Abstract: Objective To investigate the efficacy and safety of CAR-T cell therapy in treating elderly patients with B-cell acute lymphoblastic leukemia（B-ALL）. Methods Follow-up data were retrospectively analyzed for 21 B-ALL patients who underwent CAR-T cell therapy from May 2020 to December 2022 at The First Affiliated Hospital of Soochow University. We evaluated the therapy's outcomes and safety profile. Results Among the 21 elderly B-ALL patients treated with CAR-T treatment,the incidence rates of cytokine release syndrome（grade 1-2）,neutropenia,and neutropenia were 38.1%（8/21）,42.9%（9/21）,and 28.6%（6/21）,respectively. One week after CAR-T transfusion,there was no significant difference in absolute white blood cell count compared with pre-infusion levels,but a remarkable increase was observed one month later（P<0.001）. Neutrophil counts remained unchanged at one week and one month post the treatment（P>0.05）. C-reactive protein significantly increased 7 days after CAR-T and decreased after 30 days（-3 d vs 7 d,P=0.007; 30 d vs 7 d,P=0.000 6）; After one year following CAR-T-cell transfusion,85.7%（18 of 21）patients achieved complete remission,with a median follow-up duration of 17 months. The progression free survival rate（PFS）after CAR-T was 81.0%,uncorrelated with the gender,CAR-T cell type,Philadelphia chromosome status,high tumor burden,history of hematopoietic stem cell transplantation, treatment times, LDH concentration and platelet count（P>0.05）. The median PFS of elderly B-ALL patients with CAR-T was 13 months. For patients with relapsed or refractory（R/R）B-ALL,the CR rate and PFS rate were 75% and 67.5%,the median PFS was 12 months. The average relapse time was 10.5 months after infusion of CAR-T. Conclusion CAR-T cell therapy demonstrates a promising response rate in the treatment of elderly B-ALL patients,which provides a potential therapeutic avenue for this population with a poor prognosis.

Key words: Elderly B-cell acute lymphoblastic leukemia, CAR-T cell therapy, Prognosis