Protease-Activated PSMA T Cell Engagers for Cold Tumors
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Solution Overview
Problem
There is a long-felt need for therapeutic interventions targeting Prostate-Specific Membrane Antigen (PSMA)-expressing tumors, particularly immunologically 'cold' tumors, which are resistant to current immunotherapies and chemotherapy, and there is a lack of effective treatments for castration-resistant prostate cancer (CRPC) that metastasizes.
Innovation Solution
Development of antigen-binding molecules, including bispecific T cell engagers (TCEs) that target PSMA and CD3, which are administered in an inactive form and activated at the tumor site, and compositions that enhance the therapeutic response to checkpoint inhibitors by recruiting and activating effector T cells in a major histocompatibility complex-independent manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional immunotherapies (checkpoint blockade inhibitors) are used to treat prostate cancer, then treatment is provided for common solid tumors, but response rates are very low in prostate cancer due to immunologically cold tumor microenvironment and weak neoantigen burden
Solution Approach 1:
The patent introduces PSMA-targeting T cell engagers as an intermediary mechanism that directly recruits and activates effector T cells at the tumor site through CD3 engagement, bypassing the need for tumor mutational burden and immune cell infiltration that limit checkpoint blockade effectiveness. This mediator approach enables reliable T cell-mediated killing specifically in PSMA-expressing prostate cancer regardless of the immunologically cold microenvironment
Solution Approach 2:
The invention changes the therapeutic parameter from immune checkpoint modulation to direct T cell engagement via bispecific antibodies. By altering the mechanism of action from indirect immune modulation to direct cell-cell interaction through PSMA-CD3 bridging, the therapy achieves reliable response in prostate cancer while maintaining adaptability to exploit PSMA overexpression in various tumor types including metastatic lesions
2Measurement precision
If T cell engagers are designed to bind both PSMA and CD3 for targeted killing, then specific targeting of PSMA-expressing cells is achieved, but complexity of the therapeutic molecule increases
Solution Approach 1:
The T cell engager is segmented into distinct functional domains: a PSMA-binding domain (heavy chain with CDR3 modifications for PSMA specificity) and a CD3-binding domain (light chain with CDRs for CD3 epsilon recognition). This segmentation allows each domain to independently perform its specific binding function while maintaining overall molecule simplicity through modular architecture
Solution Approach 2:
The bispecific T cell engager molecule performs multiple functions simultaneously: it targets PSMA-expressing cells with high specificity while also engaging CD3 on T cells to activate them. This multi-functionality is achieved through a single molecular entity that combines both specificities, reducing the need for multiple separate therapeutic components while maintaining precise targeting capability
3Object-affected harmful factors
If mask polypeptides are added to reduce binding to CD3 or PSMA before activation, then off-target effects are reduced, but device complexity increases
Solution Approach 1:
Mask polypeptides are incorporated into the T cell engager structure to preliminarily block the PSMA and CD3 binding sites before the molecule reaches the tumor site. These masks prevent premature or off-target binding during circulation, and are designed to be cleaved by proteases in the tumor microenvironment or upon T cell binding, thereby activating the therapeutic effect only when and where needed
Solution Approach 2:
The mask polypeptides act as temporary intermediary elements that mediate between the therapeutic molecule and its target. They provide a protective layer during circulation that can be selectively removed at the target site, enabling controlled activation without requiring complex delivery systems or external activation mechanisms
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 described molecules and compositions provide targeted T cell-mediated killing of PSMA-expressing cells and enhance the therapeutic response to checkpoint inhibitors, offering a potential cure for CRPC and improving treatment outcomes for immunologically cold tumors.
Implementation Method 1
a protease-cleavable release segment positioned between the mask polypeptide and the bispecific antibody domain such that the mask polypeptide is capable of reducing the binding of the bispecific antibody domain to CD3 or PSMA, and wherein the protease-cleavable release segment is cleavable by at least one protease that is present in a tumor
Data Source
AI summary
The disclosure describes antigen-binding molecules with binding specificity to cluster of differentiation 3 T cell receptor (CD3), antigen-binding molecules with binding specificity to prostate-specific membrane antigen (PSMA), cleavable linker sequences, and protease-activatable bispecific fusion proteins such as protease-activatable T cell engagers, as well as uses and methods of treatment.