Impaired hematopoiesis affects apheresis and <scp>CAR</scp> T‐cell product composition and treatment response

BACKGROUND: T-cell yields during leukapheresis. This can be difficult in heavily pretreated patients, who often show leukopenia and reduced T-cell fitness. METHODS: We analyzed 166 leukapheresis products from 154 patients undergoing manufacturing of CD19-directed CAR T-cells, including 146 from non-Hodgkin's lymphoma (NHL) and 20 from acute lymphoblastic leukemia (ALL). Collections were performed for commercial CAR T-cell products (axi-cel, tisa-cel, brexu-cel, liso-cel; n = 121) and the HD-CAR-1 trial with in-house manufacturing (heidagenlecleucel; n = 45). RESULTS: CAR T-cells in the product correlated with improved clinical outcomes (p = .04; p = .023). CONCLUSION: These findings highlight the importance of early leukapheresis, ideally before intensive treatments, to optimize T-cell yield, product quality, and therapeutic efficacy.