Fig. 4: Ex vivo and in vivo activity of MCLA-145.

a Top panel, donut chart of relative proportion of T cell subsets including percentage of CD3+ cells in single-cell suspensions derived from five human endometrial tumors; Bottom panel, IFNγ levels in supernatant of each tumor explant 6 days after antibody incubation. Error bars: mean ± SD of three replicates, ND = not done, **p < 0.0001 in Tumor #1 and Tumor #5, *p = 0.0018 (Neg. Ctrl Ab vs. MCLA-145) and p = 0.0042 (MCLA-145 vs. atezolizumab*); Tumor #2, **p = 0.0007 (Neg. Ctrl Ab vs. MCLA-145); Tumor #4 *p = 0.0074 (MCLA-145 vs. atezolizumab*), determined by one-way ANOVA and Tukey’s test; b Ly95 T cells expressing an NY-ESO-specific TCR were transferred to NSG mice bearing A549-PD-L1^hi tumors and treated with indicated antibodies, end point data are shown, (n = 7 mice); c Stacked histogram, percentage of human CD3⁺ lymphocytes in total live cell population in blood after RBC lysis (open bar) and tumor (solid colored bar) in each of the treatment groups in (b); d Proportion of NY-ESO-1-specific T cells in tumors per treatment group (b), expressed as a percentage of CD3 + TILs, (n = 7, error bars are SEM), *p < 0.0216 (MCLA-145 vs. Ly95), determined by one-way-ANOVA and Tukey’s test; e Ly95 T cells expressing an NY-ESO-specific TCR were transferred to NSG mice bearing A549-PD-L1^hi or A549-PD-L1^null tumors and treated with indicated antibodies, end point data are shown. (n = 9 mice), **p < 0.0018 MCLA-145 treatment (A549-PD-L1^hi vs A549-PD-L1^null groups), determined by one-way-ANOVA and Tukey’s test. f Tumor volume in individual human CD34+ engrafted NSG mice following grafting with MDA-MB-231 cells and treatment with indicated concentrations MCLA-145 or reference antibody (n c= 9 mice per group). Tumor growth and moment of death are indicated for the individual mice per group, a representative experiment of two independent experiments is shown, *p < 0.05, **p < 0.005, ***p < 0.001 of treatment group vs negative control antibody, determined by a two-sided mixed-effects model and Dunnett’s test. g Proportion of CD8+ (upper panel) and CD4+ (middle panel) TILs in tumors from each treatment group, expressed as a percentage of the total population of tumor cells, bottom panel, proportion of PD-L1+ monocytes (bottom panel) in tumors per treatment group, expressed as a percentage of all monocytes (CD11b+ cells), (n = 7 mice per group, error bars are mean ± SD, *p = 0.0492 for CD8+ T cells and p = 0.0014 for PD-L1⁺ monocytes, determined by one-way ANOVA and Tukey’s test.