Timely Leukapheresis May Interfere with the “Fitness” of Lymphocytes Collected for CAR-T Treatment in High Risk DLBCL Patients

SIMPLE SUMMARY: Chimeric antigen receptor (CAR)-T cell therapy has revolutionized the treatment of specific hematological diseases, but is unsuccessful in around 60% of patients. The objective of the Bio-CAR-T BS study is to improve our understanding of the lymphocyte harvest to maximize the quality of the CAR-T cell product. We show here that “pre-emptive” lymphocyte apheresis (Ly-apheresis) of selected high-risk DLBCL patients may preserve the fitness of lymphocytes for CAR-T cell infusion. Specifically, the “pre-emptive” Ly-apheresis strategy resulted in a significantly higher CD4/CD8 ratio, significantly higher absolute counts and frequency of CD4+ naïve T cells, and a significantly higher frequency of CD8+ naïve T cells compared with the standard Ly-apheresis strategy (i.e., relapsed/refractory after two lines of treatments). Moreover, patients who underwent “pre-emptive” Ly-apheresis had a significantly lower frequency of CD8+ terminally differentiated T cells compared with standard Ly-apheresis. ABSTRACT: The development of chimeric antigen receptor (CAR)-T cell therapy has revolutionized the treatment of hematological diseases. However, approximately 60% of patients relapse after CAR-T cell therapy, and no clear cause for this failure has been identified. The objective of the Bio-CAR-T BS study (ClinicalTrials.gov: NCT05366569) is to improve our understanding of the lymphocyte harvest to maximize the quality of the CAR-T cell product. Of the 14 patients enrolled, 11 were diagnosed with DLBCL, 2 with PMBCL, and 1 with ALL. Five of 11 DLBCL patients met the criteria for “pre-emptive” Lymphocytes-apheresis (being at high risk of second relapse), and 6 were included in the standard-of-care Lymphocytes-apheresis group. Previous autologous stem cell transplantation (ASCT) and age were significantly different between the two groups. At the time of Lymphocyte-apheresis, patients in the “pre-emptive” group had more “fit” lymphocytes (higher CD4+/CD8+ ratio; higher naïve T cells levels) compared with standard group, probably due to the impact of ASCT. At the same time, also being older than 60 years results in a more “exhausted” lymphocyte profile. Overall, “pre-emptive” Ly-apheresis in DLBCL patients at high risk of relapse appears to be feasible and may allow the timely collection of “fit” lymphocytes for CAR-T cell manufacturing.