Anti-GITR Antibody Humanization via CDR Residue Mutations
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Solution Overview
Problem
Current antibody therapeutics targeting glucocorticoid-induced TNF receptor (GITR) face challenges in maintaining binding affinity and stability due to inaccurate humanization processes, leading to reduced clinical efficacy and increased immunogenicity risks.
Innovation Solution
Development of optimized anti-GITR antibodies with specific heavy and light chain variable region sequences that bind to human and cynomolgus monkey GITR, incorporating conservative substitutions and mutations to enhance binding specificity and stability, while minimizing immunogenicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If classical CDR grafting humanization is used to create anti-GITR antibodies, then immunogenicity is reduced, but binding affinity to GITR is significantly reduced
Solution Approach 1:
The patent applies parameter changes by systematically mutating specific amino acid residues in the CDR loops of the humanized anti-GITR antibody. Through site-directed mutagenesis, the inventors optimized the binding interface by changing individual residues to improve GITR binding affinity while preserving the humanized framework that reduces immunogenicity. This involved testing multiple variants and selecting those with enhanced binding characteristics.
2Reliability
If murine residues are introduced via back-mutations to restore binding affinity, then binding affinity is improved, but physical stability and immunogenicity risks increase
Solution Approach 1:
The patent applies local quality by making targeted, localized changes only at specific positions within the CDR loops that directly contact the GITR antigen. Rather than introducing widespread murine residues through back-mutations, the inventors performed site-specific mutagenesis at individual residues (e.g., positions 32, 33, 99, 100 in HCDR1) to restore binding affinity. This localized approach maintains the overall humanized structure and its associated stability and low immunogenicity while achieving the desired binding improvement.
3Reliability
If extensive CDR mutations are performed to optimize binding, then binding specificity is improved, but prediction accuracy of which residues to mutate decreases
Solution Approach 1:
The patent applies partial action by performing a limited, focused set of mutations at pre-identified key positions in the CDR loops rather than attempting to optimize all possible residues. The inventors selected specific positions based on structural analysis and prior knowledge of antigen-antibody interfaces, then tested a controlled number of variants. This approach achieved improved binding specificity without requiring exhaustive mutation screening, making the process manageable and partially predictable.
Data Source
AI summary
The invention relates to antibody molecules and antigen-binding portions thereof which bind specifically to glucocorticoid-induced TNF receptor (GITR). In particular aspects of the invention, the antibody molecules specifically bind to human GITR and cynomolgus monkey GITR. The anti-GITR antibody molecules of the invention have been developed and optimized using CDR sequences derived from a murine anti-GITR antibody 6C8. Medical uses of the antibody molecules are disclosed.