ROR1-Specific VHH Bispecific Antibodies for Immune Redirection
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Solution Overview
Problem
Current therapies lack effective methods to redirect cytolytic immune effectors towards ROR1-expressing tumor cells, which are prevalent in various cancers, including chronic lymphocytic leukemia, mantle cell lymphoma, and solid tumors like triple negative breast cancer, ovarian cancer, and melanoma.
Innovation Solution
Development of multispecific antibodies, including bispecific antibodies, that engage immune effector cells such as pro-inflammatory T helper type 1 cells and cytotoxic T lymphocytes to target ROR1-expressing tumor cells, utilizing specific CDRs and framework regions to enhance cytotoxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current therapies are used, then treatment of ROR1-expressing tumor cells is attempted, but effective redirection of cytolytic immune effectors toward target cells is lacking
Solution Approach 1:
The antibody is divided into multiple functional domains: a first binding domain that specifically binds ROR1 on tumor cells, and a second binding domain that binds to immune effector cells. This segmentation allows independent optimization of each binding function, enabling reliable tumor cell targeting while providing versatility in engaging different immune cell types through the second domain.
Solution Approach 2:
The multispecific antibody is designed with dual functionality: it simultaneously targets tumor cells via ROR1 binding and engages multiple types of immune effector cells (T cells, NK cells, macrophages) through its second binding domain. This multi-functionality resolves the contradiction by providing both reliable tumor cell targeting and broad adaptability to redirect diverse immune effectors toward the tumor target.
2Reliability
If multisspecific antibodies are developed to engage immune effector cells, then cytotoxicity against tumor cells is enhanced, but complexity of the antibody structure increases
Solution Approach 1:
The multispecific antibody structure employs a nested organization where the first and second binding domains are integrated within a single antibody molecule framework. The variable regions (VH and VL) are arranged to accommodate both ROR1-binding and immune effector cell-binding functions in a compact, organized structure, reducing the complexity that would otherwise arise from separate molecular components.
Solution Approach 2:
The antibody utilizes spatial arrangement in three-dimensional space to resolve functional complexity. The first binding domain is positioned to engage ROR1 on the tumor cell surface, while the second binding domain is oriented to interact with immune effector cells. This spatial separation and directional arrangement allow both functions to operate simultaneously without excessive structural complexity.
3Reliability
If antibodies redirect immune cell cytotoxicity to kill cancer cells, then tumor cell killing is achieved, but cytokine release may occur that could have adverse effects
Solution Approach 1:
The antibody design focuses on achieving sufficient cytotoxicity through selective engagement of immune effector cells with the tumor target, rather than attempting to completely eliminate all immune activation. By optimizing the binding affinity and stoichiometry of the multispecific antibody, adequate tumor cell killing is achieved while limiting excessive cytokine release that would occur with complete immune system activation.
Solution Approach 2:
The multispecific antibody acts as an intermediary that controls and modulates the interaction between immune effector cells and tumor cells. Rather than allowing direct, uncontrolled immune activation that would cause excessive cytokine release, the antibody mediates a controlled engagement that achieves tumor cell killing while regulating the intensity of immune activation and associated cytokine production.
Data Source
AI summary
ROR1-specific antigen-binders, and multispecific antibodies are provided, which contains one or more ROR1-specific antigen-binding sites and at least one antigen-specific binding site for an activation receptor (such as CD3) on an immune cell, wherein various configurations are presented of new VHH-based anti-ROR1 sequences in relation to the antigen-specific binding site for the immune cell activation receptor, as well as to a scaffolding segment forming a constant region of the antibodies. These multispecific antibodies have been demonstrated to bind to ROR1-positive cancer cells, induce immune cell-mediated cytotoxicity against ROR1-positive target cells, and to inhibit growth of tumor size in animals.