Fc Variant Binding Specificity for Human and Murine Receptors
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Solution Overview
Problem
Current monoclonal antibodies used in cancer therapy have limited efficacy and high cost, with a need to enhance their ability to target and destroy cancer cells, and there is a challenge in developing Fc variants that selectively interact with human versus murine Fc receptor biology.
Innovation Solution
Development of Fc variants with specific substitutions at positions such as 234, 235, 236, 239, 267, 268, 293, 295, 324, 327, 328, and 332, which exhibit increased affinity for activating FcγRI, FcγRIIa, and FcγRIIIa receptors while reducing affinity for the inhibitory FcγRIIb receptor, and creation of murine Fc variants with specific substitutions for optimal binding in animal models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Fc variants are engineered for optimal binding to human FcγRs, then affinity for human activating FcγRs (FcγRI, FcγRIIa, FcγRIIIa) is improved, but affinity for murine FcγRs deteriorates, making animal model testing unreliable for predicting human response
Solution Approach 1:
The Fc region is segmented into specific binding sites for different FcγR subtypes. By making targeted substitutions at specific positions (234, 235, 236, 239, 267, 268, 293, 295, 324, 327, 328, 332), the patent creates distinct binding characteristics for human versus murine FcγRs, allowing selective optimization for each species without affecting the other.
Solution Approach 2:
Different regions of the Fc variant are optimized for different species. The patent introduces specific local modifications (substitutions at defined positions) that create human-optimized binding in certain regions while maintaining murine compatibility in other regions, enabling the same Fc variant to function effectively in both human and mouse models.
2Reliability
If Fc variants are designed to selectively increase affinity for activating FcγRs, then therapeutic efficacy is improved, but selectivity over inhibitory FcγRIIb receptor deteriorates due to high homology among FcγRs
Solution Approach 1:
The patent applies local quality by making specific substitutions at defined positions within the Fc region that selectively enhance binding to activating FcγRs (FcγRI, FcγRIIa, FcγRIIIa) while maintaining discrimination against the inhibitory FcγRIIb receptor. This localized optimization at specific residue positions enables precise control over receptor selectivity.
Solution Approach 2:
The patent changes biochemical parameters (amino acid sequences) at specific positions to alter the binding characteristics. By modifying residues at positions 234, 235, 236, 239, 267, 268, 293, 295, 324, 327, 328, and 332, the Fc variant achieves enhanced affinity for activating FcγRs while maintaining selectivity through careful parameter selection.
3Reliability
If monoclonal antibodies are used at high doses to improve anti-tumor efficacy, then therapeutic effect is enhanced, but cost increases significantly
Solution Approach 1:
The patent changes the binding parameters of the Fc region through specific substitutions, creating Fc variants with enhanced affinity for activating FcγRs. This parameter optimization allows the use of lower antibody doses to achieve the same therapeutic effect, thereby reducing cost while maintaining efficacy.
Solution Approach 2:
The patent creates Fc variants that copy and optimize the binding properties of natural Fc receptors. By engineering Fc variants with enhanced and selective binding characteristics, the patent achieves superior effector function at lower doses, reducing the quantity of antibody needed and thus the cost.
Data Source
AI summary
The present invention relates to Fc variants with optimized Fc receptor binding properties, methods for their generation, Fc polypeptides comprising Fc variants with optimized Fc receptor binding properties, and methods for using Fc variants with optimized Fc receptor binding properties.