CD79b CAR-T Cell Design to Overcome Antigen-Loss Relapse
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Solution Overview
Problem
Current CAR-T cell therapies for non-Hodgkin lymphoma, particularly diffuse large B-cell lymphoma, face challenges due to antigen loss, leading to relapse and poor long-term remission rates, necessitating a more effective target for immunotherapy.
Innovation Solution
Development of CD79b-targeting chimeric antigen receptors (CARs) comprising specific extracellular, transmembrane, and intracellular signaling domains, including CD8a-hinge regions, to enhance T cell specificity and efficacy against CD79b-positive B-cell lymphomas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CD19-targeting CAR-T cells are used to treat B-cell malignancies, then initial response rate is improved (60-80%), but long-term remission rate deteriorates (only 40% achieve long-term complete remission) due to antigen loss
Solution Approach 1:
The patent segments the targeting approach by switching from CD19 to CD79b as the target antigen. The CD79b-targeting CAR construct is divided into specific functional domains including an extracellular domain with CD79b-binding scFv, a transmembrane domain, and an intracellular signaling domain with co-stimulatory elements, thereby resolving the limitation of CD19 antigen loss
Solution Approach 2:
The patent changes the target antigen parameter from CD19 to CD79b. This parameter change is based on the observation that CD79b is highly expressed in B-cell lymphomas and is critical for cancer cell viability, making it a more reliable target for sustained therapeutic effect and reducing relapse due to antigen loss
2Duration of action of stationary object
If novel surface antigens are targeted to prevent relapse, then long-term remission rate is improved, but manufacturing complexity increases due to need for novel CAR constructs
Solution Approach 1:
The patent applies universality by using a standardized CAR construct design that can be adapted to different target antigens. The CD79b-targeting CAR uses common structural elements (extracellular domain, transmembrane domain, intracellular signaling domain with co-stimulatory elements) that can be universally applied to various B-cell malignancies, reducing manufacturing complexity while maintaining effectiveness
Solution Approach 2:
The patent copies the successful structural framework of existing CAR constructs and applies it to the CD79b target. By replicating the proven multi-domain architecture with co-stimulatory signaling elements, the patent simplifies the development process while achieving the goal of targeting novel antigens for improved long-term remission
Data Source
AI summary
The present disclosure provides for chimeric antigen receptors (CARs) that specifically target a Cluster of Differentiation 79b protein (CD79b), and immunoresponsive cells comprising such CARs, for the treatment of cancer.