Study of Opevesostat (MK-5684) Versus Alternative NHA in mCRPC (MK-5684-003)

Merck Sharp & Dohme (MSD)

Status and phase

Enrolling

Phase 3

Conditions

Prostate Cancer Metastatic

Treatments

Drug: Dexamethasone

Drug: Hydrocortisone

Drug: Fludrocortisone acetate

Drug: Prednisone

Drug: Abiraterone acetate

Drug: Opevesostat

Drug: Enzalutamide

Study type

Interventional

Funder types

Industry

Identifiers

NCT06136624

jRCT2031240029 (Registry Identifier)

2023-504899-25 (Other Identifier)

5684-003

MK-5684-003 (Other Identifier)

Details and patient eligibility

About

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) and to radiographic progression-free survival (rPFS) per Prostate Cancer Working Group (PCWG) Modified Response Evaluation Criteria In Solid Tumors (RECIST 1.1) as assessed by blinded independent central review (BICR) 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 and rPFS per PCWG Modified RECIST 1.1 as assessed by BICR in androgen receptor ligand binding domain (AR LBD) mutation-negative and -positive participants.

Enrollment

1,200 estimated patients

Sex

All

Volunteers

No Healthy Volunteers

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 metastatic 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) performance status of 0 or 1 assessed within 7 days of randomization
Has had prior treatment with PARPi or were deemed ineligible to receive treatment by the investigator or have refused PARPi treatment
Has received prior 177Lu-PSMA-617 or were deemed ineligible to receive 177Lu-PSMA-617 treatment by the investigator or refused 177Lu-PSMA-617 treatment
Participants who have not received cabazitaxel can be enrolled if they are ineligible for cabazitaxel treatment as determined by the investigator or have refused treatment
If participant received first generation anti-androgen therapy before screening, the participant has evidence of disease progression >4 weeks since the last flutamide treatment and >6 weeks since the last bicalutamide or nilutamide treatment
Participants receiving bone resorptive therapy (including, but not limited to, bisphosphonate or denosumab) must have been on stable doses for ≥ 4 weeks before the date of randomization
Participants with human immunodeficiency virus (HIV) infection must have well controlled HIV on antiretroviral therapy (ART)
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 before randomization
Participants with history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable at Screening.
Participants who can produce sperm must agree to the following during the study treatment period and for at least 7 days after the last dose of opevesostat, for at least 30 days after the last dose of abiraterone acetate, and for at least 3 months after the last dose of enzalutamide: EITHER be abstinent OR must agree to use male condom

Exclusion criteria

Has a gastrointestinal disorder that might affect absorption
Has a history of pituitary dysfunction
Has poorly controlled diabetes mellitus
Has clinically significant abnormal serum potassium or sodium level
Has a history of active or unstable cardio/cerebro-vascular disease, including thromboembolic events
Has a history of seizure within 6 months of providing documented informed consent or any condition that may predispose to seizures within 12 months before the date of randomization
Has a history of clinically significant ventricular arrhythmias
Has received an anticancer monoclonal antibody (mAb) within 4 weeks before the date of randomization, or has not recovered from adverse events (AEs) due to mAbs administered more than 4 weeks before the date of randomization
Has undergone major surgery, including local prostate intervention (except prostate biopsy), within 28 days before the date of randomization, and has not recovered from the toxicities and/or complications
Participants who have not adequately recovered from major surgery or have ongoing surgical complications
Has used herbal or medicinal products that may have hormonal anti-prostate cancer activity and/or are known to decrease prostate-specific Antigen (PSA) (eg, saw palmetto, megesterol acetate) within 4 weeks before the date of randomization
Has received radium-223 or lutetium-177 within 4 weeks before the date of randomization, or has not recovered to Grade ≤1 or baseline from AEs due to radium-223 or lutetium-177 administered more than 4 weeks before the date of randomization
Has received treatment with 5-αreductase inhibitors (eg, finasteride or dutasteride), estrogens, or cyproterone within 4 weeks before the date of randomization
Has received colony-stimulating factors within 28 days before the date of randomization
Has received a whole blood transfusion in the last 120 days before the date of randomization. Packed red blood cells and platelet transfusions are acceptable if not given within 28 days of the date of randomization
Has received prior targeted small molecule therapy or NHA treatment within 4 weeks before the first dose of study intervention as follows: enzalutamide or apalutamide within 3 weeks or abiraterone acetate + prednisone or darolutamide within 2 weeks
Has a "superscan" bone scan
Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior the first dose of study medication
Has a known additional malignancy that is progressing or has required active treatment within the past 3 years
Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis
Has an active autoimmune disease that has required systemic treatment in past 2 years
Has an active infection requiring systemic therapy
Has concurrent active HBV or known active HCV infection
Has a history of long QTc syndrome
Has any of the following at Screening Visit: hypotension (systolic BP <110 mm Hg) or uncontrolled hypertension (systolic BP ≥160 mm Hg or diastolic BP ≥90 mm Hg, in 2 out of 3 recordings with optimized antihypertensive therapy)
Is unable to swallow capsules/tablets
Is currently being treated with cytochrome 450-inducing antiepileptic drugs for seizures
Participants on an unstable dose of thyroid hormone therapy within 6 months before the start of the study intervention
Received prior systemic anticancer therapy including investigational agents within 4 weeks before the first dose of study intervention
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 dose of study intervention
Systemic use of the following medications within 2 weeks before the first dose of study intervention: strong CYP3A4 inducers (eg, avasimibe, carbamazepine, lumacaftor, phenobarbital, rifampicin, rifapentine, or St John's Wort); P-gp inhibitors (eg, erythromycin, clarithromycin, rifampicin, ketoconazole, itraconazole, posaconazole, artesunate-pyronaridine, ritonavir, indinavir, nelfinavir, atazanavir, glecaprevir-pibrentasvir, simeprevir, ledipasvir-sofosbuvir, verapamil, diltiazem, dronedarone, propafenone, quinidine, cyclosporine, valspodar, or milk thistle [Silybum marianum])
Use of aldosterone antagonist (eg, spironolactone, eplerenone) and phenytoin within 4 weeks before the start of the study intervention

Trial design

Primary purpose

Treatment

Allocation

Randomized

Interventional model

Parallel Assignment

Masking

None (Open label)

1,200 participants in 2 patient groups

Opevesostat

Experimental group

Description:

Participants receive opevesostat 5 mg by oral tablets twice daily (bid) plus dexamethasone 1.5 mg by oral tablets once daily (qd) and 0.1 mg fludrocortisone acetate by oral tablet qd until progression. Hydrocortisone 100 mg (oral or intramuscular \[IM\]) dose will also be provided to participants for use as rescue medication.

Treatment: