Novel Anti-LY6G6D/CD3 T-Cell–Dependent Bispecific Antibody for the Treatment of Colorectal Cancer

Abstract

New therapeutics and combination regimens have led to marked clinical improvements for the treatment of a subset of colorectal cancer (CRC). Immune checkpoint inhibitors have shown clinical efficacy in patients with mismatch repair-deficient or microsatellite instability-high (MSI-H) metastatic CRC (mCRC). However, patients with microsatellite-stable (MSS) or low levels of microsatellite instable (MSI-L) CRC have not benefited from these immune modulators, and the survival outcome remains poor for the majority of patients diagnosed with mCRC. In this report, we describe the discovery of a novel T cell-dependent bispecific antibody (TDB) targeting tumor-associated antigen LY6G6D for the treatment of CRC. Expression analyses reveal limited expression of LY6G6D in normal human tissues and non-CRC tumor types; meanwhile, significant LY6G6D upregulation in CRC is observed with high prevalence in MSS and MSI-L CRC subsets. The optimized anti-LY6G6D/CD3 TDB, which targets a membrane-proximal epitope of LY6G6D and binds to CD3 with high affinity, exhibits potent anti-tumor activity both in vitro and in vivo. In vitro functional assays show that LY6G6D-TDB-mediated T-cell activation and cytotoxicity are conditional and target-dependent. In mouse xenograft tumor models, LY6G6D-TDB demonstrates anti-tumor efficacy as a single agent against established CRC tumors, and enhanced efficacy can be achieved when LY6G6D-TDB is combined with PD-1 blockade. Our studies provide evidence for the therapeutic potential of anti-LY6G6D/CD3 TDB as an effective treatment option for patients with CRC.

LY6G6D is a selectively expressed colorectal cancer antigen that can be used for targeting a therapeutic T-cell response by a T-cell engager

“…In this study, we describe the identification of LY6G6D as a high tumor specific antigen in CRC, specifically in MSS tumors, confirming the same observations made by other groups ( 7 , 23 ). This is an important finding since MSS is the most abundant CRC subtype and presents a poor response rate to immuno-oncology treatments ( 24 ).…”

“…This is an important finding since MSS is the most abundant CRC subtype and presents a poor response rate to immuno-oncology treatments (24). As confirmed by immunohistochemistry analysis by Wang et al in a recent publication (23), the expression distribution of LY6G6D makes this target a rare tumor specific antigen with differential expression in CRC versus normal tissues, which allows the generation of a TcE with very restricted on-target/ off-tumor toxicity. To further demonstrate the relevance of LY6G6D, we performed a prevalence analysis in CRC samples by immunohistochemistry and confirmed that 27% of the samples express LY6G6D on tumor cells.…”

Spatially resolved transcriptomics revealed local invasion-related genes in colorectal cancer

“…Some of the marker genes of these clusters were associated with tumor progression, such as LYPD3 and LY6G6D. LY6G6D up-regulation was predominant in MSS CRCs characterized by an enrichment of immune suppressive regulatory T-cells and a limited repertoire of PD-1/PD-L1 immune checkpoint receptors ( 30 , 31 ). Thus, LY6G6D has been used as a target for CRC therapy.…”

MHC class III lymphocyte antigens 6 as endogenous immunotoxins: Unlocking immunotherapy in proficient mismatch repair colorectal cancer

“…In vitro functional assays showed that LY6G6D-TDB-mediated T-cell activation and cytotoxicity are conditional and target-dependent (Wang et al, 2022) (Figure 4). In mouse xenograft tumor models, enhanced efficacy can be achieved when LY6G6D-TDB is combined with PD-1 blockade (Wang et al, 2022). The LY6G6D/CD3 TcE developed by (Corrales et al, 2022) similarly exhibits targeted killing of target-positive cells in in vitro experiments where LY6G6D expression is homogeneous among cells.…”

“…Zhang, Z., Huang, L., Li, J.,& Wang, P. (2022). Bioinformatics analysis reveals immune prognostic markers for overall survival of colorectal cancer patients: a novel machine learning survival predictive system.…”