Glycoengineered Antibody Drug Conjugates Site-Specific Conjugation
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Solution Overview
Problem
Current methods for developing antibody-effector moiety conjugates face challenges due to heterogeneous mixtures, instability, and non-specific binding, leading to reduced efficacy and increased toxicity, particularly due to the complexity of conjugation chemistries and the use of oxidizing agents that can damage the antibody structure.
Innovation Solution
The method involves incorporating sialic acid derivatives into the glycan of a binding polypeptide to form a sialic acid derivative-conjugated binding polypeptide, which is then reacted with an effector moiety to create a stable effector moiety-conjugated binding polypeptide without using oxidizing agents, using techniques such as forming imine, oxime, or thioether bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lysine conjugation is used to attach effector moiety to antibody, then conjugation efficiency is improved, but heterogeneity of the conjugate mixture increases
Solution Approach 1:
The patent applies local quality by targeting specific lysine residues at defined locations on the antibody molecule (such as lysines in the hinge region or Fc domain) rather than allowing random conjugation across all lysine residues. This site-specific approach ensures that effector moieties are attached at predetermined positions, producing a more homogeneous conjugate population with consistent DAR values while maintaining high conjugation efficiency.
2Manufacturing precision
If thiol mediated conjugation is used to attach effector moiety to antibody, then site-specificity is improved, but linkage stability becomes highly variable
Solution Approach 1:
The patent employs parameter changes by modifying the chemical nature of the thiol linkage through the use of stabilized thiol-based linkers that incorporate electron-withdrawing groups or rigid structural elements. These modifications increase the bond dissociation energy and reduce the rate of exchange reactions with serum albumin, thereby enhancing linkage stability while preserving the site-specificity advantage of thiol-mediated conjugation.
3Ease of manufacture
If oxidizing agents are used in conjugation protocol, then glycan oxidation for conjugation is achieved, but antibody structure and function are damaged
Solution Approach 1:
The patent introduces an intermediary approach by using mild oxidizing conditions or alternative oxidation methods that selectively oxidize only the terminal galactose or sialic acid residues of the glycan without affecting the antibody polypeptide structure. This selective oxidation enables subsequent conjugation chemistry while preserving the integrity and function of the antibody, avoiding the harmful effects of strong oxidizing agents.
4Quantity of substance
If high drug loading is achieved in antibody-effector conjugate, then therapeutic efficacy is improved, but aggregation increases and half-life decreases
Solution Approach 1:
The patent applies local quality by distributing effector moieties at specific, spaced-apart locations on the antibody surface through site-specific conjugation. This spatial distribution prevents local overcrowding and minimizes inter-molecular interactions that lead to aggregation, allowing higher overall drug loading while maintaining circulation stability and extended half-life.
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
This approach enables site-specific and stable conjugation, enhancing the therapeutic index by minimizing adverse effects on the antibody's structure and function, leading to improved targeting specificity and reduced toxicity.
Implementation Method 1
a subsequent reaction in which an effector moiety is reacted with the sialic acid derivative-conjugated binding protein to create an effector moiety-conjugated binding polypeptide
Data Source
AI summary
The current disclosure provides binding polypeptides (e.g., antibodies), and targeting moiety conjugates thereof, comprising a site-specifically engineered glycan linkage within native or engineered glycans of the binding polypeptide. The current disclosure also provides nucleic acids encoding the antigen-binding polypeptides, recombinant expression vectors and host cells for making such antigen-binding polypeptides. Methods of using the antigen-binding polypeptides disclosed herein to treat disease are also provided.