Background: Allogeneic CAR-T cell therapies offer key advantages over autologous approaches, including simplified manufacturing logistics, improved accessibility, and greater cost-efficiency. However, donor-to-donor and lot-to-lot variability in the manufacturing process has generated significant interest in the field. Understanding the extent to which this inherent variability affects clinical performance is critical—not only for elucidating the mechanism of action (MOA) of allogeneic CAR-T products, but also for assessing the consistency and robustness of their clinical responses.

Methods: CTD402, is a CD7 targeted “off-the-shelf” universal CAR-T product with a triple-knockout in CD7, TRAC and CIITA genes, as well as immune inhibitory molecule overexpression to prevent fratricide, GvHD, and host immune rejection - leading to increased expansion and persistence. CTD402 is currently being developed for the treatment of hematologic malignancies and other severe blood disorders with over 100 patients treated in several indications (T-ALL/LBL, PTCL, AML, SAA). CTD402 manufacturing process has evolved across different development phases: Process 1 (pilot scale, less optimized & controlled process with variable harvest times) and Process 2 (11-day optimized process with improved cell viability and yield) supporting multiple IIT studies; Process 3 (12-day process with optimized expansion protocol and additional TCR+ cell depletion step) supporting global clinical development in R/R T-ALL/LBL. A total of eighteen lots from thirteen donors across three process development stages have been manufactured.

Results: Despite process changes across three development stages, the quality attributes of eighteen UCAR-T lots remained consistent across donors, except for a two-fold inter-donor variation observed in IFN-γ release, HLA-II knockout levels, CD4/CD8 ratio, and T memory subset distribution. Intra-donor variation in these parameters was present but to a lesser extent. Notably, UCAR-T products manufactured using Process 3 demonstrated remarkable consistency in quality attributes across four donors, apart from the CD4/CD8 ratio. Importantly, these variations did not correlate with clinical performance, as indicated by CTD402 robust clinical responses in r/r T-ALL/LBL. Analysis of 64 patients across 14 manufacturing lots from 11 donors revealed non-significant inter-lot and donor variability in pharmacokinetic parameters (Cmax, AUC0-28) and clinical responses. UCAR-T lots derived from various donors and processes showed 100% UCAR-T lot functionality with expansion capabilities ranging from 2.1x to 4.1x fold-change and consistent 28-day median persistence. All donors demonstrated clinical activity (58.8-100% objective response rate range) with durable responses >5 months. Patients receiving UCAR-T lots from the same donor source showed highly similar results in both expansion and persistence.

Conclusion: This comprehensive analysis demonstrates the clinical response and consistency of CTD402 allogeneic CAR-T cells manufactured from different donors. The observed robust responses highlight the therapeutic potential of allogeneic CAR-T products, compared to their autologous counterparts and many other treatment modalities. The development experience with the CTD402 program offers valuable insights for the broader allogeneic CAR-T field. It is expected that standardized, large-scale manufacturing processes can reliably produce therapeutically effective products with minimal donor-to-donor and lot-to-lot variability. These findings support the viability of allogeneic CAR-T cells as a scalable, consistent, and clinically effective treatment option—overcoming the manufacturing constraints of autologous CAR-T therapies and the therapeutic effectiveness limitations of antibody-based biologics, while improving accessibility for a broader patient population.

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2025
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