Microplasmin Eye Drops for Trabeculectomy Filtration Failure

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Solution Overview

Problem

Trabeculectomy surgery often results in filtration failure due to excessive scar tissue formation, leading to closure of the sclera-corneal drainage channel, which is a significant challenge in managing glaucoma and reducing intraocular pressure.

Innovation Solution

Administration of microplasmin, either as topical eye drops or via anterior chamber injection, or a combination of both, to prevent, reduce, or retard the occurrence of filtration failure by dissolving blood clots and reducing scarring processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If filtration surgery (trabeculectomy) is performed to lower intraocular pressure, then IOP reduction is achieved, but surgical failure occurs due to excessive scar tissue formation closing the drainage channel

Engineering Contradiction:
Improveintraocular pressureVSAvoidsurgical success rate
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The patent applies preliminary action by administering plasminogen activator immediately after trabeculectomy surgery to prevent clot formation and scarring processes before they can close the drainage channel. This proactive intervention targets the early postoperative period when clot formation and inflammatory responses initiate the fibrosis process that leads to filtration failure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses plasminogen activator as an intermediary substance that converts plasminogen to plasmin, which then degrades fibrin clots and prevents excessive scarring. This mediator approach allows indirect control of the fibrotic process by activating the endogenous fibrinolytic system rather than directly inhibiting fibrosis.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If anti-metabolites (mitomycin-C, 5-Fluorouracyl) are used to prevent scarring, then surgical outcome is improved, but vision-threatening complications such as scleral thinning and infections occur

Engineering Contradiction:
Improvesurgical outcomeVSAvoidscleral thinning and infections
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs plasminogen activator as a temporary, short-acting agent that exerts its fibrinolytic effect during the critical early postoperative period and then degrades. This disposable approach provides scarring prevention during the vulnerable period without the long-term toxic effects of anti-metabolites on scleral tissue.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes the chemical mechanism of anti-metabolite inhibition (which interferes with DNA synthesis and cell division) with a proteolytic mechanism (plasmin-mediated fibrin degradation). This mechanism substitution achieves scarring prevention through clot lysis rather than cytotoxic inhibition, avoiding the harmful side effects of anti-metabolites.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If TGF-β blocking is implemented to prevent fibrosis, then animal model results are promising, but clinical study shows inefficiency

Engineering Contradiction:
Improvefibrosis preventionVSAvoidclinical efficacy
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts and targets the specific pathological process of fibrin clot formation and early scarring by using plasminogen activator to degrade fibrin. Rather than broadly blocking TGF-β signaling pathways, this approach specifically removes the fibrin scaffold that supports fibroblast migration and matrix deposition, addressing the root cause of early filtration failure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the therapeutic parameter from TGF-β inhibition to fibrinolytic activation. By shifting the mechanism of action to plasmin-mediated fibrin degradation, the treatment addresses the upstream event (clot formation) that drives subsequent fibrosis, making it more effective in the clinical setting where fibrin deposition is the primary driver of early bleb failure.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If multiple post-trabeculectomy interventions are performed to rescue filtering blebs, then filtration failure is addressed, but the incidence of bleb manipulations is as high as 78%

Engineering Contradiction:
Improvefiltration functionVSAvoidnumber of interventions
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by administering plasminogen activator immediately after surgery to prevent clot formation and early scarring that would otherwise require multiple subsequent interventions. This single upfront intervention addresses the root cause of filtration failure before it develops, reducing the need for repeated bleb manipulations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful fibrin clot formation process into a benefit by using plasminogen activator to controlledly degrade fibrin. This transforms the pathological clot that would cause scarring into a controlled fibrinolytic process that prevents filtration failure, eliminating the need for multiple corrective interventions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 use of microplasmin effectively prolongs the lifespan of the sclera-corneal drainage channel post-trabeculectomy, reducing the incidence of bleb manipulations and maintaining the desired reduction in intraocular pressure, thereby improving the surgical outcome.

Implementation Method 1

Microplasmin is a recombinant protein that dissolves blood clots by degrading fibrin

Methodology Applied
Scientific EffectEnzymatic degradation: Enzyme

Data Source

PatentEP2480249B1Plasmin for the treatment of filtration failure after trabeculectomy
Publication Date: 2015.01.28 THROMBOGENICS NV
  • EP2480249B1 patent drawingFigure 1
  • EP2480249B1 patent drawingFigure 2
  • EP2480249B1 patent drawingFigure 3

AI summary

The current invention relates to the improvement of trabeculectomy surgery. The improvement more specifically resides in an extended lifetime of the sclera-corneal drainage channel created by trabeculectomy surgery. The improvement is obtained by post-surgical administration of a plasmin or active derivative thereof in the form of topical eye drops alone, by anterior chamber injection alone, or by any combination of these.