Charged Phosphinate Linkers for Antibody Conjugation

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Solution Overview

Problem

The use of cell-binding molecule-drug conjugates in cancer therapy is limited by the formation of protein aggregates due to hydrophobic linkers, which complicates the scale-up process and decreases yield, especially when high drug loading is desired, as it leads to nonspecific toxicity and immunogenicity.

Innovation Solution

The development of charged phosphinate linkers that minimize aggregation by enabling higher drug loading while maintaining affinity, allowing for the conjugation of drugs to cell-binding agents like antibodies, and facilitating retention within target cells, even in multidrug-resistant cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If hydrophobic linkers are used for conjugation, then drug loading can be achieved, but protein aggregation occurs which complicates scale-up and decreases yield

Engineering Contradiction:
Improvedrug loadingVSAvoidconjugate yield
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent changes the chemical parameter of the linker from hydrophobic to hydrophilic (charged phosphinate group). This parameter change fundamentally alters the linker's interaction with water and protein surfaces, preventing hydrophobic aggregation while maintaining drug conjugation capability. The charged phosphinate linker achieves high drug loading (DCR up to 20) without the aggregation problems that plague hydrophobic linkers, thereby resolving the contradiction between drug loading quantity and conjugate yield.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If higher drug loading is desired, then potency increases, but nonspecific toxicity and immunogenicity occur

Engineering Contradiction:
Improvedrug-to-antibody ratioVSAvoidnonspecific toxicity
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The charged phosphinate linker acts as an intermediary between the antibody and the cytotoxic drug. This intermediary maintains proper spacing and orientation, ensuring that the drug is delivered specifically to target cells via the antibody's specificity. The charged nature of the linker prevents nonspecific interactions with off-target proteins, thereby enabling high drug-to-antibody ratios without increasing nonspecific toxicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If hydrophobic linkers are used, then conjugation can be achieved, but aggregation complicates the scale-up process

Engineering Contradiction:
Improveconjugation capabilityVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention extracts the hydrophobic character from the linker structure and replaces it with a hydrophilic charged phosphinate group. This extraction of the problematic hydrophobic property eliminates the aggregation tendency that complicates scale-up, while retaining the essential conjugation functionality. The result is a simplified manufacturing process that does not require complex aggregation management steps.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3122757B1Charged linkers and their uses for conjugation
Publication Date: 2023.09.06 HANGZHOU DAC BIOTECH CO LTD
  • EP3122757B1 patent drawingFigure 1
  • EP3122757B1 patent drawingFigure 2~3
  • EP3122757B1 patent drawingFigure 4~5

AI summary

Cell binding agent-drug conjugates comprising phosphinate-based charged linkers and methods of using such linkers and conjugates are provided.