117 Rapid point-of-care subcutaneous CAR-T from blood draw to injection in 4 hours with modified LV encoding CARs and synthetic driver elements enables efficient CAR-T expansion and tumor regression

• Published in: Journal for immunotherapy of cancer 2020-11, Vol.8 (Suppl 3), p.A72-A72
• Main Authors: Vigant, Frederic, He, Qun, Zhang, Wei, Zong, Hongliang, Kundu, Anirban, Jaruga-Killeen, Ewa, Schreiber, Gregory, Andraza, Michelle, Kerner, Alissa, Frost, Gregory
• Format: Article
• Language: English
• Subjects: Blood cancer; Genomes; Immunotherapy; Lymphocytes
• ISSN: 2051-1426
• DOI: 10.1136/jitc-2020-SITC2020.0117

BackgroundAdoptive cellular therapy with chimeric antigen receptor (CAR)-T cells has demonstrated remarkable clinical activity in a number of hematologic malignancies, but product chain of custody, individualized manufacturing, preparative chemotherapy, and patient management present technical and logistical hurdles to broader implementation.MethodsLentiviral constructs for CARs (either CD19- or CD22-directed) co-expressed with a synthetic driver domain were identified from a >6 × 10 diversity combinatorial library of proliferative elements, transmembrane domains, leucine zippers, and an EGFR epitope screened for cellular expansion in a lymphoreplete model. Modified serum-free-lentiviral manufacturing process was developed to reduce complexity of CAR-T and to introduce CD3-activating elements into the viral envelope allowing activation and transduction of resting lymphocytes from peripheral blood.ResultsFour-hour exposure of as little as 1 ml of blood to the CD3-directed CD19-targeted CAR encoding lentivirus followed by subcutaneous injection in NSG mice bearing CD19+/CD22+ Raji cells resulted in tumor regression (figure 1) and robust CAR-T cell expansion as determined by flow cytometry (figure 2) and qPCR (table 1), with peak levels >10,000 CAR-T cells/µl and less than three CAR copies per genome. In contrast, administration of the same products intravenously failed to support significant CAR-T expansion or control tumor growth (figure 3). Regression of established Raji tumors was also observed in NSG-(KbDb) (IA) animals following SC administration of CD19 or CD22 CARs with driver domains. CAR-T cells contracted in peripheral blood following tumor regression.Abstract 117 Figure 1Tumor Regression[Figure omitted. See PDF]Regression of Raji tumor from the initial median volume of 151 mm3 throughout 40 days post subcutaneous administration of the LV transduced (at MOI 1 or 5) CD19-directed CAR T product (1M or 5M cells) in the NSG miceAbstract 117 Figure 2CAR-T Cells expansion in Vivo Post SC injectionExpansion of CAR-T cells throughout 35 days post subcutaneous administration of the LV transduced (at MOI 1 or 5) CD19-directed CAR T product (1M or 5M cells) in the NSG mice bearing Raji tumor (groups G1-G4) or w/o tumor (G5-7G)[Figure omitted. See PDF]Abstract 117 Figure 3CAR-T Cells expansion in vivo post IV injectionExpansion of CAR-T cells throughout 35 days post intravenous administration of the LV transduced (at MOI 1 or 5) CD19-directed CAR T product (1M