Cd33 Car T Cells

Cd33 or cd123 targeted chimeric antigen receptor car t cell therapies have shown promise but struggle with on target off tumor toxicities complicated allogeneic hsc transplants and aml relapse.

Cd33 car t cells.

Our aim was to engineer and validate cd33 directed car t cells with the intention to open a phase i clinical. Previously we demonstrated the profound anti tumor activity of cll1 cd33 compound car ccar t cells. This is a phase 1 2 trial which aims to determine the safety and feasibility of anti cd33 chimeric antigen receptor car expressing t cells cd33cart in children and adolescents young adults ayas with relapsed refractory acute myeloid leukemia aml. Cll1 and cd33 are often used as targets for aml car t cell therapy.

However aml cells lack ideal targeting antigens that are safe to target with car t cells. Inactivation of cd33 in hspcs permits cd33 directed car t cell treatment of aml. A chimeric antigen receptor expressing t cell that targets and kills cd33 expressing cancers such as acute myeloid leukemia aml. Gene editing of normal cells is a potential therapeutic approach to generate cancer specific antigens.

In response novel bispecific human cd33 123 car t cells with split signaling costimulation domains were highly efficacious in vitro at killing target cells proliferating and generating substantial. These studies illuminate a novel approach to antigen specific immunotherapy by genetically engineering the host to avoid on target off tumor toxicity. Cd33 ablated hspcs exhibited normal myeloid function and differentiation in vivo. Anti cd33 car or vector transduced t cells were co cultured with cd33 modified or cd33 parental cell lines at an e t ratio of 1 2 and viable tumor cells were determined by quantitative flow cytometry.

Cd33 deficient cells were impervious to cd33 targeting car t cells allowing for efficient elimination of leukemia without myelotoxicity. In this study we describe the in vivo efficacy and safety of using cytokine induced killer cik cells genetically modified to express anti cd33 or anti cd123 car to target aml. We show that both these modified t cells are very efficient in reducing leukemia burden in vivo but only the anti cd123 car has limited killing on normal hspcs thus. The car construct works by using a novel anti cd33 scfv region to enable t cell targeting of cd33 expressing cancer cells and t cell activation through the incorporation of co stimulator and intracellular signaling regions.

Little difference in tumor cell numbers was apparent when anti cd33 car t cells or vector transduced t cells were co cultured with the cd33. Cd33 a commonly targeted antigen is expressed in about 85 90 of aml cases but is also present on normal myeloid progenitors and myelocytes.