Selective Antigen Specific T Cells and CAR T Cells in Subjects With Relapsed/Refractory Embryonal Tumors (SABRE)

This is a phase I dose-escalation study to determine the safety and feasibility of autologous CAR-TA T cells (B7-H3 CAR+ T cells administered with DNR-PRAME Tumor Antigen-specific T cells) following lymphodepleting chemotherapy in participants with relapsed/refractory rhabdomyosarcoma, Ewing sarcoma, neuroblastoma and Wilms tumor. Patients will be enrolled to one of three planned dose levels with B7-H3 CAR T cell dose determined based on the percentage of B7-H3 transduced cells (B7-H3+ population of cells), and dTBRII-transduced PRAME TA-specific T cell dose based on the total cell population. Both doses will be based on the recipient's body weight and combined in a 1:1 ratio. The safety of the CAR-TA T cell product will be evaluated and the maximum tolerated dose (MTD) will be determined. The safety endpoint will be assessed by monitoring for dose limiting toxicities for 28 days following CAR-TA T cell administration.

NCT Number	NCT07172958
Lead Sponsor	Children's National Research Institute Collaborators: National Cancer Institute (NCI), Cancer Research UK
Conditions	Rhabdomyosarcoma, Ewing Sarcoma, Neuroblastoma, Wilms Tumor
Enrollment	18 participants
Start Date	2026-01-27
Primary Completion	2041-12 (estimated)
Study Completion	2044-12 (estimated)
Updated on ClinicalTrials.gov	2026-08-13