AZD0120 (GC012F), a BCMA/CD19 dual-targeting fastcar T-cell therapy, demonstrates potent preclinical efficacy in multiple myeloma Free

Introduction: BCMA-targeted CAR T-cell therapies have shown remarkable clinical benefit for patients (pts) with multiple myeloma (MM), although relapse remains a challenge. Recurrent disease tends to maintain BCMA expression, possibly indicating the existence of cancer stem cells resistant to BCMA-targeted therapies. Clonotypic CD19⁺ B cells from pts with MM have been shown to be resistant to anti-MM therapies. These B cells may serve as a progenitor cell reservoir, although their contribution to disease relapse is unknown. We previously reported that GC012C, a BCMA/CD19 dual-targeting CAR T-cell therapy manufactured conventionally, can eliminate more myeloma colony-forming cells in vitro than CAR T cells targeting BCMA or CD19 alone. AZD0120 (GC012F) is a clinical-stage BCMA/CD19 dual-targeting CAR T-cell therapy (using the same binders as GC012C) manufactured using the proprietary FasTCAR platform to generate younger, fitter cells, enabling robust in vivo expansion to achieve deeper and more durable clinical responses in pts with MM. Here we present the preclinical characterization and efficacy of AZD0120.

Methods: AZD0120 is a second-generation CAR T-cell therapy using a 4-1BB costimulatory domain and 2 antigen binders configured in a loop orientation and manufactured on the FasTCAR platform, in which T cells are transduced with lentivirus and cryopreserved shortly after activation to retain a young CAR T-cell phenotype and maximize in vivo expansion. Lead binders to BCMA and CD19 were selected based on their cytotoxic potential against cancer cell lines with low antigen expression and are the same for GC012C and AZD0120. Binding kinetics of the CAR were measured using surface plasmon resonance, and total cellular avidity for tumor cells was evaluated by z-Movi. Binder specificity was assessed through membrane protein array and tissue cross-reactivity assays. Phenotypic and proliferative characteristics, as well as cytokine release profiles of AZD0120 and GC012C, were characterized by flow cytometry. Cytotoxicity against BCMA⁺ and/or CD19⁺ target cells was quantified by flow cytometry, luciferase-based reporter assays, or real-time cell analysis. In vivo studies were performed in immunodeficient mice bearing xenografts expressing BCMA and/or CD19 to evaluate pharmacokinetic and pharmacodynamic responses.

Results: The extracellular domain of the AZD0120 CAR demonstrated high specificity for both BCMA and CD19, with no detectable off-target binding. GC012C exhibited higher avidity for Nalm6 (CD19⁺BCMA^low), MM.1S (CD19⁻BCMA⁺), and JeKo-1 (CD19⁺BCMA⁺) cancer cell lines versus monospecific CAR T cells. GC012C exhibited comparable or superior capacity for cytolytic activity against all 3 tumor cell lines versus monospecific CAR T cells. Lastly, GC012C demonstrated minimal IFN-γ release or CD107α mobilization in culture alone or in response to soluble BMCA versus benchmark CAR T cells. AZD0120 (manufactured with the FasTCAR platform), as compared with GC012C, was enriched for naive/stem cell memory (Tn/scm) and central memory T cells (Tcm) and demonstrated enhanced proliferation upon encountering cells expressing BCMA or CD19. On day 2 post thaw, AZD0120 showed higher Tn/scm levels than GC012C in both donor 1 (71.4% vs 12.5%) and donor 2 (35% vs 22.4%), with Tcm levels of 15.7% vs 13.6% and 49.8% vs 7.7%, respectively. AZD0120 showed potent cytotoxicity against CD19⁺ and/or BCMA⁺ cell lines in vitro, coupled with robust IFN-γ release. In mouse models, GC012C demonstrated robust antitumor activity in a disseminated MM.1S MM model and subcutaneous RPMI-8226 model, with peak CAR T-cell expansion (C_max) observed ~day 14 post dose. However, AZD0120 had a more durable and profound antitumor response than GC012C against Nalm6 and MM.1S xenografts in vivoat comparable doses, with a 10- to 100-fold higher C_max levels in the blood. Furthermore, AZD0120-treated mice had increased frequencies of CXCR4⁺ CAR T cells within the blood, spleen, and bone marrow, a subset that may be critical for effective MM targeting.

Conclusion: The FasTCAR-based AZD0120, designed to target BCMA and/or CD19 and maximize in vivo expansion, demonstrated potent, dose-dependent, and antigen-specific cytotoxicity both in vitro and in vivo. The superior antitumor function of AZD0120 versus GC012C suggests benefit of the FasTCAR manufacturing platform and supports continued development of AZD0120 as a promising therapeutic option for pts with MM.