A Safety and Efficacy Study of Combined Fianlimab + Cemiplimab in Children and Young Adults With Recurrent or Progressive High-Grade Glioma or Posterior Fossa-A Ependymoma

NCT07567469 — Phase 1 / Phase 2, Not yet recruiting, 120 participants, Regeneron Pharmaceuticals

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A Phase 1/2 Open-Label, Safety and Efficacy Study of Neoadjuvant Fianlimab (Anti-LAG-3 Antibody) in Combination With Cemiplimab (Anti-PD-1 Antibody) and Cemiplimab Alone Followed by Adjuvant Fianlimab in Combination With Cemiplimab in Pediatric and Young Adult Participants With Recurrent or Progressive High-Grade Glioma or Pediatric and Adult Participants With Recurrent or Progressive Posterior Fossa-A Ependymoma

Registry	NCT07567469
Status	Not yet recruiting
Phase	Phase 1 / Phase 2
Study type	Interventional; randomized, parallel, masking: none, treatment
Enrollment	120 (Estimated)
Sponsor	Regeneron Pharmaceuticals (Industry)
Conditions	High-Grade Glioma (HGG), Posterior Fossa-A Ependymoma
Interventions	Cemiplimab, Cemiplimab+Fianlimab Fixed Dose Combination (FDC) (Drug)
Dates	start 2026-08-31 (estimated), primary completion 2032-08-27 (estimated), completion 2034-08-17 (estimated), first posted 2026-05-05, last updated 2026-05-05

-Summary

This study is researching an experimental drug called cemiplimab (called "study drug") and the combination of experimental drugs of fianlimab and cemiplimab (called "study drugs"). The study is focused on children and young adults with recurrent or progressive High-Grade Glioma (HGG) or ependymoma. "Recurrent" means that the cancer came back after treatment. "Progressive" means that the tumor has grown or spread.

The aim of the study is to see how safe, tolerable, and effective cemiplimab and the combination of fianlimab and cemiplimab are.

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

* What side effects may happen from receiving the study drug(s)
* Do the study drug(s) help study participants live longer without their tumors growing or spreading
* How much of the study drug(s) is in the blood at different times
* Whether the body makes antibodies against the study drug(s) (which could make the study drug\[s\] less effective or lead to side effects)

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+Arms and interventions

Arm	Type	Interventions	Description
Phase 1 Arm A	Experimental	Drug: Cemiplimab; Drug: Cemiplimab+Fianlimab Fixed Dose Combination (FDC)	Neoadjuvant Period: cemiplimab Adjuvant Period: fianlimab+cemiplimab
Phase 1 Arm B	Experimental	Drug: Cemiplimab+Fianlimab Fixed Dose Combination (FDC)	Neoadjuvant Period: fianlimab+cemiplimab Adjuvant Period: fianlimab+cemiplimab
Phase 2	Experimental	Drug: Cemiplimab+Fianlimab Fixed Dose Combination (FDC)	Neoadjuvant Period: fianlimab+cemiplimab Adjuvant Period: fianlimab+cemiplimab

Cemiplimab (Drug), also known as REGN2810, Libtayo®: Administered per the protocol
Cemiplimab+Fianlimab Fixed Dose Combination (FDC) (Drug), also known as REGN 2810, Libtayo®, REGN3767: Administered per the protocol

+Outcome measures

Primary outcomes

Occurrence of Treatment Emergent Adverse Events (TEAEs) [Up to 26 months]
Severity of TEAEs [Up to 26 months]
Overall Survival (OS) [12 months]
Progression Free Survival (PFS) [12 months]

Secondary outcomes

Concentrations of fianlimab in serum [Up to 5 years]
Concentrations of cemiplimab in serum [Up to 5 years]
Occurrence of Anti-Drug Antibody (ADA) to fianlimab [Up to 5 years]
Occurrence of ADA to cemiplimab [Up to 5 years]
Magnitude of ADA to fianlimab [Up to 5 years]
Magnitude of ADA to cemiplimab [Up to 5 years]
Progression Free Survival (PFS) [Up to 5 years]
Death due to any cause [Up to 5 years]
Overall Survival [Up to 5 years]
Occurrence of TEAEs [Up to 5 years]
Severity of TEAEs [Up to 5 years]

+Eligibility

Sex: All, ages: 0 Years to 39 Years

Key Inclusion Criteria:

1. Participant must be diagnosed with recurrent/progressive HGG or PF-A ependymoma with unequivocal progression on Magnetic Resonance Imaging (MRI) as described in the protocol
2. Participant must have histologically confirmed (at initial diagnosis or relapse) HGG or PF-A ependymoma
3. Participant must be an adequate medical candidate for surgical resection as described in the protocol
4. Karnofsky Performance Status (KPS) score ≥50 (in participants ≥16 years) or Lansky Performance Status (LPS) score ≥50 (in participants <16 years) as described in the protocol
5. Adequate organ function as described in the protocol

Key Exclusion Criteria:

1. Active autoimmune disease requiring systemic immunosuppressive therapy in the past 2 years
2. Active, serious medical illness, infection or other systemic illness which would limit participation in the trial
3. Has not yet recovered from any acute toxicities resulting from prior therapy
4. History of myocarditis
5. Prior treatment with antibodies to Programmed Cell Death Protein -1 (PD-1), Programmed Cell Death Protein Ligand -1 (PD-L1), Lymphocyte Activation Gene 3 (LAG3), or Cytotoxic T-Lymphocyte Associated protein 4 (CTLA-4)
6. Treatment with high dose systemic corticosteroids as described in the protocol
7. History of interstitial lung disease (eg, idiopathic pulmonary fibrosis, organizing pneumonia) or active, noninfectious pneumonitis that required immune-suppressive doses of glucocorticoids to assist with management

Note: Other protocol defined Inclusion/ Exclusion Criteria apply

+Investigators

Clinical Trial Management, Study director, Regeneron Pharmaceuticals

+Funding

NIH grants: 2025