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Study identifier: NCT03972657 Synced from ClinicalTrials.gov · July 28, 2026
● Recruiting

A Trial to Find Out if REGN5678 (Nezastomig) is Safe and How Well it Works Alone or in Combination With Cemiplimab for Adult Participants With Metastatic Castration-Resistant Prostate Cancer and Other Tumors

Condition: Metastatic Castration-Resistant Prostate Cancer (mCRPC) · Clear Cell Renal Cell Carcinoma (ccRCC)  ·  Sponsor: Regeneron Pharmaceuticals

PhasePhase 1/Phase 2
Planned participants345
Who can joinAll sexes, 18 Years to no upper limit
Healthy volunteersNo

About this study

The main purpose of this study is to determine the safety, tolerability (how the body reacts to the drug\[s\]) and effectiveness (ability to treat the cancer) of REGN5678 (Nezastomig) alone, or in combination with cemiplimab. The study has 2 parts. The goal of Part 1 (dose escalation) is to determine a safe dose(s) of REGN5678 when it is given alone or in combination with cemiplimab. The goal of Part 2 (dose expansion) is to use the REGN5678 drug dose(s) found in Part 1 to see how well REGN5678 alone or in combination with cemiplimab works to shrink tumors. This study is looking at several other research questions, including: 1. Side effects that may be experienced by taking REGN5678 alone or in combination with cemiplimab 2. How REGN5678 alone or in combination with cemiplimab works in the body 3. How much REGN5678 and/or cemiplimab are present in the blood 4. To see if REGN5678 alone or in combination with cemiplimab works to reduce the size of the tumor by helping the immune system destroy the tumor

This description comes directly from the study's public registry record.

Talk to the study team

Clinical Trials Administrator  ·  844-734-6643  ·  clinicaltrials@regeneron.com

Always discuss trial participation with your own doctor first.

Locations (24)

Banner MD Anderson Cancer CenterGilbert, Arizona, United StatesRecruiting
Mayo ClinicPhoenix, Arizona, United StatesRecruiting
University of ArizonaTucson, Arizona, United StatesRecruiting
John Wayne Cancer Institute (JWCI)Santa Monica, California, United StatesRecruiting
Sarah Cannon Research Institute (SCRI)Denver, Colorado, United StatesRecruiting
Yale University HospitalNew Haven, Connecticut, United StatesRecruiting
Mayo Clinic JacksonvilleJacksonville, Florida, United StatesRecruiting
Moffitt Cancer Center - McKinley DriveTampa, Florida, United StatesRecruiting
Massachusetts General HospitalBoston, Massachusetts, United StatesRecruiting
Henry Ford HealthDetroit, Michigan, United StatesRecruiting
Mayo ClinicRochester, Minnesota, United StatesRecruiting
NYU Langone Health Perlmutter Cancer CenterNew York, New York, United StatesRecruiting

+ 12 more locations — full list on the registry record.

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Source record: clinicaltrials.gov/study/NCT03972657