PBD Dimer Linkers Prevent Antibody Aggregation

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Solution Overview

Problem

Pyrrolo[2,1-c][1,4]benzodiazepine (PBD) dimers, despite their potential as antitumor agents, face challenges with poor bioavailability and protein aggregation when used in antibody-drug conjugates, particularly in water-based buffer solutions, limiting their therapeutic efficacy.

Innovation Solution

Development of novel PBD dimer derivatives that are linkable to cell surface binding ligands, allowing for conjugation without protein aggregation, enhancing bioavailability and therapeutic efficacy by facilitating targeted delivery to cancer cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PBD dimers are used as cytotoxic agents in antibody-drug conjugates, then antitumor activity is enhanced, but protein aggregation occurs in water-based buffer solutions

Engineering Contradiction:
Improveantitumor activityVSAvoidprotein aggregation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a water-soluble linker as an intermediary component between the PBD dimer and the antibody. This linker acts as a mediator that prevents direct interaction between the hydrophobic PBD dimer and the aqueous environment, thereby preventing protein aggregation while maintaining the cytotoxic activity of the PBD dimer when conjugated to the antibody.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical structure of the PBD dimer by changing parameters such as introducing water-soluble groups or modifying the linker chemistry. These parameter changes enhance the water solubility of the conjugate, preventing aggregation while preserving the DNA-binding and cytotoxic properties of the PBD dimer.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If PBD dimers are conjugated to cell binding agents, then targeted delivery to cancer cells is achieved, but bioavailability remains poor

Engineering Contradiction:
Improvetargeted deliveryVSAvoidbioavailability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The water-soluble linker serves as an intermediary that improves the bioavailability of the PBD dimer-antibody conjugate. By providing a hydrophilic interface between the PBD dimer and the aqueous physiological environment, the linker enhances the conjugate's stability and uptake by cancer cells while maintaining targeted delivery through the antibody's cell-binding properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If conventional PBD dimers are used, then DNA binding affinity is high, but they cause significant protein aggregation in water-based media

Engineering Contradiction:
ImproveDNA binding affinityVSAvoidprotein aggregation
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality modification by introducing water-soluble functional groups specifically at the linker region, while preserving the hydrophobic PBD dimer core that provides high DNA binding affinity. This localized modification allows the conjugate to maintain strong DNA binding capability while the water-soluble linker region prevents aggregation in aqueous environments.

Inventive Principle:
Principle #3Local quality

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

The novel PBD dimer derivatives effectively block cell proliferation and demonstrate improved antitumor activity when conjugated to cell binding agents, addressing the issues of bioavailability and aggregation, thereby enhancing their therapeutic potential for cancer treatment.

Implementation Method 1

These agents exert their antitumor antibiotics activity by the formation of a covalent adduct in the minor groove of a DNA with preference of a three base pairs of Pu-G-Pu (where Pu = purine; G = guanine) sequences, wherein their C11-position is electrophilic, enabling the molecules to alkylate the NH 2 group of a guanine in the minor groove of DNA

Methodology Applied
Scientific EffectCovalent bonding: Chemical Bonding

Implementation Method 2

The three carbon space ((n=3) C8/C8'-linked PBD dimer analog (DSB-120) covalently bind to a 5'-Pu-GATC-Py sequence by crosslinking opposite-strand guanines separately by 2 base pairs, span six DNA base pairs

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentEP3041846B1Novel cytotoxic agents for conjugation of drugs to cell binding molecule
Publication Date: 2018.11.07 HANGZHOU DAC BIOTECH CO LTD
  • EP3041846B1 patent drawingFigure 1
  • EP3041846B1 patent drawingFigure 2
  • EP3041846B1 patent drawingFigure 3

AI summary

Provided are cytotoxic agents, pyrrolo[2,1-c][1,4]benzodiazepine (PBD) derivatives, their conjugates with a cell-binding agent, the preparation and the therapeutic uses in the targeted treatment of cancers, autoimmune disorders, and infectious diseases.