Design and Validation of an Automated Process for the Expansion of Peripheral Blood‐Derived CD34+ Cells for Clinical Use After Myocardial Infarction

摘要

We previously demonstrated that intracardiac delivery of autologous peripheral blood‐derived CD34sup+/sup stem cells (SCs), mobilized by granulocyte‐colony stimulating factor (G‐CSF) and collected by leukapheresis after myocardial infarction, structurally and functionally repaired the damaged myocardial area. When used for cardiac indication, CD34sup+/sup cells are now considered as Advanced Therapy Medicinal Products (ATMPs). We have industrialized their production by developing an automated device for ex vivo CD34sup+/sup‐SC expansion, starting from a whole blood (WB) sample. Blood samples were collected from healthy donors after G‐CSF mobilization. Manufacturing procedures included: (a) isolation of total nuclear cells, (b) CD34sup+/sup immunoselection, (c) expansion and cell culture recovery in the device, and (d) expanded CD34sup+/sup cell immunoselection and formulation. The assessment of CD34sup+/sup cell counts, viability, and immunophenotype and sterility tests were performed as quality tests. We established graft acceptance criteria and performed validation processes in three cell therapy centers. 59.4?×?10sup6/sup?±?36.8?×?10sup6/sup viable CD34sup+/sup cells were reproducibly generated as the final product from 220?ml WB containing 17.1?×?10sup6/sup?±?8.1?×?10sup6/sup viable CD34sup+/sup cells. CD34sup+/sup identity, genetic stability, and telomere length were consistent with those of basal CD34sup+/sup cells. Gram staining and mycoplasma and endotoxin analyses were negative in all cases. We confirmed the therapeutic efficacy of both CD34sup+/sup‐cell categories in experimental acute myocardial infarct (AMI) in immunodeficient rats during preclinical studies. This reproducible, automated, and standardized expansion process produces high numbers of CD34sup+/sup cells corresponding to the approved ATMP and paves the way for a phase I/IIb study in AMI, which is currently recruiting patients.