Recruiting
Phase 1
Phase 2

REGN5668, Cemiplimab & REGN4018

Sponsor:

Regeneron Pharmaceuticals

Code:

NCT04590326

Conditions

Ovarian Cancer

Fallopian Tube Cancer

Primary Peritoneal Cancer

Endometrial Cancer

Eligibility Criteria

Sex: Female

Age: 18+

Healthy Volunteers: Not accepted

Interventions

REGN5668

Cemiplimab

Ubamatamab

Sarilumab

Cemiplimab + Fianlimab [Fixed Dose Combination (FDC)]

Study Details

Brief summary:

This study is researching an investigational drug called REGN5668 :

  • alone or,
  • combined with cemiplimab (also known as REGN2810) or,
  • combined with both cemiplimab and fianlimab (also known as REGN3767), or
  • combined with ubamatamab (also known as REGN4018), with or without sarilumab.

The main purposes of this study are to:

  • Learn about the safety and profile of any side effects from the study drugs and to determine the highest, safe dose that can be given to participants with ovarian cancer or cancer of the uterus
  • Look for signs that the study drugs can treat ovarian cancer or cancer of the uterus

This study has 2 parts. The purpose of Part 1 (Escalation) is to find the highest, safe dose of the study drug(s). The purpose of Part 2 (Expansion) is to use the doses chosen in Part 1. Participants with cancer of the uterus will only participate in Part 2.

The study is looking at several other research questions, including:

  • Side effects that may be experienced by participants taking REGN5668 alone and/or in combination with cemiplimab, cemiplimab and fianlimab, or ubamatamab
  • How REGN5668 works in the body either alone and/or in combination with cemiplimab, cemiplimab and fianlimab, or ubamatamab
  • How much of the study drugs (REGN5668, cemiplimab, fianlimab, ubamatamab) are in the blood
  • To see if REGN5668 in combination with cemiplimab, cemiplimab and fianlimab, or ubamatamab works to treat cancer

Conditions

Ovarian Cancer

Fallopian Tube Cancer

Primary Peritoneal Cancer

Endometrial Cancer

Study ID

NCT04590326

Start date

Dec 8, 2020

Status verified date

Aug, 2026

Completion date

Nov 30, 2027

Anticipated

Primary completion date

Mar 25, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 18+

Healthy Volunteers: Not accepted

Key Inclusion Criteria:

1. Ovarian Cancer Cohorts Only: Has histologically or cytologically confirmed diagnosis of advanced epithelial ovarian cancer (except carcinosarcoma), primary peritoneal, or fallopian tube cancer that has received at least 1 line of platinum-based systemic therapy as defined in the protocol
2. Expansion cohorts only: Has at least 1 lesion that is measurable by RECIST 1.1 as described in the protocol.
3. Has a serum CA-125 level ≥2x ULN (in screening, not applicable to endometrial cohorts)
4. Has adequate organ and bone marrow function as defined in the protocol
5. Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
6. Has a life expectancy of at least 3 months
7. Endometrial Cancer Cohorts Only: histologically confirmed endometrial cancer that has progressed or recurrent after prior anti-PD-1 therapy and platinum-based chemotherapy as described in the protocol

Key Exclusion Criteria:

1. Current or recent (as defined in the protocol) treatment with an investigational agent, systemic biologic therapy, or anti-cancer immunotherapy
2. Has had another malignancy within the last 5 years that is progressing, requires active treatment, or has a high likelihood of recurrence as defined in the protocol
3. Prior treatment with a Mucin 16 (MUC16)-targeted therapy
4. Ovarian Expansion cohorts only: More than 5 prior lines of systemic therapy
5. Has any condition that requires ongoing/continuous corticosteroid therapy as defined in the protocol within 1 week prior to the first dose of study drug
6. Has ongoing or recent (within 5 years) evidence of significant autoimmune disease that required treatment with systemic immunosuppressive treatments as defined in the protocol
7. Has untreated or active primary brain tumor, CNS metastases, leptomeningeal disease, or spinal cord compression as defined in the protocol
8. Has history of clinically significant cardiovascular disease as defined in the protocol
9. Has known allergy or hypersensitivity to cemiplimab and/or components of study drug(s).

Note: Other protocol-defined Inclusion/Exclusion criteria apply

Study Design

Enrollment

612 participants

Anticipated

Allocation

Non randomized

Intervention Model

Sequential

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Module 1

REGN5668 in combination with cemiplimab, or cemiplimab + fianlimab

experimental: Module 2

REGN5668 and ubamatamab

Interventions

REGN5668

Administer per the protocol

Cemiplimab

Administer per the protocol

Ubamatamab

Administer per the protocol

Sarilumab

Administer per the protocol

Cemiplimab + Fianlimab [Fixed Dose Combination (FDC)]

Administer per the protocol

Primary outcome measure

  • Incidence of Dose Limiting Toxicities (DLT) [ Time Frame: 42 days ]
  • Incidence of DLTs [ Time Frame: 21 days post combination administration ]
  • Incidence of Treatment-Emergent Adverse Events (TEAEs) [ Time Frame: Through study completion, up to 5 years ]
  • Incidence of Serious Adverse Events (SAEs) [ Time Frame: Through study completion, up to 5 years ]
  • Incidence of deaths [ Time Frame: Through study completion, up to 5 years ]
  • Incidence of laboratory abnormalities (Grade 3 or higher per National Cancer Institute Common Terminology Criteria for Adverse Events [NCI-CTCAE] version 5.0 [v5.0]) [ Time Frame: Through study completion, up to 5 years ]
  • Concentrations of REGN5668 in serum when dosed alone and in combination with cemiplimab or ubamatamab [ Time Frame: Through study completion, up to 5 years ]
  • Objective Response Rate (ORR) defined by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 (Eisenhauer, 2009) of REGN5668 in combination with cemiplimab, cemiplimab + fianlimab, or ubamatamab (separately by cohort and combination) [ Time Frame: Through study completion, up to 5 years ]

Central Contacts and Locations

Central contacts

Clinical Trials Administrator

844-734-6643clinicaltrials@regeneron.com

Locations

City of Hope Comprehensive Cancer Center

Recruiting

Duarte, California, United States, 91010

The City of Hope Orange County Lennar Foundation Cancer Center

Recruiting

Irvine, California, United States, 92618

Chao Family Comprehensive Cancer Center

Recruiting

Orange, California, United States, 92868

Robert H. Lurie Comprehensive Cancer Center of Northwestern University

Recruiting

Chicago, Illinois, United States, 60611

University of Chicago Medical Center

Recruiting

Chicago, Illinois, United States, 60637

Massachusetts General Hospital

Recruiting

Boston, Massachusetts, United States, 02114

Dana Farber Cancer Institute Brookline Avenue

Recruiting

Boston, Massachusetts, United States, 02215

Karmanos Cancer Institute

Recruiting

Detroit, Michigan, United States, 48201

Memorial Sloan Kettering Cancer Center

Recruiting

New York, New York, United States, 10065

The Ohio State University Wexner Medical Center

Recruiting

Columbus, Ohio, United States, 43210

Perelman School of Medicine at the University of Pennsylvania

Recruiting

Philadelphia, Pennsylvania, United States, 19104

Seattle Cancer Care Alliance at South Lake Union - G3630

Recruiting

Seattle, Washington, United States, 98109

More Information

Sponsor

Regeneron Pharmaceuticals

Last update posted

Aug 20, 2026

Last verified

Aug, 2026

Keywords

  • Progressive
  • Recurrent
  • Refractory
  • Serum CA-125 levels >= 2x ULN

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Regeneron Pharmaceuticals on 2026-08-20.