A Study of Opevesostat (MK-5684) in China Participants With Metastatic Castration-Resistant Prostate Cancer (mCRPC) (MK-5684-001)

March 18, 2026 updated by: Merck Sharp & Dohme LLC

A Phase 1 Clinical Study to Investigate the Safety and Pharmacokinetics of MK-5684 in China Participants With Metastatic Castration-Resistant Prostate Cancer

The primary objectives of this study are to evaluate the safety and tolerability of opevesostat in the treatment of male Chinese participants with metastatic castration-resistant prostate cancer (mCRPC) and to characterize the pharmacokinetic profile of opevesostat. There are no formal hypotheses to be tested in this study.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
14

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
    • Beijing Municipality
      • Beijing, Beijing Municipality, China, 100034
        • Peking University First Hospital-Urology ( Site 0001)
    • Guangdong
      • Guangzhou, Guangdong, China, 510700
        • Sun Yat-sen University Cancer Center-Neurosurgery department ( Site 0003)
    • Hubei
      • Wuhan, Hubei, China, 430000
        • Tongji Hospital Tongji Medical,Science & Technology ( Site 0002)

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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

Inclusion Criteria:

  • Has histologically or cytologically confirmed adenocarcinoma of the prostate without small cell histology.
  • Has prostate cancer while receiving androgen deprivation therapy (ADT), or post-bilateral orchiectomy, within 6 months before screening.
  • Has evidence of progression >4 weeks since last flutamide treatment or >6 weeks since last bicalutamide or nilutamide treatment.
  • Has evidence of metastatic disease documented by either bone lesions on bone scan and/or soft tissue shown by CT/MRI.
  • Has disease that progressed during or after treatment with at least 1 line of next-generation hormonal agents (NHAs) for hormone-sensitive prostate cancer (HSPC) or castration-resistant prostate cancer (CRPC) for at least 8 weeks (at least 14 weeks for participants with bone progression).
  • Has received at least 1 line of taxane-based chemotherapy for HSPC or CRPC and have had progressed disease during or on treatment, or refused or ineligible to receive chemotherapy.
  • Has a life expectancy of >3 months.

Exclusion Criteria:

  • Has history of a second malignancy, unless potentially curative treatment has been completed with no evidence of malignancy for 3 years.
  • Has presence of gastrointestinal condition, e.g. malabsorption, that might affect the adsorption of study intervention.
  • Has a history of pituitary dysfunction.
  • Has poorly controlled diabetes mellitus.
  • Has active or unstable cardio/cerebro-vascular disease, including thromboembolic events.
  • Has undergone major surgery, including local prostate intervention (except prostate biopsy), within 4 weeks of the date of allocation.
  • Has received an anticancer monoclonal antibody (mAb) within 4 weeks of allocation, or has not recovered from adverse events (AEs) due to mAbs administered more than 4 weeks before the date of allocation.
  • Received prior systemic anticancer therapy including investigational agents within 4 weeks before the date of allocation.
  • Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any form of immunosuppressive therapy within 7 days prior to the start of study intervention.
  • Has a known active central nervous system (CNS) metastases and/or carcinomatous meningitis.
  • Has an active autoimmune disease that has required systemic treatment in the past 2 years.
  • Has a history of or current human immunodeficiency virus (HIV) infection.
  • Has a concurrent Hepatitis B or Hepatitis C virus infection.
  • Has a history of allogenic tissue or solid organ transplant.

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Opevesostat
Participants will receive opevesostat by oral tablets twice daily plus dexamethasone and fludrocortisone by oral tablets once daily continuously until unacceptable toxicity or documented progression. Hydrocortisone will also be provided to participants for use as rescue medication.
Drug: Dexamethasone
Tablets to be taken orally
Other Names:
  • Dexamethasone acetate
Drug: Fludrocortisone
Tablets to be taken orally.
Other Names:
  • Fludrocortisone acetate
Drug: Hydrocortisone
Tablet to be taken orally as a rescue medication.
Other Names:
  • Hydrocortisone acetate
Drug: Opevesostat
Tablets to be taken orally.
Other Names:
  • MK-5684

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Maximum Plasma Concentration (Cmax) of opevesostat
Time Frame: Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Blood samples will be collected at pre-specified timepoints to determine the Cmax of opevesostat.
Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Time to Maximum Plasma Concentration (Tmax) of opevesostat
Time Frame: Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Blood samples will be collected at pre-specified timepoints to determine the Tmax of opevesostat.
Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Area Under the Curve from Time 0 to 12 hours postdose (AUC0-12) of opevesostat
Time Frame: Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Blood samples will be collected at pre-specified timepoints to determine the AUC0-12 of opevesostat.
Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Apparent Volume of Distribution (Vz/F) of opevesostat
Time Frame: Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Blood samples will be collected at pre-specified timepoints to determine the Vz/F of opevesostat.
Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Oral Clearance (CL/F) of opevesostat
Time Frame: Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Blood samples will be collected at pre-specified timepoints to determine the CL/F of opevesostat.
Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Half-Life (t1/2) of opevesostat
Time Frame: Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Blood samples will be collected at pre-specified timepoints to determine the t1/2 of opevesostat.
Day 1 and Day 8: predose and 0.5, 1, 2, 3, 4, 6, 9, and 12 hours postdose, Day 29, Day 57, and Day 89: pre-dose
Number of Participants Who Experience an Adverse Event (AE)
Time Frame: Up to approximately 20 months
An AE is defined as any untoward medical occurrence associated with the use of a drug in a participant, whether or not considered drug related. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a medicinal product and does not imply any judgment about causality.
Up to approximately 20 months
Number of Participants Who Discontinue Study Intervention Due to an AE
Time Frame: Up to approximately 20 months
An AE is defined as any untoward medical occurrence associated with the use of a drug in a participant, whether or not considered drug related. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a medicinal product and does not imply any judgment about causality.
Up to approximately 20 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Prostate-specific Antigen (PSA) Response Rate
Time Frame: Up to approximately 37 months
The PSA response rate is defined as the percentage of participants in the analysis population with a reduction in PSA level of ≥50% measured twice ≥3 weeks apart.
Up to approximately 37 months
Radiographic Progression-free Survival (rPFS) Per Prostate Cancer Working Group (PCWG)-modified Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1)
Time Frame: Up to approximately 37 months
rPFS is defined as the time from first dose of study intervention to radiographic progression per PCWG-modified RECIST 1.1 as assessed by the investigator OR death due to any cause, whichever occurs first.
Up to approximately 37 months
Objective Response Rate (ORR) Per PCWG-modified RECIST 1.1
Time Frame: Up to approximately 37 months
ORR is defined as the percentage of participants who have a best overall response of either confirmed Complete Response (CR: disappearance of all target lesions) or a confirmed Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per PCWG-modified RECIST 1.1 as assessed by the investigator.
Up to approximately 37 months
Duration of Response (DOR) Per PCWG-modified RECIST 1.1
Time Frame: Up to approximately 37 months
For participants who demonstrate a confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per PCWG-modified RECIST 1.1, DOR is defined as the time from first documented evidence of confirmed CR or PR until disease progression or death from any cause, whichever occurs first.
Up to approximately 37 months
Overall Survival (OS)
Time Frame: Up to approximately 37 months
OS is defined as time from first dose of study intervention to death due to any cause.
Up to approximately 37 months
Blood Concentrations of Steroids
Time Frame: At designated timepoints (up to approximately 37 months)
Blood samples collected at multiple timepoints after the administration of opevesostat will be used to determine the blood concentrations of steroids.
At designated timepoints (up to approximately 37 months)

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Merck Sharp & Dohme LLC

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Orion Corporation, Orion Pharma

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 30, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 9, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 9, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 13, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 13, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 18, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 19, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 18, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 5684-001
  • MK-5684-001 (Other Identifier: MSD)

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

No

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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