Multiple site place-of-care manufactured anti-CD19 CAR-T cells induce high remission rates in B-cell malignancy patients.

Chimeric antigen receptor (CAR) T cells targeting the CD19 antigen are effective in treating adults and children with B-cell malignancies. Place-of-care manufacturing may improve performance and accessibility by obviating the need to cryopreserve and transport cells to centralized facilities. Here we develop an anti-CD19 CAR (CAR19) comprised of the 4-1BB co-stimulatory and TNFRSF19 transmembrane domains, showing anti-tumor efficacy in an in vivo xenograft lymphoma model. CAR19 T cells are manufactured under current good manufacturing practices (cGMP) at two disparate clinical sites, Moscow (Russia) and Cleveland (USA). The CAR19 T-cells is used to treat patients with relapsed/refractory pediatric B-cell Acute Lymphocytic Leukemia (ALL; n = 31) or adult B-cell Lymphoma (NHL; n = 23) in two independently conducted phase I clinical trials with safety as the primary outcome (NCT03467256 and NCT03434769, respectively). Probability of measurable residual disease-negative remission was also a primary outcome in the ALL study. Secondary outcomes include complete remission (CR) rates, overall survival and median duration of response. CR rates are 89% (ALL) and 73% (NHL). After a median follow-up of 17 months, one-year survival rate of ALL complete responders is 79.2% (95%CI 64.5‒97.2%) and median duration of response is 10.2 months. For NHL complete responders one-year survival is 92.9%, and median duration of response has not been reached. Place-of-care manufacturing produces consistent CAR-T cell products at multiple sites that are effective for the treatment of patients with B-cell malignancies.

Generation of a packaging cell line for prolonged large-scale production of high-titer HIV-1-based lentiviral vector.

BACKGROUND: A stable packaging cell line facilitates large-scale lentivirus vector manufacture. However, it has been difficult to produce clinical-scale HIV-1-based lentiviral vectors using a packaging cell line, in part due to toxicity of packaging genes, and gene silencing that occurs during the long culture period necessary for sequential addition of packaging constructs. METHODS: To avoid these problems, we developed a three-level cascade gene regulation system designed to remove tetracycline transactivator (tTA) from cytomegalovirus immediate early promoter (CMV)-controlled expression to reduce cytotoxicity from constitutive expression of tTA and leaky expression of packaging genes. We also performed a one-step integration of the three packaging plasmids to shorten the culture time for clonal selection. RESULTS: Although leaky expression of p24 and vector production still occurred despite the three-level regulation system, little cytotoxicity was observed and producer cells could be expanded for large-scale production. Producer cells yielded remarkably stable vector production over a period greater than 11 days with the highest titer 3.5 x 10(7) transducing units (TU)/ml and p24 300 ng/ml, yielding 2.2 x 10(11) TU and 1.8 milligram (mg) p24 from one cell factory. No replication-competent lentivirus (RCL) was detected. Long-term analysis demonstrated that, although the cells are genetically stable, partial gene silencing occurs after 2-3 months in culture; however, the one-step construct integration allowed prolonged vector production before significant gene silencing. Concentrated vector resulted in 90% transduction in CD4+ lymphocytes at 20 TU per cell. CD34+ progenitor cells were transduced at 41-46% efficiency, and long-term initiating culture (LTC-IC) was transduced at 45-51%. CONCLUSIONS: These results demonstrate for the first time HIV-1-based lentiviral vector production on the large scale using a packaging cell line.