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

NCT03972657 | Recruiting Phase 1 FDA Drug

• 1 other identifier: R5678-ONC-1879
• Study Type: interventional
• Target: 345
• Locations: 1 country
• Sites: 24

Brief Summary

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. 1.Side effects that may be experienced by taking REGN5678 alone or in combination with cemiplimab
2. 2.How REGN5678 alone or in combination with cemiplimab works in the body
3. 3.How much REGN5678 and/or cemiplimab are present in the blood
4. 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

Conditions

Metastatic Castration-Resistant Prostate Cancer (mCRPC); Clear Cell Renal Cell Carcinoma (ccRCC)

Outcome Measures

Primary Outcomes (9)

• Incidence and severity of Treatment-Emergent Adverse Events (TEAEs)

  Dose Escalation Phase

  Through study completion, up to 5 years

• Incidence and severity of Adverse Event of Special Interests (AESIs)

  Dose Escalation Phase

  Through study completion, up to 5 years

• Incidence and severity of Serious Adverse Events (SAEs)

  Dose Escalation Phase

  Through study completion, up to 5 years

• Number of participants with Grade ≥3 laboratory abnormalities

  Dose Escalation Phase

  Through study completion, up to 5 years

• Incidence of Dose-Limiting Toxicities (DLTs)

  Dose Escalation Phase

  First dose through day 42 of last participant in each dose level

• Concentration of REGN5678 in serum over time

  Dose Escalation Phase

  Through study completion, up to 5 years

• Concentration of REGN5678 in combination with cemiplimab in serum over time

  Dose Escalation Phase

  Through study completion, up to 5 years

• Composite Response Rate (CRR) of 50% decline of Prostate Specific Antigen (PSA) and/or confirmed radiographic response of complete (CR) or partial response (PR)

  Dose Expansion Phase - mCRPC cohort

  Through study completion, up to 5 years

• Objective Response Rate (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria

  Dose Expansion Phase - ccRCC cohort

  Through study completion, up to 5 years

Secondary Outcomes (12)

• CRR of 50% decline of PSA and/or confirmed radiographic of CR or PR

  Through study completion, up to 5 years

• ORR per RECIST 1.1 criteria

  Through study completion, up to 5 years

• Incidence and severity of TEAEs

  Through study completion, up to 5 years

• Incidence and severity of AESIs

  Through study completion, up to 5 years

• Incidence and severity of SAEs

  Through study completion, up to 5 years

Study Arms (4)

mCRPC - dose escalation cohort

EXPERIMENTAL

REGN5678 with or without cemiplimab

Drug: REGN5678; Drug: Cemiplimab

mCRPC - dose expansion cohort

EXPERIMENTAL

REGN5678 with or without cemiplimab

Drug: REGN5678

ccRCC - dose escalation cohort

EXPERIMENTAL

REGN5678 with or without cemiplimab

Drug: REGN5678; Drug: Cemiplimab

ccRCC - dose expansion cohort

EXPERIMENTAL

REGN5678 with or without cemiplimab

Drug: REGN5678

Interventions

REGN5678 DRUG

Administered as per the protocol

Also known as: Nezastomig

ccRCC - dose escalation cohort; ccRCC - dose expansion cohort; mCRPC - dose escalation cohort; mCRPC - dose expansion cohort

Cemiplimab DRUG

Administered as per the protocol

Also known as: REGN2810, LIBTAYO

ccRCC - dose escalation cohort; mCRPC - dose escalation cohort

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• mCRPC cohorts (men):
• Men with histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma.
• PSA value at screening ≥4 ng/mL that has progressed within 6 months prior to screening as defined in the protocol.
• Has received ≥2 lines prior systemic therapy approved in the metastatic and/or castration-resistant setting (in addition to Androgen Deprivation Therapy \[ADT\]) including at least:
• one second-generation anti-androgen therapy (eg, abiraterone, enzalutamide, apalutamide, or darolutamide)
• Lu-PSMA-617 radiotherapy, or another lutetium-based PSMA targeted radioligand, as described in the protocol
• ccRCC cohorts (men and women):
• Histologically or cytologically confirmed RCC with a clear-cell component.
• Diagnosis of metastatic ccRCC with at least one measurable lesion via RECIST 1.1 criteria
• Has progressed on or after ≥1 line prior systemic therapy approved in the metastatic setting. Prior treatment must include an anti-Programmed Death-1 (receptor) \[PD-1\]/Programmed Death-Ligand 1 (PD-L1) therapy and either ipilimumab and/or a tyrosine kinase inhibitor

You may not qualify if:

• Has received treatment with an approved systemic therapy within 3 weeks of dosing or has not yet recovered (ie, grade ≤1 or baseline) from any acute toxicities, as described in the protocol
• Has received any previous systemic biologic therapy within 5 half-lives of first dose of study therapy, as described in the protocol
• Has received prior PSMA-targeting therapy with the exception of a PSMA targeting radioligand (eg. 177Lu-PSMA-617) in mCRPC
• Dose Escalation: Has had prior anti-cancer immunotherapy (other than sipuleucel-T) within 5 half-lives prior to study therapy.
• Dose Expansion (mCRPC only): Has had prior anti-cancer immunotherapy, as described in the protocol
• Any condition that requires ongoing/continuous corticosteroid therapy (\>10 mg prednisone/day or anti-inflammatory equivalent) within 1 week prior to the first dose of study therapy
• Ongoing or recent (within 5 years) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments, as described in the protocol
• Encephalitis, meningitis, neurodegenerative disease (with the exception of mild dementia that does not interfere with Activities of Daily Living \[ADLs\]) or uncontrolled seizures in the year prior to first dose of study therapy
• Uncontrolled infection with Human Immunodeficiency Virus (HIV), hepatitis B or hepatitis C infection; or diagnosis of immunodeficiency

Sponsors & Collaborators

• Regeneron Pharmaceuticals: lead

Study Sites (24)

Banner MD Anderson Cancer Center

Gilbert, Arizona, 85234, United States

RECRUITING

Mayo Clinic

Phoenix, Arizona, 85054, United States

RECRUITING

University of Arizona

Tucson, Arizona, 85724, United States

RECRUITING

John Wayne Cancer Institute (JWCI)

Santa Monica, California, 90404, United States

RECRUITING

Sarah Cannon Research Institute (SCRI)

Denver, Colorado, 80218, United States

RECRUITING

Yale University Hospital

New Haven, Connecticut, 06510, United States

RECRUITING

Mayo Clinic Jacksonville

Jacksonville, Florida, 32224, United States

RECRUITING

Moffitt Cancer Center - McKinley Drive

Tampa, Florida, 33612, United States

RECRUITING

Massachusetts General Hospital

Boston, Massachusetts, 02114, United States

RECRUITING

Henry Ford Health

Detroit, Michigan, 48202, United States

RECRUITING

Mayo Clinic

Rochester, Minnesota, 55905, United States

RECRUITING

NYU Langone Health Perlmutter Cancer Center

New York, New York, 10016, United States

RECRUITING

Icahn School of Medicine at Mount Sinai

New York, New York, 10029, United States

RECRUITING

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

New York, New York, 10032, United States

RECRUITING

Montefiore Medical Center

New York, New York, 10461, United States

RECRUITING

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

Rochester, New York, 14642, United States

RECRUITING

James Cancer Hospital and Solove Research Institute

Columbus, Ohio, 43210, United States

RECRUITING

Providence Portland Medical Center

Portland, Oregon, 97213, United States

WITHDRAWN

Oregon Health & Science University (3485 S. Bond)

Portland, Oregon, 97239, United States

RECRUITING

Thomas Jefferson University Hospital

Philadelphia, Pennsylvania, 19107, United States

RECRUITING

Lifespan Cancer Institute

Providence, Rhode Island, 02903, United States

RECRUITING

MD Anderson Cancer Center

Houston, Texas, 77030, United States

RECRUITING

Emily Couric Clinical Cancer Center

Charlottesville, Virginia, 22908, United States

RECRUITING

West Virginia University

Morgantown, West Virginia, 26506, United States

RECRUITING

MeSH Terms

Conditions

Carcinoma, Renal Cell

Interventions

cemiplimab

Condition Hierarchy (Ancestors)

Adenocarcinoma; Carcinoma; Neoplasms, Glandular and Epithelial; Neoplasms by Histologic Type; Neoplasms; Kidney Neoplasms; Urologic Neoplasms; Urogenital Neoplasms; Neoplasms by Site; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Kidney Diseases; Urologic Diseases; Male Urogenital Diseases

Study Officials

• Clinical Trials Management

  Regeneron Pharmaceuticals

  STUDY DIRECTOR

Central Study Contacts

Clinical Trials Administrator

CONTACT

844-734-6643; clinicaltrials@regeneron.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 30, 2019
• First Posted: June 3, 2019
• Study Start: August 12, 2019
• Primary Completion (Estimated): November 15, 2027
• Study Completion (Estimated): November 15, 2027
• Last Updated: July 9, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR, ANALYTIC CODE
• Time Frame: When Regeneron has: * received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development * made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry) * the legal authority to share the data, and * ensured the ability to protect participant privacy
• Access Criteria: Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf

Locations

US (24)