Anti-CTLA4 Antibody Selectivity for Lower Autoimmune Toxicity
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Solution Overview
Problem
Existing anti-CTLA4 antibodies used in cancer therapy are associated with significant autoimmune side effects, limiting their therapeutic potential, and combining them with other immune checkpoint inhibitors exacerbates these issues, necessitating the development of antibodies with reduced autoimmune side effects and enhanced anti-tumor activity.
Innovation Solution
Development of chimeric and humanized anti-CTLA4 antibodies with specific amino acid sequences and mutations that enhance CTLA4 blocking activity, preferentially bind to membrane-bound CTLA4, and reduce binding to soluble CTLA4, administered alone or in combination with other checkpoint inhibitors like anti-PD-1 and anti-4-1BB, to enhance anti-tumor activity while minimizing autoimmune reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing anti-CTLA4 antibodies are used for cancer therapy, then anti-tumor activity is improved, but autoimmune side effects increase
Solution Approach 1:
The patent introduces specific amino acid mutations at defined positions in the antibody sequence to alter its binding properties locally. These targeted mutations change the antibody's interaction with CTLA4 isoforms, enhancing selectivity for membrane-bound CTLA4 while reducing binding to soluble CTLA4, thereby improving the therapeutic index by differentiating between desired and undesired binding sites
Solution Approach 2:
The patent systematically modifies physical and chemical parameters of the antibody by introducing specific amino acid substitutions. These parameter changes include altering binding affinity, specificity, and immunogenicity characteristics of the antibody, transforming it from a non-selective binder to one that preferentially targets membrane-bound CTLA4 while sparing soluble CTLA4, thus reducing autoimmune side effects
2Reliability
If anti-CTLA4 antibodies are combined with other immune checkpoint inhibitors, then anti-tumor activity is enhanced, but autoimmune side effects are exacerbated
Solution Approach 1:
The engineered antibody maintains localized binding specificity at the membrane-bound CTLA4 interface, allowing it to function effectively in combination regimens without broadly activating autoimmune responses. This localized action enables safer combination therapy by concentrating the immunomodulatory effect at the tumor-relevant site
3Reliability
If antibodies with enhanced CTLA4 blocking activity are developed, then anti-tumor efficacy is improved, but binding to soluble CTLA4 may increase causing off-target effects
Solution Approach 1:
Instead of enhancing binding to all forms of CTLA4, the patent inverts the approach by engineering the antibody to selectively ignore soluble CTLA4 while maintaining or enhancing binding to membrane-bound CTLA4. This inverted selectivity strategy prevents off-target effects associated with soluble CTLA4 binding while preserving anti-tumor efficacy
Solution Approach 2:
The patent uses the concept of an intermediary by introducing a selectivity filter through amino acid mutations that act as a molecular gatekeeper. This intermediary mechanism allows the antibody to distinguish between membrane-bound and soluble CTLA4 forms, permitting beneficial interactions while blocking harmful ones
Data Source
AI summary
This invention relates to compositions of chimeric and humanized antibodies that bind to the human CTLA4 molecule and their use in cancer immunotherapy and for reduction of autoimmune side effects compared to other immunotherapeutic agents.