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Willis KM, Haerr M, Meza M, Ahn SJ, Kaplan M, Ortiz-Barquero G, Pandit R, Abalos R, Chen Y, Holley S, Lozano R, Hwang I, Rowell E, Eckelman BP. Abstract 2912: INBRX-130, a 5T4-targeted CONTRA-MAB, is a potent CD3 bispecific antibody engineered to have minimal off-tumor activity. Cancer Res 2022. [DOI: 10.1158/1538-7445.am2022-2912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Bispecific T cell engagers that target CD3 on T cells and cell-surface antigens on tumor cells have demonstrated meaningful clinical activity against hematological cancers but have yet to achieve similar efficacy for the treatment of solid tumors. A variety of factors may be contributing to this lack of success in the solid tumor setting, including insufficient exposure of tumor cells to these targeted therapeutics due to target-independent interactions with peripheral T cells. Not only can circulating cells act as a sink for CD3 bispecifics but these interactions can lead to cytokine release syndrome (CRS), a common and dose-limiting toxicity for this class of therapeutics. We have developed a CD3 bispecific platform, CONTRA-MAB® (Constrained T Cell Redirecting and Activating Multispecific Antibody), that combines high-affinity tumor-associated antigen binding single-domain antibodies (sdAbs) with a constrained CD3-targeting VH/VL pair that has been strategically positioned and affinity engineered to minimize T cell activation and cytokine production in the absence of target antigen engagement. INBRX-130 is a CONTRA-MAB® that targets trophoblast glycoprotein (TPBG; 5T4), a cell-surface protein that is upregulated across many solid tumor indications but has restricted expression on normal adult tissues. As determined by flow cytometry, INBRX-130 exhibits specific and high-affinity binding to 5T4-positive cells but shows no detectable binding to T cells, absent target, at concentrations up to one micromolar. Additionally, treatment of peripheral blood mononuclear cells (PBMCs) with high concentration INBRX-130 does not result in production of detectable levels of CRS-associated inflammatory cytokines. Upon binding to 5T4-expressing tumor cells in vitro, INBRX-130 potently induces T cell activation, proliferation, cytokine production, and cytotoxicity, resulting in target cell death. INBRX-130 has favorable pharmacokinetic properties and the capacity to effect regression of 5T4+ tumors in humanized mice, even in models that display minimal initial T-cell infiltrate. INBRX-130 is well-tolerated by cynomolgus monkeys at the maximally administered dose of 2 mg/kg without the requirement of a priming dose. Preliminary in vitro data with CONTRA-MABs® targeting other solid tumor antigens supports the broad applicability of this unique T cell engager platform. CONTRA-MABs® have the potential to have enhanced accumulation in solid tumors relative to other CD3 bispecific antibodies as a result of reduced systemic engagement of T cells and increased tolerability at high doses. These attributes, coupled with the broad tumor biased expression of 5T4 across solid tumors, may enable INBRX-130 to have a greater therapeutic index and provide a significant benefit to patients in need.
Citation Format: Katelyn M. Willis, Margaret Haerr, Marchelle Meza, Sae Jeong Ahn, Michael Kaplan, Georgina Ortiz-Barquero, Rajay Pandit, Rafael Abalos, Yao Chen, Samuel Holley, Raul Lozano, Iljin Hwang, Emily Rowell, Brendan P. Eckelman. INBRX-130, a 5T4-targeted CONTRA-MAB, is a potent CD3 bispecific antibody engineered to have minimal off-tumor activity [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 2912.
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Erdmann E, Destéfanis HA, Abalos R, Frontini PM, Abraham GA. Transport properties and mechanical behavior of poly(methyl-phenylsiloxane) membranes as a function of methyl to phenyl groups ratio. J Appl Polym Sci 2002. [DOI: 10.1002/app.10710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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