[PDF][PDF] Genetic inactivation of CD33 in hematopoietic stem cells to enable CAR T cell immunotherapy for acute myeloid leukemia

MY Kim, KR Yu, SS Kenderian, M Ruella, S Chen… - Cell, 2018 - cell.com
MY Kim, KR Yu, SS Kenderian, M Ruella, S Chen, TH Shin, AA Aljanahi, D Schreeder…
Cell, 2018cell.com
The absence of cancer-restricted surface markers is a major impediment to antigen-specific
immunotherapy using chimeric antigen receptor (CAR) T cells. For example, targeting the
canonical myeloid marker CD33 in acute myeloid leukemia (AML) results in toxicity from
destruction of normal myeloid cells. We hypothesized that a leukemia-specific antigen could
be created by deleting CD33 from normal hematopoietic stem and progenitor cells (HSPCs),
thereby generating a hematopoietic system resistant to CD33-targeted therapy and enabling …
Summary
The absence of cancer-restricted surface markers is a major impediment to antigen-specific immunotherapy using chimeric antigen receptor (CAR) T cells. For example, targeting the canonical myeloid marker CD33 in acute myeloid leukemia (AML) results in toxicity from destruction of normal myeloid cells. We hypothesized that a leukemia-specific antigen could be created by deleting CD33 from normal hematopoietic stem and progenitor cells (HSPCs), thereby generating a hematopoietic system resistant to CD33-targeted therapy and enabling specific targeting of AML with CAR T cells. We generated CD33-deficient human HSPCs and demonstrated normal engraftment and differentiation in immunodeficient mice. Autologous CD33 KO HSPC transplantation in rhesus macaques demonstrated long-term multilineage engraftment of gene-edited cells with normal myeloid function. CD33-deficient cells were impervious to CD33-targeting CAR T cells, allowing for efficient elimination of leukemia without myelotoxicity. These studies illuminate a novel approach to antigen-specific immunotherapy by genetically engineering the host to avoid on-target, off-tumor toxicity.
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