2C4-Derived HER2 ECD2 Antibody Constructs for Higher Affinity
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Solution Overview
Problem
Existing therapeutic antibodies targeting HER2 have limitations in affinity and efficacy for treating HER2-expressing cancers, necessitating improved antigen-binding constructs with enhanced specificity and binding capabilities.
Innovation Solution
Development of antigen-binding constructs with specific amino acid modifications in the framework regions and CDRs of the 2C4 antibody, such as pertuzumab, to increase affinity for HER2 ECD2 by at least 2-fold, and potential bispecific formats for targeted cancer treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing therapeutic antibodies targeting HER2 are used, then treatment is provided for HER2-expressing cancers, but the affinity and efficacy are limited
Solution Approach 1:
The patent applies parameter changes by systematically modifying amino acid residues at specific positions (73-77 in VH framework, 49 in VL framework, and CDR regions) to optimize the antibody's binding affinity to HER2. Multiple variants are generated with different amino acid substitutions to identify combinations that enhance affinity while maintaining manufacturability
Solution Approach 2:
The patent applies local quality by making targeted amino acid modifications at specific local positions within the antibody structure rather than global changes. The modifications are concentrated in the framework regions and CDRs that directly contact the antigen, allowing localized optimization of binding properties without altering the entire antibody structure
2Reliability
If amino acid modifications are introduced to increase affinity, then binding capability is enhanced, but construct complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the antibody structure into distinct functional regions (VH framework, VL framework, CDRs) and independently optimizing each region through targeted amino acid modifications. This modular approach allows systematic improvement of binding capability while managing complexity through structured variant generation
Solution Approach 2:
The patent systematically varies amino acid parameters at specific positions to enhance binding capability. By changing parameters such as hydrophobicity, charge, and side chain volume at key positions, the patent optimizes affinity while maintaining a manageable number of variants through focused modification strategies
Data Source
Figure 1A~1E
Figure 2A~2B
Figure 2C
AI summary
Described herein are high affinity antigen binding constructs, e.g., antibodies, directed to the ECD2 domain of HER2. The antigen-binding constructs comprise at least one antigen- binding polypeptide construct that binds to ECD2 of HER2 (HER2 ECD2) with increased affinity compared to a wild-type 2C4 antibody. Such antigen-binding polypeptide constructs comprise one or more amino acid modifications in the framework region and/or CDRs compared to the amino acid sequence of a wild-type 2C4 antibody that increase affinity of the antigen- binding polypeptide construct for ECD2 by 2-fold or greater. The antigen-binding constructs can inhibit the growth of HER2-expressing breast cancer cells and gastric cancer cells. Antigen- binding constructs in biparatopic format are internalized in HER2-expressing cells.