CD20-Specific CARs Resistant to Rituximab Blockade
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Solution Overview
Problem
Current CD20-targeted CAR T cell therapies are limited by residual rituximab levels, which can block CAR binding to CD20, reducing therapy effectiveness, particularly in patients with relapsed or refractory lymphoma.
Innovation Solution
Development of CD20-specific chimeric antigen receptors (CARs) with scFvs from anti-CD20 antibodies, such as Leu16, 1F5, and 1.5.3, that are resistant to rituximab and ofatumumab blockade, allowing effective T cell activation and cytotoxicity despite residual antibody presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rituximab-containing regimens are used to treat lymphoma, then initial therapeutic response is achieved, but residual rituximab blocks subsequent CAR T cell therapy by preventing CAR binding to CD20
Solution Approach 1:
The patent changes the binding parameters of anti-CD20 antibodies by selecting scFvs (Leu16, 1F5, 1.5.3) with distinct epitope specificities that differ from rituximab's binding site. This parameter change in antibody-antigen interaction allows CAR T cells to bind CD20 effectively even when rituximab is present, overcoming the blockade effect while maintaining therapeutic efficacy
Solution Approach 2:
The patent uses scFv-based CAR constructs as intermediary binding molecules that bridge T cells to CD20 on tumor cells. These scFvs serve as mediators with unique binding characteristics that are not blocked by rituximab, enabling effective T cell activation and cytotoxicity against CD20-expressing lymphoma cells despite residual rituximab presence
2Adaptability or versatility
If CD19 is targeted for CAR T cell therapy, then broader coverage of B-cell malignancies is achieved, but CD19 loss becomes an escape mechanism reducing long-term efficacy
Solution Approach 1:
The patent creates CAR T cells with universal applicability to multiple B-cell malignancies by targeting CD20, which is expressed across various B-cell lymphomas including mantle cell lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma. This multi-functional targeting approach provides both broad coverage and sustained efficacy by avoiding antigen loss escape mechanisms
3Reliability
If patients recently treated with rituximab are excluded from CAR T cell trials, then therapy effectiveness is maintained, but patient accrual and treatment availability are significantly reduced
Solution Approach 1:
The patent changes the binding characteristics of CAR T cells by using scFvs with epitope specificities distinct from rituximab. This parameter change in antibody binding allows the inclusion of patients recently treated with rituximab in CAR T cell therapy, expanding patient accrual while maintaining therapeutic effectiveness through effective CAR-CD20 binding despite residual rituximab
Data Source
AI summary
The present disclosure provides compositions and uses thereof for treating a disease or disorder associated with CD20 expression. Treatments of this disclosure include use of a host cell expressing a fusion protein, such as an anti-CD20 CAR, optionally in combination with a CD20-specific binding molecule, a chemotherapeutic, an inhibitor of an immunosuppression component, or combinations thereof.