Cancer

Mouse studies suggest CAR T cells targeting B7-H3 could help treat pediatric osteosarcoma, Ewing sarcoma and brain cancer. In tumor samples from 388 patients with pediatric solid tumors and brain tumors, 325 (84%) were positive for B7-H3, with 70% showing high expression. In xenograft mouse models of pediatric osteosarcoma and Ewing sarcoma, CAR T cells targeting B7-H3 decreased tumor growth and increased survival compared with CD19-targeting CAR T cells. In a xenograft mouse model of osteosarcoma, amputation of the affected hind limb followed by the B7-H3-targeting CAR T cells increased survival compared with amputation alone. In two xenograft mouse models of pediatric medulloblastoma, the B7-H3-targeting CAR T cells decreased tumor growth compared with CD19-targeting CAR T cells, and in one of the models, the CAR T cells increased survival. Next steps include Phase I testing of the B7-H3 CAR T cells in adult patients with high-grade brain tumors.

Y-mAbs Therapeutics Inc. and Memorial Sloan Kettering Cancer Center have omburtamab, an iodine 131-radiolabelled humanized mAb targeting B7-H3 in Phase II testing for neuroendocrine tumors, Phase I/II testing for sarcoma and preclinical testing for B7-H3-positive leptomeningeal tumors...