Single-Chain T Cell Engager scFab scFv Architecture

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Solution Overview

Problem

There is a need for bispecific T cell engager (TCE) molecules that bind a target antigen and CD3, demonstrating increased lysis of target cells and improved manufacturing properties such as higher aggregation temperatures and steeper HIC elution peak slopes.

Innovation Solution

The development of single-chain TCE molecules with an scFab that binds a tumor antigen and an scFv that binds CD3, some of which also include an scFc to extend the molecule's half-life, along with CCR8 TCE molecules that specifically target CCR8 and CD3.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional BiTE molecules are used, then T cell activation against target cells is achieved, but the lysis efficiency of target cells is insufficient and manufacturing properties are suboptimal

Engineering Contradiction:

Improvelysis efficiency of target cellsVSAvoidmanufacturing properties

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the antibody structure into separate domains (scFab and scFv) connected by linkers, creating modular single-chain TCE molecules. This segmentation allows independent optimization of antigen-binding (scFab) and T cell engagement (scFv) functions, improving both lysis efficiency and manufacturing characteristics through domain-specific engineering

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent systematically varies linker lengths, compositions, and positions between scFab and scFv domains to optimize molecular properties. By changing physical parameters such as linker flexibility and length, the invention achieves improved target cell lysis efficiency while simultaneously enhancing manufacturing properties including aggregation temperature and chromatography behavior

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If full-length bispecific antibodies are used, then dual antigen binding capability is achieved, but the molecular complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvedual antigen binding capabilityVSAvoidmolecular structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the Fc region from full-length antibodies, retaining only the essential antigen-binding Fab regions as scFab and scFv domains. This extraction eliminates unnecessary molecular complexity while preserving the critical dual antigen-binding capability, simplifying the overall molecular structure for easier manufacturing

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the variable and constant domains of heavy and light chains into single continuous polypeptide chains (scFab and scFv). This merging simplifies the molecular architecture by eliminating separate chain assemblies while maintaining the dual antigen-binding function through strategic domain connectivity via linkers

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If short half-life TCE molecules are used, then rapid clearance is achieved, but the therapeutic duration and efficacy are reduced

Engineering Contradiction:

Improveclearance rateVSAvoidhalf-life of TCE molecule

Core Design Contradiction:

ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent designs the scFab domain to serve multiple functions: maintaining antigen-binding specificity while also providing a platform for optional Fc region attachment. When Fc is added, it imparts both extended half-life through reduced clearance and potential effector functions, making the molecule multi-functional without compromising the core T cell engagement mechanism

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250129160A1T cell engager molecules and uses thereof

Publication Date: 2025.04.24 AMGEN RESEARCH (MUNICH) GMBH

AI summary

The present invention provides single chain T cell engager (TCE) molecules having an scFab that binds a target antigen and an scFv that binds CD3, and TCE molecules that bind CCR8 and CD3. Methods of treating cancer are also provided.