1. IOS-1002, a Stabilized HLA-B57 Open Format, Exerts Potent Anti-Tumor Activity.
- Author
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Rafiei, Anahita, Gualandi, Marco, Yang, Chia-Lung, Woods, Richard, Kumar, Anil, Brunner, Kathrin, Sigrist, John, Ebersbach, Hilmar, Coats, Steve, Renner, Christoph, and Marroquin Belaunzaran, Osiris
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IN vitro studies , *MACROPHAGES , *MONOCYTES , *KILLER cells , *RESEARCH funding , *IMMUNOGLOBULINS , *CELLULAR signal transduction , *MYELOID-derived suppressor cells , *TUMOR markers , *IMMUNE system , *DESCRIPTIVE statistics , *GENE expression , *TUMORS , *HLA-B27 antigen , *PHAGOCYTOSIS , *IMMUNOSUPPRESSION , *CELL receptors - Abstract
Simple Summary: The human leukocyte antigen (HLA) system is crucial for immune responses against infections and cancer. Certain HLA class Ia molecules, like HLA-B27 and HLA-B57, are linked to both viral control (e.g., HIV, HCV) and development of autoimmune diseases (e.g., Spondylarthritis and psoriasis, respectively). Here we explore the use of HLA class I molecules as therapeutics in an "open format" (peptide free) construct, designed to activate immune cells through the interaction of LILRB and KIR receptors. The study identified IOS-1002, a modified version of HLA-B57:01:01 molecule fused to an IgG4 engineered to enhance stability and manufacturability. The research described in this manuscript highlights IOS-1002's unique mechanism of action, which includes binding to LILRB1, LILRB2, KIR3DL1 and CD64 receptors leads to the stimulation of multiple effector cells from both the innate and adaptive immune system. IOS-1002 is a first-in-class, multi-target, and multi-functional agent, currently being evaluated in a first-in-human phase I trial for various solid tumor indications. HLA-B27 and HLA-B57 are associated with autoimmunity and long-term viral control and protection against HIV and HCV infection; however, their role in cancer immunity remains unknown. HLA class I molecules interact with innate checkpoint receptors of the LILRA, LILRB and KIR families present in diverse sets of immune cells. Here, we demonstrate that an open format (peptide free conformation) and expression- and stability-optimized HLA-B57-B2m-IgG4_Fc fusion protein (IOS-1002) binds to human leukocyte immunoglobulin-like receptor B1 and B2 (LILRB1 and LILRB2) and to killer immunoglobulin-like receptor 3DL1 (KIR3DL1). In addition, we show that the IgG4 Fc backbone is required for engagement to Fcγ receptors and potent activation of macrophage phagocytosis. IOS-1002 blocks the immunosuppressive ITIM and SHP1/2 phosphatase signaling cascade, reduces the expression of immunosuppressive M2-like polarization markers of macrophages and differentiation of monocytes to myeloid-derived suppressor cells, enhances tumor cell phagocytosis in vitro and potentiates activation of T and NK cells. Lastly, IOS-1002 demonstrates efficacy in an ex vivo patient-derived tumor sample tumoroid model. IOS-1002 is a first-in-class multi-target and multi-functional human-derived HLA molecule that activates anti-tumor immunity and is currently under clinical evaluation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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