ATM-deficiency allows feasible CAR-T cell production at the risk of chromosomal translocations and potential leukemogenicity.. Genotoxicity associated with CAR transduction of ATM-defficient T-cells

Mutations in the ATM gene lead to ataxia-telangiectasia (A-T), a disease manifested by radio-sensitivity, immunodeficiency and a tendency to lymphoid malignancy. Loss of the ATM protein function leads to a malfunction in repairing double-strand DNA breaks. A-T patients diagnosed with malignancies have poor tolerance to chemotherapy or radiation, thus alternative therapies are required. We investigated chimeric-antigen receptor (CAR) T cells, known for clinical success in patients with lymphoid malignancies, in preclinical models using primary T-cells from patients with A-T (ATM-/-), heterozygote donors (ATM+/-) and healthy donors. Our results indicate that ATM-/- T-cells proliferate and be successfully transduced with CARs. A functional impairment of ATM-/- CAR-T cells was observed under stress conditions. Retroviral transduction of the CAR in ATM-/- T-cells resulted in high rates of chromosomal translocations. Next-generation long-read sequencing confirmed the CAR insert within translocations. In summary, ATM-deficiency allows feasible CAR-T cell production at the risk of chromosomal translocations and potential leukemogenicity