Fibrin-Binding uPA Polypeptide for Targeted Clot Dissolution

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Solution Overview

Problem

Current thrombolytic agents like rtPA are unstable, difficult to produce, and can cause systemic side effects due to nonspecific binding, while broad thrombin inhibitors affect multiple coagulation processes, leading to complications such as bleeding and reduced effectiveness.

Innovation Solution

A novel polypeptide comprising a fibrin-binding domain derived from a llama antibody (VHH) and a urokinase-type plasminogen activator (uPA) domain, specifically targeting fibrin for localized clot degradation, enhancing stability and specificity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If recombinant tissue plasminogen activator (rtPA) is used as a thrombolytic agent, then clot dissolution efficacy is improved, but stability and ease of production deteriorate

Engineering Contradiction:
Improveclot dissolution efficacyVSAvoidease of production
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention segments the thrombolytic function from the complex rtPA structure by using a simplified uPA domain combined with a fibrin-binding VHH domain. This segmentation maintains clot dissolution efficacy through the uPA-plasminogen activation pathway while eliminating the production difficulties associated with full-length rtPA's complex structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts only the essential functional domains needed for thrombolysis: the catalytic uPA domain for plasminogen activation and the fibrin-targeting VHH domain for localization. This extraction removes the unstable and difficult-to-produce portions of rtPA while retaining therapeutic efficacy.

Inventive Principle:
Principle #2Taking out (Extraction)

2Object-affected harmful factors

If broad thrombin inhibitors are used to prevent clotting, then clot formation is reduced, but bleeding risk and effectiveness deteriorate

Engineering Contradiction:
Improveclot formationVSAvoidbleeding risk
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The invention applies local quality by directing the thrombolytic action specifically to the clot site through the fibrin-binding VHH domain. The uPA-fibrin complex locally activates plasminogen to plasmin at the thrombus location, dissolving clots without systemically inhibiting coagulation pathways, thereby avoiding bleeding complications.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses the fibrin-binding VHH domain as an intermediary that delivers the uPA catalyst specifically to the fibrin clot. This targeted delivery mechanism ensures that plasminogen activation occurs only at the clot site rather than throughout the bloodstream, preventing systemic anticoagulation and bleeding risks.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If thrombin generation is broadly monitored in plasma, then coagulation process estimation is improved, but specificity for localized clot dissolution deteriorates

Engineering Contradiction:
Improvecoagulation process estimationVSAvoidspecificity for localized action
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The invention transitions from broad plasma-based thrombin generation monitoring to localized clot-targeted therapy. The VHH-uPA fusion protein specifically binds to fibrin at the clot site, delivering thrombolytic activity locally rather than systemically, thereby achieving both measurement precision in identifying clot presence and localized action for dissolution.

Inventive Principle:
Principle #3Local quality

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 polypeptide achieves efficient and targeted clot dissolution with minimal systemic effects, maintaining hemostatic balance and reducing the risk of bleeding, while being easier to produce and more stable than rtPA.

Implementation Method 1

an immunoglobulin single variable domain able to bind to fibrin

Methodology Applied
Scientific EffectMolecular binding: Adsorption

Implementation Method 2

a urokinase-type plasminogen activator (uPA) domain

Methodology Applied
Scientific EffectEnzyme catalysis: Enzyme

Data Source

PatentEP4644415A1Anti-fibrin agent
Publication Date: 2025.11.05 SYNAPSE INC
  • EP4644415A1 patent drawingFigure 1A~1F(iii)
  • EP4644415A1 patent drawingFigure 2A(i)~3F
  • EP4644415A1 patent drawingFigure 4A(i)~4C(iii)

AI summary

The current invention relates to a polypeptide comprising an immunoglobulin single variable domain and an urokinase-type plasminogen activator (uPA) domain wherein the immunoglobulin single variable domain is able to bind to fibrin via a fibrin-binding domain.