REGN15505 (PSMAx4-1BB) Alone or in Combination With Cemiplimab or REGN4336 (PSMAxCD3) in Adult Pa… (NCT07594106) | Clinical Trial Compass
Not Yet RecruitingPhase 1/2
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
265 participantsStarted 2026-05-25
Plain-language summary
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.
The study will evaluate the use of REGN15505 when administered alone, in combination with cemiplimab, or in combination with REGN4336 for:
* Any side effects of study drugs
* How well the study drugs work
* How much REGN15505, cemiplimab, and REGN4336 are in the blood at different times
* If the body makes antibodies to REGN15505 or REGN4336, which may mean the study drugs will not work as well as expected
* What is the best dose of REGN15505 when administered alone and with cemiplimab and the best dose of REGN15505 and REGN4336 when used in combination
Who can participate
Age range
18 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. 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
. 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
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Occurrence of Dose Limiting Toxicities (DLTs)
Timeframe: Up to 5 years
2
Occurrence of Treatment-Emergent Adverse Events (TEAEs)
Timeframe: Up to 5 years
3
Occurrence of Serious Adverse Events (SAEs)
Timeframe: Up to 5 years
4
Occurrence of Adverse Events of Special Interest (AESIs)
Timeframe: Up to 5 years
5
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)
Timeframe: Up to 5 years
6
Objective response per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1
. 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)
Exclusion criteria
. 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
. Has received prior Prostate Specific Membrane Antigen (PSMA)-targeting therapy with the exception of a PSMA-targeting radioligand (eg, 177Lu-PSMA-617)