126P Novel B7-H3 targeting dual nanobody NK cell engagers display robust activity against a broad spectrum of solid and hematologic malignancies

B7-H3 is a checkpoint molecule under intense investigation as an immune therapy target. We previously showed that dual camelid nanobody tri-specific killer engager (TriKE) (GTB-5550) specifically bound B7-H3 on PC3/C4-2 prostate cancer (PCa) cells and activated peripheral blood (PB) NK cells. We have since developed a dual camelid bispecific killer engager (BiKE) targeting B7-H3 and show that both GTB-5550, which harbors wild-type IL-15, and BiKE display broad activity against B7-H3-expressing tumors.