NCT07594106 · Regeneron Pharmaceuticals
REGN15505 (PSMAx4-1BB) Alone or in Combination With Cemiplimab or REGN4336 (PSMAxCD3) in Adult Patients With Metastatic Castration-Resistant Prostate Cancer and Clear Cell Renal Cell Carcinoma
What this study is about
This study is researching a new drug called REGN15505 when used alone or in combination with cemiplimab or in combination with REGN4336 in adult patients with mCRPC and ccRCC. The goal is to explore new ways to treat these cancers by helping immune cells target and destroy cancer cells.
View original scientific description
This study is researching a new drug called REGN15505 when used alone or in combination with cemiplimab or in combination with REGN4336 in adult patients with mCRPC and ccRCC. The goal is to explore new ways to treat these cancers by helping immune cells target and destroy cancer cells.
Interventions
DRUG
REGN15505
Administered per protocol
DRUG
REGN15505+Cemiplimab
Administered per protocol
DRUG
REGN15505+REGN4336
Administered per protocol
Primary outcome measures
Occurrence of Dose Limiting Toxicities (DLTs)
Time frame: Up to 5 years
Dose Escalation
Occurrence of Treatment-Emergent Adverse Events (TEAEs)
Time frame: Up to 5 years
Dose Escalation
Occurrence of Serious Adverse Events (SAEs)
Time frame: Up to 5 years
Dose Escalation
Occurrence of Adverse Events of Special Interest (AESIs)
Time frame: Up to 5 years
Dose Escalation
Composite Response (CompR) based on ≥50% decline of Prostate Specific Antigen (PSA) and/or confirmed radiographic assessment of complete response (CR) or partial response (PR)
Time frame: Up to 5 years
Dose Expansion-mCRPC
Objective response per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1
Time frame: Up to 5 years
Dose Expansion-ccRCC
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
- Participants with mCRPC:
- Men with histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma
- mCRPC with PSA value at screening ≥4 ng/mL and that has progressed within 6 months prior to screening as described in the protocol
- Has received ≥2 lines of prior systemic therapy approved in the metastatic and/or castration-resistant setting as described in the protocol
- Have had either Orchiectomy or be on Luteinizing Hormone-Releasing Hormone (LHRH) agonist or antagonist therapy with serum testosterone \<50 ng/dL AND agree to stay on LHRH agonist or antagonist therapy during the study Participants with ccRCC:
- Men and women with histologically or cytologically confirmed Renal Cell Carcinoma (RCC) with a clear-cell component
- Diagnosis of metastatic ccRCC with at least 1 measurable lesion via Response evaluation criteria in solid tumors (RECIST) 1.1 criteria
- Has progressed on or after ≥1 line of prior systemic therapy approved in the metastatic setting. Prior treatment must include an Anti Program Cell Death 1 (PD-1)/ Program Death Ligand 1 (PD-L1) therapy and either ipilimumab and/or a Tyrosine Kinase Inhibitor (TKI) Key
Exclusion criteria
- For Both mCRPC and ccRCC Cohorts:
- Has received treatment with an approved systemic therapy (including sipuleucel-T for mCRPC patients) within 3 weeks of dosing or has not yet recovered (ie, grade ≤1 or baseline) from any acute toxicities except for laboratory changes as described in the protocol mCRPC Cohort Only:
- Has received prior Prostate Specific Membrane Antigen (PSMA)-targeting therapy with the exception of a PSMA-targeting radioligand (eg, 177Lu-PSMA-617) Note: Other protocol defined inclusion/exclusion criteria apply
Where
- Goodyear, Arizona
- Duarte, California
- Zion, Illinois
- Houston, Texas
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 Aug 5, 2026 · Source of record for eligibility and locations