Advancing CAR-T Cell Therapy: Insights into Patient Biology, Leukapheresis, and Cryopreservation

Commercial chimeric antigen receptor T (CAR-T) cells are manufactured from autologous patient-derived leukapheresis starting material. The quality and characteristics of the leukapheresis starting material has been identified as a potential root cause of manufacturing failure in autologous CAR-T cell products. An unsuccessful CAR-T production constitutes not only an obstacle for treatment, but also presents several hurdles for patients, healthcare providers, and CAR-T manufacturers. In this literature review, we describe published factors that might affect the quality of autologous leukapheresis starting materials. We characterize patient-related factors such as cancer treatments and wash-out periods prior to collection, disease status, and clinical/laboratory findings and their impact on the leukapheresis cell composition. Factors relating to the leukapheresis procedure including cell collection procedures, current best practices and guidelines, nurse experience, and challenges are also addressed. Next, cryopreservation prior to manufacturing is discussed in relation to timing, cryoprotectants, concentration, cooling rates, and cellular stability. Last, gaps in knowledge and future directions are presented for each of these arguments. Our thorough literature assessment can support discussions for process optimization, reducing manufacturing failures, and long-term harmonization practices.