Modified von Willebrand Factor Binding
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Solution Overview
Problem
Current methods for prolonging the half-life of Factor VIII in plasma are inadequate, particularly in conditions like von Willebrand disease, where the binding affinity with von Willebrand Factor (VWF) is compromised, leading to premature catabolism and reduced efficacy in hemostasis.
Innovation Solution
A modified polypeptide comprising an amino acid sequence from the D' domain of human von Willebrand Factor with specific mutations, such as S764P/S766I, S764P/S766W, or S766Y/P769K, that binds Factor VIII with an off-rate at least 5-fold lower than the unmodified sequence, forming a stable complex to enhance its plasma residence time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional methods (PEGylation, fusion proteins, polymer attachment) are used to prolong Factor VIII half-life, then plasma residence time is extended, but binding affinity to VWF is compromised or structural complexity increases
Solution Approach 1:
The patent applies local quality by introducing specific point mutations (S764P, S766I, S766W, P769K) at targeted positions within the D' domain of VWF. These localized amino acid substitutions enhance FVIII binding affinity without modifying the entire protein structure, thereby maintaining natural VWF properties while improving half-life through strengthened VWF-FVIII interaction.
Solution Approach 2:
The patent employs parameter changes by altering the amino acid sequence parameters at specific positions (764, 766, 769) in the D' domain. These parameter modifications change the binding characteristics of VWF to FVIII, resulting in slower dissociation rates and prolonged plasma residence time of the FVIII-VWF complex without requiring PEGylation or fusion protein approaches.
2Duration of action of stationary object
If VWF multimers are used to carry FVIII, then half-life is prolonged, but in von Willebrand disease the binding affinity is reduced leading to premature catabolism
Solution Approach 1:
The patent addresses VWD-specific binding defects by applying local quality modifications at the D' domain of VWF. The targeted amino acid substitutions (S764P, S766I/W, P769K) locally enhance the binding interface between VWF and FVIII, compensating for the reduced binding affinity characteristic of von Willebrand disease and preventing premature FVIII catabolism.
Solution Approach 2:
The patent creates a stabilized VWF-FVIII complex that acts as a protective carrier system. The modified VWF serves as a durable binding platform that protects FVIII from premature degradation, effectively extending the functional lifetime of FVIII in plasma even in VWD patients where natural binding is compromised.
3Reliability
If high molecular weight VWF multimers are used, then hemostatic activity is enhanced, but binding stability with FVIII is insufficient
Solution Approach 1:
The patent applies local quality by introducing specific point mutations (S764P, S766I, S766W, P769K) at targeted positions within the D' domain of VWF. These localized amino acid substitutions enhance FVIII binding affinity without modifying the entire protein structure, thereby maintaining natural VWF properties while improving half-life through strengthened VWF-FVIII interaction.
Solution Approach 2:
The patent creates a composite VWF-FVIII complex with enhanced stability. By modifying the D' domain of VWF to have superior binding characteristics, the patent forms a more stable composite structure that maintains both the hemostatic activity of high molecular weight VWF multimers and improved binding stability with FVIII, preventing premature dissociation and catabolism.
Data Source
AI summary
The present invention provides a modified polypeptide which binds Factor VIII. The modified polypeptide comprises a sequence as shown in SEQ ID NO:3 in which the sequence comprises at least a modification at position 1 or 3 such that the modified polypeptide binds to Factor VIII with an off rate at least 5 fold lower than a reference polypeptide comprising an unmodified SEQ ID NO:3.