Actively Recruiting

Phase 1
Phase 2
Age: 18Years +
All Genders
ID03972657

A Phase 1/2 Study of REGN5678 (Anti-PSMAxCD28) With or Without Cemiplimab (Anti-PD-1) in Adults With Metastatic Castration-Resistant Prostate Cancer and Other Tumors Expressing PSMA

Led by Regeneron Pharmaceuticals · Updated on 2025-11-06

345

Participants Needed

21

Research Sites

N/A

Total Duration

On this page

AI-Summary

What this Trial Is About

Researchers are evaluating the safety, tolerability, and effectiveness of the drug REGN5678 (Nezastomig), alone or combined with cemiplimab, in adults with metastatic castration-resistant prostate cancer (mCRPC) and other tumors that express PSMA. This study includes two parts: dose escalation to find safe REGN5678 doses alone or with cemiplimab, and dose expansion to assess how well these doses shrink tumors. Additional questions include side effects, drug behavior in the body, blood levels of the drugs, and tumor response through immune system activation. The study involves giving REGN5678 with or without cemiplimab to participants in different cohorts based on tumor type and dose phase. Treatment doses are determined during the dose escalation phase. Participants receive these drugs as outlined in the study protocol during both the dose escalation (Part 1) and dose expansion (Part 2) phases. The study is non-randomized and open-label, meaning all participants receive the investigational drugs without placebo. Participants will be monitored through various safety checks including tracking adverse events and laboratory tests for up to five years. Researchers will measure drug concentrations in the blood and track tumor response using prostate-specific antigen (PSA) levels and imaging criteria. The study also observes immune responses and monitors for any serious side effects or dose-limiting toxicities. This comprehensive follow-up allows for long-term assessment of drug safety and tumor effects.

CONDITIONS

Brief Title

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

Who Can Participate

Age: 18Years +
All Genders

Eligibility Criteria

Eligible

You may qualify if you...

  • Men with confirmed adenocarcinoma of the prostate without pure small cell carcinoma for mCRPC cohorts
  • PSA value at screening of 4 ng/mL or higher with progression within 6 months prior to screening for mCRPC
  • Received at least 2 prior systemic therapies approved for metastatic or castration-resistant prostate cancer including second-generation anti-androgen therapy and lutetium-based PSMA radioligand for mCRPC
  • Histologically or cytologically confirmed clear cell renal cell carcinoma with at least one measurable lesion for ccRCC cohorts
  • Diagnosis of metastatic ccRCC with progression after at least 1 prior approved systemic therapy including PD-1/PD-L1 therapy and ipilimumab or tyrosine kinase inhibitor
Not Eligible

You will not qualify if you...

  • Received any approved systemic therapy within 3 weeks before dosing or not recovered from acute toxicities
  • Received systemic biologic therapy within 5 half-lives before first study dose
  • Prior PSMA-targeting therapy except lutetium-based PSMA radioligand for mCRPC
  • Prior anti-cancer immunotherapy within 5 half-lives before study therapy for dose escalation phase
  • Prior anti-cancer immunotherapy for dose expansion in mCRPC
  • Requires ongoing corticosteroid therapy greater than 10 mg prednisone per day within 1 week before first dose
  • Recent or ongoing significant autoimmune disease treated with systemic immunosuppressives within 5 years
  • History of encephalitis, meningitis, neurodegenerative disease (except mild dementia not affecting daily living), or uncontrolled seizures in the past year
  • Uncontrolled infections including HIV, hepatitis B or C, or diagnosis of immunodeficiency

AI-Screening

AI-Powered Screening

Complete this quick 3-step screening to check your eligibility

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Your Study Journey

Screening

Duration - 2 to 4 weeks

Participants are screened for eligibility to participate in the trial.

1 visit (in-person)

Treatment

Duration - Up to 5 years or until discontinuation

Participants receive REGN5678 with or without cemiplimab as per the study protocol to evaluate safety and effectiveness.

Visits occur according to dosing and safety monitoring schedules during treatment

Follow-up

Duration - Up to 5 years following treatment completion

Participants are monitored for safety and treatment response after completing active treatment.

Periodic visits for long-term safety and response assessments

Trial Site Locations

Total: 21 locations

1

Banner MD Anderson Cancer Center

Gilbert, Arizona, United States, 85234

Actively Recruiting

2

Mayo Clinic

Phoenix, Arizona, United States, 85054

Actively Recruiting

3

University of Arizona

Tucson, Arizona, United States, 85724

Actively Recruiting

4

John Wayne Cancer Institute (JWCI)

Santa Monica, California, United States, 90404

Actively Recruiting

5

Sarah Cannon Research Institute (SCRI)

Denver, Colorado, United States, 80218

Actively Recruiting

6

Yale University Hospital

New Haven, Connecticut, United States, 06510

Actively Recruiting

7

Mayo Clinic Jacksonville

Jacksonville, Florida, United States, 32224

Actively Recruiting

8

Moffitt Cancer Center - McKinley Drive

Tampa, Florida, United States, 33612

Actively Recruiting

9

Massachusetts General Hospital

Boston, Massachusetts, United States, 02114

Actively Recruiting

10

Mayo Clinic

Rochester, Minnesota, United States, 55905

Actively Recruiting

11

NYU Langone Health Perlmutter Cancer Center

New York, New York, United States, 10016

Actively Recruiting

12

Icahn School of Medicine at Mount Sinai

New York, New York, United States, 10029

Actively Recruiting

13

Columbia University - The Trustees of Columbia University in the City of New York

New York, New York, United States, 10032

Actively Recruiting

14

Montefiore Medical Center

New York, New York, United States, 10461

Actively Recruiting

15

University of Rochester Medical Center (URMC) - Wilmot Cancer Institute (WCI) (James P. Wilmot Cancer Center) - Rochester

Rochester, New York, United States, 14642

Actively Recruiting

16

Providence Portland Medical Center

Portland, Oregon, United States, 97213

Withdrawn

17

Oregon Health & Science University (3485 S. Bond)

Portland, Oregon, United States, 97239

Actively Recruiting

18

Thomas Jefferson University Hospital

Philadelphia, Pennsylvania, United States, 19107

Actively Recruiting

19

Lifespan Cancer Institute

Providence, Rhode Island, United States, 02903

Actively Recruiting

20

MD Anderson Cancer Center

Houston, Texas, United States, 77030

Actively Recruiting

21

Emily Couric Clinical Cancer Center

Charlottesville, Virginia, United States, 22908

Actively Recruiting

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Research Team

C

Clinical Trials Administrator

How is the study designed?

Study Type

INTERVENTIONAL

Masking

NONE

Allocation

NON_RANDOMIZED

Model

PARALLEL

Primary Purpose

TREATMENT

Number of Arms

4

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