Amy Schienschang

CD24 is highly expressed in aggressive B-cell malignancies and represents a novel immunologic vulnerability to overcome resistance to CD19 chimeric antigen receptor T-cell (CAR-T) therapy. We developed a CD24 × CD3 bispecific antibody (CD24 BsAb) and CXCR3-armed CD24 CAR-T cells, both exhibiting potent antitumor activity in lymphoma and leukemia models. CD24 BsAb and CD24 CAR-T overcome CD19 CAR-T resistance driven by antigen loss and apoptosis defects in vitro and in vivo. Beyond direct cytotoxicity, CD24-targeted T cells reprogram macrophages toward an M1-like phenotype and enhance phagocytic clearance. We further engineered a dual-specific, dual-functional CD19 CAR-T that secretes a CD24 bispecific T-cell engager (CD24 BiTE), enabling simultaneous targeting of CD19 and CD24 to address tumor heterogeneity and achieve superior efficacy. Collectively, our study demonstrates that CD24-directed adoptive T-cell therapies are warranted for B-cell malignancies through robust induction of both innate and adaptive immune responses.

Shows Phenotype, Viability, and Cytotoxicity of the Product.

A and B. Evaluation of Vβ repertoire. The three distinct patterns were observed for Vβ repertoire in CD3+/IFN-γ+ T cells post IT. Pattern 1) the proportions of Vβ repertoire noticeably higher after IT relative to preIT PBMC (solid black arrows); Pattern 2) the proportions of Vβ repertoire that were marginally higher at mid- and/or post-IT relative to pre-IT PBMC (dashed black arrows); Pattern 3) large proportions of Vβ repertoire were either lower or similar at mid-IT or post-IT relative to preIT PBMC in all four patients tested. PreIT (pretherapy), midIT (preinfusion 5) postIT (1 week post infusion 8 of BATs).

A-C. FFPE sections of PC were stained by multiplex staining panel for CD4, CD8, FoxP3 (T regulatory cells), CD19 (B cells), CD68 (macrophages). Stained sections were imaged on the Hamamatsu slide scanner NanoZoomer S360 and images were viewed on the NDP viewer software. Analysis of images were performed on online Visiopharm software. Using the low power image, high-powered Fields (HPFs) were selected from specific tumor regions. Data shows the distribution of CD4+ (teal), CD8+ (purple), FoxP3 (brown), CD19+ (green) and CD68+ (yellow) cells on two representative whole scanned slide images (KCI 04 and KCI 11) are shown. Top panel shows whole scanned tumor sections, inset 1 and 2 are shown below at high magnification (40x). B and C) Show the second set of serial sections of tumor specimens stained for IFN-γ and IL-10 from two patients shown in the upper panel, both IFN-γ (brown) and IL-10 (brown) were stained individually.

Representativeness of Study Participants.

Shows the persistence of anti-CD3 x anti-HER2 bispecific antibody armed activated T cells (HER2 BATs) in the peripheral blood of two out of four patients.

Co-stimulatory and co-inhibitory marker expression on CD4+ and CD8+ T cells in AA (n=29) and non-AA (n=28).

Antibody and IFN-γ responses and co-stimulatory and co-inhibitory marker expressions in mCRPC patients.

Waterfall plot showing PSA change from baseline to nadir.

Waterfall plot showing PSA change from baseline to week 10.