HER2-Binding Polypeptides for Rapid Tumor Penetration
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Solution Overview
Problem
Current diagnostic and therapeutic approaches for HER2-positive tumors face challenges such as slow tumor penetration, long biodistribution time, and immunogenicity of monoclonal antibodies, which limit their effectiveness and safety, necessitating the development of new molecules that can specifically target HER2 with high affinity and stability.
Innovation Solution
Development of novel HER2-binding polypeptides, specifically affitins with sequences like VKVKFWGAGVEKEVDTSKITWVTRSGKYVIFTYDDNGKAGPGRVPEKDAPKELLDMLARAEREK, which are engineered for high affinity, rapid tissue penetration, and stability, allowing for efficient conjugation with imaging moieties for diagnostic applications, and are distinct from existing monoclonal antibodies in their epitope recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monoclonal antibodies are used to target HER2, then therapeutic efficacy is improved, but toxic effects and side-effects on healthy tissues increase
Solution Approach 1:
The patent divides the antibody function into two separate components: a small polypeptide fragment (4-20 kDa) containing the HER2-binding epitope and a separate carrier molecule or imaging moiety. This segmentation allows the small polypeptide to penetrate tissues rapidly while the carrier provides the necessary stability and imaging capabilities, reducing toxic effects on healthy tissues while maintaining therapeutic efficacy.
Solution Approach 2:
The patent changes the molecular weight parameter from large antibodies (150 kDa) to small polypeptides (4-20 kDa). This parameter change enables rapid tissue penetration and early tumor/blood ratio achievement, improving the safety profile by reducing exposure of healthy tissues to the targeting agent while maintaining HER2-specific binding through epitope recognition.
2Measurement precision
If monoclonal antibodies are used for diagnostic imaging, then target recognition is achieved, but tumor penetration is slow and biodistribution time is long
Solution Approach 1:
The patent segments the diagnostic probe into a small polypeptide fragment containing the HER2 epitope and a separate imaging moiety or carrier. This segmentation allows the small polypeptide to rapidly penetrate tumor tissues while the imaging moiety provides the necessary detectability, achieving early tumor/blood ratio suitable for imaging without compromising target recognition precision.
Solution Approach 2:
The patent changes the size parameter of the targeting molecule from large antibodies to small polypeptides (4-20 kDa). This parameter change enables rapid tissue penetration and early accumulation in tumors, reducing biodistribution time from hours to minutes while maintaining high target recognition through conserved epitope binding sites.
3Reliability
If monoclonal antibodies are used repeatedly for diagnostic procedures, then continuous monitoring is possible, but immunogenicity prevents repeated administration
Solution Approach 1:
The patent extracts the HER2-binding function from the full antibody molecule and places it in a small polypeptide fragment (4-20 kDa). This extraction eliminates the immunogenic components present in full antibodies while retaining the essential epitope recognition capability, enabling repeated administrations for continuous monitoring without triggering immunogenic responses.
Solution Approach 2:
The patent uses small polypeptide fragments that are rapidly cleared from circulation (half-life of minutes to hours) compared to antibodies. This short circulation life reduces cumulative immunogenic exposure, allowing repeated diagnostic procedures without building up immunogenicity, effectively enabling continuous monitoring capability.
4Measurement precision
If antibodies are used for imaging, then specific target binding is achieved, but radiation burden on patients increases due to long-lived radioisotopes
Solution Approach 1:
The patent changes the pharmacokinetic parameters of the targeting molecule from slow-clearing antibodies to rapid-clearing small polypeptides. This parameter change allows the use of short-lived radioisotopes (e.g., 11C, 18F with half-lives of minutes to hours) instead of long-lived isotopes, reducing the radiation burden on patients while maintaining specific target binding through conserved epitope recognition.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These polypeptides demonstrate nanomolar affinity for HER2, rapid clearance, and low immunogenicity, enabling early cancer diagnosis, effective therapeutic monitoring, and reduced overtreatment by providing specific imaging agents for HER2-positive tumors, with the ability to recognize HER2 at distinct epitopes from existing antibodies.
Implementation Method 1
new polypeptide sequences, characterized by the affitins structure, specifically targeting HER2 receptor with high affinity
Implementation Method 2
small molecules clear rapidly from circulation and thus reach at early time-points after administration a tumor/blood ratio suitable for imaging
Data Source
AI summary
The present invention provides new polypeptide derivatives binding to Human Epidermal Growth Factor Receptor 2 (HER2) and their conjugates thereof, and to their use as a diagnostic agent, particularly for early detection, patient stratification and treatment monitoring of forms of cancer characterized by over-expression of HER2.