Disulfide-Bridging Linkers for Homogeneous Antibody–Drug Conjugates
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Solution Overview
Problem
Current methods for producing antibody drug conjugates (ADCs) face challenges with stability, drug-antibody ratio (DAR) heterogeneity, and drug distribution, leading to unreliable pharmacokinetic profiles and toxic side effects due to pseudorandom nucleophilic bioconjugation and unstable maleimide linkages.
Innovation Solution
A disulfide bridging linker platform is developed, allowing for precise attachment of active agents to proteins or peptides, enhancing stability and drug distribution by re-bridging reduced disulfide bonds, thereby improving the targeted delivery of cytotoxic payloads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If maleimide conjugation is used to link cytotoxin to antibody, then the ADC can be produced, but the linkage becomes unstable in circulation leading to premature dissociation
Solution Approach 1:
The patent changes the chemical parameters of the linker by using dibromomaleimide instead of traditional maleimide. This parameter change transforms the unstable succinimide thioether ring into a more stable structure that resists hydrolysis, thereby maintaining linkage stability throughout circulation while enabling prolonged duration of action
Solution Approach 2:
The invention creates a composite linker structure combining dibromomaleimide with PEG chains and cysteine residues. This composite material integrates the stability of dibromomaleimide with the flexibility and solubility of PEG, achieving both linkage stability and appropriate circulation characteristics
2Ease of manufacture
If pseudorandom nucleophilic bioconjugation is used, then ADC production is simplified, but heterogeneity in DAR and drug distribution increases
Solution Approach 1:
The patent introduces site-specific cysteine residues at predetermined locations on the antibody molecule. This creates local quality differences where only specific sites undergo conjugation, enabling simplified production processes while achieving homogeneous DAR and controlled drug distribution at defined attachment points
Solution Approach 2:
The dibromomaleimide linker acts as an intermediary that selectively reacts with engineered cysteine residues. This intermediary enables controlled conjugation at specific sites while maintaining ease of manufacture through a straightforward one-step reaction process
3Reliability
If disulfide bridging is used to improve stability, then premature payload release is reduced, but the conjugation process becomes more complex
Solution Approach 1:
The patent extracts and utilizes the disulfide bonding capability from native antibody structures and applies it through dibromomaleimide-mediated cysteine re-bridging. This approach achieves enhanced stability through disulfide bonds while simplifying the overall process compared to traditional multi-step methods requiring separate reduction and conjugation steps
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 linker platform provides stable and homogeneous ADCs with controlled drug distribution, reducing toxic side effects and improving the tolerability and efficacy of targeted drug delivery.
Implementation Method 1
cysteine re-bridging reactions with DBM linkers
Implementation Method 2
reduced cysteine disulfide bond
Implementation Method 3
leading to covalent re-bridging of the protein
Data Source
AI summary
A conjugate comprising a protein or a peptide, a linker and an active agent, wherein the linker comprises the moiety of formula (III): (III) wherein two of A1, A2 and A3 are N and the other of A1, A2 and A3 is CH; X is selected from N, O and S, and Pep indicates where the moiety is linked to the protein or peptide, either directly or indirectly.