Reduced-Affinity EGFR Antibody Conjugates for Lower Off-Target Toxicity
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Solution Overview
Problem
Existing anti-EGFR antibodies, such as Panitumumab, exhibit high affinity leading to significant toxicities in normal tissues due to off-target effects, limiting their use in antibody-drug conjugates (ADCs) for cancer treatment.
Innovation Solution
Development of modified antibodies with reduced affinity for EGFR by specific amino acid mutations in the CDR regions, maintaining binding specificity while minimizing off-target toxicity, and conjugation with cytotoxic drugs via chemical linkers to form ADCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high affinity anti-EGFR antibodies are used, then binding potency to EGFR is improved, but toxicity in normal tissues increases
Solution Approach 1:
The patent applies parameter changes by systematically mutating amino acid residues in the CDR regions of the antibody to modulate binding affinity. Specific mutations (e.g., H3L3, H3L2, H2L3, H2L2 patterns) were introduced to reduce affinity from KD=10^-11M to KD=10^-9M to 10^-8M range, thereby reducing off-target toxicity while preserving sufficient binding potency for therapeutic effect.
2Object-affected harmful factors
If affinity of anti-EGFR antibody is reduced, then toxicity in normal tissues is reduced, but binding potency decreases
Solution Approach 1:
The patent optimizes the affinity parameter within a specific range (KD=10^-9M to 10^-8M) that balances reduced toxicity with maintained binding potency. This parameter optimization was achieved through controlled amino acid mutations that prevent excessive affinity reduction while ensuring sufficient toxicity mitigation.
Solution Approach 2:
The patent introduces chemical linkers as intermediaries between the antibody and cytotoxic drug in ADC construction. This intermediary approach allows the antibody to bind EGFR with moderate affinity while the linker controls drug delivery, separating the binding function from the cytotoxic function and enabling independent optimization of each component.
3Productivity
If high affinity antibody is used for ADC construction, then targeting efficiency is improved, but off-target effects are compounded
Solution Approach 1:
The patent changes the binding affinity parameter to an optimal range for ADC therapy (KD=10^-9M to 10^-8M), which provides sufficient targeting efficiency for tumor cells while reducing off-target binding to normal tissues. This parameter optimization was validated through in vitro and in vivo studies showing improved therapeutic index.
Solution Approach 2:
The patent introduces dynamics by creating a modular ADC system where the antibody, linker, and drug components can be independently optimized and adjusted. The dynamic affinity modulation through mutations allows flexible tuning of the ADC's behavior in different physiological contexts, balancing targeting efficiency with safety.
Data Source
AI summary
The present invention provides isolated antibodies that bind to the human EGFR protein, and ADCs of the antibodies. Pharmaceutical compositions including the antibodies and ADCs, and methods of treating cancer are also provided.