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    Cellular and T cell engager Immunotherapy

    Overcoming Challenges: Development of Two Potent, Domestic BCMA-targeted CAR-T Cell Products for the Treatment of Multiple Myeloma in Brazil

    P-085: Overcoming Challenges: Development of Two Potent, Domestic BCMA-targeted CAR-T Cell Products for the Treatment of Multiple Myeloma in Brazil

    Wednesday, September 25, 2024
    Introduction: B cell maturation antigen (BCMA) targeted chimeric antigen receptor (CAR)-T cell therapy has emerged as a breakthrough treatment for multiple myeloma. However, disease relapse is still a major issue after treatment. In this context, 4th generation CAR-T cells with cytokine production came up as an alternative to enhance tumor cell killing as well as CAR-T cells’ persistence. In Brazil, access to CAR-T cell therapy is hampered by extremely high costs and long waiting times for CAR-T cell production. In this work, we aimed to produce BCMA-targeted 2nd and 4th-generation CARs for future use in the treatment of multiple myeloma patients.

    Methods: We developed two BCMA-targeted CAR constructs, a 2nd-generation one (BCMA-4-1BB-CD3z, named CAR-BCMA) and its 4th-generation counterpart with soluble IL-15 (sIL-15) production (BCMA-4-1BB-CD3z-IL-15, named CAR-BCMA-IL15). Lentiviral particles containing the CAR sequences were produced by transfection of HEK293T cells and primary T cells were transduced with the lentiviral particles. CAR-T cells were tested regarding cytotoxicity and cytokine production (TNFα and IFNγ) against BCMA+ (MM1.S, U266) and BCMA- (K562) cell lines. In addition, CAR-T cells’ memory and exhaustion profiling tests are underway.

    Results: Both 2nd and 4th generation BCMA-targeted CARs were transduced into primary T cells from healthy donors with high transduction rates (75-85% for CAR-BCMA and 35-55% for CAR-BCMA-IL15, n=3) and were able to proliferate in culture (up to 400-fold expansion in 14 days) with high viability rates ( >90%). When tested regarding cytotoxicity and cytokine production, both CAR-T cells showed BCMA-specific action, as they were able to kill the BCMA+ target cell lines MM1.S and U266 and to produce TNFα and IFNγ cytokines when co-cultured with these cell lines. In contrast, CAR-T cells either produced TNFα and IFNγ or were able to kill the BCMA- K562 cell line. Initial tests show no evidence of increase in T cell exhaustion markers (PD-1, TIM-3, LAG-3) on CAR-T cells when compared to non-transduced T cells as well as a tendency of larger proportions of memory T cell populations on IL-15 producing CAR-T cells. Additional tests are being performed and will be presented at the meeting.



    Conclusions: In this work, we developed two new BCMA-targeted CAR-T cell products, including a 2nd-generation CAR and its 4th-generation version with sIL-15 production. Both CARs revealed cytotoxic action and cytokine production restricted to BCMA+ target cells as well as appropriate memory and exhaustion profiling. Additionally, CAR-T cell production, testing, and profiling were performed as short as 10 days. Benefits from IL-15 incorporation into CAR’s structure are expected to be clearer in in vivo experiments, so we are importing the animals. In conclusion, our work shows hope for the enhancement of access to Brazilian multiple myeloma patients for CAR-T cell therapy.