A Study of Opevesostat (MK-568)4 in Japanese Participants With Metastatic Castration-resistant Prostate Cancer (mCRPC) (MK-5684-005)

NCT ID: NCT06104449

Last Updated: 2025-09-16

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: PHASE1
• Total Enrollment: 6 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-11-14
• Study Completion Date: 2026-04-12

Brief Summary

The purpose of this study is to assess the efficacy and safety of opevesostat in the treatment of Japanese men with metastatic castration-resistant prostate cancer (mCRPC) previously treated with Next Generation Hormonal Agent (NHA) and taxane-based chemotherapy.

Conditions

Prostatic Neoplasms; Metastatic Castration-Resistant Prostate Cancer

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Opevesostat

Participants receive opevesostat 5 mg by oral tablets twice daily plus dexamethasone 1.5 mg by oral tablets and fludrocortisone acetate 0.1 mg oral tablet once daily continuously until progression. Hydrocortisone up to 100 mg oral dose will also be provided to participants for use as rescue medication.

Group Type: EXPERIMENTAL

Opevesostat

Intervention Type: DRUG

Tablets to be taken orally.

Dexamethasone

Intervention Type: DRUG

Tablets to be taken orally.

Fludrocortisone acetate

Intervention Type: DRUG

Tablet to be taken orally.

Hydrocortisone

Intervention Type: DRUG

Tablets to be taken orally as a recue medication.

Interventions

Opevesostat

Tablets to be taken orally.

Intervention Type: DRUG

Dexamethasone

Tablets to be taken orally.

Intervention Type: DRUG

Fludrocortisone acetate

Tablet to be taken orally.

Intervention Type: DRUG

Hydrocortisone

Tablets to be taken orally as a recue medication.

Intervention Type: DRUG

Other Intervention Names

MK-5684; Decadron

Eligibility Criteria

Inclusion Criteria

• Has histologically- or cytologically-confirmed adenocarcinoma of the prostate without small cell histology
• Has current evidence of metastatic disease documented by either bone lesions on bone scan and/or soft tissue disease by computed tomography/magnetic resonance imaging (CT/MRI)
• Has ongoing androgen deprivation with serum testosterone <50 ng/dL (<1.7 nmol/L)
• Participants receiving bone anti-resorptive therapy (including, but not limited to bisphosphonate or denosumab) must have been on stable doses for ≥4 weeks prior to the start of study intervention.
• Has progressed on or after treatment with at least 1 line of NHAs in metastatic hormone-sensitive prostate cancer (mHSPC) or in castration-resistant prostate cancer (CRPC) for a minimum of 12 weeks (e.g. abiraterone, enzalutamide, darolutamide, apalutamide), and with at least 1 line of taxane-based chemotherapy in mHSPC or in CRPC, or ineligibility for chemotherapy
• Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 within 10 days prior to allocation
• If capable of producing sperm, participant must agree to the following during the study treatment period and for at least 7 days after the last dose of opevesostat: Refrain from donating sperm, plus EITHER be abstinent OR must agree to use male condom.

Exclusion Criteria

• Has a history of pituitary dysfunction
• Has brain metastases
• History of a second malignancy, unless potentially curative treatment has been completed with no evidence of malignancy for 3 years
• Has an active or uncontrolled autoimmune disease that has required systemic treatment in past 2 years (ie, with use of disease modifying agents, corticosteroids, or immunosuppressive drugs)
• Has an active infection or other medical condition that would make corticosteroid contraindicated
• Has serious persistent infection within 2 weeks prior to the start of the study intervention
• Participants on an unstable dose of thyroid hormone therapy within 6 months prior to the start of the study intervention
• Has poorly controlled diabetes mellitus
• Hypotension: systolic blood pressure (BP) < 110 mmHg, or uncontrolled hypertension: systolic BP ≥ 160 mmHg or diastolic BP ≥ 95 mmHg, in 2 out of 3 recordings with optimized antihypertensive therapy
• Has active or unstable cardio/cerebro-vascular disease, including thromboembolic event
• Is unable to swallow orally administered medication or known gastrointestinal (GI) disease or GI procedure that may interfere with absorption of study intervention
• Has undergone major surgery including local prostate intervention (excluding prostate biopsy) within 28 days prior to the start of the study intervention and not adequately recovered from the toxicities and/or complications
• Has received aldosterone antagonist (e.g. spironolactone, eplerenone) and phenytoin within 4 weeks prior to the start of the study intervention
• Has received radiotherapy within 4 weeks prior to the start of the study intervention, or radiation related toxicities, requiring corticosteroids
• Has received chemotherapy within the last 4 weeks (2 weeks for oral or weekly chemotherapy; 6 weeks for nitrosoureas and mitomycin C) prior to the start of the study intervention
• Has received prior enzalutamide and apalutamide within 3 weeks, or abiraterone and darolutamide within 2 weeks prior to the start of the study intervention
• Systemic use of the following medications within 2 weeks prior to the start of study intervention: strong cytochrome P450 (CYP)3A4 inducers: e.g., carbamazepine, rifampicin, phenobarbital, phenytoin, St John's Wort) and strong CYP3A4 inhibitors: e.g., itraconazole, ketoconazole, posaconazole, voriconazole, clarithromycin, telithromycin, grapefruit juice
• Received a live or live-attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines are allowed.
• Has used herbal products that may have hormonal anti-prostate cancer activity and/or are known to decrease PSA levels (eg, saw palmetto) within 4 weeks prior to the start of the study intervention
• Has received treatment with 5-α reductase inhibitors (eg, finasteride or dutasteride), estrogens, and/or cyproterone within 4 weeks prior to the start of the study intervention
• Has received an investigational agent or has used an investigational device within 4 weeks prior to study intervention administration
• History of human immunodeficiency virus (HIV) infection
• Has a history of Hepatitis B or active Hepatitis C virus
• Has a "superscan" bone scan
• Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the start of the study intervention

• Minimum Eligible Age: 18 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: No

Sponsors

Orion Corporation, Orion Pharma

INDUSTRY

Sponsor Role: collaborator

Merck Sharp & Dohme LLC

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Medical Director

Role: STUDY_DIRECTOR

Merck Sharp & Dohme LLC

Locations

National Cancer Center Hospital East ( Site 0001)

Kashiwa, Chiba, Japan

Toho University Sakura Medical Center ( Site 0003)

Sakura, Chiba, Japan

Yokohama City University Medical Center ( Site 0002)

Yokohama, Kanagawa, Japan

Countries

Japan

Related Links

http://www.merckclinicaltrials.com

Merck Clinical Trials Information

Other Identifiers

MK-5684-005

Identifier Type: OTHER

Identifier Source: secondary_id

jRCT2031230431

Identifier Type: REGISTRY

Identifier Source: secondary_id

5684-005

Identifier Type: -

Identifier Source: org_study_id