Journal: Clinical and Experimental Medicine

Article Title: Selective depletion of tumor-infiltrating regulatory T cells with BAY 3375968, a novel Fc-optimized anti-CCR8 antibody

doi: 10.1007/s10238-024-01362-8

Figure Lengend Snippet: Correlation of the intratumoral Treg depletion efficacy with antitumor responses and plasma exposure of anti-mouse CCR8 antibodies. A Correlation between the intratumoral Treg depletion and in vivo antitumor efficacy and anti-mouse CCR8 antibodies (hIgG1 and mIgG2a), across three independent studies using two different mouse tumor models (CT26 and EMT6). Treg depletion efficacy was analyzed by flow cytometry 24 h after second treatment dose and determined in percentages (%) relative to isotype control ( n = 5–6 mice/group). T/C ratio calculated from mean tumor volumes at study end ( n = 10 mice/group). The solid and dashed lines indicate the regression line and the associated 95% confidence intervals, respectively. B Correlation between the plasma exposure of anti-mouse CCR8 mIgG2a antibody and depletion of intratumoral CCR8 + Tregs (CD4+CD25+FoxP3+CCR8+) in EMT6 tumor-bearing mice treated with a single dose of antibody (0.25, 1, or 4 mg/kg; i.p.), as determined on different time points upon treatment (2, 24, 48, 120, 192 and 336 h, n = 5 mice/group/time point)

Article Snippet: For studying the PK/PD relationship, female BALBc mice (12-week-old, Charles River) were inoculated s.c. with 5 × 10 5 EMT6 murine mammary carcinoma cells, and on day 8, at an average tumor size of 35 mm 2 , mice were treated i.p. with a single-dose of non-binding isotype control (4 mg/kg) or with anti-mouse CCR8 mIgG2a antibody (0.25, 1, or 4 mg/kg).

Techniques: Clinical Proteomics, In Vivo, Flow Cytometry, Control

Journal: Clinical and Experimental Medicine

Article Title: Selective depletion of tumor-infiltrating regulatory T cells with BAY 3375968, a novel Fc-optimized anti-CCR8 antibody

doi: 10.1007/s10238-024-01362-8

Figure Lengend Snippet: Combination of CCR8 + Treg depletion with anti-PD-L1 immune checkpoint blockade results in enhanced antitumor activity. A EMT6 tumor-bearing mice were treated with anti-mouse CCR8 mIgG2a antibody and with the respective non-binding isotype control, and intratumoral IFNγ protein concentration was measured with ELISA on day 19 at study end ( n = 5). ** p < 0.01 indicate statistical significance in comparison to isotype control. B Intratumoral PD-L1 (CD274) expression as determined by RNA-Seq upon treatment of PANC02, Hepa1-6, MBT2, MC38, H22, and CT26 syngeneic tumor-bearing mice with anti-mouse CCR8 mIgG2a and hIgG1 antibody variants and with the respective non-binding isotype controls ( n = 8–10 mice/group). Log2 fold change expressions were 1.375 in PANC02, 1.453 in Hepa1-6, 1.963 in MBT2, 2.669 in MC38, 4.516 in H22 and 5.202 in CT26 model. C Efficacy of anti-mouse CCR8 mIgG2a antibody and anti-PD-L1 antibody as monotherapy and as combination treatment in syngeneic MC38 murine tumor model (also referred as C38). Tumor growth in mice treated with non-binding isotype controls mIgG2a (10 mg/kg, Q3/4Dx5, i.p.) and mIgG1 (3 mg/kg, Q3/4Dx5, i.p.), anti-mouse CCR8 mIgG2a antibody (10 mg/kg, Q3/4Dx5, i.p.), anti-PD-L1 mIgG1 antibody (3 mg/kg, Q3/4Dx5, i.p.), or the combination of anti-mouse CCR8 mIgG2a (10 mg/kg, Q3/4Dx5, i.p.) and anti-PD-L1 mIgG1 antibodies (3 mg/kg, Q3/4Dx5, i.p.). Black arrows indicate treatment days (days 10, 13, 17, 20, and 24) relative to tumor inoculation ( n = 10 mice/group). Treatment with anti-mouse CCR8 mIgG2a and anti-PD-L1 antibodies resulted in T/C values of 0.17 ( p < 0.001) and 0.38 ( p < 0.001), respectively. Combinatorial treatment with anti-mouse CCR8 mIgG2a and anti-PD-L1 antibodies resulted in T/C of 0.02 ( p < 0.001). Statistical analysis was performed using an ANOVA model with contrasts. *** p < 0.001 is significance in comparison to isotype controls, § p < 0.05 in comparison to anti-PD-L1 monotherapy. D Survival of mice described in (C). The treatments started on day 10 and the last treatment doses were given on day 24. Mice were sacrificed individually when they met the predefined termination criteria (tumor area of 220 mm 2 ). The survival times from inoculation to sacrifice are presented as Kaplan–Meier survival plots. Asterisks, hashtags, and section signs indicate statistical significance in comparison to isotype controls, anti-mouse CCR8 monotherapy, and anti-PD-L1 monotherapy, respectively ( # p < 0.05, ***, §§§ p < 0.001; n = 10 mice/group). E Intratumoral Tregs (CD4+CD25+FoxP3+) and F ratio of CD8 + T cells to Tregs were determined by flow cytometry in MC38 tumors of mice treated as described in (C). Tumors were collected 24 h after the second treatment dose on day 14. Asterisks and section signs indicate statistical significance in comparison to isotype control and anti-PD-L1 monotherapy, respectively (*, § p < 0.05, ** p < 0.01, n = 5/group)

Article Snippet: For studying the PK/PD relationship, female BALBc mice (12-week-old, Charles River) were inoculated s.c. with 5 × 10 5 EMT6 murine mammary carcinoma cells, and on day 8, at an average tumor size of 35 mm 2 , mice were treated i.p. with a single-dose of non-binding isotype control (4 mg/kg) or with anti-mouse CCR8 mIgG2a antibody (0.25, 1, or 4 mg/kg).

Techniques: Activity Assay, Binding Assay, Control, Protein Concentration, Enzyme-linked Immunosorbent Assay, Comparison, Expressing, RNA Sequencing, Flow Cytometry