Trimeric Scaffold Fusion Protein for Therapeutic Polypeptide Half-Life Extension
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Therapeutic polypeptides face challenges with short in vivo half-life due to rapid renal clearance and enzymatic degradation, and existing methods like PEGylation can reduce biological activity and increase production costs, while fusion with IgG Fc or HSA requires expensive eukaryotic expression systems.
Innovation Solution
A fusion protein is created by combining a therapeutic polypeptide with a trimeric scaffold protein and one or more flexible unstructured polypeptide sequences, which increases the apparent molecular weight and extends half-life, using a proteinous connecting moiety like the human Fibronectin type III domain, and the pCloud polypeptide derived from human fibrinogen alpha chain to enhance stability and solubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If PEGylation is used to extend the half-life of a therapeutic polypeptide, then the retention time in blood is improved, but the biological activity reduces by 20-50 fold
Solution Approach 1:
The patent introduces a trimeric scaffold protein as an intermediary carrier to extend the half-life of therapeutic polypeptides. Unlike PEGylation which directly modifies the therapeutic protein, the scaffold protein serves as a separate entity that binds multiple polypeptides, providing extended circulation time while preserving the native structure and activity of the therapeutic agents through non-covalent interactions.
Solution Approach 2:
The invention creates a composite structure where a trimeric scaffold protein forms a complex with multiple therapeutic polypeptides. This composite assembly combines the long circulation properties of the scaffold (formed by three interconnected subunits) with the therapeutic functions of the bound polypeptides, achieving both extended half-life and preserved biological activity.
2Stability of the object's composition
If PEGylation is applied to increase drug stability, then the pharmacokinetic behavior is improved, but the production cost increases due to complex purification
Solution Approach 1:
The trimeric scaffold protein acts as an intermediary that simplifies the overall manufacturing process. By using a stable, well-characterized scaffold with defined binding properties, the system avoids the complex heterogeneous mixtures produced by PEGylation, enabling simpler purification steps and more consistent quality control while maintaining drug stability.
3Duration of action of stationary object
If fusion with IgG Fc fragment or HSA is used to increase half-life, then the in vivo residence time is extended, but the production cost significantly increases due to requirement of eukaryotic expression systems
Solution Approach 1:
The patent employs a simplified protein scaffold that can be produced in inexpensive prokaryotic expression systems rather than costly eukaryotic systems. This approach uses a more economical production platform (prokaryotic cells) to create the half-life extending scaffold, significantly reducing manufacturing costs while achieving the same pharmacokinetic benefits.
Solution Approach 2:
The invention extracts only the essential functional elements needed for half-life extension, creating a minimal trimeric scaffold structure that performs the pharmacokinetic enhancement function without requiring the complex post-translational modifications and processing capabilities of eukaryotic systems. This extracted, simplified version can be produced in cheaper prokaryotic systems.
4Duration of action of stationary object
If the apparent molecular weight is increased to extend half-life, then the renal clearance is reduced, but the biological activity may be compromised due to steric hindrance
Solution Approach 1:
The therapeutic complex is segmented into distinct functional components: a trimeric scaffold that provides molecular weight and circulation time, and separate bound polypeptides that retain their native structures and biological activities. This segmentation allows the scaffold to extend half-life through increased size while the individual therapeutic polypeptides remain structurally independent and functionally active.
Solution Approach 2:
The trimeric scaffold serves as an intermediary that increases the apparent molecular weight of the complex to reduce renal clearance, while its binding mode preserves the native conformation and activity of the therapeutic polypeptides. The scaffold mediates between the need for size extension and the need to maintain biological function through specific binding interactions.
Data Source
AI summary
The present invention provides a fusion protein comprising a therapeutic polypeptide fused to one or more flexible unstructured polypeptides and a trimeric scaffold protein. The flexible unstructured polypeptide sequence within the fusion protein is exhibited as one or more pCloud sequences derived from human fibrinogen alpha chain, and may be flanked by a proteinous connecting moiety of human origin. Also provided are pharmaceutical compositions comprising the fusion protein, nucleic acid molecules encoding the fusion protein, vectors containing the nucleic acids, host cells transformed with the vectors, and methods of making the fusion proteins of the invention, and use thereof.