NCT05125016 · Regeneron Pharmaceuticals
A Trial to Find Out if REGN4336 is Safe and How Well it Works Alone and in Combination With Cemiplimab or REGN5678 for Adult Participants With Advanced Prostate Cancer
What this study is about
This study is researching an experimental drug called REGN4336. Some participants may receive additional experimental drugs in combination with REGN4336. These additional drugs include REGN5678, cemiplimab and sarilumab.
View original scientific description
This study is researching an investigational drug called REGN4336. Some participants may receive additional investigational drugs in combination with REGN4336. These additional drugs include REGN5678, cemiplimab and sarilumab. The main purpose of this study is to determine the safety, tolerability (how the body reacts to the drug) and effectiveness of REGN4336 alone, in combination with cemiplimab, or in combination with REGN5678.
Interventions
DRUG
REGN4336
Administered per the protocol
DRUG
REGN5678
Administered per the protocol
Primary outcome measures
Incidence of Dose-Limiting Toxicities (DLTs)
Time frame: up to 21 days
Dose escalation
Incidence and severity of Treatment-Emergent Adverse Events (TEAEs)
Time frame: Up to 5 years
Dose escalation
Incidence and severity of Serious Adverse Events (SAEs)
Time frame: Up to 5 years
Dose escalation
Incidence and severity of Adverse Events of Special Interest (AESIs)
Time frame: Up to 5 years
Dose escalation
REGN4336 monotherapy concentrations in serum
Time frame: Up to 5 years
Dose escalation
REGN4336 concentrations in serum in combination with REGN5678
Time frame: Up to 5 years
Dose escalation
Composite Response Rate (CRR) of ≥50% decline of prostate specific antigen (PSA) and/or confirmed radiographic response of complete response (CR) or partial response (PR)
Time frame: Up to 5 years
Dose expansion
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
- Histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma 2. Metastatic, castration-resistant prostate cancer (mCRPC) with PSA value at screening ≥4 ng/mL that has progressed within 6 months prior to screening, according to 1 of the following: 1. PSA progression as defined by a rising PSA level confirmed with an interval of ≥1 week between each assessment 2. Radiographic disease progression in soft tissue based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria with or without PSA progression 3. Radiographic disease progression in bone defined as the appearance of 2 or more new bone lesions on bone scan with or without PSA progression NOTE: Measurable disease per RECIST version 1.1 per local reading at screening is not an eligibility criterion for enrollment 3. Has progressed upon or intolerant to ≥2 lines prior systemic therapy approved in the metastatic and/or castration-
Where
- Palo Alto, California
- New Haven, Connecticut
- Louisville, Kentucky
- Baltimore, Maryland
- New Brunswick, New Jersey
- Buffalo, New York
- Charlotte, North Carolina
- Columbus, Ohio
- Philadelphia, Pennsylvania
- Houston, Texas
- Milwaukee, Wisconsin
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