Cathepsin L-Cleavable ADC Linker for Stable Tumor Drug Release

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Solution Overview

Problem

Existing conjugate drugs lack stability and efficacy in targeting tumor cells, leading to inefficient release of cytotoxic molecules and potential off-target toxicity.

Innovation Solution

A linker (-GGFL-) that is specifically cleaved by cathepsin L in tumor environments, ensuring high stability outside tumors and rapid release of cytotoxic substances within, while maintaining stability in non-tumor environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional linkers are used in conjugate drugs, then the drugs can be administered systemically, but the drugs lack stability and show off-target toxicity

Engineering Contradiction:
Improvestability of conjugate drugVSAvoidoff-target toxicity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by designing a linker with specific amino acid sequence (-GGFL-) that changes its stability parameter based on the enzymatic environment. The linker is stable in normal physiological conditions but becomes unstable when exposed to cathepsin L in tumor microenvironment, enabling selective drug release only at the target site and reducing off-target toxicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses cathepsin L as an intermediary enzyme that mediates the cleavage of the linker. The linker sequence -GGFL- is specifically designed to be recognized and cleaved by cathepsin L, which is overexpressed in tumor cells. This intermediary mechanism ensures that the cytotoxic drug is released only when the conjugate is internalized by tumor cells, providing selective targeting and reducing systemic toxicity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the linker is designed to be cleaved by cathepsin L, then rapid release of cytotoxic substances occurs in tumors, but stability in non-tumor environments must be maintained

Engineering Contradiction:
Improverelease rate of cytotoxic substancesVSAvoidstability in non-tumor environment
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by designing the linker with different stability characteristics for different locations. The -GGFL- sequence maintains stable composition in non-tumor environments (blood circulation, normal tissues) but is designed to be rapidly cleaved in the specific local environment of tumor cells where cathepsin L is present, achieving location-dependent drug release

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by creating a linker whose stability is not fixed but changes dynamically based on the enzymatic environment. The linker transitions from a stable state in circulation to an unstable state upon encountering cathepsin L, enabling the system to adapt its drug release properties according to the biological environment

Inventive Principle:
Principle #15Dynamics

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

Enhances tumor-targeted drug delivery with high specificity and reduced off-target toxicity, achieving effective cytotoxicity in tumors with minimal side effects.

Implementation Method 1

A linker (-GGFL-) that is specifically cleaved by cathepsin L in tumor environments

Methodology Applied
Scientific EffectEnzyme cleavage: Enzyme

Data Source

PatentEP4682156A1Linker and drug conjugate using same, and antibody-drug conjugate and use thereof
Publication Date: 2026.01.21 SHANGHAI AFFINITY BIOPHARMACEUTICAL CO LTD
  • EP4682156A1 patent drawingFigure 1
  • EP4682156A1 patent drawingFigure 2
  • EP4682156A1 patent drawingFigure 3

AI summary

Provided are a linker and a drug conjugate using same, and an antibody-drug conjugate and a use thereof. Specifically, provided is a conjugate as shown in formula (II) or a stereoisomer thereof or a pharmaceutically acceptable salt thereof, wherein L is a linker (-GGFL-) as shown in formula (I). The conjugate comprising the linker as shown in formula (I) has high stability at a non-target site and can be quickly activated at a target site         R1-L-R2     Formula (II)