Antibody-Drug Conjugate Linkers for Plasma Stability and Drug Release
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Solution Overview
Problem
Existing antibody-drug conjugates (ADCs) exhibit instability in mouse plasma due to differences in pharmacokinetics compared to human plasma, making efficacy evaluation in humans difficult, and are prone to high hydrophobicity leading to faster plasma clearance.
Innovation Solution
Development of conjugates with linkers containing both hydrophilic groups and cleavable sites in the side chain connecting the antibody and drug, which attenuate hydrophobicity before cleavage and allow for enhanced cell permeability post-cleavage, using specific structures represented by formulas (I-1) to (VIII).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linkers containing VC structure are used in ADCs, then drug release in human cancer cells is achieved, but instability in mouse plasma occurs due to Ces1c recognition
Solution Approach 1:
The patent modifies the linker structure locally by replacing the VC structure with a non-peptidic isostere that maintains the cleavable function but eliminates recognition by mouse plasma enzymes. This local structural change preserves drug release capability in human cancer cells while conferring stability in mouse plasma, enabling preclinical evaluation.
Solution Approach 2:
The invention changes the chemical parameters of the linker by substituting the peptide-based VC structure with a non-peptidic isostere having different chemical composition and bonding characteristics. This parameter change fundamentally alters the enzyme recognition profile, making the linker stable in mouse plasma while maintaining cleavability in human cancer cells through alternative mechanisms.
2Power
If hydrophobic drugs are conjugated to antibodies, then direct cytotoxic activity is achieved, but faster plasma clearance occurs due to high hydrophobicity
Solution Approach 1:
The patent introduces a hydrophilic spacer as an intermediary component between the antibody and the hydrophobic drug. This spacer acts as a mediator that reduces the overall hydrophobicity of the conjugate, thereby decreasing plasma clearance rate and extending residence time, while still allowing the drug to exert its cytotoxic effect upon release.
Solution Approach 2:
The invention creates a composite linker structure combining hydrophobic and hydrophilic segments. The hydrophobic portion maintains drug conjugation and release functionality, while the hydrophilic portion reduces plasma clearance. This composite approach balances the conflicting requirements of maintaining cytotoxic activity while extending plasma residence time.
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 conjugates achieve long in vivo residence time, low aggregation rates, and improved drug efficacy through hydrophilic masking and subsequent hydrophobic exposure, maintaining antibody functionality.
Implementation Method 1
Such disulfide bonds can be cleaved by a reducing agent. For example, if all four disulfide bonds in an IgG are cleaved, an IgG antibody with eight thiol groups is generated.
Implementation Method 2
the VC structure is recognized by cathepsin B in the lysosomes of human cancer cells, and the amide bond on the carboxy-terminal side of citrulline is cleaved.
Implementation Method 3
mouse plasma contains Ces1c, a carboxylase that recognizes the VC structure and cleaves the amide bond on the carboxy-terminal side of citrulline
Data Source
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AI summary
A conjugate of an antibody and a functional substance, or a salt thereof, that has excellent properties is provided. More specifically, a conjugate of an antibody and a functional substance, or a salt thereof, in which (1) the conjugate includes an immunoglobulin unit including two heavy chains and two light chains, (2) the immunoglobulin unit includes: (a) two or more cysteine residue-modifying moieties connected to the immunoglobulin unit by bonding to the sulfur atoms in the side chains of two or more cysteine residues in the two heavy chains and two light chains; and (ii) two or more lysine residue-modifying moieties regioselectively connected to the immunoglobulin unit by bonding to the nitrogen atoms in the side chains of two or more lysine residues in said two heavy chains, and (3) the cysteine residue-modifying moiety is represented by a specific formula, and related substances thereof, are provided.