Modular Scaffolds for Bispecific Antibody Assembly

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Solution Overview

Problem

Current methods for producing bispecific antibodies face challenges in manufacturability, immunogenicity, and pharmacokinetic properties, such as high immunogenicity, short serum half-life, and loss of Fc effector functions, due to non-natural structures and heavy- and light-chain mispairing in scFv formats, limiting their therapeutic potential.

Innovation Solution

A eukaryotic expression system is developed to select modular scaffolds with desired attributes, such as expressibility and binding affinity, using N-terminus-occupied functional single domain protein scaffolds fused to the C-terminus of existing antibodies, allowing for the generation of bispecific functional agents with improved properties like low immunogenicity and long half-life, using yeast surface display and mutagenesis techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If scFv-based formats are used to generate bispecific antibodies, then binding specificity to target antigens is improved, but heavy- and light-chain mispairing occurs leading to reduced manufacturing purity

Engineering Contradiction:

Improvebinding specificityVSAvoidpururity

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent divides the antibody structure into separate single-chain variable fragments (scFv) that can be independently selected and combined. By using phage display technology to screen for specific scFv combinations, the invention achieves precise binding specificity while avoiding mispairing issues through controlled assembly of pre-selected fragments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses phage display technology as an intermediary system to select and validate scFv combinations before production. This intermediary screening process ensures that only correctly paired, high-specificity combinations are advanced to manufacturing, eliminating mispairing problems at the source.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If non-natural structures are used in bispecific antibodies, then dual target binding capability is improved, but immunogenicity increases

Engineering Contradiction:

Improvedual target binding capabilityVSAvoidimmunogenicity

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses homogeneous IgG framework regions from human antibodies to construct the bispecific format. By maintaining the natural human IgG structure and using identical framework sequences throughout, the invention achieves dual target binding while minimizing immunogenicity through structural homogeneity with endogenous human proteins.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent creates a composite antibody structure by combining scFv fragments with IgG framework regions. This composite design allows dual target binding capability while the IgG framework provides a natural, low-immunogenicity backbone that mimics endogenous human antibodies.

Inventive Principle:

Principle #40Composite materials

3Reliability

If traditional bispecific antibody formats are used, then therapeutic index is improved, but serum half-life is shortened due to loss of Fc effector functions

Engineering Contradiction:

Improvetherapeutic indexVSAvoidserum half-life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent merges the scFv binding specificity with the intact IgG Fc region in a single molecular construct. By combining the target-binding scFv fragments with the full IgG framework including Fc domains, the invention simultaneously achieves dual target binding capability and retains Fc-mediated effector functions that extend serum half-life.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The IgG framework region serves multiple functions simultaneously: it provides structural stability, enables Fc receptor binding for effector functions, and facilitates complement activation. This multi-functional IgG backbone supports the bispecific scFv fragments while extending serum half-life through natural Fc-mediated mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If chemical cross-linking methods are used to generate bispecific antibodies, then dual specificity is achieved, but manufacturing complexity and aggregation increase

Engineering Contradiction:

Improvedual specificityVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the complexity of bispecific assembly by separately selecting scFv fragments through phage display and then combining them with IgG frameworks in controlled recombinant expression systems. This extraction of the pairing problem into a pre-screening step eliminates the need for complex chemical cross-linking procedures during manufacturing.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS10968444B2Methods for generating bispecific functional agents

Publication Date: 2021.04.06 ABZYME THERAPEUTICS LLC

AI summary

The present invention provides a method for preparing a modular scaffold that can bind to a target antigen and a method for engineering a bispecific functional agent consisting of an existing polypeptide binder fused at its C-terminus with said modular scaffold.