Development of a 3-day manufacturing method to generate CD19-CD20-CD22 trispecific CAR T-cells from whole blood

Abstract

Chimeric antigen receptor (CAR) T-cell therapy has transformed the treatment landscape for many hematological malignancies. However, high relapse rates and limited accessibility remain significant challenges. We developed a 3-day streamlined process to address these limitations. T-cells were isolated from whole blood collected from healthy donors via an automated density gradient separation that included a T-isopure™ antibody cocktail, which isolates T-cells through negative selection. T-cells were activated then transduced with a lentiviral vector encoding a trispecific CAR. T-cells were cultured in G-Rex vessels and harvested at day 3 or day 7 for analysis. CAR expression and T-cell phenotype were assessed by flow cytometry and gene expression analysis. Functional activity was evaluated by measuring cytotoxicity and cytokine secretion following co-culture with target cell lines. The T-isopure isolation enriched CD3+ T-cells in whole blood from 18.9% to 88.5% of CD45+ cells, with a mean recovery of 40.6%. RBCs were depleted with ≥ 99% efficiency, with monocytes and NK cells comprising the bulk of remaining CD45+ cells. The 3-day manufacturing process produced T-cells with > 95% viability, 53% transduction efficiency, and vector copy number < 3 copies/cell. Phenotypic analysis revealed a high proportion of stem/central memory T-cells at both timepoints, with no significant differences observed. Cytotoxicity assays demonstrated strong and sustained killing of NALM6 tumor cells, comparable between both products. Gene expression profiling indicated that day 3 products were less differentiated, exhibiting a memory-like phenotype and reduced inflammatory signaling, further supported by protein analysis of culture supernatants. This study establishes a rapid, GMP-compliant method for manufacturing polyfunctional, CAR T-cells directly from whole blood. The workflow outlined here achieved a potent, phenotypically favorable CAR T-cell product without compromising viability or cytotoxic function. Compared to the standard 7-day method, the 3-day approach resulted in expression of genes associated with a more stem-like phenotype while reducing manufacturing time and cost. This method may provide a practical alternative for decentralized CAR T-cell manufacturing, particularly in resource-limited settings.