Affinity-Guided Cleavable Conjugates for Uniform IgG Drug Loading

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Solution Overview

Problem

Existing antibody drug conjugates (ADCs) face issues with nonuniform drug conjugation, leading to variations in drug-antibody ratio (DAR) and conjugation position, affecting pharmacokinetics and drug release rates, which current methods like genetic engineering and chemical modification under complex environments struggle to address effectively.

Innovation Solution

A novel compound with an affinity substance, reactive group, and cleavable portion is used to regioselectively modify soluble proteins, particularly the IgG antibody, using a bioorthogonal functional group to achieve precise drug conjugation without peptide linkers, ensuring consistent DAR and conjugation positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If random conjugation method is used, then productivity is improved, but manufacturing precision deteriorates

Engineering Contradiction:
Improveconjugation speedVSAvoiddrug-antibody ratio uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention introduces a peptide tag with a specific sequence (e.g., GPGPG or similar glycine-rich sequences) at a defined location on the antibody molecule. This localized structural feature provides specific recognition sites for the conjugation reagent, ensuring that drugs are attached only at these predetermined positions rather than randomly throughout the antibody. This achieves uniform DAR and consistent conjugation positions while maintaining efficient conjugation kinetics.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If genetic engineering methods are used, then manufacturing precision is improved, but device complexity deteriorates

Engineering Contradiction:
ImproveregioselectivityVSAvoidexpression system construction
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention uses a small molecule peptide conjugation reagent as an intermediary that specifically recognizes and binds to the peptide tag on the antibody. This reagent acts as a bridge between the antibody and the drug, enabling regioselective conjugation through a simple chemical reaction. The method avoids the need for complex genetic engineering of the antibody expression system, as the peptide tag can be easily incorporated and the conjugation is achieved through straightforward chemical biology techniques.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If peptide linkers are used, then ease of manufacture is improved, but object-generated harmful factors worsen

Engineering Contradiction:
Improveconjugation simplicityVSAvoidimmunogenicity
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention extracts the peptide sequence from the final conjugate structure by using a cleavable peptide linker that can be hydrolyzed under physiological conditions. The peptide tag serves only as a temporary recognition element during conjugation, and the cleavable linker allows the peptide to be removed after drug attachment. This results in a final ADC product with reduced or eliminated peptide content, thereby minimizing immunogenicity while maintaining the benefits of regioselective conjugation during manufacturing.

Inventive Principle:
Principle #2Taking out (Extraction)

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 method enables regioselective modification of IgG antibodies with high regioselectivity and yield, overcoming the limitations of existing methods by providing consistent drug conjugation and reducing immunogenicity, thus enhancing the efficacy and stability of ADCs.

Implementation Method 1

a compound having an affinity substance to a soluble protein, a cleavable portion, and a reactive group

Methodology Applied
Scientific EffectMolecular recognition: Adsorption

Implementation Method 2

a reactive group to an amino acid residue constituting the soluble protein

Methodology Applied
Scientific EffectChemical bonding: Chemical Bonding

Implementation Method 3

a cleavable portion between the affinity substance and the reactive group, and capable of producing a structural unit having a bioorthogonal functional group by cleavage at the cleavable portion

Methodology Applied
Scientific EffectBond cleavage: Hydrolysis

Data Source

PatentEP3617235B1Compound having substance that has affinity for soluble protein, cleavable moiety, and reactive group, or salt thereof
Publication Date: 2026.02.18 AJINOMOTO CO INC
  • EP3617235B1 patent drawingFigure 1-1
  • EP3617235B1 patent drawingFigure 1-2
  • EP3617235B1 patent drawingFigure 1-3

AI summary

The present invention provides a technique enabling modification of a soluble protein and in particular regioselective modification of a soluble protein. More specifically, the present invention provides a compound having an affinity substance to a soluble protein, a cleavable portion, and a reactive group represented by the following Formula (I):         A-L-B-R     (I) wherein A is an affinity substance to a soluble protein; L is a cleavable linker which is a divalent group comprising a cleavable portion; B is (a) a divalent group comprising a bioorthogonal functional group or (b) a divalent group comprising no bioorthogonal functional group; and R is a reactive group to the soluble protein; or a salt thereof.