Humanized CD3 Antibodies With Tuned Affinity for Safer T Cell Killing
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Solution Overview
Problem
Existing CD3 antibodies face challenges with immunogenicity, cytokine storm, and dose-limiting toxicities, and their efficacy is dependent on affinity to CD3, which can be customized for tailored treatment needs but requires improved cross-reactivity and affinity optimization.
Innovation Solution
Development of humanized or chimeric CD3 antibodies with optimized affinity to CD3 through specific mutations in CDR sequences, allowing for reduced or increased binding affinity while maintaining cytotoxic activity, and the creation of bispecific antibodies for targeted tumor cell killing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high affinity CD3 antibodies are used, then cytotoxic activity is improved, but adverse effects such as cytokine storm and immunogenicity increase
Solution Approach 1:
The patent applies parameter changes by systematically varying the affinity of the CD3 binding arm across multiple orders of magnitude (from 10^-9 M to 10^-6 M KD values). This is achieved through site-directed mutagenesis of the VH region CDR sequences, creating a series of antibody variants with progressively reduced affinity. The result is that therapeutic efficacy is maintained while adverse effects are minimized, as the reduced affinity prevents excessive T cell activation and cytokine release.
Solution Approach 2:
The patent employs partial action by using only the portion of T cell activation necessary for therapeutic efficacy while avoiding excessive activation that leads to adverse effects. By reducing the affinity below the level that causes full T cell engagement and cytokine storm, the antibody achieves a partial activation state that is sufficient for tumor cell killing but insufficient to trigger severe immune responses.
2Reliability
If high affinity CD3 antibodies are used, then T cell binding is improved, but interference with normal T cell immune responses increases
Solution Approach 1:
The patent changes the affinity parameter to a level that allows selective T cell binding. The reduced affinity (KD values from 10^-9 M to 10^-6 M) enables the antibody to bind T cells in the context of tumor antigen presentation while allowing normal T cell function to proceed in the absence of such presentation. This parameter optimization resolves the contradiction between achieving sufficient binding for therapy and preserving normal immune adaptability.
3Reliability
If mouse/rat hybrid antibodies are used, then cytotoxic activity is improved, but immunogenicity increases
Solution Approach 1:
The patent changes the structural composition parameter by transitioning from mouse/rat hybrid antibodies to fully humanized or chimeric formats. This fundamental parameter change eliminates the immunogenicity issue inherent in non-human antibody structures while maintaining the desired cytotoxic activity through optimized CD3 binding affinity in the humanized variable regions.
Data Source
AI summary
The present invention relates to humanized or chimeric antibodies binding CD3. It furthermore relates to bispecific antibodies, compositions, pharmaceutical compositions, use of said antibodies in the treatment of a disease, and method of treatment.