A Trial to Find Out if REGN4336 is Safe and How Well it Works Alone and in Combination With REGN5678 for Adult Participants With Advanced Prostate Cancer

NCT05125016 | Recruiting Phase 1 FDA Drug

• 2 other identifiers: R4336-ONC-201042022-502130-17-00
• Study Type: interventional
• Target: 228
• Locations: 1 country
• Sites: 14

Brief Summary

This study is researching an investigational drug called REGN4336 both alone or together with another investigational drug called REGN5678. The study is focused on participants with previously treated metastatic prostate cancer. The main purpose of the study is to look at the safety, tolerability (how the body reacts to the drug) and effectiveness (how well the drug works to shrink tumors) of REGN4336 when given in combination with REGN5678. The study has 2 parts. The purpose of Part 1 is to determine a safe dose(s) of REGN4336 to be given alone or in combination with REGN5678. Part 1 is known as the "dose escalation" phase. The purpose of Part 2, (known as the "dose expansion" phase), is to use the doses of REGN4336 and REGN5678 selected in Part 1 to further test how well the combination treatment with REGN4336 and REGN5678 works to shrink tumors. The study is looking at several other research questions, including:

• What side effects may happen from taking REGN4336 alone or in combination with REGN5678
• How well does REGN4336 in combination with REGN5678 reduce tumor size
• How much REGN4336 is in the blood at different times when it is given alone or in combination with REGN5678
• Does the body make antibodies against the study drugs (REGN4336 or REGN5678)

Conditions

Metastatic Castration-resistant Prostate Cancer

Keywords

Treatment-experienced metastatic Castration-Resistant Prostate Cancer (mCRPC)

Outcome Measures

Primary Outcomes (7)

• Incidence of Dose-Limiting Toxicities (DLTs)

  Dose escalation

  up to 21 days

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

  Dose escalation

  Up to 5 years

• Incidence and severity of Serious Adverse Events (SAEs)

  Dose escalation

  Up to 5 years

• Incidence and severity of Adverse Events of Special Interest (AESIs)

  Dose escalation

  Up to 5 years

• REGN4336 monotherapy concentrations in serum

  Dose escalation

  Up to 5 years

• REGN4336 concentrations in serum in combination with REGN5678

  Dose escalation

  Up to 5 years

• Composite Response Rate (CRR) of ≥50% decline of prostate specific antigen (PSA) and/or confirmed radiographic response of complete response (CR) or partial response (PR)

  Dose expansion

  Up to 5 years

Secondary Outcomes (9)

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

  Up to 5 years

• Anti-Drug Antibodies (ADA) to REGN4336

  Up to 5 years

• ADA to REGN4336 and REGN5678

  Up to 5 years

• Incidence and severity of TEAEs

  Up to 5 years

• Incidence and severity of SAEs

  Up to 5 years

Study Arms (2)

Module 1- Monotherapy

EXPERIMENTAL

Drug: REGN4336

Module 3-Combo Therapy

EXPERIMENTAL

Drug: REGN4336; Drug: REGN5678

Interventions

REGN4336 DRUG

Administered per the protocol

Module 1- Monotherapy; Module 3-Combo Therapy

REGN5678 DRUG

Administered per the protocol

Module 3-Combo Therapy

Eligibility Criteria

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

You may qualify if:

• Histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma
• Metastatic, Castration-Resistant Prostate Cancer (mCRPC) with PSA value at screening ≥4 ng/mL and that has progressed within 6 months prior to screening, according to at least 1 of the following:
• PSA progression as defined by a rising PSA level confirmed with an interval of ≥1 week between each assessment
• Radiographic disease progression in soft tissue based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria with or without PSA progression
• Radiographic disease progression in bone defined as the appearance of 2 or more new bone lesions on bone scan with or without PSA progression NOTE: Measurable disease per RECIST version 1.1 per local reading at screening is not an eligibility criterion for enrollment
• Has progressed upon or intolerant to ≥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 (e.g. abiraterone, enzalutamide, apalutamide, or darolutamide)

You may not qualify if:

• Has received any previous systemic biologic or anti-cancer immunotherapy within 5 half-lives of first dose of study therapy, as described in the protocol
• Has received prior Prostate-Specific Membrane Antigen (PSMA)-targeting therapy NOTE: Prior therapy with PSMA-targeting radioligand(s) (eg, 177Lu-PSMA-617) is permitted. However, a period of 12 weeks must elapse between the last dose of the PSMA- targeting radioligand and the first dose of study drug
• 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
• 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 Virus (HBV), or Hepatitis C Virus (HCV) infection; or diagnosis of immunodeficiency, as described in the protocol.

Sponsors & Collaborators

• Regeneron Pharmaceuticals: lead

Study Sites (14)

Stanford University Medical Center - Blake Wilbur Drive

Palo Alto, California, 94304, United States

RECRUITING

Yale University Hospital

New Haven, Connecticut, 06510, United States

RECRUITING

Norton Cancer Institute

Louisville, Kentucky, 40207, United States

RECRUITING

University of Maryland Greenebaum Cancer Center

Baltimore, Maryland, 21201, United States

RECRUITING

Rutgers Cancer Institute of New Jersey

New Brunswick, New Jersey, 08901, United States

RECRUITING

Roswell Park Cancer Institute

Buffalo, New York, 14263, United States

RECRUITING

Atrium Health Levine Cancer Institute

Charlotte, North Carolina, 28204, United States

RECRUITING

The Ohio State University James Cancer Hospital

Columbus, Ohio, 43210, United States

RECRUITING

Penn Medicine University of Pennsylvania Health System

Philadelphia, Pennsylvania, 19104, United States

RECRUITING

Thomas Jefferson University Hospital

Philadelphia, Pennsylvania, 19107, United States

RECRUITING

Fox Chase Cancer Center

Philadelphia, Pennsylvania, 19111, United States

WITHDRAWN

Fox Chase Cancer Center

Philadelphia, Pennsylvania, 19111, United States

RECRUITING

MD Anderson Cancer Center

Houston, Texas, 77030, United States

RECRUITING

Medical College of Wisconsin

Milwaukee, Wisconsin, 53226, United States

RECRUITING

Study Officials

• Clinical Trial 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

Model Details: Note: Prior to the current protocol amendment (PA), a Module to evaluate REGN4336 in combination with cemiplimab was included in the study design (Module 2). This Module was de-prioritized in this PA and removed. No patients were dosed in Module 2

Study Record Dates

• First Submitted: October 25, 2021
• First Posted: November 18, 2021
• Study Start: November 30, 2021
• Primary Completion (Estimated): March 28, 2030
• Study Completion (Estimated): March 28, 2030
• Last Updated: May 5, 2026

Record last verified: 2026-04

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 (14)