NCT06136624 · Merck Sharp & Dohme LLC
Study of Opevesostat (MK-5684) Versus Alternative NHA in mCRPC (MK-5684-003)
(OMAHA-003)
What this study is about
This is a phase 3, randomly assigned, where both patients and doctors know the treatment given study of opevesostat compared to alternative abiraterone acetate or enzalutamide in participants with metastatic castration-resistant prostate cancer (mCRPC) with respect to how long patients live (OS) in participants with mCRPC previously treated with next-generation hormonal agent (NHA) and taxane-based chemotherapy. It is hypothesized that opevesostat is superior with respect to OS in androgen receptor ligand binding domain (AR LBD) mutation-negative and -p
View original scientific description
This is a phase 3, randomized, open-label study of opevesostat compared to alternative abiraterone acetate or enzalutamide in participants with metastatic castration-resistant prostate cancer (mCRPC) with respect to overall survival (OS) in participants with mCRPC previously treated with next-generation hormonal agent (NHA) and taxane-based chemotherapy.
Interventions
DRUG
Opevesostat
Administered orally
DRUG
Abiraterone acetate
Administered orally
DRUG
Enzalutamide
Administered orally
DRUG
Hydrocortisone
Administered orally or IM as a rescue medication
DRUG
Fludrocortisone acetate
Administered orally
DRUG
Prednisone
Administered orally
DRUG
Dexamethasone
Administered orally as rescue medication
Primary outcome measures
Overall Survival (OS) in Androgen Receptor Ligand Binding Domain (AR LBD) Mutation-Positive Participants
Time frame: Up to ~54 months
OS is defined as time from randomization to death due to any cause. OS in AR LBD mutation-positive participants will be reported for each study arm.
OS in AR LBD Mutation-Negative Participants
Time frame: Up to ~54 months
OS is defined as time from randomization to death due to any cause. OS in AR LBD mutation-negative participants will be reported for each study arm.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Has histologically- or cytologically-confirmed adenocarcinoma of the prostate without small cell histology.
- Has prostate cancer progression while on androgen deprivation therapy (or post bilateral orchiectomy) within 6 months before Screening
- Has current evidence of distant metastatic disease (M1 disease) documented by either bone lesions on bone scan and/or soft tissue disease by computed tomography/magnetic resonance imaging (CT/MRI).
- Has disease that progressed during or after treatment with 1 novel hormonal agent (NHA)
- Has received 1 but no more than 2 taxane-based chemotherapy regimens for metastatic castration-resistant prostate cancer (mCRPC) and has had progressive disease (PD) during or after treatment
- Has ongoing androgen deprivation with serum testosterone \<50 ng/dL (\<1.7 nM)
- Has provided tumor tissue from a fresh core or excisional biopsy from soft tissue not previously irradiated
- Has an Eastern Cooperative Oncology Group (ECOG) perfor
Where
- Orange, California
- Palo Alto, California
- Riverside, California
- Aurora, Colorado
- Highlands Ranch, Colorado
- Lakewood, Colorado
- Lone Tree, Colorado
- New Haven, Connecticut
- Fort Myers, Florida
- Miami, Florida
- Chicago, Illinois
- Iowa City, Iowa
And 28 more locations — see the full list below.
Collaborators
Orion Corporation, Orion Pharma
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 5, 2026 · Source of record for eligibility and locations