CD70-directed CAR-T

Additionally, CD33 TEAMs successfully redirected T cells isolated from AML patients to activate, secrete cytokines, and kill tumor targets despite exposure to substantial prior cytotoxic therapies. In summary, our findings demonstrate the feasibility of our 7033 CAR to overcome AML heterogeneity and leverage the bystander T cells of patients; this approach warrants further study in patients with this dire clinical need.

We then use orthogonal approaches to increase binding on both the tumor and CAR-T cell sides of the immune synapse: a pharmacologic approach (azacitidine) to increase antigen density of CD70 in myeloid tumors, and an engineering approach to stabilize binding of the CAR to CD70. Our CD8 hinge and transmembrane-modified CD70 CAR-T cells are less prone to cleavage, have enhanced binding avidity, and increased expansion, leading to more potent in vivo activity. This enhanced CD70-targeted CAR is a promising candidate for further clinical development.

The TNF-alpha family member CD70 has emerged as a promising surface target antigen in AML after high complete response rates (CR) were seen in a Phase 1 trial of the CD70 antibody cusatuzumab (Riether et al, Nature Medicine 2020). Our findings demonstrate that natural-ligand binding domains of CARs targeting CD70 in AML can be effective but require mechanisms to overcome surface cleavage. CD70-targeted CARs comprised of a fusion of truncated CD27 to a CD8 hinge and transmembrane domain have promise in patients with AML, with and without combination with azacitidine.