Fc Variants With Heterodimeric Mutations for Enhanced Antibody Binding
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Solution Overview
Problem
There is a need for therapeutic monoclonal antibodies with enhanced effector functions such as ADCC, CDC, and ADCP, as existing antibodies may not effectively interact with FcγRs to induce these cytotoxic activities, particularly in cancer treatment.
Innovation Solution
Development of heterodimeric Fc-containing proteins with specific amino acid substitutions in the Fc region that enhance binding to FcγRIIIA, including combinations like K392D and K409D, E356K, and D399K, which improve the affinity and efficacy of ADCC and ADCP activities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild type human IgG Fc region is used, then the protein structure is simple and easy to manufacture, but the binding affinity to FcγRIIIA is insufficient and effector functions are weak
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid substitutions (K392D, K409D, E356K, D399K) in the Fc region to alter its binding parameters. These substitutions change the electrostatic properties and surface characteristics of the Fc region, enabling enhanced affinity for FcγRIIIA receptors while maintaining the overall IgG structure and manufacturability.
Solution Approach 2:
The patent creates a composite Fc region by combining multiple amino acid substitutions within the heterodimeric structure. The A chain and B chain are engineered with complementary mutations that work synergistically - the charge pair mutations (K392D/K409D in one chain, E356K/D399K in the other) create a composite interface that dramatically enhances FcγRIIIA binding compared to wild type.
2Reliability
If heterodimeric Fc region with multiple amino acid substitutions is introduced, then effector function is enhanced, but the manufacturing complexity and production difficulty increase
Solution Approach 1:
The patent segments the Fc region into two distinct polypeptide chains (A chain and B chain) with different amino acid sequences. This segmentation allows independent optimization of each chain - the A chain can carry specific mutations (e.g., K392D, K409D) while the B chain carries complementary mutations (e.g., E356K, D399K), enabling controlled heterodimer formation with enhanced effector functions while facilitating modular manufacturing.
Solution Approach 2:
The patent applies local quality by introducing mutations only in specific regions of the Fc region (primarily in the CH3 domain at positions 392, 409, 356, and 399) rather than throughout the entire protein. This localized modification approach enhances effector functions through improved FcγR binding while minimizing impacts on other functional regions and maintaining overall protein stability and manufacturability.
3Reliability
If charge pair mutations (K392D/K409D and E356K/D399K) are introduced to enhance FcγRIIIA binding, then ADCC activity increases, but the protein may have reduced stability or increased aggregation
Solution Approach 1:
The patent introduces asymmetry through charge pair mutations where one chain (A or B) contains K392D and K409D while the other chain contains E356K and D399K. This asymmetric arrangement creates complementary electrostatic interactions at the Fc-FcγRIIIA interface, enhancing binding affinity and ADCC activity. The symmetric heterodimeric structure (A chain with B chain) maintains overall stability while the asymmetric mutations provide the enhanced functional properties.
Data Source
AI summary
Disclosed are Fc-containing proteins comprising a binding region and a variant Fc region that can elicit one or more immune effector function and/or bind to an Fc receptor more effectively than a similar Fc-containing protein comprising a wild type Fc region. Also disclosed are nucleic acids encoding such Fc-containing proteins, methods for making such proteins, and methods of treatment utilizing such proteins.