Chimeric Checkpoint Receptor for Selective B-Cell Lymphoma Targeting
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Solution Overview
Problem
Existing CAR T cell therapies for B-cell lymphoma, such as Tisagenlecleucel, cause generalized depletion of healthy CD19+ B lymphocytes, neurotoxicity, and cytokine release syndrome due to unspecific targeting of CD19+ pericytes, leading to B cell aplasia, hypogammaglobulinemia, and tumor recurrence.
Innovation Solution
A fusion protein comprising an extracellular domain with specific affinity to CD80 and/or CD86, a transmembrane domain, and an intracellular co-stimulatory domain, such as CTLA-4 or CD28, is used to create a chimeric checkpoint receptor (CCR) that activates T cells only when CD19, CD80, and/or CD86 are expressed on the same target cell, reducing off-tumor activation and cytokine release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CD19-specific CAR T cells are used to treat B-cell lymphoma, then malignant B lymphocytes are effectively targeted, but healthy CD19+ B lymphocytes and CD19+ pericytes are also depleted causing B cell aplasia and neurotoxicity
Solution Approach 1:
The invention segments the targeting mechanism by requiring dual recognition: the CAR component targets CD19 while the CCR component targets CD80/CD86. This segmentation allows differentiation between malignant B cells (which express both CD19 and CD80/CD86) and healthy cells (which express only CD19), thereby achieving selective targeting and reducing off-tumor effects.
Solution Approach 2:
The invention applies local quality by making T cell activation conditional upon the local presence of both CD19 and CD80/CD86 markers. The CCR's co-stimulatory function is locally activated only when engaged by CD80/CD86 on malignant cells, creating a spatially and functionally restricted activation zone that spares healthy CD19+ cells lacking CD80/CD86.
2Reliability
If CD19-specific CAR T cells are used to treat B-cell lymphoma, then tumor cells are eliminated, but neurotoxicity occurs due to targeting of CD19+ pericytes
Solution Approach 1:
The targeting system is segmented into two independent components: CAR for CD19 recognition and CCR for CD80/CD86 recognition. This segmentation ensures that pericytes (which express CD19 but lack CD80/CD86) cannot activate the full T cell response, preventing neurotoxicity while maintaining efficacy against malignant B cells that express both markers.
Solution Approach 2:
The invention creates a locally restricted activation condition where T cell cytotoxicity is triggered only in the specific microenvironment where both CD19 and CD80/CD86 are co-expressed. This local quality control prevents systemic activation against healthy pericytes, eliminating neurotoxic side effects.
3Reliability
If CD19-specific CAR T cells are used to treat B-cell lymphoma, then malignant B cells are depleted, but tumor recurrence occurs in about 50% of cases
Solution Approach 1:
The dual-component targeting system segments the activation requirements, forcing T cells to recognize both CD19 and CD80/CD86 simultaneously. This segmentation creates a more specific and sustained anti-tumor response that prevents tumor escape and recurrence, as malignant cells cannot evade therapy by downregulating a single marker.
Solution Approach 2:
The invention establishes a locally activated co-stimulatory signal only at malignant B cell sites where both CD19 and CD80/CD86 are present. This localized quality enhancement ensures persistent T cell activation and memory formation specifically against tumor cells, leading to durable remission and preventing recurrence.
4Reliability
If conventional CAR T cell therapy is used, then initial tumor response is achieved, but cytokine release syndrome occurs due to alarm cytokine release
Solution Approach 1:
The T cell activation process is segmented into two distinct recognition steps: CD19 binding by CAR and CD80/CD86 binding by CCR. This segmentation creates a more controlled and gradual activation process that prevents the abrupt, massive cytokine release associated with conventional single-antigen CAR T cell therapy, reducing CRS severity.
Solution Approach 2:
The invention localizes the co-stimulatory signal activation to specific malignant B cell contact sites where both CD19 and CD80/CD86 are engaged. This localized quality control prevents systemic cytokine storm by restricting intense T cell activation to discrete tumor-cell interaction zones rather than allowing widespread activation.
Data Source
AI summary
The invention is related to a chimeric checkpoint receptor (CCR) fusion protein, a nucleic acid molecule encoding said fusion protein, a vector comprising said nucleic acid molecule, a host cell comprising said nucleic acid molecule and/or expressing the fusion protein, a method for providing said host cell, a pharmaceutical composition comprising said fusion protein, nucleic acid molecule or host cell, and said products for use as a medicament and in the treatment of B cell lymphoma.