Heterodimeric IgG1 Charge Engineering for Homodimer Separation
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Solution Overview
Problem
Existing methods for producing heterodimeric antibodies result in significant production of undesirable homodimers, necessitating difficult purification steps, and there is a need to extend the serum half-life of antibodies by altering the constant domains without affecting antigen binding affinity or immunogenicity.
Innovation Solution
Engineering heterodimeric antibodies with variant heavy and light chain constant regions that have isoelectric points (pIs) at least 0.5 logs apart, allowing for purification by charge-based methods and reducing immunogenicity through the use of human sequence content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to produce heterodimeric antibodies, then production is straightforward, but significant amounts of undesirable homodimers are produced requiring difficult purification steps
Solution Approach 1:
The patent introduces asymmetric modifications to specific regions of the heavy chains (different constant regions in different positions) to create local differences in charge properties. This allows the heterodimer to have a distinct isoelectric point from homodimers, enabling charge-based purification and resolving the contamination issue while maintaining high productivity
Solution Approach 2:
The patent modifies the isoelectric point parameter of the antibody chains through engineered charge differences in constant regions. By changing this physical parameter, the heterodimers can be separated from homodimer contaminants using ion exchange chromatography or other charge-based methods, eliminating the need for difficult purification steps
2Ease of manufacture
If purification steps are simplified, then manufacturing becomes easier, but separation of heterodimers from homodimers becomes more difficult
Solution Approach 1:
The patent engineers charge differences in constant regions to create distinct isoelectric points for heterodimers versus homodimers. This parameter change enables simple charge-based purification methods (ion exchange chromatography) to achieve high separation precision, making the manufacturing process easier while maintaining the ability to cleanly separate antibody species
3Duration of action of stationary object
If constant regions are modified to extend serum half-life, then pharmacokinetic properties improve, but immunogenicity may increase
Solution Approach 1:
The patent introduces modifications at specific local positions within the constant regions rather than extensive changes. By making targeted, localized modifications to amino acid sequences, the patent extends serum half-life through improved FcRn binding while minimizing overall sequence changes, thereby reducing the risk of immunogenicity
Solution Approach 2:
The patent modifies specific parameters of the constant regions (amino acid composition, charge distribution) to enhance FcRn binding affinity and extend serum half-life. These controlled parameter changes are designed to improve pharmacokinetics while maintaining structural similarity to natural antibodies, thus minimizing immunogenic responses
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables high-yield purification of desired heterodimers and extends serum half-life by altering the constant regions, minimizing immunogenicity and simplifying purification processes.
Implementation Method 1
purification by charge-based methods
Implementation Method 2
modifying the isoelectric point
Data Source
AI summary
The invention relates generally to compositions and methods for purifying the desired species from a mixture of desired heterodimer and contaminating homodimer immunoglobulin variants by modifying the isoelectric point(s) of the individual chains.