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) — USA Trial Details

Condition(s) studied

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

Investigational drug(s) / intervention(s)

REGN5678: Administered as per the protocol

Cemiplimab: Administered as per the protocol

Study 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. 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

Eligibility

Sex

ALL

Min age

18 Years

Max age

—

Healthy volunteers

No

Key Inclusion Criteria: mCRPC cohorts (men): 1. Men with histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma. 2. PSA value at screening ≥4 ng/mL that has progressed within 6 months prior to screening as defined in the protocol. 3. 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: 1. one second-generation anti-androgen therapy (eg, abiraterone, enzalutamide, apalutamide, or darolutamide) 2. 177Lu-PSMA-617 radiotherapy, or another lutetium-based PSMA targeted radioligand, as described in the protocol ccRCC cohorts (men and women): 1. Histologically or cytologically confirmed RCC with a clear-cell component. 2. Diagnosis of metastatic ccRCC with at least one measurable lesion via RECIST 1.1 criteria 3. 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 Key Exclusion Criteria: 1. 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 2. Has received any previous systemic biologic therapy within 5 half-lives of first dose of study therapy, as described in the protocol 3. Has received prior PSMA-targeting therapy with the exception of a PSMA targeting radioligand (eg. 177Lu-PSMA-617) in mCRPC 4. Dose Escalation: Has had prior anti-cancer immunotherapy (other than sipuleucel-T) within 5 half-lives prior to study therapy. 5. Dose Expansion (mCRPC only): Has had prior anti-cancer immunotherapy, as described in the protocol 6. 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 7. Ongoing or recent (within 5 years) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments, as described in the protocol 8. 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 9. Uncontrolled infection with Human Immunodeficiency Virus (HIV), hepatitis B or hepatitis C infection; or diagnosis of immunodeficiency NOTE: Other protocol defined Inclusion/Exclusion Criteria apply

Primary outcome measure(s)

Incidence and severity of Treatment-Emergent Adverse Events (TEAEs) — Through study completion, up to 5 years
Dose Escalation Phase
Incidence and severity of Adverse Event of Special Interests (AESIs) — Through study completion, up to 5 years
Dose Escalation Phase
Incidence and severity of Serious Adverse Events (SAEs) — Through study completion, up to 5 years
Dose Escalation Phase
Number of participants with Grade ≥3 laboratory abnormalities — Through study completion, up to 5 years
Dose Escalation Phase
Incidence of Dose-Limiting Toxicities (DLTs) — First dose through day 42 of last participant in each dose level
Dose Escalation Phase
Concentration of REGN5678 in serum over time — Through study completion, up to 5 years
Dose Escalation Phase
Concentration of REGN5678 in combination with cemiplimab in serum over time — Through study completion, up to 5 years
Dose Escalation Phase
Composite Response Rate (CRR) of 50% decline of Prostate Specific Antigen (PSA) and/or confirmed radiographic response of complete (CR) or partial response (PR) — Through study completion, up to 5 years
Dose Expansion Phase - mCRPC cohort
Objective Response Rate (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria — Through study completion, up to 5 years
Dose Expansion Phase - ccRCC cohort

Trial sites (24)

Facility	City	Region	Status
Banner MD Anderson Cancer Center	Gilbert	Arizona	Recruiting
Mayo Clinic	Phoenix	Arizona	Recruiting
University of Arizona	Tucson	Arizona	Recruiting
John Wayne Cancer Institute (JWCI)	Santa Monica	California	Recruiting
Sarah Cannon Research Institute (SCRI)	Denver	Colorado	Recruiting
Yale University Hospital	New Haven	Connecticut	Recruiting
Mayo Clinic Jacksonville	Jacksonville	Florida	Recruiting
Moffitt Cancer Center - McKinley Drive	Tampa	Florida	Recruiting
Massachusetts General Hospital	Boston	Massachusetts	Recruiting
Henry Ford Health	Detroit	Michigan	Recruiting
Mayo Clinic	Rochester	Minnesota	Recruiting
NYU Langone Health Perlmutter Cancer Center	New York	New York	Recruiting
Icahn School of Medicine at Mount Sinai	New York	New York	Recruiting
Columbia University - The Trustees of Columbia University in the City of New York	New York	New York	Recruiting
Montefiore Medical Center	New York	New York	Recruiting
University of Rochester Medical Center (URMC) - Wilmot Cancer Institute (WCI) (James P. Wilmot Cancer Center) - Rochester	Rochester	New York	Recruiting
James Cancer Hospital and Solove Research Institute	Columbus	Ohio	Recruiting
Providence Portland Medical Center	Portland	Oregon	Withdrawn
Oregon Health & Science University (3485 S. Bond)	Portland	Oregon	Recruiting
Thomas Jefferson University Hospital	Philadelphia	Pennsylvania	Recruiting
Lifespan Cancer Institute	Providence	Rhode Island	Recruiting
MD Anderson Cancer Center	Houston	Texas	Recruiting
Emily Couric Clinical Cancer Center	Charlottesville	Virginia	Recruiting
West Virginia University	Morgantown	West Virginia	Recruiting

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