Multimeric Chelator Stability for Targeted Alpha Therapy
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Solution Overview
Problem
Current chelating agents for alpha-emitting radionuclides lack sufficient stability for targeted alpha therapy, leading to poor performance in vivo due to rapid dissociation and instability of complexes, which limits their effectiveness in minimizing side effects and maximizing tumor targeting.
Innovation Solution
Development of multimeric chelator compounds with multiple chelator interactions, utilizing macrocyclic chelating agents like macropa, linked through multi-functional linker moieties and tissue-targeting moieties, such as monoclonal antibodies, to enhance stability and specificity in alpha-particle emitting radionuclide delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If monomeric chelating agents (DOTA, DTPA, calix[4]-tetraacetic acid) are used to complex radium, then the chelators can be conjugated to targeted ligands, but the complexes dissociate rapidly and show poor stability in vivo
Solution Approach 1:
The patent combines multiple chelating agent units (n≥2) into a multimeric structure where each unit can interact with the radionuclide simultaneously. This merging of multiple chelating sites creates a more stable complex that prevents rapid dissociation while maintaining the ability to conjugate to targeting ligands through available functional groups.
Solution Approach 2:
The invention creates a composite chelating structure by linking multiple chelator units through spacer moieties. This composite approach combines the radium-binding capability of each chelator unit with the structural flexibility of spacers, resulting in a multimeric agent that achieves both stability and conjugation versatility.
2Power
If alpha-emitting radionuclides are used for targeted therapy, then high energy deposition and cytotoxicity are achieved, but stringent control of radionuclide distribution is required to avoid unacceptable side effects
Solution Approach 1:
The multimeric chelating agent serves as an intermediary that bridges the alpha-emitting radionuclide and the targeting ligand. The stable multimeric structure ensures the radionuclide remains bound during circulation and targeting, while the conjugated ligand guides the complex to the desired tissue, thereby controlling distribution and minimizing off-target effects.
Solution Approach 2:
Instead of attempting to control radionuclide distribution after administration, the invention inverts the approach by ensuring stable complex formation before targeting occurs. The multimeric chelator pre-organizes the radionuclide in a stable configuration that resists dissociation, thereby preventing harmful free radionuclide distribution from the outset.
3Reliability
If chelating agents with high radium affinity are used, then better complex formation is achieved, but the complexes still dissociate rapidly in vivo
Solution Approach 1:
The patent merges multiple high-affinity chelating units into a single multimeric structure that collectively binds the radium ion. The combined effect of multiple chelating sites creates a much more stable complex than any single unit could achieve alone, preventing rapid dissociation in vivo while maintaining reliable complex formation.
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 multimeric compounds demonstrate improved stability and reduced bone uptake, resulting in reduced myelosuppression and enhanced survival rates in rodent models, indicating improved pharmacodynamic and pharmacokinetic properties for targeted alpha therapy.
Implementation Method 1
The compounds of the present invention can be used for targeted alpha therapy using alpha-particle emitting radionuclides such as radium-223, radium-224, bismuth-212, bismuth-213, actinium-225, thorium-227, astatine-211, terbium-149, lead-212 and polonium-210
Data Source
AI summary
The present invention covers compounds of general formula (I): [(C)n-L]-(V)m (I) where C is a chelator and n>1, L is a multi-functional linker moiety comprising multiple functional groups for the covalent attachment of chelator such as a polyamine or polyacid-containing backbone or amino acid containing polymer comprising side-chains with amino, thiol or carboxylic acid moieties such as lysine, cysteine or glutamic acid and V is a tissue targeting moiety where m=1-5 which preferentially coupled through a coupling moiety to either the multifunctional linker moiety L or directly to the chelator moiety C, and stereoisomers, tautomers, N-oxides, hydrates, solvates, and salts thereof, and mixtures of same.