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Investigating the safety and effectiveness of REGN5668 with other drugs for advanced ovarian and uterine cancers

A Phase 1/2 Study of REGN5668 (MUC16xCD28, a Costimulatory Bispecific Antibody) Administered in Combination With Other Agents in MUC16 + Malignancies

Phase1; Phase2 Interventional Regeneron Pharmaceuticals · NCT04590326

This study is testing if a new drug called REGN5668, used with other medications, can safely help people with advanced ovarian or uterine cancers.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment612 (estimated)
Ages18 Years and up
SexFemale
SponsorRegeneron Pharmaceuticals Industry-sponsored
Drugs / interventionscemiplimab, chemotherapy, immunotherapy, fianlimab, ubamatamab, sarilumab
Locations24 sites (Duarte, California and 23 other locations)
Trial IDNCT04590326 on ClinicalTrials.gov

What this trial studies

This clinical trial is evaluating the investigational drug REGN5668 in combination with either cemiplimab or REGN4018 for patients with advanced ovarian cancer or cancer of the uterus. The study is divided into two parts: the first part focuses on determining the highest safe dose of the drugs, while the second part aims to assess the effectiveness of these doses in treating the targeted cancers. Participants will be monitored for safety and side effects, as well as any signs of treatment efficacy. The trial includes specific eligibility criteria to ensure that participants have measurable disease and adequate organ function.

Who should consider this trial

Good fit: Ideal candidates include individuals with advanced ovarian cancer or endometrial cancer who have received prior treatments and meet specific health criteria.

Not a fit: Patients who have not received prior anti-cancer immunotherapy or those with carcinosarcoma may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new treatment option for patients with advanced ovarian and uterine cancers.

How similar studies have performed: Other studies have shown promise with similar immunotherapy approaches, suggesting potential for success in this trial.

Eligibility criteria

Show full inclusion / exclusion criteria 
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

Where this trial is running

Duarte, California and 23 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Ovarian CancerFallopian Tube CancerPrimary Peritoneal CancerEndometrial CancerProgressiveRecurrentRefractorySerum CA-125 levels >= 2x ULN
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.