Radiolabeled HER2-Binding Peptide Conjugates for PET Imaging
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Solution Overview
Problem
Current PET and SPECT-labeled HER2 ligands have low radiochemical yields and inefficient conjugation processes, and exhibit poor in vivo performance with high liver uptake and limited tumor detection capabilities, necessitating improved chemistries for radiolabeling and renal clearance.
Innovation Solution
Development of imaging agents comprising isolated polypeptides conjugated with 99mTc, 67Ga, or 18F via diaminedioxime or NOTA chelators, or linkers with aminoxy, azido, or alkyne groups, which provide higher yields and improved biodistribution profiles, including enhanced tumor uptake and reduced liver accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional radiolabeling chemistries are used for HER2 ligands, then the conjugation process is simple, but the radiochemical yields are low and in vivo performance is poor
Solution Approach 1:
The patent introduces bifunctional chelators (such as DOTA, NOTA, and diaminedioxime) as intermediary molecules that bridge the polypeptide and radionuclide. These chelators contain both a conjugation moiety that binds to the polypeptide and a chelating moiety that binds to the radionuclide, enabling efficient radiolabeling with high radiochemical yields while maintaining a relatively simple two-step process.
Solution Approach 2:
The patent optimizes various parameters including the choice of chelator type, conjugation site on the polypeptide, radionuclide selection, and labeling conditions (pH, temperature, time) to maximize radiochemical yield. By systematically varying these parameters, the invention achieves high yields without requiring overly complex procedures.
2Reliability
If existing HER2 ligands are used for imaging, then the binding specificity is adequate, but the in vivo performance is limited with high liver uptake and poor tumor detection
Solution Approach 1:
The patent modifies specific local regions of the polypeptide structure, particularly the N-terminal and C-terminal sequences, to optimize pharmacokinetic properties. By altering local sequences rather than the entire molecule, the invention achieves improved biodistribution with reduced liver uptake while maintaining HER2 binding specificity.
Solution Approach 2:
The invention creates composite imaging agents by combining polypeptide HER2 binders with radiolabeled chelator-conjugated moieties. This composite structure integrates the binding functionality of the polypeptide with the radiolabeling capability of the chelator system, achieving superior in vivo performance and tumor detection compared to simple ligands.
3Measurement precision
If conventional radiolabeling methods are used, then the synthesis steps are few, but the tumor uptake is insufficient and detection capability is limited
Solution Approach 1:
The patent performs preliminary conjugation of the chelator to the polypeptide before radionuclide labeling. This preliminary action ensures that the chelator is properly positioned and bonded to the polypeptide, enabling efficient and specific radionuclide incorporation. The pre-conjugated chelator-polypeptide complex then achieves high tumor uptake and detection capability through optimized binding and clearance properties.
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 new imaging agents demonstrate improved radiochemical yields, better biodistribution, and increased tumor uptake with reduced liver accumulation, facilitating more effective HER2-targeted imaging and diagnosis.
Implementation Method 1
reacting a diaminedioxime chelator with the polypeptide to form a chelator conjugated polypeptide
Implementation Method 2
reacting the linker with an 18F-fluorinated diaminedioxime chelator to form a chelator-conjugated polypeptide
Implementation Method 3
capable of binding specifically to HER2 or variants thereof
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3
AI summary
Imaging agents comprising an isolated polypeptide conjugated with a radionucleide and a chelator; wherein the isolated polypeptide binds specifically to HER2, or a variant thereof; and methods for preparing and using these imaging agents.