Masked Single-Domain Antibody Protease Activation
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Solution Overview
Problem
Current cancer immunotherapeutics face challenges with 'on-target, off-tumor' toxicity, where treatments target cancer cells but also affect healthy tissues, leading to unwanted side effects.
Innovation Solution
Development of a recombinant protein comprising a masking polypeptide linked to a single-domain antibody (sdAb) via a protease-sensitive linker, which reduces the binding affinity of the sdAb to its target antigen, allowing for targeted delivery to tumor cells while minimizing interaction with normal tissues. This protein can be administered as a pharmaceutical composition or used in a chemically self-assembled nanoring (CSAN) for enhanced specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current cancer immuno-therapeutics are used to target tumor-associated antigens, then cancer cells can be targeted, but healthy tissues are also affected causing on-target off-tumor toxicity
Solution Approach 1:
The patent applies preliminary action by pre-assembling the sdAb and masking polypeptide into a masked complex before administration. The sdAb is rendered inactive (masked) prior to reaching the target site, preventing premature binding to healthy tissues. The masking polypeptide is designed to be cleaved by tumor-specific proteases, thereby activating the sdAb only at the tumor site and eliminating off-tumor toxicity.
Solution Approach 2:
The masking polypeptide serves as an intermediary that temporarily blocks the sdAb's binding capability. This intermediary is specifically designed to be degraded by tumor-associated proteases, thereby controlling the activation of the sdAb. The masking polypeptide mediates between the sdAb and the tumor microenvironment, enabling selective activation only in the presence of tumor-specific enzymes.
2Object-affected harmful factors
If the binding affinity of sdAb to target antigen is reduced by masking polypeptide, then off-tumor toxicity is minimized, but therapeutic efficacy may be compromised
Solution Approach 1:
The patent applies local quality by creating a spatial gradient of binding affinity. The masked sdAb has low binding affinity in circulation (reducing off-tumor toxicity), but upon protease-mediated cleavage of the masking polypeptide at the tumor site, the binding affinity is restored to high levels (ensuring therapeutic efficacy). This local transformation of binding properties ensures that the sdAb is inactive where not needed and highly active where required.
Solution Approach 2:
The patent implements dynamics by making the binding affinity of the sdAb changeable rather than static. The masking polypeptide dynamically controls the binding affinity based on the local protease environment. In the bloodstream, the masked sdAb exhibits low affinity, but upon encountering tumor-specific proteases, the masking polypeptide is cleaved and the sdAb transitions to a high-affinity state, enabling dynamic adaptation to different physiological environments.
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 masked sdAb approach significantly reduces binding to healthy tissues, enhancing the therapeutic index by allowing selective targeting and activation of immune cells within the tumor microenvironment, thereby minimizing off-tumor toxicity and improving treatment efficacy.
Implementation Method 1
the linker is a flexible polypeptide linker. In certain embodiments, the linker is cleavable polypeptide linker that is capable of being cleaved by a proteolytic enzyme expressed within a solid tumor
Data Source
AI summary
Certain embodiments of the invention provide a masked single-domain antibody as described herein, as well as methods of use thereof. Certain embodiments of the invention provide a masked CSAN as described herein, as well as methods of use thereof.