Figure 2 from Preclinical Characterization and Phase I Trial Results of a Bispecific Antibody Targeting PD-L1 and 4-1BB (GEN1046) in Patients with Advanced Refractory Solid Tumors

Abstract

<p>GEN1046 therapeutic efficacy and antitumor immune responses in MC38-hPD-L1 tumor–bearing hPD-L1/h4-1BB dKI mice. <b>A,</b> MC38-hPD-L1 cells (1 × 10<sup>6</sup> tumor cells) were injected s.c. in the right flank of hPD-L1/h4-1BB dKI mice. After tumor establishment (average tumor volume, ∼80 mm<sup>3</sup>), mice were randomized and treated with GEN1046 or isotype control antibody (each 5 mg/kg intravenous) at the indicated time points (<i>n</i> = 9 per group). <b>B,</b> Tumor growth of individual mice in each group, with CR defined as number of animals with CR. <b>C,</b> Progression-free survival, defined as the percentage of mice with tumor volume smaller than 500 mm<sup>3</sup>, is shown as a Kaplan–Meier curve. Mantel–Cox analysis was used to compare survival between treatment groups. ****, <i>P</i> < 0.0001. <b>D,</b> Mice with CR after treatment with GEN1046 (shown in <b>B</b>) were rechallenged by s.c. injection of 1 × 10<sup>6</sup> MC38-hPD-L1 tumor cells in the left flank on day 164. As a control group, a second cohort of naïve dKI animals was inoculated with 1 × 10<sup>6</sup> MC38-hPD-L1 tumor cells. Tumor growth of individual mice in each group is shown. <b>E–I,</b> MC38-hPD-L1 or MC38-WT cells (1 × 10<sup>6</sup> tumor cells) were injected s.c. in the right flank of hPD-L1/h4-1BB dKI mice. After tumor establishment (mean tumor volume, ∼75 mm<sup>3</sup>), mice were randomized and treated with GEN1046, a durvalumab analogue, or isotype control antibody (all 5 mg/kg intravenous) at the indicated time points. The mice were sacrificed 2 days after the last treatment (<i>n</i> = 5 per treatment group), and the tumors and spleens were excised. <b>F,</b> Sections of resected tumors (4 µm) were stained using anti-CD3, anti-CD8, or anti-FoxP3 antibodies by IHC. The number of positive cells was quantified per mm<sup>2</sup>. Mann–Whitney <i>U</i> statistical analysis was performed to compare the number of cellular subsets between treatment groups in MC38-hPD-L1 or MC38-WT tumor–bearing mice. *, <i>P</i> < 0.05. <b>G</b> and <b>H,</b> Flow cytometry analysis of dissociated splenocytes. Data from individual mice are shown as well as group mean ± SEM. *, <i>P</i> < 0.05; **, <i>P</i> < 0.01; ***, <i>P</i> < 0.001, Wilcoxon rank sum test. <b>I,</b> Peripheral blood samples were taken 1 day before treatment (d−1) and 2 days after each treatment. Cytokine analysis was performed by electrochemiluminescence immunoassay. s.c., subcutaneous; Treg, regulatory T cell.</p>

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