Variant IL-13 CAR T Cells for IL13Rα2-Selective Cancer Targeting
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Solution Overview
Problem
Existing IL13-based chimeric antigen receptors (CARs) face challenges in selectively targeting IL13Rα2 over IL13Rα1, leading to safety concerns and reduced efficacy due to wide expression of IL13 binding partners outside diseased tissue, necessitating further mutations to enhance specificity.
Innovation Solution
Development of variant IL13 CARs with specific mutations, including amino acid sequences (SEQ ID NO: 26 and 27), spacers, transmembrane domains, co-stimulatory domains, and CD3 zeta signaling domains, to enhance selectivity for IL13Rα2 while minimizing recognition of IL13Rα1, and administering these CARs in autologous or allogeneic T cells for targeted cancer treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IL13-based CARs are used to target IL13Rα2, then therapeutic efficacy against cancer is improved, but off-target binding to IL13Rα1 in healthy tissue causes safety concerns and reduced efficacy
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid mutations (E13K, R109K, and additional mutations) in the IL13 binding domain of the CAR to alter its binding parameters. These mutations change the affinity and selectivity characteristics of the IL13 variant, enabling it to distinguish between IL13Rα2 (cancer target) and IL13Rα1 (healthy tissue target), thereby resolving the contradiction between therapeutic efficacy and off-target binding toxicity
Solution Approach 2:
The patent applies local quality by making specific localized mutations at particular amino acid positions (E13, R109, and other specific residues) within the IL13 binding domain. Each mutation is strategically placed to affect binding interactions with specific receptor subtypes, creating localized changes in binding properties that enhance selectivity for IL13Rα2 while preserving or reducing binding to IL13Rα1
2Reliability
If mutations are introduced to enhance IL13Rα2 specificity, then selectivity is improved, but the impact on CAR function becomes unpredictable
Solution Approach 1:
The patent applies segmentation by dividing the CAR into distinct functional modules: the IL13 binding domain (with specific mutations for selectivity), the transmembrane domain, the co-stimulatory domain, and the signaling domain. This modular structure allows independent optimization of each segment, where mutations in the binding domain can be tuned for selectivity without compromising the standardized functions of other domains, thus managing complexity while enhancing selectivity
3Adaptability or versatility
If wide expression of IL13 binding partners exists in healthy tissue, then IL13-based therapy can be delivered systemically, but the partners act as a sink resulting in safety concerns
Solution Approach 1:
The patent applies parameter changes by modifying the binding affinity parameters of the IL13 variant through specific mutations. The mutated IL13 has altered kinetic parameters (affinity, on-rate, off-rate) that reduce its interaction with IL13Rα1 in healthy tissue while maintaining or enhancing interaction with IL13Rα2 in cancer cells. This parameter optimization allows systemic delivery to proceed while minimizing the sink effect in healthy tissue, thereby reducing IL13 consumption and safety concerns
Data Source
AI summary
Chimeric antigen receptor molecules that include a variant IL-13. The variant IL-13 are more selective for IL13Rα2 than IL13Rα1 by virtue of weaker binding to IL13Rα1. The chimeric antigen receptors can be used to treat IL13Rα2 expressing cancers.