Phosphate Linkers for Stable Blood Circulation and Lysosomal Drug Release
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Solution Overview
Problem
Existing antibody drug conjugates (ADCs) face challenges in achieving optimal intracellular drug release due to limitations in linker stability and specificity, leading to reduced efficacy and potential toxicity, particularly in environments like lysosomes.
Innovation Solution
Phosphate-based linkers with tunable stability are developed, comprising monophosphate, diphosphate, triphosphate, or tetraphosphate groups, which are stable in circulation but cleavable in intracellular compartments, allowing controlled drug release through a phosphate group structure and tuning element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stable linkers such as mcc are used in ADCs, then circulatory stability is improved and toxicity is reduced, but intracellular drug release efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the linker structure from stable mcc linkers to phosphate-based linkers with tunable stability. The phosphate-based linkers incorporate different phosphate groups (monophosphate, diphosphate, triphosphate, or tetraphosphate) and tuning elements to adjust the rate of intracellular cleavage while maintaining circulatory stability, thereby resolving the contradiction between stability and release efficiency
Solution Approach 2:
The patent uses composite materials by combining phosphate groups with various tuning elements (aromatic rings, heterocyclic groups, amino acids) to create phosphate-based linkers with differentiated stability profiles. This composite approach enables the linker to exhibit both circulatory stability and controlled intracellular cleavage, addressing the technical contradiction
2Productivity
If unstable disulfide linkers are used in ADCs, then intracellular drug release is improved, but circulatory stability deteriorates and bystander killing toxicity increases
Solution Approach 1:
The patent applies parameter changes by transitioning from unstable disulfide linkers to phosphate-based linkers with engineered stability parameters. The phosphate-based linkers maintain appropriate stability in circulation while enabling controlled intracellular release through enzymatic cleavage, eliminating the need for premature disulfide bond reduction that causes bystander killing
3Productivity
If self-immolative linkers are used in ADCs, then complete drug release is improved, but aggregate formation increases and manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the phosphate-based linker structure with specific tuning elements that control cleavage rates. This enables complete drug release through controlled enzymatic hydrolysis of phosphate esters, achieving self-immolative functionality with reduced aggregate formation compared to traditional PABC linkers
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
These linkers enhance the therapeutic efficacy of ADCs by reducing aggregation and enabling targeted drug delivery, improving safety and efficacy by controlling drug release within cells.
Implementation Method 1
These phosphate-based linkers have a differentiated and tunable stability in blood vs. an intracellular environment (e.g. lysosomal compartment). Thus, conjugates that comprise these phosphate-based linkers are stable in circulation (plasma/blood) but reactive or cleavable in intracellular compartments (lysosome)
Data Source
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AI summary
Phosphate-based linkers with tunable stability for intracellular delivery of drug conjugates are described. The phosphate-based linkers comprise a monophosphate, diphosphate, triphosphate, or tetraphosphate group (phosphate group) and a linker arm comprising a tuning element and optionally a spacer. A payload is covalently linked to the phosphate group at the distal end of the linker arm and the functional group at the proximal end of the linker arm is covalently linked to a cell-specific targeting ligand such as an antibody. These phosphate-based linkers have a differentiated and tunable stability in blood vs. an intracellular environment (e.g. lysosomal compartment).