Antibody-Drug Conjugate Linker Design for Defined DAR Control

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Solution Overview

Problem

Current antibody-drug conjugates (ADCs) face challenges such as linker instability, heterogeneous drug-to-antibody ratios (DAR), and inefficient delivery of multiple payloads, leading to toxicity and reduced efficacy in clinical applications.

Innovation Solution

The development of an antibody-drug conjugate (ADC) with controlled pharmacokinetic properties, where drug-linker conjugates are specifically attached to cysteine or lysine residues of the antibody using enzyme-sensitive linkers, allowing for homogeneous and flexible payload ratios, and the use of dual-payload ADCs with defined DARs to enhance therapeutic efficacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional ADCs use unstable linkers to achieve simple conjugation, then manufacturing complexity is reduced, but linker stability deteriorates leading to toxicity

Engineering Contradiction:
Improveconjugation simplicityVSAvoidlinker stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the linker by using site-specific conjugation chemistry (e.g., thiol-maleimide reaction at cysteine residues or enzymatic conjugation) to create more stable drug-antibody conjugates while maintaining controlled manufacturing processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces site-specific conjugation intermediaries such as engineered cysteine residues or enzymatic reaction sites that mediate the connection between drug and antibody, providing both stability and controlled manufacturing

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If ADCs use heterogeneous DAR profiles to increase drug payload, then therapeutic potency is improved, but manufacturing precision deteriorates

Engineering Contradiction:
Improvedrug payloadVSAvoidDAR homogeneity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies local quality by introducing specific amino acid residues (e.g., engineered cysteines at defined positions) that serve as dedicated conjugation sites, allowing precise control over drug attachment locations and achieving homogeneous DAR profiles

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the conjugation process by using multiple distinct site-specific conjugation sites on the antibody, enabling controlled attachment of a defined number of drug molecules and achieving uniform DAR distribution

Inventive Principle:
Principle #1Segmentation

3Productivity

If ADCs use unstable linkers to facilitate drug release, then drug delivery efficiency is improved, but toxicity increases due to premature cleavage

Engineering Contradiction:
Improvedrug delivery efficiencyVSAvoidtoxicity
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the environmental sensitivity parameters of the linker by designing pH-sensitive or enzyme-sensitive bonds that remain stable at physiological pH but cleave selectively in the acidic endosomal/lysosomal environment or in presence of specific intracellular enzymes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical/chemical instability with biological responsiveness by using linkers that respond to specific intracellular conditions (pH, enzymes) to trigger drug release, ensuring stability in circulation while enabling controlled release in target cells

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If ADCs target antigens expressed in normal tissues to achieve broad coverage, then adaptability is improved, but harmful factors increase due to off-target toxicity

Engineering Contradiction:
Improvetarget coverageVSAvoidoff-target toxicity
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by designing linkers with specific environmental responsiveness (pH, enzyme sensitivity) that enables selective drug activation only in the target tissue microenvironment, reducing off-target effects even when targeting antigens present in normal tissues

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent converts the potential harm of antigen presence in normal tissues into a benefit by using the unique microenvironmental conditions (pH, enzyme profiles) of target tissues to trigger selective drug release, turning a risk factor into a selectivity mechanism

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 precise control over drug delivery, reducing toxicity and improving efficacy by ensuring consistent drug release and targeted cytotoxicity, addressing the limitations of conventional ADCs.

Implementation Method 1

proteases in the acidic environment of the endosome cleave the linker

Methodology Applied
Scientific EffectEnzyme cleavage: Enzyme

Implementation Method 2

the acidic environment of the endosome

Methodology Applied
Scientific EffectAcidic environment effect:

Data Source

PatentEP4670741A1Antibody-drug conjugate in which one or more drug-linker conjugates are linked to antibody and method for preparing same
Publication Date: 2025.12.31 PINOTBIO INC
  • EP4670741A1 patent drawingFigure 1~2
  • EP4670741A1 patent drawingFigure 3
  • EP4670741A1 patent drawingFigure 4

AI summary

The present invention relates to an antibody-drug conjugate (ADC) in which one or more drug-linker conjugates are linked to an antibody and an efficient method for preparing same. Particularly, each of at least one type of drug-linker conjugate selected from the group consisting of: a drug-linker conjugate (A) which is a combination of a camptothecin-based drug and an acid-sensitive linker; a drug-linker conjugate (B) which is a combination of a non-camptothecin-based super-toxin drug and an enzyme-sensitive linker; a drug-linker conjugate (C) which is a combination of a camptothecin-based drug and an enzyme-sensitive linker; and a drug-linker conjugate (D) which is a combination of an antiapoptotic protein inhibitor drug and an enzyme-sensitive linker may be linked to cysteine and lysine residues of an antibody.