Manufacturing highly potent CD20/CD19-targeted iCasp9 regulatable CAR-T cells using the Quantum pBac-based CAR-T (qCART) system for clinical application

BackgroundCD19-targeted chimeric antigen receptor therapies (CAR19) have driven a paradigm shift in the treatment of relapsed/refractory B-cell malignancies. However, >50% of CAR19-treated patients experienced progressive disease mainly due to antigen escape and low persistence. Clinical prognosis is heavily influenced by CAR-T cell function and systemic cytokine toxicities. Furthermore, it remains a challenge to efficiently, cost-effectively, and consistently manufacture clinically relevant number of virally engineered CAR-T cells. MethodsUsing a highly efficient piggyBac transposon-based vector, Quantum pBac, we developed a virus-free cell engineering system, Quantum CART (qCART), for development and production of multiplex CAR-T therapies. ResultsHere, we demonstrated in vitro and in vivo that consistent, robust, and functional CD20/CD19 dual-targeted CAR-T stem cell memory (TSCM) cells can be efficiently manufactured using the qCART system for clinical application. qCART-manufactured CAR-T cells from cancer patients expanded efficiently, rapidly eradicated tumors, and can be safely controlled via an iCasp9 suicide gene-inducing drug. ConclusionsThe qCART system is an elegant system for the manufacturing of CAR-T products having all the desired CAR-T therapy attributes. We believe that the simplicity of manufacturing multiplex CAR-T cells using the qCART system will not only significantly enhance the accessibility of CAR-T therapy but also unlock the full potential of armored CAR-T therapy for the treatment of solid tumors in the future. What is already known on this topicDespite the considerable success which has been achieved with CD19-targeted chimeric antigen receptor therapies (CAR19), >50% of CAR19-treated patients still experienced progressive disease. Therefore, there is a need to further improve CAR19 therapies. Current CAR19 therapies commonly utilize virus-based cell engineering methods. CAR-T production using these methods face multiple hurdles, including difficulties to efficiently, cost-effectively, and consistently manufacture clinically relevant number of CAR-T cells. We have previously used a highly efficient piggyBac transposon-based vector, Quantum pBac, to establish Quantum CART (qCART) which is a virus-free cell engineering system for development and production of multiplex CAR-T therapies. What this study addsIn this report, we further demonstrate in vitro and in vivo that consistent, robust, and functional iCasp9-regulatable, CD20/CD19 dual-targeted CAR-T stem cell memory (TSCM) cells can be efficiently manufactured using the qCART system for clinical application. These cells possess all the desired attributes for ensuring therapeutic efficacy in CAR-T therapy, including high CAR-TSCM, balanced CD8/CD4 ratio, low exhaustion and senescence marker expressions, and high ex vivo and in vivo expansion capacity. Importantly, we show that qCART-manufactured CAR-T cells from hematological cancer patients expanded efficiently, effectively eradicated tumors, and can be safely controlled via an iCasp9 suicide gene-inducing drug. We believe that the simplicity of manufacturing multiplex CAR-T cells using the qCART system will not only significantly enhance the accessibility of CAR-T therapy but also unlock the full potential of armored CAR-T therapy for the treatment of solid tumors in the future. How this study might affect research, practice or policyOur findings demonstrate that qCART is a virus-free CAR-T engineering system for manufacturing CAR-TSCM cells from either healthy donors or hematological cancer patients, that possess all the desired attributes for a successful CAR-T therapy. These cells expanded efficiently, rapidly eradicated tumors, and can be safely controlled via activation of iCasp9. We expect that this simple yet robust system for manufacturing multiplex CAR-T cells will advance the CAR-T field.