Patent: 7,547,435

Summary for Patent: 7,547,435

Title:	Pharmacological vitreolysis
Abstract:	Methods of treating or preventing a disorder, or a complication of a disorder, of an eye of a subject, comprising contacting a vitreous and/or aqueous humor with a composition comprising a truncated form of plasmin comprising a catalytic domain of plasmin (TPCD) are disclosed. TPCDs include, but are not limited to, miniplasmin, microplasmin and derivatives and variants thereof. The methods of the invention can be used to reduce the viscosity of the vitreous, liquefy the vitreous, induce posterior vitreous detachment, reduce hemorrhagic blood from the eye, clear or reduce materials toxic to the eye, clear or reduce intraocular foreign substances from the eye, increase diffusion of a composition administered to an eye, reduce extraretinal neovascularization and any combinations thereof. The method can be used in the absence of, or as an adjunct to, vitrectomy.
Inventor(s):	Pakola; Steve (Sleepy Hollow, NY), De Smet; Marc (Amstelveen, NL)
Assignee:	ThromboGenics NV (Leuven, BE)
Application Number:	10/729,475
Patent Claims:	see list of patent claims

Critical analysis of US Patent 7,547,435: microplasmin vitreous liquefaction and posterior vitreous detachment claims

US 7,547,435 claims methods that use intravitreal microplasmin to liquefy vitreous and/or induce posterior vitreous detachment (PVD). The claims are drafted around (i) the biological target outcome (vitreous liquefaction/PVD), (ii) the active (microplasmin with defined variants), and (iii) delivery and use conditions (liquid injection, human use, dose window, and use with or without non-pharmacologic vitrectomy). The estate is conceptually coherent but the claim breadth creates both enforcement leverage (clear outcome-based method steps tied to microplasmin contact) and vulnerability (prior art and design-around options around product attributes, administration sequence, and what constitutes “effective amount” or “contacting” under claim construction).

This analysis breaks down each claim theme, maps likely patent-landscape interactions, and identifies enforcement and generic/biologic risk factors relevant to US litigation and FDA commercialization strategy.

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What does US 7,547,435 claim, in plain legal terms?

Answer: A method claim set covering intravitreal microplasmin administration to achieve vitreous liquefaction and/or posterior vitreous detachment, including therapeutic indications in vitreoretinal disease contexts and procedural use tied to vitrectomy timing.

Core independent claim architecture

US 7,547,435 contains three independent method groupings, with dependent claims that narrow variations:

1. Liquefying vitreous and/or inducing PVD using microplasmin (Claim 1).
2. Treating vitreoretinal disease/disorder or complication by achieving vitreous liquefaction/PVD with microplasmin (Claim 9).
3. Performing a vitrectomy by contacting the vitreous/aqueous humor with microplasmin prior to or at the same time as vitreous removal (Claim 16).

Common claim prerequisites

Across claims 1, 9, and 16, the repeated elements are:

• “Contacting the vitreous and/or aqueous humor” with a composition comprising microplasmin.
• The method must “result in” vitreous liquefaction and/or PVD.
• Microplasmin variant options: recombinant microplasmin, stabilized microplasmin, stabilized recombinant microplasmin (Claims 2/10/17).
• Delivery form: liquid solution injected into vitreous and/or aqueous humor (Claims 3/11/18).
• Human use: subject is human (Claims 4/12/19).
• Dose window: 0.005 mg to 0.2 mg per eye (Claims 8/15/20).
• Vitrectomy relationship:
  • in absence of non-pharmacological vitrectomy (Claims 6/13)
  • as adjunct to vitrectomy (Claims 7/14)
  • contacting prior to or at the same time as vitreous removal (Claim 16)

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What is the claim scope for “contacting vitreous and/or aqueous humor” and “wherein the method results”

Answer: The claims are tied to an intravitreal contact-and-outcome linkage, making them outcome-enforcing but also subject to disputes over what constitutes “contact,” what “results in” requires, and how timing/dosing affects causation.

“Contacting” scope: injection vs other delivery modes

Dependent claims explicitly define contacting via injecting a liquid solution into vitreous and/or aqueous humor (Claims 3/11/18). That suggests the specification supports injection as the primary embodiment. However, Claim 1/9/16 are not limited to injection unless the dependent narrowing is asserted, so “contacting” could be argued broadly as any administration that achieves microplasmin presence in the vitreous/aqueous compartment.

Enforcement implication: If a competitor administers microplasmin via a method that still achieves intraocular exposure but differs from “injecting,” the literal “injecting” limitations may be avoided, but the broader “contacting” language could still capture the method if the product demonstrably reaches vitreous/aqueous compartments.

Outcome language: “liquefying” and “posterior vitreous detachment”

The claims require the method to result in:

• vitreous liquefaction, and/or
• posterior vitreous detachment.

This is a strong enforcement hook because it ties the method to measurable clinical/structural endpoints (e.g., imaging-confirmed PVD). It is also a likely litigation focal point because proving “results in” can be disputed:

• Is partial liquefaction enough?
• Must PVD be complete?
• Is historical background PVD incidence sufficient to negate causation?
• Does the claim require that microplasmin be the causal agent?

Design-around lever: A challenger can argue that their regimen does not reliably induce the claimed outcomes at the claim level, even if it includes microplasmin contact.

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Which microplasmin variants are covered, and how does that affect product design?

Answer: The claims cover recombinant and stabilized microplasmin forms, including stabilized recombinant microplasmin, limiting easy substitutions if those variants are used by competitors.

Covered variant group

Claims 2, 10, and 17 restrict microplasmin selection to:

• recombinant microplasmin
• stabilized microplasmin
• stabilized, recombinant microplasmin

This triad is intended to block substitutes that are “microplasmin” but presented in an engineered or formulation-stabilized form. It also captures typical commercial framing used for protein therapeutics where stabilization affects shelf-life and activity.

Design-around lever: A competitor could attempt to use:

• a different protease,
• an alternative form not characterized as “microplasmin,” or
• a microplasmin analog that avoids being characterized as stabilized recombinant or stabilized microplasmin under the patent’s definitions (which in practice hinge on claim construction and specification definitions).

Because the dependent claims include variant-by-variant selection, litigation will likely focus on whether the accused product falls within the defined variant categories.

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What do the dose and formulation limitations do to enforceability?

Answer: The dose window (0.005 to 0.2 mg per eye) and “liquid solution injected” language can narrow infringement proof, but they also create a litigation measurement target.

Dose window (0.005 mg to 0.2 mg per eye)

Claims 8/15/20 specify an effective amount range. If an accused regimen uses:

• less than 0.005 mg,
• more than 0.2 mg,
• a different per-eye calculation (e.g., due to injection volume assumptions), then non-infringement arguments can be framed on range.

Enforcement implication: If the commercial product dose is engineered to sit just outside the range, the patentee’s claims may still be enforced via broader claims that do not require the range (Claim 1 and 9 and 16, without dependent dose limitation). But in practice, infringement often proceeds on the best-fitting dependent claim set, especially where the specification describes that window as the operative “effective amount.”

Liquid solution injection limitation

Claims 3/11/18 require “liquid solution” and “injecting” in the dependent layers. If a competitor’s delivery differs materially (cartridge system, depot, sustained-release format, or ex vivo contact), the “injecting” dependent limitation may not be met. But again, Claim 1/9/16 are not expressly injection-limited unless the dependent claim is asserted.

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How do the vitrectomy relationship limitations shift infringement risk?

Answer: Claims create alternative theories: treatment without vitrectomy, treatment as adjunct to vitrectomy, and use timing relative to vitreous removal. This reduces the ability to avoid by steering clinicians toward a different procedural pathway.

Absence of non-pharmacological vitrectomy (Claims 6/13)

These dependent limitations target a regimen used without non-pharmacological vitrectomy. If a competitor’s label or real-world use always includes vitrectomy (phaco + vitrectomy style pathways), an accused activity may argue it does not satisfy the “absence” condition.

Adjunct to vitrectomy (Claims 7/14)

This covers use where microplasmin is used alongside vitrectomy. That captures the common clinical workflow where pharmacologic vitreolysis is used to facilitate surgical outcomes or reduce surgical complexity.

Timing tied to removal (Claim 16)

Claim 16 is procedural. It requires microplasmin contacting prior to or at the same time as removal. That blocks a key “timing” design-around: using microplasmin earlier and then waiting a period so it is not “prior to or at the same time.” Whether “prior to or at the same time” is construed as strict temporal proximity depends on how the specification supports the timing and what the litigation record shows.

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What does the disease-treatment claim add, beyond the outcome method?

Answer: Claim 9 converts the vitreolysis/PVD outcome into a therapeutic method for vitreoretinal disease/disorder or complications.

How the “disease or complication” element expands or complicates litigation

Compared with Claim 1, Claim 9 adds:

• “treating a vitreoretinal disease or disorder, or a complication … of a vitreoretinal disease or disorder”

This element can increase relevance for clinical documentation and real-world evidence, but it also adds a second causation chain:

1. microplasmin contact must cause vitreous liquefaction/PVD, and
2. that outcome must treat the named clinical condition/complication.

Enforcement implication: If accused use is off-label or for a different indication not constituting “vitreoretinal disease or disorder” within the claim’s scope, infringement arguments become harder. If the disease set is broad in the specification, the patentee’s burden can remain manageable.

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What likely prior art pressure exists for microplasmin vitreolysis/PVD methods?

Answer: Microplasmin-based pharmacologic vitreolysis has longstanding scientific positioning in the US vitreoretinal space. That history creates validity risk around obviousness and enablement for method claims that are largely outcome driven and routine in administration once microplasmin is recognized as a vitreous liquefying agent.

Likely validity pressure points (claim-type dependent)

1. Outcome-driven broad methods (Claims 1/9/16)
   If prior art teaches administering microplasmin intravitreally to induce liquefaction/PVD, then the novelty may hinge on dose, formulation stability, variant identity, or specific clinical workflow constraints.

2. Dose window dependence (Claims 8/15/20)
   If prior art doses overlap or suggest titration within this window, the range may be treated as a routine optimization rather than a patentable boundary.

3. Adjunct or “prior to or at the same time” timing (Claims 7/14/16)
   If surgical adjunct use is already described, this may be obvious. If not, this timing language can be a stronger differentiator.

4. “Absence of non-pharmacological vitrectomy” (Claims 6/13)
   This is likely more niche, but if prior art describes non-vitrectomy pharmacologic vitreolysis, it will not differentiate.

Critical lens: US method patents that focus on intravitreal protein delivery and vitreous changes are vulnerable when the concept is already known and the claim distinctions are incremental (dose window, stabilization label, or procedural timing).

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Where are the strongest infringement levers and the cleanest design-arounds?

Answer: The strongest levers are microplasmin identity, intravitreal contact, and clinically observable PVD/liquefaction outcomes. The cleanest design-arounds center on avoiding one of the required elements in a dependent-claim pathway: dose range, delivery mode “injecting liquid solution,” and timing/adjunct conditions.

Strongest levers

• Microplasmin as the active (variant group captured in dependent claims).
• Intraocular compartment contact (vitreous/aqueous).
• Outcome requirement (liquefaction and/or PVD).
• Human administration (though this is typically not a hard design-around).

Cleanest design-arounds (strategy-level)

• Dose outside 0.005–0.2 mg per eye and asserting dependent dose claim non-infringement.
• Alternate delivery form that is not a “liquid solution” or not administered by “injecting” if dependent delivery limitations are asserted.
• Timing separation from “prior to or at the same time” for Claim 16 if asserted for vitrectomy facilitation.
• Procedural routing that avoids “absence of non-pharmacological vitrectomy” when Claims 6/13 are asserted, or aligns fully with vitrectomy so Claim 6/13 is not met.

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How does this patent likely interact with the microplasmin commercial and FDA landscape?

Answer: This patent’s claim themes align with pharmacologic vitreolysis product strategies in the US: intravitreal microplasmin to induce PVD. The most likely commercial interaction is whether an existing or developing microplasmin product is marketed for vitreolysis and PVD induction, and whether competing products seek to enter by arguing non-infringement based on dose, formulation, or procedural framing.

Practical litigation triggers

• Label indication mapping: whether marketed use tracks Claim 9 disease/complication language.
• Commercial dosing compliance: whether the approved regimen falls within the 0.005–0.2 mg per eye window.
• Real-world administration method: whether the delivery is injection of a liquid solution.
• Procedure playbook: whether use is positioned as vitrectomy adjunct or non-vitrectomy pharmacologic vitreolysis.

Because the claims are method-oriented, litigation often centers on medical practice and product administration documents rather than only on product manufacturing.

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What is the patent strength profile for US 7,547,435 as an enforcement asset?

Answer: Moderate-to-high enforcement potential against microplasmin intravitreal vitreolysis competitors, with meaningful validity risk for broad outcome-driven method claims.

Strength factors

• Narrow biological mechanism anchored in microplasmin.
• Clear anatomic contact (vitreous/aqueous).
• Measurable clinical outcomes (liquefaction/PVD).
• Dose and delivery constraints provide multiple dependent claim ladders.

Weakness factors

• Outcome-based method claims can be obvious if prior art already teaches microplasmin-induced vitreous liquefaction/PVD.
• “Effective amount” and overlapping dose prior art can undermine the novelty of the dose range.
• Timing/workflow limitations may not be sufficient if surgical adjunct use is already disclosed in prior art.
• Claim causation disputes: “wherein the method results” invites arguments over causality and baseline PVD progression in the treated population.

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Claim-by-claim critical assessment (what must be proven)

Claims 1 and 9: independent outcome methods

• Claim 1 requires: microplasmin contact + vitreous liquefaction and/or PVD result.
• Claim 9 adds: treat vitreoretinal disease/disorder or complication, tethered to that same outcome.

Proof focus in infringement: medical evidence, imaging outcomes, dosing regimen, and documentation that the regimen used microplasmin rather than an analog.

Dependent claim narrowing ladders

• Claims 2/10/17: microplasmin variant category
• Claims 3/11/18: liquid solution injection into vitreous/aqueous
• Claims 4/12/19: human subject
• Claims 5: vitreoretinal disease/disorder use framing (Claim 1 version lacks explicit disease text but Claim 9 does; here Claim 5 depends on Claim 1)
• Claims 6/13 and 7/14: procedural condition relative to vitrectomy
• Claims 8/15/20: dose range
• Claim 16: vitrectomy procedural timing

Proof focus in invalidity: prior art that discloses intravitreal microplasmin inducing PVD and vitreous liquefaction, including dosing and clinical workflow.

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Key Takeaways

• US 7,547,435 is a method patent centered on intravitreal microplasmin to induce vitreous liquefaction and posterior vitreous detachment.
• The claims provide multiple enforceable “ladders” via dependent limitations on microplasmin variant, dose (0.005–0.2 mg per eye), formulation delivery (liquid solution injection), and vitrectomy workflow/timing.
• The main vulnerability is validity pressure against broad, outcome-driven method claims if earlier art already taught microplasmin vitreolysis and PVD induction in the US.
• For design-around, the most actionable levers are dose window avoidance, delivery mode change away from “liquid solution injecting,” and timing alignment for vitrectomy facilitation.

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FAQs

1) What is the most litigated claim element in microplasmin vitreolysis patents: microplasmin identity or the outcome (PVD/liquefaction)?
The outcome element typically drives medical-evidence battles, but microplasmin identity and intravitreal exposure are usually the first infringement filters.

2) How does changing the microplasmin form affect infringement risk under this patent?
If the competitor’s product is categorized as recombinant and/or stabilized microplasmin, the dependent variant claims tighten. A form that avoids the claim’s variant definitions can be a design-around route, subject to claim construction.

3) Can a competitor avoid infringement by using a dose outside 0.005–0.2 mg per eye?
It can defeat dependent dose claims (8/15/20), but broader independent claims (1/9/16) may still capture an “effective amount” if the range is not required and the regimen still achieves liquefaction/PVD.

4) What procedural positioning matters most: adjunct to vitrectomy or non-vitrectomy treatment?
Dependent “absence” and “adjunct” claims create branching infringement theories. Clinical workflow alignment to avoid one branch can reduce likelihood of meeting those dependent limitations.

5) What is the main risk for a competitor who labels their use differently from the claim’s disease-treatment framing?
Label and off-label evidence can matter in method-treatment claims. If the real-world indication maps onto “vitreoretinal disease or disorder or a complication,” label differences may not fully protect.

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References

No sources were provided for the bibliographic record, file history, prosecution documents, examiner statements, or any Orange Book or litigation docket entries tied to US 7,547,435. As a result, no external citations can be correctly attributed to support an analysis with patent-number-specific accuracy.

Details for Patent 7,547,435

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Thrombogenics Inc.	JETREA	ocriplasmin	Injection	125422	February 22, 2017		2023-12-05
Thrombogenics Inc.	JETREA	ocriplasmin	Injection	125422	October 17, 2012		2023-12-05

International Patent Family for US Patent 7,547,435

Country	Patent Number	Estimated Expiration
South Africa	200505193
World Intellectual Property Organization (WIPO)	2004052228
United States of America	2005118158