Dual-Specific CAR-T Cells Targeting CD20 and CD19
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Solution Overview
Problem
Current treatments for CD20-positive B cell lymphoma, such as Rituximab and CART19, face challenges with limited efficacy and short duration of response, and there is a need for more effective targeting strategies beyond CD19 to address relapse and tumor escape mechanisms.
Innovation Solution
Development of chimeric antigen receptors (CARs) targeting CD20, comprising specific antigen binding domains from antibodies like Ofatumumab, Obinutuzumab, and Rituximab, combined with co-stimulatory signaling domains, for enhanced specificity and killing efficiency in T cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CART19 is used to treat CD19-expressed B cell lymphoma, then complete remission rate is improved (94%), but relapse occurs with CD19-negative tumor cells escape (more than 60% of relapsed patients)
Solution Approach 1:
The patent constructs chimeric antigen receptors with dual specificity that can recognize both CD19 and CD20 antigens simultaneously. This multi-targeting capability allows the CAR-T cells to eliminate tumor cells expressing either antigen, preventing escape mechanisms while maintaining high remission rates. The dual-specificity CAR structure incorporates binding domains for both CD19 and CD20, enabling comprehensive coverage of B-cell lymphoma targets.
2Reliability
If Rituximab is used to treat CD20-positive lymphoma, then response rate is improved (50% CR or PR), but duration of response is limited and efficacy is short-lived
Solution Approach 1:
The patent employs cytokine secretion domains in the CAR-T cell design that enable the engineered cells to autonomously produce and secrete cytokines such as IL-2, IL-15, and IL-21. This self-service capability allows the CAR-T cells to sustain their own activation, proliferation, and persistence in the tumor microenvironment without continuous external support, thereby extending the duration of therapeutic response significantly compared to Rituximab monotherapy.
3Measurement precision
If multiple antibody types (Rituximab, Ofatumumab, Obinutuzumab) are used to target CD20, then recognition specificity is improved, but differentiation of killing mechanisms becomes complex
Solution Approach 1:
The patent merges the antigen recognition capabilities of multiple anti-CD20 antibodies (Rituximab, Ofatumumab, Obinutuzumab) into a single dual-specificity CAR construct. By combining the variable regions of these antibodies with co-stimulatory domains (CD28, 4-1BB) and cytokine secretion domains, the invention creates a unified CAR-T cell platform that achieves high recognition specificity while standardizing the killing mechanism through integrated signaling and cytokine-mediated pathways, thereby reducing overall system complexity.
Data Source
AI summary
Provided are a chimeric antigen receptor targeting CD20 antigen and a preparation method thereof. The extracellular antigen binding domain of the chimeric antigen receptor includes an antibody heavy chain variable region shown in SEQ ID NO: 7 or 9 or 33 and an antibody light chain variable region shown in SEQ ID NO: 11 or 13 or 35, and is capable of killing tumor cells.