Pancreatic T reg cells control the availability of CD4+ T cell–secreted IL-2 to limit NK cell function.

Ox40 ligand (Ox40L) locus genetic variants are associated with the risk for systemic lupus erythematosus (SLE); however, it is unclear how Ox40L contributes to SLE pathogenesis. In this study, we evaluated the contribution of Ox40L and its cognate receptor, Ox40, using in vivo agonist and antagonist approaches in the NZB 3 NZW (NZB/W) F1 mouse model of SLE. Ox40 was highly expressed on several CD4 Th cell subsets in the spleen and kidney of diseased mice, and expression correlated with disease severity. Treatment of aged NZB/W F1 mice with agonist anti-Ox40 mAbs potently exacerbated renal disease, which was accompanied by activation of kidney-infiltrating T cells and cytokine production. The agonist mAbs also induced activation and inflammatory gene expression in splenic CD4 T cells, including IFN-regulated genes, increased the number of follicular helper T cells and plasmablasts in the spleen, and led to elevated levels of serum IgM and enhanced renal glomerular IgM deposition. In a type I IFN-accelerated lupus model, treatment with an antagonist Ox40:Fc fusion protein significantly delayed the onset of severe proteinuria and improved survival. These data support the hypothesis that the Ox40/Ox40L pathway drives cellular and humoral autoimmune responses during lupus nephritis in NZB/W F1 mice and emphasize the potential clinical value of targeting this pathway in human lupus.

Background: Myeloid immune suppression in the tumor microenvironment is known to contribute to tumor immune evasion. ILT2 (aka LILRB1) and ILT4 (aka LILRB2) are distinct ITIM-containing immunosuppressive receptors that recognize shared MHC-I ligands. Both ILT2 and ILT4 are highly expressed on tumor infiltrating myeloid cells, while ILT2 is also expressed on tumor-associated T and NK cells. Furthermore, both ILT2 and ILT4 are upregulated in patients who do not respond to T cell checkpoint inhibitor therapy, implicating these receptors as potential resistance mechanisms. Given their regulation in human cancers and their potential to mediate immune suppression in a broad range of tumor-associated immune cells, ILT2 and ILT4 may represent promising targets for cancer immunotherapy. The complementary nature of ILT2 and ILT4 activities suggests a dual antagonist strategy is warranted. To this end, we have developed NGM707. NGM707 is a humanized monoclonal antibody with specificity for both ILT2 and ILT4, blocking their interaction with both classical MHC-I (HLA-A, HLA-B, HLA-C) as well as the non-classical MHC-I molecule HLA-G. We present here preclinical data on the pharmacology of NGM707. Methods: NGM707 was evaluated for ILT2 and ILT4 specificity, ligand blocking and functional activity. Activity was assessed on various myeloid cell subsets, including monocyte-derived macrophages, myeloid-derived suppressor cells (MDSC) and dendritic cells. ILT2 blockade by NGM707 was also assessed on NK cells and T cells. Results: In vitro and biochemical pharmacology studies demonstrated that NGM707 bound potently to human ILT2 (1.03 nM KD) and ILT4 (0.205 nM KD). NGM707 binding to ILT2 and ILT4 blocked interaction with their ligands, including classical MHC-I and non-classical MHC-I (HLA-G). Functional studies demonstrated that NGM707-mediated ILT2 and ILT4 blockade reprogrammed suppressive myeloid cells and enhanced their activity, including stimulation of allogeneic T cell responses. NGM707-mediated ILT2 blockade also enhanced NK- and CD8 T cell-mediated killing of tumor cells. NGM707 in combination with an anti-PD-1 antibody additively enhanced macrophage-mediated allogeneic stimulation of CD4 T cells, suggesting combined treatment with NGM707 and an anti-PD-1 antibody can lead to complementary immune-modulatory activities. Conclusions: NGM707 is a novel dual antagonist antibody targeting both ILT2 and ILT4. The preclinical data presented indicate that by blocking ILT4, NGM707 can reprogram suppressive myeloid cells to a stimulatory state, and that by blocking ILT2, NGM707 can stimulate the activation of both myeloid and lymphoid cells. These data support the clinical evaluation of NGM707 as a therapeutic for patients with solid tumor malignancies. Citation Format: Kalyani Mondal, Christina Song, Jane Tian, Carmence Ho, Lee B. Rivera, Jiawei Huang, Peirong Chen, Suzanne Crawley, Vicky Y. Lin, Jonathan Sitrin, Julie M. Roda, David Shen, Hui Tian, Yan Wang, Alan Kutach, Jeong Kim, James Sissons, Daniel D. Kaplan, Geoffrey W. Stone. Preclinical evaluation of NGM707, a novel anti-ILT2/anti-ILT4 dual antagonist monoclonal antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB156.

Background: Collagen is an abundant component of the extracellular matrix-enriched stromal microenvironment of solid cancers. Emerging research suggests that effective anti-tumor immunity and responsiveness to immune checkpoint inhibitor (CPI) therapy, may be subverted by the presence of collagen and tumor stroma. LAIR1 functions as an inhibitory receptor for collagen, and is highly expressed on tumor-associated macrophages, and to an extent on T cells. LAIR1 expression correlates with poor overall survival and CPI therapy resistance. To test the hypothesis that LAIR1 mediates tumor stroma-driven immune suppression and promotes CPI resistance, we generated NGM438, a monoclonal mAb to antagonize LAIR1 activity in solid cancers. Herein, we describe NGM438, characterize LAIR1 expression and distribution in human tumors, and provide evidence that LAIR1 antagonism reverses collagen-driven immune suppression and improves CPI responsiveness in immune cell-based assays and preclinical animal models. Methods: NGM438 was identified and developed based on its ability to bind specifically to LAIR1, antagonize ligand binding, and reverse collagen-based immune suppression. NGM438 was tested using several immune cell-based functional assays, alone and in combination with the anti-PD1 mAb, pembrolizumab. Expression and distribution of LAIR1 was evaluated using flow cytometry and immunohistochemistry on healthy donor and cancer patient samples. A surrogate anti-mouse LAIR1 antagonist mAb was also developed and evaluated in preclinical animal models in combination with anti-PD1 mAbs. Results: NGM438 reversed collagen-induced immune suppression in myeloid cells and promoted anti-PD1 mAb-driven T cell responses in immune cell-based functional assays. LAIR1 was expressed on circulating immune cells from cancer patients actively receiving CPI therapy, and was elevated on patient-matched intratumoral macrophages. Histological assessments revealed LAIR1 expression on mononuclear immune cells that infiltrated the parenchyma and collagen-rich tumor stroma across indications. Finally, LAIR1 antagonism, in combination with anti-PD1 mAb treatment, led to significant tumor growth inhibition in a preclinical model resistant to either treatment alone. Conclusions: NGM438 is a novel LAIR1 antagonist mAb that reverses collagen-based immune suppression. LAIR1 was expressed on cancer patient circulating and intratumoral immune cells, and LAIR1-expressing cells were often found in collagen-rich tumor stroma. Preclinical data demonstrated that LAIR1 antagonism sensitized a resistant mouse tumor model to respond to anti-PD1 mAb treatment. These data support clinical evaluation of LAIR1 antagonist mAb NGM438. We aim to test the hypothesis that LAIR1 mediates collagen-driven immune suppression, alone and in combination with PD1 inhibition, in patients with solid cancers. As such, we will be advancing NGM438 to the clinic in early 2022. Citation Format: Sisi He, Jiawei Huang, Leticia Rodriguez, Czrina Cortez, Betty Li, Carmence Ho, Amir Ashique, Kalyani Mondal, Vicky Lin, Julie Roda, Hui Tian, Yan Wang, Bin Fan, Igor Mikaelian, James Sissons, Lee Rivera, Don Gibbons, Jonathan Sitrin. Preclinical development of NGM438, a novel anti-LAIR1 antagonist monoclonal antibody for the treatment of collagen-rich solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB219.

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