HER2 Binding Polypeptide Tumor Penetration
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Solution Overview
Problem
Current therapeutic antibodies for targeting HER2 in cancer treatment face challenges such as limited penetration into solid tumors, reduced vascular permeability, cross-reactivity with normal tissues, heterogeneous tumor uptake, increased metabolism, and immune-mediated complications, leading to reduced efficacy and significant side effects.
Innovation Solution
A high-affinity HER2 binding polypeptide derived from a staphylococcal protein A domain with specific substitution mutations, which exhibits minimal non-specific binding and can be used as a therapeutic agent or for targeted delivery of other therapeutic agents, offering improved specificity and reduced toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If therapeutic antibodies are used to target HER2 in cancer treatment, then HER2 binding affinity is achieved, but penetration into solid tumors is limited and vascular permeability is reduced
Solution Approach 1:
The patent extracts the essential HER2 binding function from the complex antibody structure, isolating only the necessary binding domain to create a smaller polypeptide that retains therapeutic activity while improving tumor penetration capabilities
Solution Approach 2:
The invention creates a simplified copy of the antibody's HER2 binding function using a polypeptide based on staphylococcal protein A domain, which replicates the target binding capability without the structural limitations of full-size antibodies
2Reliability
If therapeutic antibodies are used for HER2 targeting, then cancer cells can be targeted, but cross-reactivity with normal tissues occurs leading to side effects
Solution Approach 1:
The patent applies local quality by designing a polypeptide with highly specific local binding properties to HER2, concentrating the binding activity in a optimized region that minimizes off-target interactions with normal tissues
Solution Approach 2:
The invention changes the binding parameters by using a polypeptide with different physicochemical properties compared to antibodies, achieving high specificity through optimized amino acid sequence and binding interface characteristics
3Reliability
If therapeutic antibodies are administered, then HER2-overexpressing cancers can be treated, but heterogeneous tumor uptake and increased metabolism reduce efficacy
Solution Approach 1:
The patent employs a smaller, more rapidly clearing polypeptide that can be administered at higher frequencies with optimized dosing, replacing the long-lived antibody to achieve better therapeutic outcomes through improved pharmacokinetic properties
Solution Approach 2:
The invention utilizes the shorter half-life of the polypeptide to implement periodic administration schedules that maintain therapeutic levels while allowing complete clearance between doses, optimizing tumor uptake with each administration cycle
4Reliability
If therapeutic antibodies are used, then HER2 binding is achieved, but immune-mediated complications and significant side effects occur
Solution Approach 1:
The patent removes the immunogenic portions of the antibody structure, retaining only the essential HER2 binding polypeptide sequence, thereby eliminating the trigger for immune-mediated complications while preserving therapeutic function
Solution Approach 2:
The invention creates a non-immunogenic copy of the antibody's therapeutic effect using a heterologous protein scaffold (staphylococcal protein A domain) that replicates HER2 binding without eliciting adverse immune responses
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
The HER2 binding polypeptide demonstrates strong affinity for HER2 with a dissociation constant of up to 1×10−7 M, enabling effective targeting and treatment of HER2-overexpressing cancers with reduced side effects and improved delivery of therapeutic agents.
Implementation Method 1
a polypeptide, which has a binding affinity for HER2 and which is related to a domain of staphylococcal protein A (SPA) in that the sequence of the polypeptide corresponds to the sequence of the SPA domain having from 1 to about 20 substitution mutations
Data Source
AI summary
A polypeptide is provided, which has a binding affinity for HER2 and which is related to a domain of staphylococcal protein A (SPA) in that the sequence of the polypeptide corresponds to the sequence of the SPA domain having from 1 to about 20 substitution mutations. Nucleic acid encoding the polypeptide, as well as expression vector and host cell for expressing the nucleic acid, are also provided. Also provided is the use of such a polypeptide as a medicament, and as a targeting agent for directing substances conjugated thereto to cells overexpressing HER2. Methods, and kits for performing the methods, are also provided, which methods and kits rely on the binding of the polypeptide to HER2.