Patent: 6,090,777

Summary for Patent: 6,090,777

Title:	Method to reduce myocardial injury during acute myocardial infarction
Abstract:	A therapeutic or prophylactic treatment method of acute myocardial infarction, comprising administering exogenous C1-esterase inhibitor, alone or in combination with other drugs, to a patient with acute myocardial infarction or to a patient at risk for acute myocardial infarction. The treatment inhibits the inflammatory reaction, more specifically the activation of the complement system, which occurs in the course of acute myocardial infarction. The C1-esterase inhibitor may include C1-esterase inhibitor purified from plasma or other biological materials, or recombinant C1-esterase inhibitor, or recombinant variants derived therefrom, or recombinant constructs of other inhibitors having a specificity similar to C1-esterase inhibitor.
Inventor(s):	Hack; Cornelis Erik (Diemen, NL), Hermens; Willem Theodoor (Gronsveld, NL)
Assignee:	Stiching Centraal Laboratorium Van de Bloedtransfusiedienst Van Het (Amsterdam, NL)
Application Number:	08/604,933
Patent Claims:	see list of patent claims

United States Patent 6,090,777 (C1-Esterase Inhibitor for Acute Myocardial Infarction): Claim Scope, Validity Attack Surface, and US Patent Landscape

United States Patent 6,090,777 claims therapeutic and prophylactic uses of exogenous C1-esterase inhibitor (C1-INH) for acute myocardial infarction (AMI), including routes (notably IV), dosing ranges, and multiple sourcing/modification modalities (human/animal/plasma/non-plasma; recombinant and engineered variants). The patent also contains composition claims combining C1-INH with myocardial blood-flow improving agents and with anti-inflammatory substances. The landscape risk for market exclusivity is high because C1-INH use is broadly anchored in older immunology/vascular indications and because AMI treatment combinations invite obviousness and lack-of-novelty attacks unless the filing history and prosecution record show narrow, specific experimental support for AMI-specific efficacy.

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What claims does US 6,090,777 cover for acute myocardial infarction (AMI)?

Core independent concept: method of treatment/prophylaxis using exogenous C1-INH

The claim set is built around a single central proposition: administer exogenous C1-INH to (i) a patient with acute myocardial infarction or (ii) a patient at risk for AMI.

This structure matters legally because it can read on:

• active AMI treatment
• early intervention/“at risk” prophylaxis
• any formulation delivering functional C1-INH activity in vivo
• monotherapy or combination regimens

Claim 1 (independent) scope drivers

Claim 1 is a functional-medical use claim:

• exogenous C1-INH
• therapeutic or prophylactic method
• acute myocardial infarction or patient at risk
• alone or with other drugs

Key claim interpretation levers:

• “exogenous” excludes endogenous expression changes and focuses on administered protein activity.
• “C1-esterase inhibitor” is not limited to plasma-derived only; dependent claims broaden to recombinant and engineered forms.
• “patient at risk” can be argued as an imprecise pre-event category, creating both enforceability breadth and validity vulnerability (indefiniteness and anticipation concerns if the prior art uses similar risk-framing).

Dependent claims expand to dosing, purification origin, and engineered variants

The remaining claims add alternating layers of specificity and breadth.

Dose/route specifics

• Claim 3: intravenous injection, with “usually” 30 to 40 U/kg.
  • This is a partial narrowing: it does not require exact dosing since “usually” is soft language, but it can still constrain literal infringement for lower or higher dosing regimens.

Source and modification Claims 4 to 11 cover purification from:

• human plasma (claim 4)
• human plasma with subsequent chemical/other modification while maintaining activity (claim 5)
• animal plasma (claim 6)
• animal plasma with modification while maintaining activity (claim 7)
• human biological material other than plasma (claim 8)
• human biological material other than plasma with modification (claim 9)
• animal biological material other than plasma (claim 10)
• animal biological material other than plasma with modification (claim 11)

Recombinant and engineering

• Claim 12: recombinant C1-INH
• Claim 13: recombinant C1-INH modified while maintaining activity
• Claim 14: variant of recombinant C1-INH maintaining activity
• Claim 15: variant with additional modification maintaining activity
• Claim 16 to 17: recombinant “proteinase inhibitor other than C1-INH,” mutated to yield C1-INH activity, optionally modified while maintaining activity

This is an aggressive claim architecture designed to capture:

• biosimilar-like substitution (recombinant manufacture)
• engineered activity-preserving variants
• cross-family engineered variants that achieve C1-INH function

Legally, these dependents cut in both directions:

• They broaden infringement pathways across manufacturing approaches.
• They also increase obviousness risk because broad “functional maintenance of activity” language can be read as covering predictable variants.

Combination treatment

• Claim 18: C1-INH in combination with blood-flow improving agents “such as tissue plasminogen activator, urokinase or streptokinase.”
• Claim 19: C1-INH in combination with anti-inflammatory properties “such as an oxygen radical scavenger or a cytokine antagonist.”

Claims 20–21 are composition counterparts to these combination concepts.

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How do the claims risk being non-limiting or obvious under US patent law?

1) Functional “C1-INH activity maintained” language

Claims 5, 7, 9, 11, 13, 15, 17 use “chemical or other manipulations with maintenance of C1-esterase inhibitor activity.”

For infringement, that is beneficial: many manufacturing and formulation changes can be argued to preserve activity. For validity, it is a common obviousness vulnerability because:

• a prior art C1-INH source (human plasma, animal plasma, recombinant) plus known methods for engineering, stabilization, or chemical modifications can be argued as routine.
• “maintenance of activity” can be treated as a functional result that is predictable for a person of ordinary skill.

2) “Patient at risk” creates breadth that can be attacked

“Acute myocardial infarction or a patient at risk for acute myocardial infarction” is a broad medical population claim.

• If prior art included C1-INH administration in pre-infarct or early ischemic settings, anticipation arguments strengthen.
• If the boundary between “at risk” and non-AMI is not defined by clinical criteria, indefiniteness and lack of enablement arguments can arise in litigation posture, especially for method-of-use claims.

3) Combination claims face obviousness constraints

Combining a known anti-inflammatory/vascular regulator with thrombolytics (tPA/urokinase/streptokinase) or with oxygen radical/cytokine antagonists is a typical “reasonable combination” framing.

An obviousness attack would map:

• C1-INH’s known vascular/inflammatory pathway role
• standard AMI care includes reperfusion and anti-inflammatory strategy exploration
• motivation to combine based on known mechanisms

Unless the patent shows AMI-specific mechanistic insight and experimental results that were not previously suggested, claim 18 and composition claims 20–21 are likely to be the primary weakness points for validity.

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What is the likely priority date and claim filing strategy implied by the claim set?

The claim set is broad in modalities and includes both:

• method-of-treatment uses (medical use)
• composition claims tied to combination categories (not to specific carriers or excipient lists)

This pattern often reflects a prosecution strategy to cover:

• product form variations (plasma-derived vs recombinant; engineered variants)
• regimen variations (monotherapy and combinations)
• route and dosing anchors for IV delivery

In enforcement, that strategy supports wide reach. In validity challenges, it increases the number of independent factual hooks the challenger can use to attack novelty and nonobviousness for each dependent layer.

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How could a challenger structure a US validity attack on US 6,090,777?

Possible anticipation/obviousness theories

A challenger would typically target these claim elements:

1. Exogenous C1-INH for therapeutic/prophylactic use in AMI

   • Look for prior publications, abstracts, or clinical trial disclosures using C1-INH in myocardial ischemia, infarct prevention, or reperfusion injury.

2. Combination with thrombolytics

   • Identify earlier disclosures combining C1-INH with thrombolysis agents or using C1-INH in a thrombosis/inflammation context involving fibrinolytic therapy.

3. Anti-inflammatory combinations

   • Identify prior use of C1-INH with oxygen radical scavengers or cytokine antagonists.

4. Recombinant/engineered variants

   • If C1-INH recombinant products and engineered variants are established in the art, the AMI method-of-use mapping becomes the central issue.

Claim-by-claim vulnerability assessment (practical)

• Stronger: claim 3’s IV dosing range and claim 4’s human plasma purification if AMI-specific evidence exists tied to those parameters.
• More vulnerable: claims 5, 7, 9–11, 13–17 because “activity maintained” broadens coverage to predictable modifications.
• Highly vulnerable: claim 18 and claim 19 and the composition counterparts (20–21) unless the record shows AMI-specific synergy rather than routine combination.

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What patent estate surrounds US 6,090,777 in the C1-INH + cardiovascular/ischemia space?

A full “neighboring patents” map requires Orange Book and full PAIR/USPTO prosecution record review; the provided input only includes the claims text and the patent number, not the family members, citing patents, or prosecution history. Without those, a comprehensive landscape with numbered, verifiable patent citations cannot be produced to a litigation-grade standard.

What can be stated from the claim architecture is directional:

Expected adjacency types in the US landscape

1. Prior art foundational C1-INH patents

   • Plasma purification, recombinant expression, formulation/stabilization, and activity-preserving modifications.

2. AMI reperfusion injury and inflammation method patents

   • Therapies aimed at reducing ischemia-reperfusion injury, cytokine cascades, oxidative stress, complement activation, or endothelial injury.

3. Thrombolytic combination regimens

   • Patents covering combination thrombolysis with adjunct agents.

4. Engineered “functional” serpin/proteinase inhibitor variants

   • C1-INH activity via variants, chimeras, and mutants.

In practice, US 6,090,777 is likely to be challenged not because C1-INH chemistry is novel, but because the AMI therapeutic use and combination selection may be framed as an obvious application of known C1-INH immunovascular effects.

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How would biosimilar or recombinant substitutes affect freedom-to-operate (FTO)?

Even without knowing the specific product targeted, the claims indicate that infringement could occur with:

• recombinant C1-INH (claims 12–15)
• engineered variants maintaining activity (claims 14–15)
• recombinant proteinase inhibitors mutated to yield C1-INH activity (claims 16–17)

That means a “manufacturing change” is unlikely to provide a clean avoidance route if the product retains C1-INH activity and is administered as a method for AMI or prophylaxis in the covered patient population.

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What is the Orange Book status of US 6,090,777?

US 6,090,777 is a method-of-use patent and combination/composition claims that may or may not be listed in the FDA Orange Book for a particular C1-INH product, depending on the active ingredient and the listed patents for that NDA/BLA.

A verifiable Orange Book status requires the NDA/BLA listing and patent linkage, which is not present in the provided input. Without that, the article cannot provide a definitive Orange Book status.

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Key claim construction implications for litigation

“Therapeutic or prophylactic”

This opens two infringement timelines:

• post-diagnosis treatment
• pre-event administration in a “risk” population

Litigation tends to hinge on clinical criteria for “at risk.” If evidence shows physicians would administer C1-INH before AMI is confirmed, infringement posture strengthens.

“Exogenous C1-INH alone or in combination”

Even if a competitor tries to position C1-INH as an adjunct to standard reperfusion care, claim 1 already covers combination use. Claims 18 and 20 provide additional coverage specific to thrombolytics and categories of anti-inflammatory substances.

“A pharmaceutical composition comprising” (claims 20–21)

Composition claims may be used to argue direct infringement based on product manufacture or sale if the marketed combination includes:

• C1-INH
• a carrier
• the specified category agent (blood-flow improving substance or anti-inflammatory substance)

The practical enforcement pathway depends on whether the competitor markets a fixed combination or a kit that includes both components.

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Commercial entry scenarios most exposed by these claims

Scenario A: Adjunct to thrombolysis in AMI

If a therapy regimen administers C1-INH alongside tPA/urokinase/streptokinase for AMI, claims 18 and 1 are the most directly implicated.

Scenario B: C1-INH as an AMI prophylaxis

If used in a preventive setting for at-risk patients, claim 1 is the core hook.

Scenario C: Recombinant C1-INH in IV dosing

If a recombinant C1-INH is used IV with doses near the “30 to 40 U/kg” range and the indication is AMI or at-risk prophylaxis, claims 1, 2, 3, and 12-15 align.

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Key Takeaways

• US 6,090,777 claims a broad AMI therapeutic/prophylactic method using exogenous functional C1-esterase inhibitor, with dependent coverage for IV dosing, human/animal plasma and non-plasma sources, and recombinant and engineered variants.
• The combination architecture (thrombolytics and anti-inflammatory agents) creates multiple infringement pathways but also expands the obviousness attack surface.
• The strongest practical vulnerability of the claim set is that many dependent limitations rely on predictable modifications of a known protein while “maintaining activity,” and on combination selections that can be framed as rational adjuncts in AMI care.
• A competitor cannot rely on recombinant manufacturing or “activity-preserving” engineering alone to avoid infringement if the clinical use targets AMI or “at risk” prophylaxis and the administered agent is C1-INH functional activity.

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FAQs

1. Does US 6,090,777 cover recombinant C1-esterase inhibitor for AMI?
   Yes. Claims include recombinant C1-INH and recombinant variants modified to maintain C1-INH activity.

2. Can fixed-dose combinations or kits trigger infringement of US 6,090,777 composition claims?
   Yes, if the marketed composition includes C1-INH with a carrier and a blood-flow improving substance (claims 20) or an anti-inflammatory substance (claim 21) as part of the composition sold.

3. What part of the patent is most likely to be attacked in an obviousness challenge?
   The combination claims tied to thrombolytics and anti-inflammatory substances, plus the broad functional “modified while maintaining activity” dependents.

4. How does the “patient at risk” language affect enforcement risk?
   It expands the covered population beyond confirmed AMI, increasing potential infringement exposure for preventive or early-intervention protocols.

5. Would changing IV dosing avoid infringement under claim 3?
   Only partially. Claim 3 uses “usually” 30 to 40 U/kg, so large deviations can reduce literal fit, but claim 1 and claim 2 can still be asserted depending on the actual dosing used and evidence of “reduce myocardial cell injury.”

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References

No references are provided because the required patent-family, prosecution-history, and Orange Book/related-citation sources are not included in the input.

Details for Patent 6,090,777

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Microbix Biosystems Inc.	KINLYTIC	urokinase	For Injection	021846	January 16, 1978	6,090,777	2016-04-02
Pharming Americas Bv	RUCONEST	c1 esterase inhibitor (recombinant)	For Injection	125495	July 16, 2014	6,090,777	2016-04-02