In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 81, No. 13_Supplement ( 2021-07-01), p. 1854-1854
Abstract:
Background: TIGIT (T-cell immunoglobulin and ITIM domain) is a “checkpoint” inhibitory receptor, which is primarily expressed on activated and “exhausted” T and NK cells. Engagement of TIGIT to its ligands (i.e., PVR and PVR-L2) leads to inhibitory signaling in T cells, promoting functional exhaustion of tumor-infiltrating T lymphocytes. BGB-A1217 is a novel humanized IgG1 anti-TIGIT antibody under clinical development. The immunomodulatory activity of BGB-A1217 was evaluated both in vitro and in vivo. Materials and methods: BGB-A1217 was generated through hybridoma fusion, humanized by CDR grafting and structural simulation. The binding affinity and specificity were studied by FACS and SPR. The immunomodulatory functions of BGB-A1217 were evaluated using primary immune cells as well as using animal models. Results: BGB-A1217 binds to the extracellular domain of human TIGIT with high affinity (KD = 0.135 nM) and specificity. In a competition assay, BGB-A1217 efficiently blocks the interaction between TIGIT and PVR. In vitro, BGB-A1217 significantly enhances T-cell functions and induces potential ADCC against TIGITHi targets. In a human T-cell assay, BGB-A1217 enhances IFN-γ production of CMV-specific T cells. In a PBMC assay, BGB-A1217 augments T cell response, either alone or in combination with an anti-PD-1 antibody BGB-A317. Besides blocking TIGIT signaling, BGB-A1217 can also remove TIGIT from cell surface through trogocytosis. This activity is Fc-dependent. In vivo, the Fc effector function is critical for the activity of BGB-A1217 against CT26WT tumor implanted in humanized TIGIT knock-in mice. The observed anti-tumor efficacy is associated with pharmacodynamic change of TIGIT down-regulation, CD226 upregulation and Treg depletion at 48hrs after first dosing. Conclusions: BGB-A1217, either alone or in combination with anti-PD-1 mAb promotes immune cell activation both in vitro and in vivo, supporting its clinical development for the treatment of human cancers. Citation Format: Xin Chen, Liu Xue, Xiao Ding, Qi Liu, Jing Zhang, Lei Jiang, Sha Liu, Hongjia Hou, Qing Zhu, Bin Jiang, Lijie Zhang, Xiaosui Zhou, Jie Ma, Yucheng Li, Wei Jin, Min Wei, Zhirong Shen, Mike Liu, Kang Li, Tong Zhang. A Fc-competent anti-human TIGIT blocking antibody BGB-A1217 elicits strong immune responses and potent anti-tumor efficacy in pre-clinical models [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 1854.
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/1538-7445.AM2021-1854
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2021
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
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