Camptothecin Ligand-Drug Conjugates for Lower Toxicity Chemotherapy

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Solution Overview

Problem

Existing camptothecin derivatives, such as exatecan, suffer from high cellular toxicity and a narrow therapeutic window, limiting their effectiveness as standalone chemotherapy agents despite their potent anticancer activity.

Innovation Solution

Development of camptothecin derivatives represented by Formula 1, which are designed with specific substituents and linkers to enhance safety and efficacy, forming ligand-drug conjugates that target cancer cells effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If camptothecin derivatives are used as standalone chemotherapy agents, then potent anticancer activity is achieved, but high cellular toxicity and narrow therapeutic window occur

Engineering Contradiction:
Improveanticancer activityVSAvoidcellular toxicity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention divides the drug delivery system into three distinct components: an antibody (ligand) for target recognition, a linker for conjugation, and the camptothecin derivative (drug) for cytotoxic action. This segmentation allows the drug to be delivered specifically to cancer cells while minimizing exposure to healthy cells, thereby reducing cellular toxicity while maintaining anticancer activity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an antibody-ligand complex as an intermediary carrier to transport the camptothecin derivative specifically to cancer cells. This intermediary mechanism enables targeted delivery, ensuring the drug reaches its destination efficiently while reducing off-target effects and cellular toxicity in non-cancerous tissues.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If camptothecin derivatives are used as standalone chemotherapy agents, then potent anticancer activity is achieved, but narrow therapeutic window occurs

Engineering Contradiction:
Improveanticancer activityVSAvoidtherapeutic window
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

By segmenting the drug delivery into target-specific components (antibody, linker, drug), the invention enables selective action against cancer cells. This segmentation expands the therapeutic window by allowing higher drug concentrations at the tumor site without proportionally increasing systemic toxicity, thus improving the ratio between effective dose and toxic dose.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by concentrating the camptothecin derivative's cytotoxic effect specifically at the cancer cell location through antibody-mediated targeting. The drug exhibits high potency locally at the tumor site while maintaining low toxicity systemically, thereby expanding the therapeutic window through spatial differentiation of drug action.

Inventive Principle:
Principle #3Local quality

3Reliability

If ligand-drug conjugates are developed with specific substituents and linkers, then safety and efficacy are enhanced, but device complexity increases

Engineering Contradiction:
Improvesafety and efficacyVSAvoidconjugate structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention employs a universal linker structure that can conjugate various camptothecin derivatives to different antibody ligands. This multi-functional linker design maintains consistent pharmacokinetic properties and targeting mechanisms across different conjugate variants, enhancing safety and efficacy while managing complexity through standardized modular components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention systematically varies specific parameters (substituent groups R1-R6 on the camptothecin core, linker length and composition) to optimize safety and efficacy. By controlling and adjusting these parameters within defined ranges, the invention enhances therapeutic performance while maintaining manageable structural complexity through rational molecular design.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4711371A1Camptothecin derivative, linker, ligand-drug conjugate and medical use thereof
Publication Date: 2026.03.18 GAN & LEE PHARM CO LTD
  • EP4711371A1 patent drawingFigure 1~3
  • EP4711371A1 patent drawingFigure 4~6
  • EP4711371A1 patent drawingFigure 7~9

AI summary

Disclosed in the present invention are a new camptothecin derivative, a linker, a ligand-drug conjugate, and a pharmaceutical composition thereof containing the camptothecin derivative or the conjugate, and the corresponding medical use.