EGFR-Binding Fab Graft Design to Block Receptor Dimerization
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Solution Overview
Problem
Existing anti-EGFR therapeutic antibodies face intrinsic and acquired resistance mechanisms, limiting their therapeutic efficacy in treating cancers with EGFR over-expression.
Innovation Solution
Development of novel EGFR-binding antibody variable regions, specifically targeting EGFR domains I and II, incorporated into Fabs, which are designed using a phage-displayed Fab library to enhance binding specificity and inhibit ligand-induced receptor activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing anti-EGFR therapeutic antibodies are used, then EGFR targeting is achieved, but therapeutic efficacy is limited due to intrinsic and acquired resistance mechanisms
Solution Approach 1:
The patent applies parameter changes by developing antibodies with altered binding characteristics - specifically targeting different epitopes (domains I and II instead of domain III) and achieving nanomolar dissociation constants. This changes the binding parameters to overcome resistance mechanisms that have adapted to existing therapies.
Solution Approach 2:
The invention applies local quality by focusing on specific local regions (epitopes) of the EGFR protein - domains I and II - rather than relying on the previously used domain III. This localized targeting approach allows the antibodies to engage with different functional regions of the receptor to overcome resistance.
2Reliability
If novel EGFR-binding agents targeting domains I and II are developed, then resistance mechanisms are overcome, but manufacturing complexity increases due to synthetic antibody engineering
Solution Approach 1:
The patent replaces traditional mechanical/combinatorial phage display library screening methods with a rational design approach based on structural information about EGFR domains. This substitution of the discovery methodology reduces the complexity of identifying specific binding agents while maintaining high binding specificity.
Solution Approach 2:
The invention applies preliminary action by pre-grafting the dimerization loop motif into the CDR-H3 region before library construction. This preliminary structural configuration biases the library toward binding EGFR domains I and II, simplifying the subsequent screening process and reducing manufacturing complexity.
3Reliability
If phage-displayed Fab library with grafted dimerization loop motif is used, then binding affinity is enhanced, but library construction complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-grafting the dimerization loop motif into the CDR-H3 region of the Fab framework before constructing the combinatorial library. This preliminary configuration establishes the correct binding orientation and affinity potential, reducing the complexity of subsequent library screening while enhancing binding affinity.
Solution Approach 2:
The invention applies local quality by specifically diversifying only certain CDR regions (CDR-H1, CDR-L1, CDR-L2) while keeping the CDR-H3 region fixed with the grafted dimerization loop motif. This localized diversification approach reduces library construction complexity compared to full randomization while maintaining high binding affinity through the pre-configured motif.
Data Source
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AI summary
An Epidermal Growth Factor Receptor (EGFR, HER1, ErbB1)-binding agent has a heavy chain and a light chain, wherein the dimerization loop from EGFR's Domain II is grafted within complementarity determining region 3 (CDR3) of the heavy chain, and the binding agent is affinity matured. The graft directs the binding agent to bind EGFR at its dimerization region, to thereby inhibit EGFR dimerization and activation. In another embodiment, an EGFR-binding agent is panned out of Library F, a Fab library. The binding agents are for detecting and/or quantifying EGFR expression, for targeting EGFR-expressing cells, and for decreasing levels of EGFR in EGFR-expressing cells.