Figure 3.

CD19-CD28 boosts the efficacy of glofitamab in a dose-dependent manner in vivo and enhances its activity on patient-derived T cells. (A) Experimental design of in vivo efficacy study. Humanized NSG mice bearing orthotopic WSU-DLCL2-Fluc tumors (8 mice per group) were treated with vehicle (histidine buffer), glofitamab (0.15 mg/kg), and CD19-CD28 (1 mg/kg) IV according to the displayed timeline. (B) Visualization of tumor growth in treated mice after luciferin injection. (C) Tumor burden evaluated by bioluminescence signal (total flux, photons/second) calculated as the mean radiance integrated over the region of interest. Dots represent individual mice. Bars show the median signal + IQR for each treatment group. Statistical analysis was performed using an ordinary 1-way analysis of variance (ANOVA) with Fisher least significant test. ∗∗∗P < .0001. (D) Body weight kinetics. Dots represent means -SEM of 8 mice per group. (E) Overlay of in vivo dose finding experiment with in silico modeling for trimeric complex formation. (F) Overlay of predicted human PK from on hFcRn tg32 mice and preclinical efficacy thresholds based on in vivo studies in NSG mice with PK measurements in participants of the ongoing CD19-CD28 phase 1 trial (NCT05219513). (G) PBMCs from 2 patients with DLBCL (patient 1 and 2) were depleted for internal B cells and were stimulated with the indicated treatments (glofitamab, untargeted TCB, and CD19-CD28 were used at a concentration of 1 nM) in the presence of NALM-6 target cells (E:T ratio: 3:1). Graphs show IFNγ and granzyme B release after 72 hours, assessed via cytokine bead array. Bars show means and dots show individual values from technical triplicates (patient 1) and duplicates (patient 2). BLI, bioluminescence imaging; IQR, interquartile range; max, maximum.