Fig. 5: The anti-huPD-1-huGITR-L bispecific induces MC-38 tumor growth inhibition in genetically engineered and humanized mouse models.
a,b, Growth inhibition of MC-38 cells by anti-muPD-1-huGITR-L (a) and anti-huPD-1-muGITR-L chimeric bispecific (b) in human GITR and PD-1 transgenic models in comparison to anti-muPD-muGITR-L surrogate bispecific in WT mice. Bispecific domains are indicated by the following colors: purple, variable domain of anti-muPD-1; green, muGITR-L; yellow, huGITR-L; and orange, variable domain of anti-huPD-1. Mice were treated with one dose of isotype at 1.0 mg kg–1, surrogate bispecific at 1.3 mg kg–1 and chimeric bispecific at 1.46 mg kg–1 (n = 8 mice). c,d, TIGIT+, CD62L−CD44+ TCM and Ki67+ are shown as a percentage of CD4+ in blood while CD62L−CD44+ TCM and Ki67+ are shown as a percentage of CD8+ T cells following treatment with anti-muPD-1-huGITR-L in huGITR homozygous (HO) mice (c) and anti-huPD-1-muGITR-L in huPD-1 HO mice (d). e,f, ICOS+, CD62L−CD44+ TEM, Ki67+ and CD226+ are shown as a percentage of CD4+ and CD8+ T cells in TDLN following treatment with anti-muPD-1-huGITR-L in huGITR HO mice (e) and anti-huPD-1-muGITR-L in huPD-1 HO mice (f). g,h, Ki67+, CD226+, KCNA3+, SLAMF6−TIM3+ and TOX+ are shown as a percentage of CD8+ T cells in the tumor, and CD25+FoxP3+ as a percentage of CD4+ T cells following treatment with anti-muPD-1-huGITR-L in huGITR HO mice (g) and anti-huPD-1-muGITR-L in huPD-1 HO mice (h). Tissues were collected 120 h after treatment. Results from five animals per group were averaged, and standard deviations are shown. i,j, Growth inhibition of xenograft PC-3 (i) and HCT-116 (j) cells in NSG allogeneic PBMC-reconstituted mice following treatment with one dose of anti-huPD-1-huGITR-L at the indicated doses. Each point on the curve represents mean ± s.e.m. of tumor volume for each group (n = 8 per group in transgenic HO huPD-1 and huGITR and PC-3 mouse models, and n = 10 per group in HCT-116 mouse model). Statistical significance was calculated by two-way ANOVA with Tukey’s correction for multiple comparisons (statistics refer to chimeric anti-PD-1–GITR-L bispecific versus isotype control). **P = 0.0005, ***P = 0.0001.
