Tetramaleimide Linkers for Homogeneous Antibody-Drug Conjugates
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Solution Overview
Problem
Traditional antibody-drug conjugates (ADCs) face challenges due to heterogeneity in drug-to-antibody ratios (DAR) and conjugation sites, leading to varying pharmacokinetics, efficacy, and toxicity profiles, primarily because of non-selective linking methods that result in a mixture of conjugates with different drug loads and attachment sites.
Innovation Solution
Development of a novel tetramaleimide linker that incorporates four maleimide groups for site-specific conjugation to cysteine residues, allowing for a controlled average Drug/Antibody Ratio (DAR) of approximately 2, with the DAR2 fraction being the main component, thereby enhancing homogeneity and reducing heterogeneity in ADC products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional bifunctional linkers are used to conjugate drugs to lysine or cysteine residues, then the conjugation process is simple and widely applicable, but the ADC products exhibit high heterogeneity in drug-to-antibody ratio and conjugation sites
Solution Approach 1:
The invention divides the conjugation process into two independent stages: first, the tetramaleimide linker conjugates to four cysteine residues at fixed sites; second, the drug conjugates to the linker. This segmentation eliminates the heterogeneity caused by random conjugation at multiple sites while maintaining process simplicity through modular design
Solution Approach 2:
The tetramaleimide linker acts as an intermediary molecule with four maleimide groups that specifically conjugate to cysteine residues. This intermediary provides controlled, site-specific attachment points between the antibody and drug, resolving the contradiction between simple conjugation and homogeneous products
2Ease of manufacture
If non-selective reducing agents are used to reduce interchain disulfide bonds for cysteine conjugation, then the conjugation process is straightforward, but the ADC products contain multiple conjugates with different DAR values and sites
Solution Approach 1:
The invention applies local quality by making the reducing agent selective for interchain disulfide bonds only, rather than reducing all disulfide bonds. This localized reduction creates specific conjugation sites at the Fc region, ensuring uniform DAR distribution while keeping the process straightforward
Solution Approach 2:
The invention changes the parameter of reducing agent selectivity to specifically target interchain disulfide bonds. By controlling which disulfide bonds are reduced (only interchain, not intrachain), the process achieves precise DAR control while remaining operationally simple
3Quantity of substance
If higher DAR ADCs are produced to increase drug load, then the therapeutic efficacy may be improved, but the clearance rate increases and toxicity becomes more severe
Solution Approach 1:
The invention applies partial action by using a tetramaleimide linker that conjugates to exactly four cysteine residues (not all eight possible sites). This partial conjugation achieves optimal DAR 2-4 with homogeneous distribution, avoiding the excessive action of conjugating to all sites which would create high DAR heterogeneity and increased toxicity
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 use of tetramaleimide linkers in ADCs results in a more homogeneous drug distribution, improving both structural and pharmacological homogeneities, leading to more consistent and targeted therapeutic effects while minimizing toxicity associated with higher or lower drug loads.
Implementation Method 1
a novel tetramaleimide linker that incorporates four maleimide groups for site-specific conjugation to cysteine residues
Implementation Method 2
four maleimide groups for site-specific conjugation to cysteine residues
Data Source
AI summary
The present invention is directed to tetramaleimide linkers and use thereof, more specifically to the compounds represented by formula I and their use in the preparation of antibody-drug conjugates (ADCs). The ADCs obtained from the tetramaleimide linkers have high homogeneity and stability, and could be used effectively for the treatment of various diseases including tumors. The definition of the groups in formula I is the same as that in the description.