
        • Hôpital Européen Georges Pompidou-Service d'Oncologie Médicale ( Site 0702)
        • Contact:
          • Study Coordinator
          • Phone Number: +33 1 56 09 20 00
    • Aquitaine
      • Bordeaux, Aquitaine, France, 33076
        • Recruiting
        • Institut Bergonié - Centre Régional de Lutte Contre Le Cancer de Bordeaux et Sud Ouest ( Site 0703)
        • Contact:
          • Study Coordinator
          • Phone Number: +33556333261
    • Bas-Rhin
      • Strasbourg, Bas-Rhin, France, 67200
        • Recruiting
        • Hopitaux Universitaires de Strasbourg ( Site 0700)
        • Contact:
          • Study Coordinator
          • Phone Number: +33368766767
    • Île-de-France Region
      • Villejuif, Île-de-France Region, France, 94805
        • Recruiting
        • Gustave Roussy ( Site 0701)
        • Contact:
          • Study Coordinator
          • Phone Number: +33 1 42 11 42 11
  • Germany
      • Berlin, Germany, 10117
        • Active, not recruiting
        • Charité Universitaetsmedizin Berlin - Campus Mitte ( Site 0800)
      • Hamburg, Germany, 20246
        • Recruiting
        • Universitaetsklinikum Hamburg-Eppendorf-Onkologisches Zentrum ( Site 0804)
        • Contact:
          • Study Coordinator
          • Phone Number: +4915222815585
    • Baden-Wurttemberg
      • Heidelberg, Baden-Wurttemberg, Germany, 69120
        • Recruiting
        • Universitaetsklinikum Heidelberg ( Site 0805)
        • Contact:
          • Study Coordinator
          • Phone Number: +496221565982
      • Tübingen, Baden-Wurttemberg, Germany, 72076
        • Recruiting
        • Universitaetsklinikum Tuebingen-Urologie ( Site 0801)
        • Contact:
          • Study Coordinator
          • Phone Number: +4970712987235
    • Bavaria
      • Munich, Bavaria, Germany, 81675
        • Recruiting
        • klinikum rechts der isar der technischen universität münchen-Urologische Klinik und Poliklinik ( Site 0802)
        • Contact:
          • Study Coordinator
          • Phone Number: +498941402522
  • Ireland
      • Cork, Ireland, T12 DC4A
        • Recruiting
        • Cork University Hospital ( Site 0902)
        • Contact:
          • Study Coordinator
          • Phone Number: +353 0214922687
      • Dublin, Ireland, D24 NR0A
        • Recruiting
        • Tallaght University Hospital ( Site 0900)
        • Contact:
          • Study Coordinator
          • Phone Number: +353014144209
    • Dublin
      • Dublin, Dublin, Ireland, D04 T6F4
        • Recruiting
        • St. Vincent's University Hospital ( Site 0901)
        • Contact:
          • Study Coordinator
          • Phone Number: +353012214000
  • Israel
      • Haifa, Israel, 3109601
        • Recruiting
        • Rambam Health Care Campus-Oncology Division ( Site 1002)
        • Contact:
          • Study Coordinator
          • Phone Number: 047776234
      • Petah Tikva, Israel, 4941492
        • Recruiting
        • Rabin Medical Center ( Site 1001)
        • Contact:
          • Study Coordinator
          • Phone Number: +97239378110
      • Ramat Gan, Israel, 5265601
        • Recruiting
        • Sheba Medical Center ( Site 1000)
        • Contact:
          • Study Coordinator
          • Phone Number: +972525505090
  • Italy
      • Verona, Italy, 37134
        • Recruiting
        • Azienda Ospedaliera Universitaria Integrata Verona - Ospedal-Centro Ricerche Cliniche di Verona ( Site 1100)
        • Contact:
          • Study Coordinator
          • Phone Number: +390458126564
    • Lazio
      • Rome, Lazio, Italy, 00168
        • Completed
        • Fondazione Policlinico Universitario Agostino Gemelli IRCCS -Medical Oncology ( Site 1102)
    • Lombardy
      • Milan, Lombardy, Italy, 20133
        • Recruiting
        • Fondazione IRCCS Istituto Nazionale dei Tumori-Struttura Complessa Oncologia Medica 1 ( Site 1103)
        • Contact:
          • Study Coordinator
          • Phone Number: +390223904449
    • Milano
      • Rozzano, Milano, Italy, 20089
        • Recruiting
        • Istituto Clinico Humanitas-U.O di Oncologia medica ed Ematologia ( Site 1101)
        • Contact:
          • Study Coordinator
          • Phone Number: +390282244080
  • Japan
      • Fukuoka, Japan, 812-8582
        • Recruiting
        • Kyushu University Hospital ( Site 1204)
        • Contact:
          • Study Coordinator
          • Phone Number: +81-92-641-1151
    • Chiba
      • Sakura, Chiba, Japan, 285-8741
        • Recruiting
        • Toho University Sakura Medical Center ( Site 1201)
        • Contact:
          • Study Coordinator
          • Phone Number: +81-43-462-8811
    • Kanagawa
      • Yokohama, Kanagawa, Japan, 232-0024
        • Recruiting
        • Yokohama City University Medical Center ( Site 1203)
        • Contact:
          • Study Coordinator
          • Phone Number: +81-45-261-5656
    • Tokyo
      • Mitato, Tokyo, Japan, 105-8471
        • Completed
        • The Jikei University Hospital ( Site 1202)
  • New Zealand
      • Auckland, New Zealand, 1023
        • Recruiting
        • Auckland City Hospital ( Site 1333)
        • Contact:
          • Study Coordinator
          • Phone Number: +6493074949
  • Poland
    • Kuyavian-Pomeranian Voivodeship
      • Bydgoszcz, Kuyavian-Pomeranian Voivodeship, Poland, 85-796
        • Recruiting
        • Centrum Onkologii im. Prof. Franciszka Lukaszczyka-Ambulatorium Chemioterapii ( Site 1402)
        • Contact:
          • Study Coordinator
          • Phone Number: +48523743525
    • Masovian Voivodeship
      • Warsaw, Masovian Voivodeship, Poland, 02-781
        • Recruiting
        • Narodowy Instytut Onkologii im. Marii Sklodowskiej-Curie - P-Oddzial Badan Wczesnych Faz ( Site 1400)
        • Contact:
          • Study Coordinator
          • Phone Number: 48225463381
    • Pomeranian Voivodeship
      • Gdansk, Pomeranian Voivodeship, Poland, 80-952
        • Recruiting
        • Uniwersyteckie Centrum Kliniczne ( Site 1405)
        • Contact:
          • Study Coordinator
          • Phone Number: 48585844466
  • South Korea
      • Seoul, South Korea, 03722
        • Recruiting
        • Severance Hospital, Yonsei University Health System-Medical oncology ( Site 1502)
        • Contact:
          • Study Coordinator
          • Phone Number: +82222288138
      • Seoul, South Korea, 06351
        • Recruiting
        • Samsung Medical Center-Division of Hematology/Oncology ( Site 1501)
        • Contact:
          • Study Coordinator
          • Phone Number: +82234101767
    • Seoul
      • Songpagu, Seoul, South Korea, 05505
        • Recruiting
        • Asan Medical Center-Oncology ( Site 1500)
        • Contact:
          • Study Coordinator
          • Phone Number: +82230106095
  • Spain
      • Barcelona, Spain, 08035
        • Recruiting
        • Hospital Universitari Vall d'Hebron-Departamento de Oncologia- VHIO ( Site 1602)
        • Contact:
          • Study Coordinator
          • Phone Number: +34934894374
      • Madrid, Spain, 28040
        • Recruiting
        • Hospital Clinico San Carlos-Oncology Department ( Site 1604)
        • Contact:
          • Study Coordinator
          • Phone Number: +34 91 330 35 46
      • Madrid, Spain, 28007
        • Recruiting
        • Hospital General Universitario Gregorio Marañón ( Site 1601)
        • Contact:
          • Study Coordinator
          • Phone Number: +34914269393
    • Barcelona
      • L'Hospitalet de Llobregat, Barcelona, Spain, 08908
        • Recruiting
        • Institut Català d'Oncologia - L'Hospitalet-Medical Oncology ( Site 1603)
        • Contact:
          • Study Coordinator
          • Phone Number: +34932607744
    • Madrid, Comunidad de
      • Madrid, Madrid, Comunidad de, Spain, 28034
        • Recruiting
        • Hospital Universitario Ramón y Cajal-Medical Oncology ( Site 1600)
        • Contact:
          • Study Coordinator
          • Phone Number: 34913368263
  • Taiwan
      • Taichung, Taiwan, 404332
        • Recruiting
        • China Medical University Hospital ( Site 1703)
        • Contact:
          • Study Coordinator
          • Phone Number: +886-975681629
      • Taipei, Taiwan, 112
        • Recruiting
        • Taipei Veterans General Hospital ( Site 1701)
        • Contact:
          • Study Coordinator
          • Phone Number: +886228757519
      • Taoyuan, Taiwan, 333
        • Recruiting
        • Chang Gung Medical Foundation-Linkou Branch-Medical Oncology ( Site 1702)
        • Contact:
          • Study Coordinator
          • Phone Number: +88633281200
    • Kaohsiung
      • Kaohsiung Niao Sung Dist, Kaohsiung, Taiwan, 83301
        • Recruiting
        • Chang Gung Memorial Hospital at Kaohsiung-Oncology and Hematology ( Site 1704)
        • Contact:
          • Study Coordinator
          • Phone Number: +886-77317123x3267
  • Turkey (Türkiye)
      • Adana, Turkey (Türkiye), 01250
        • Recruiting
        • Baskent University Dr. Turgut Noyan Research and Training Center-ONCOLOGY ( Site 1802)
        • Contact:
          • Study Coordinator
          • Phone Number: 03223272727
      • Ankara, Turkey (Türkiye), 06230
        • Recruiting
        • Hacettepe Universite Hastaneleri-oncology hospital ( Site 1800)
        • Contact:
          • Study Coordinator
          • Phone Number: +90312 305 43 30
      • Ankara, Turkey (Türkiye), 06800
        • Recruiting
        • Ankara Bilkent Şehir Hastanesi ( Site 1801)
        • Contact:
          • Study Coordinator
          • Phone Number: 0090312 552 60 00
      • Istanbul, Turkey (Türkiye), 34668
        • Recruiting
        • Istanbul Universitesi Cerrahpasa-Medical Oncology ( Site 1804)
        • Contact:
          • Study Coordinator
          • Phone Number: +902124143434
      • Istanbul, Turkey (Türkiye), 34722
        • Recruiting
        • TC Saglik Bakanligi Goztepe Prof. Dr. Suleyman Yalcin Sehir Hastanesi-oncology ( Site 1803)
        • Contact:
          • Study Coordinator
          • Phone Number: +90 216 606 52 00
  • United Kingdom
      • Birmingham, United Kingdom, B15 2TH
        • Recruiting
        • Queen Elizabeth Hospital Birmingham ( Site 1903)
        • Contact:
          • Study Coordinator
          • Phone Number: 01213712000
    • Cambridgeshire
      • Cambridge, Cambridgeshire, United Kingdom, CB2 2QQ
        • Recruiting
        • Addenbrooke's Hospital ( Site 1902)
        • Contact:
          • Study Coordinator
          • Phone Number: +441223216083
    • Glasgow City
      • Glasgow, Glasgow City, United Kingdom, G12 0YN
        • Recruiting
        • The Beatson West of Scotland Cancer Centre ( Site 1904)
        • Contact:
          • Study Coordinator
          • Phone Number: +441413017070
    • Lancashire
      • Preston, Lancashire, United Kingdom, PR2 9HT
        • Recruiting
        • Royal Preston Hospital-Lancashire Clinical Research Facility ( Site 1900)
        • Contact:
          • Study Coordinator
          • Phone Number: 01772522031
    • London, City of
      • London, London, City of, United Kingdom, NW1 2PG
        • Recruiting
        • University College London Hospital ( Site 1905)
        • Contact:
          • Study Coordinator
          • Phone Number: +442034472930
  • United States
    • California
      • La Jolla, California, United States, 92037
        • Recruiting
        • UCSD Moores Cancer Center ( Site 0039)
        • Contact:
          • Study Coordinator
          • Phone Number: 858-822-6100
      • Los Angeles, California, United States, 90404
        • Recruiting
        • UCLA Hematology/Oncology - Santa Monica ( Site 0044)
        • Contact:
          • Study Coordinator
          • Phone Number: 310-825-2631
    • Florida
      • Miami, Florida, United States, 33136
        • Recruiting
        • University of Miami Hospital and Clinics, Sylvester Cancer Center-Cancer Research Services ( Site 0051)
        • Contact:
          • Study Coordinator
          • Phone Number: 305-243-1543
    • Maryland
      • Baltimore, Maryland, United States, 21201
        • Active, not recruiting
        • University of Maryland-Greenebaum Comprehensive Cancer Center ( Site 0049)
    • New Jersey
      • New Brunswick, New Jersey, United States, 08903-2681
        • Active, not recruiting
        • Rutgers Cancer Institute of New Jersey ( Site 0033)
    • Ohio
      • Cleveland, Ohio, United States, 44106
        • Recruiting
        • University Hospitals Cleveland Medical Center ( Site 0043)
        • Contact:
          • Study Coordinator
          • Phone Number: 216-844-3951
    • Wisconsin
      • Milwaukee, Wisconsin, United States, 53226
        • Recruiting
        • MEDICAL COLLEGE OF WISCONSIN-Cancer Center Clinical Trials Office ( Site 0020)
        • Contact:
          • Study Coordinator
          • Phone Number: 414-955-8296

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

The main inclusion criteria include but are not limited to the following:

  • Histologically or cytologically confirmed diagnosis of adenocarcinoma of the prostate without small cell histology.
  • Prostate cancer progression and received androgen deprivation therapy (ADT) or post bilateral orchiectomy within 6 months before screening.
  • Evidence of disease progression from either, >4 weeks from last flutamide treatment, or >6 weeks from last bicalutamide or nilutamide treatment, if receiving first generation anti-androgen therapy as last treatment therapy.
  • Current evidence of metastatic disease.
  • Prior treatment with 1 to 2 novel hormonal agent(s) (NHA) for non-metastatic, or metastatic, hormone-sensitive prostate cancer or castration-resistant prostate cancer and have disease progression during or after treatment.
  • Treatment with bone resorptive therapy (including, but not limited to, bisphosphonate or denosumab) must have been on stable doses for >4 weeks before randomization.
  • Participants who experienced adverse events (AEs) due to previous anticancer therapies must have recovered to <Grade 1 or baseline.
  • Human immunodeficiency virus (HIV)-infected participants must have well controlled HIV on antiretroviral therapy.
  • Participants who are Hepatitis B surface antigen (HBsAg) positive are eligible if they have received Hepatitis B Virus (HBV) antiviral therapy for at least 4 weeks, and have undetectable HBV viral load.
  • Participants with a history of Hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable.

Exclusion Criteria:

The main exclusion criteria include but are not limited to the following:

  • History of pituitary dysfunction.
  • Poorly controlled diabetes mellitus.
  • Active or unstable cardio/cerebro-vascular disease, including thromboembolic events and history of stroke or transient ischemic attack within 6 months before the first dose of study intervention, history of myocardial infarction within 6 months before the first dose of study intervention, New York Heart Association Class III or IV cardiac disease or congestive heart failure, coronary heart disease that is symptomatic, or unstable angina
  • History or family history of long corrected QT interval (QTc) syndrome.
  • Myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) or features suggestive of MDS/AML.
  • History or current condition of adrenal insufficiency.
  • History of (noninfectious) pneumonitis requiring steroids, or current pneumonitis.
  • HIV-infected participants with a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease.
  • Undergone major surgery, including local prostate intervention (except prostate biopsy) within 28 days before randomization, and has not recovered from the toxicities and/or complications.
  • Is on an unstable dose of thyroid hormone therapy within 6 months prior to first dose of study intervention.
  • Received a whole blood transfusion in the last 120 days before randomization (packed red blood cells and platelet transfusions are acceptable if not given within 28 days before randomization).
  • Received prior systemic anticancer therapy including investigational agents within 4 weeks before randomization.
  • Received prior radiotherapy within 2 weeks of start of study intervention or radiation-related toxicities, requiring corticosteroids.
  • Received a live or live-attenuated vaccine within 30 days before the first does of study intervention. Administration of killed vaccines is allowed.
  • Diagnosis of immunodeficiency, or is receiving chronic systemic steroid therapy, or any other form of immunosuppressive therapy, within 7 days prior to the first dose of study intervention.
  • Known additional malignancy that is progressing or has required active treatment within the past 3 years.
  • Known active central nervous system (CNS) metastases and/or carcinomatous meningitis.
  • Active autoimmune disease that has required systemic treatment in the past 2 years.
  • Active infection requiring systemic therapy.
  • Concurrent active HBV or HCV infections.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Arm A1: Opevesostat
Participants receive 5 mg of opevesostat twice daily (BID) via oral tablet plus dexamethasone 1.5 mg by oral tablets once daily (QD) and 0.1 mg fludrocortisone acetate by oral tablet QD until progression or discontinuation.
Drug: Dexamethasone
Oral Tablet
Drug: Opevesostat
Oral Tablet
Other Names:
  • MK-5684
Drug: Fludrocortisone acetate
Oral Tablet
Experimental: Arm A2: Olaparib + Opevesostat
Participants receive 5 mg of opevesostat BID via oral tablet plus dexamethasone 1.5 mg by oral tablets QD and 0.1 mg fludrocortisone acetate by oral tablet QD, PLUS 300 mg of olaparib BID via oral tablet until progressive disease or discontinuation.
Drug: Dexamethasone
Oral Tablet
Drug: Olaparib
Oral Tablet
Other Names:
  • LYNPARZA®
Drug: Opevesostat
Oral Tablet
Other Names:
  • MK-5684
Drug: Fludrocortisone acetate
Oral Tablet
Experimental: Arm A3: Docetaxel + Opevesostat
Participants receive 5 mg of opevesostat BID via oral tablet plus dexamethasone 1.5 mg by oral tablets QD and 0.1 mg fludrocortisone acetate by oral tablet QD, PLUS 75 mg/m^2 of docetaxel once every 3 weeks (Q3W) via IV infusion, plus prednisone per approved product label BID by oral tablets until progressive disease or discontinuation.
Drug: Docetaxel
IV Infusion
Other Names:
  • TAXOTERE®
Drug: Prednisone
Oral Tablet
Drug: Dexamethasone
Oral Tablet
Drug: Opevesostat
Oral Tablet
Other Names:
  • MK-5684
Drug: Fludrocortisone acetate
Oral Tablet
Experimental: Arm A4: Cabazitaxel + Opevesostat
Participants receive 5 mg of opevesostat BID via oral tablet plus dexamethasone 1.5 mg by oral tablets QD and 0.1 mg fludrocortisone acetate by oral tablet QD, PLUS 20 mg/m^2 of cabazitaxel Q3W via IV infusion, plus prednisone per approved product label BID by oral tablets until progressive disease or discontinuation.
Drug: Prednisone
Oral Tablet
Drug: Dexamethasone
Oral Tablet
Drug: Cabazitaxel
IV Infusion
Other Names:
  • JEVTANA®
Drug: Opevesostat
Oral Tablet
Other Names:
  • MK-5684
Drug: Fludrocortisone acetate
Oral Tablet

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of participants who experience one or more dose-limiting toxicities (DLTs)
Time Frame: Up to approximately 28 days
The following events, if considered drug related by the investigator, will be considered a DLT: Grade 4 nonhematologic toxicity (not laboratory value); Grade 4 hematologic toxicity lasting >7 days, except thrombocytopenia (Grade 4 thrombocytopenia of any duration, Grade 3 thrombocytopenia associated with clinically significant bleeding); Any nonhematologic adverse event (AE) >Grade 3 in severity should be considered a DLT (with exceptions); Any Grade 3 or Grade 4 nonhematologic laboratory value (if certain criteria are met); Febrile neutropenia Grade 3 or Grade 4; Prolonged delay (>2 weeks) in initiating treatment after the first 28 days due to study intervention-related toxicity; Missing >25% of study intervention doses as a result of drug-related AE(s) during the first 28 days; Grade 5 toxicity.
Up to approximately 28 days
Number of participants who experience one or more adverse events (AEs)
Time Frame: Up to approximately 46 months
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Up to approximately 46 months
Number of participants who discontinue study intervention due to an AE
Time Frame: Up to approximately 46 months
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Up to approximately 46 months
Prostate-specific antigen (PSA) response rate
Time Frame: Up to approximately 46 months
The Prostate-specific Antigen (PSA) response rate is the percentage of participants who had PSA response defined as a reduction in the PSA level from baseline by ≥50%. The reduction in PSA level will be confirmed by an additional PSA evaluation performed ≥3 weeks from the original response per Prostate Cancer Working Group (PCWG) criteria.
Up to approximately 46 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall survival (OS)
Time Frame: Up to approximately 46 months
OS is defined as the time from randomization to death due to any cause.
Up to approximately 46 months
Objective response rate (ORR)
Time Frame: Up to approximately 46 months
The ORR is defined as the percentage of participants with complete response (CR: disappearance of all target lesions per Response Criteria in Solid Tumors version 1.1 (RECIST 1.1); and no evidence of disease (NED) on base scan per Prostate Cancer Working Group (PCWG) or partial response (PR: at least a 30% decrease in the sum of diameters of target lesions per RECIST 1.1; and non-progressive disease, non-evaluable [NE], or NED on bone scan or CR with non-progressive disease or NE bone scan per PCWG). ORR will be assessed by Blinded Independent Central Review (BICR).
Up to approximately 46 months
Radiographic progression-free survival (rPFS)
Time Frame: Up to approximately 46 months
rPFS is defined as the time from randomization to occurrence of: radiological tumor progression using RECIST 1.1 as assessed by BICR; progression of bone lesions using PCWG criteria; or death due to any cause. Progression as per modified RECIST 1.1 is ≥20% increase in the sum of diameters of target lesions and progression of existing non-target lesions. Progression of bone lesions by PCWG criteria is the appearance of ≥2 new bone lesions on bone scan, that have been confirmed to not represent tumor flare, and are persistent for ≥6 weeks. rPFS will be assessed by BICR.
Up to approximately 46 months
Duration of response (DOR)
Time Frame: Up to approximately 46 months
DOR is defined as the time from first documented evidence of complete response (CR) or partial response (PR) per PCWG and RECIST 1.1 criteria until progressive disease (PD) or death. PD per RECIST 1.1 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 a least 5 mm. PD per PCWG is the appearance of >2 new bone lesions on bone scan, that have been confirmed to not represent tumor flare, and are persistent for >6 weeks. DOR will be assessed by BICR.
Up to approximately 46 months
Time to first subsequent anticancer therapy (TFST)
Time Frame: Up to approximately 46 months
TFST is defined as the time from randomization to initiation of the first subsequent anticancer therapy or death, whichever occurs first.
Up to approximately 46 months
Time to pain progression (TTPP)
Time Frame: Up to approximately 46 months
TTPP is defined as the time from randomization to pain progression based on the Brief Pain Inventory-Short Form (BPI-SF) Item 3 "worst pain in 24 hours" and by opiate analgesic use.
Up to approximately 46 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Merck Sharp & Dohme LLC

Collaborators

Orion Corporation, Orion Pharma

Investigators

  • Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 20, 2024

Primary Completion (Estimated)

January 15, 2029

Study Completion (Estimated)

January 15, 2029

Study Registration Dates

First Submitted

April 3, 2024

First Submitted That Met QC Criteria

April 3, 2024

First Posted (Actual)

April 9, 2024

Study Record Updates

Last Update Posted (Actual)

May 26, 2026

Last Update Submitted That Met QC Criteria

May 21, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 5684-01A
  • MK-5684-01A (Other Identifier: MSD)
  • U1111-1292-6912 (Registry Identifier: UTN)
  • jRCT2031240224 (Registry Identifier: Japan Registry of Clinical Trials (jRCT))
  • 2023-506288-33-00 (Registry Identifier: EU CT)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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