Phosphate-Based Linkers for Antibody Drug Conjugates
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Solution Overview
Problem
Current antibody drug conjugates (ADCs) face limitations in linker stability and solubility, particularly for anti-inflammatory agents like dexamethasone, which require self-immolative linkers that can handle payloads with an oxygen terminus, and existing linkers may cause aggregation or have poor solubility issues.
Innovation Solution
Development of phosphate-based linkers with tunable stability, comprising monophosphate, diphosphate, triphosphate, or tetraphosphate groups, that are stable extracellularly but labile intracellularly, allowing for targeted release of anti-inflammatory agents via a reactive functional group conjugated to antibodies targeting CD74 or CD163 proteins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If self-immolative linkers are used to handle payloads with oxygen terminus, then the linker can release drug moiety effectively, but the conjugate may suffer from poor solubility and aggregation
Solution Approach 1:
The patent introduces phosphate-based linkers as intermediary structures between the antibody and the anti-inflammatory payload. These linkers contain phosphate groups that provide negative charge and hydrophilicity, acting as mediators that improve solubility and prevent aggregation while maintaining the self-immolative drug release mechanism. The phosphate group serves as a bridge that connects the hydrophilic requirements with the hydrophobic payload.
Solution Approach 2:
The patent modifies the chemical parameters of the linker by incorporating phosphate groups with different degrees of phosphorylation (mono-, di-, tri-, or tetraphosphate). This changes the physical and chemical properties of the conjugate, specifically improving solubility through increased hydrophilicity and negative charge, while also affecting stability and drug release kinetics.
2Stability of the object's composition
If stable linkers are used to maintain circulatory stability, then the ADC remains stable in circulation, but the drug release inside cells is limited
Solution Approach 1:
The patent creates a dynamic linker system where the phosphate-based linker exhibits different stability characteristics in different environments. The linker is stable in extracellular circulation but becomes labile intracellularly due to pH changes and enzymatic conditions, enabling dynamic transition from stable to unstable state to facilitate drug release at the target site.
Solution Approach 2:
The patent applies different stability properties to different locations of the ADC system. The phosphate-based linker provides extracellular stability where needed for circulation, while its structure allows intracellular lability where drug release is required. This spatial differentiation of stability properties resolves the contradiction between circulatory stability and intracellular release.
3Productivity
If disulfide linkers are used for reductive cleavage, then drug release can occur at tumor site, but inappropriate release may occur at cell membrane causing toxicity
Solution Approach 1:
The patent employs a disposable self-immolative mechanism where the phosphate-based linker is designed to be stable during circulation and then undergo controlled degradation inside the cell. The linker serves its purpose once (holding the drug during circulation, then releasing it intracellularly) and is then discarded, preventing premature release toxicity while enabling targeted delivery.
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 phosphate-based linkers provide enhanced solubility and stability, ensuring the anti-inflammatory agents are retained within cells until fully cleaved, minimizing aggregation and releasing the payload in its native form, thus improving therapeutic efficacy and safety.
Implementation Method 1
The phosphate-based linker has a differentiated and tunable stability in blood vs. an intracellular environment... the rate at which the phosphate group is cleaved in the intracellular environment to release the anti-inflammatory agent
Data Source
AI summary
Antibody drug conjugates (ADCs) comprising an antibody conjugated to an anti-inflammatory therapeutic agent via a phosphate-based linker with tunable extracellular and intracellular stability are described.