Development of anti-CSF1R-chimeric antigen receptors for the treatment of acute myeloid leukemia

• Applicants: Dr. Adrian Gottschlich; Professor Dr. Sebastian Kobold
• Subject Area: Hematology, Oncology ; Pharmacology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 510821390

Chimeric antigen receptor (CAR) T cells have revolutionized the treatment of refractory, chemotherapy-resistant leukemias and lymphomas. However, to date, CAR T cells have only been successfully used in B-cell lineage diseases (acute lymphoblastic leukemia, lymphoma, multiple myeloma). In contrast, identifying a suitable target antigen is more challenging in many non-B-cell malignancies. Many different target antigens have been identified for the treatment of acute myeloid leukemia (AML), but co-expression on healthy immune or non-immune cells hinders the clinical applicability of these therapies. In parallel, the field of single-cell RNA sequencing (scRNA-seq) has made incredible progress, enabling unprecedented, detailed analysis of off-tumor expression of target antigens. We have developed an scRNA algorithm capable of identifying novel target antigens on AML blasts while predicting off-target expression of these antigens in vital human organs with unprecedented resolution. In unpublished preliminary experiments, we demonstrated that CAR T cells directed against one of the identified candidates (CSF1R) is capable of lysing AML blasts in vitro and in vivo. Furthermore, expression of the target antigen was confirmed in a small cohort of patients using primary AML blasts. Building on these promising results, we would now like to comprehensively investigate the potential of the newly developed anti-CSF1R CAR-T cells. We would like to further characterize these anti-CSF1R CAR T cells both in vitro and in vivo. In work packages one to three, we will demonstrate the efficacy of the CAR T cells against AML cell lines and primary AML blasts. In addition, the expression of the target antigen will be verified in a large AML cohort. The efficacy of the newly developed anti-CSF1R CAR T cells will be investigated with already established anti-CD33 CAR T cells in cell line models and patient-derived xenograft models in vivo. In work packages four and five, potential toxicities of anti-CSF1R CAR T cells will be investigated in comprehensive in vitro and in vivo experiments. For this purpose, the potential for possible hematological side effects as well as potential neurological toxicities will be analyzed. Possible neurological off-tumor effects will be analyzed in syngeneic mouse models (efficacy of murine surrogate CAR T cells has already been demonstrated in preliminary experiments) as well as against iPSC-derived human microglia-like cells (iMGL).

• DFG Programme: Research Grants