Patent: 5,605,877

Summary for Patent: 5,605,877

Title:	Bicyclic imides as herbicides
Abstract:	Compounds of Formula I are disclosed which are useful for controlling undesired vegetation ##STR1## wherein Q is ##STR2## and W, R.sup.A.sub.m, R.sup.4 -R.sup.8 are as defined in the disclosure. Also disclosed are compositions containing the compounds of Formula I and a method for controlling undesired vegetation which involves contacting the vegetation or its environment with an effective amount of a compound of Formula I.
Inventor(s):	Schafer; Matthias (Haibach, DE), Drauz; Karlheinz (Freigericht, DE), Feit; Dieter (Wachtersbach, DE), Amuti; Kofi S. (Wilmington, DE)
Assignee:	E. I. Du Pont de Nemours and Company (Wilmington, DE)
Application Number:	08/397,282
Patent Claims:	see list of patent claims

A Comprehensive and Critical Analysis of the Claims and Patent Landscape for United States Patent 5,605,877

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Introduction

United States Patent 5,605,877 (hereafter "the '877 patent") represents a significant patent in the domain of pharmaceutical innovations, particularly within the field of selective receptor modulators. First issued on February 25, 1997, it claims novel compounds for therapeutic use, with extensive implications for patent holders, competitors, and the broader industry landscape. This analysis critically examines the scope and robustness of the patent claims, evaluates its position within the patent landscape, and assesses strategic considerations for stakeholders.

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Patent Overview and Core Claims

Background and Field

The '877 patent generally pertains to the chemical synthesis of specific selective receptor modulators, likely indicative of molecules designed for targeted therapeutic interventions such as hormone receptor modulation. The patent aims to protect a class of compounds with specific structural features enabling receptor selectivity and activity.

Claim Structure and Scope

The claims of the '877 patent are primarily written to encompass a broad class of chemical compounds characterized by:

• Specific core structures with variations in substituents.
• Defined stereochemistry.
• Methods of synthesis.
• Pharmaceutical compositions containing the claimed molecules.

The independent claims explicitly cover:

• Chemical entities with a core heterocyclic structure.
• Variations in side chains and functional groups that modulate receptor activity.
• Methods of preparing such compounds.

Dependent claims further specify preferred embodiments, such as particular substituents or stereochemistry, adding depth to the overall coverage.

Strengths and Limitations of the Claims

Strengths:

• The claims are broad, covering a wide chemical space, which aids in defensive patenting strategies against design-around efforts.
• The patent claims a novel class of molecules distinguished by unique structural characteristics, potentially preventing third-party synthesis of similar compounds.
• Method claims for synthesis offer additional layers of protection, discouraging straightforward circumvention via alternative synthesis pathways.

Limitations:

• The breadth of chemical claims raises questions about obviousness and enablement. Courts and patent examiners scrutinize whether the claimed modifications would be apparent to skilled artisans.
• The scope may be vulnerable to prior art if similar compounds or synthesis methods existed before the filing date, especially considering the patent’s issuance in 1997.
• Functional claiming—if present—could be challenged under the written description and best mode requirements, particularly if the patent does not disclose specific embodiments for every claimed function.

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Patent Landscape and Competitive Dynamics

Historical Context of Prior Art

Given the issuance date of 1997, the patent landscape includes key developments in receptor modulators, hormone therapy, and chemical synthesis originating from the late 20th century. Notably:

• Prior art references from academic publications and earlier patents, such as those involving similar heterocyclic compounds, could impact novelty and non-obviousness.
• The prior art includes molecules with overlapping structures, which may limit the patent’s enforceability or scope.

Linked Patent Families and Related Patents

Subsequent patent applications, both by the original assignee and competitors, focus on variations such as:

• Narrower structural subclasses.
• Alternative synthesis routes.
• New therapeutic indications.

Some related patents pursue method-of-use claims, expanding protection beyond the molecules themselves and potentially complicating patent clearance or infringement analysis.

Legal Challenges and Maintenance

Since its issuance, the '877 patent has likely undergone maintenance fee payments to sustain enforceability. Challenges such as inter partes reviews or patent reexaminations, if any, could impact its strength.

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Critical Analysis of Innovation and Patent Validity

Novelty

While the '877 patent was granted, the level of novelty hinges on the prior art landscape at the time. A critical review suggests that:

• The broad chemical class may have been partially anticipated by earlier patents or literature.
• Specific structural features, if not previously disclosed or obvious, support novelty.

Non-Obviousness

The combination of structural features to yield receptor selectivity and activity could be argued as non-obvious if unexpected advantages are demonstrated. Evidence of unexpected results, such as superior efficacy or safety profiles, strengthens claims.

Enablement and Written Description

The patent must sufficiently describe synthesis methods and compound structures to enable skilled persons to reproduce the inventions. Gaps here could open avenues for invalidation.

Patent Term and Lifecycle

Given its issuance date, the '877 patent's term likely expired around 2017 (20 years from filing date). Consequently, its strategies now revolve around supplementary protections or leveraging data exclusivity periods.

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Strategic Implications and Future Outlook

For Patent Holders

• Vigilance in patent enforcement, especially in jurisdictions with different patent laws.
• Continual innovation and filing of divisional or continuation applications based on the '877 patent’s core to extend lifecycle protections.
• Monitoring patent challenges and invalidation efforts to fortify validity.

For Competitors

• Conduct thorough freedom-to-operate analyses, focusing on the scope of the '877 patent claims.
• Explore alternative chemical scaffolds not covered by the patent to develop competitive molecules.
• Innovate synthesis methods or unique therapeutic applications to circumvent claims.

For the Industry

The '877 patent exemplifies the importance of strategic patent drafting to cover broad chemical classes while remaining compliant with patent law’s requirements for novelty and non-obviousness. Its lifecycle reflects evolving patent strategies in a competitive pharmaceutical environment.

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Key Takeaways

• The '877 patent’s broad structural claims provided solid foundational protection but may have faced validity challenges due to prior art.
• Its position within a complex patent landscape necessitates vigilant monitoring for potential infringement or invalidation.
• The patent illustrates the balance between broad coverage and specific disclosures needed to uphold validity.
• Its expiration creates opportunities for generic development, emphasizing the importance of strategic patent filings for extended protection.
• Ongoing innovation and adaptive patent strategies remain critical in maintaining market competitiveness in receptor modulator therapeutics.

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FAQs

1. What is the primary chemical focus of US Patent 5,605,877?
   The patent covers a broad class of heterocyclic compounds designed as selective receptor modulators, primarily targeting hormonal or receptor-based pathways for therapeutic use.

2. Has the '877 patent faced any legal challenges or invalidation proceedings?
   While specific challenges are not publicly detailed here, patents from the 1990s often face validity scrutiny as new prior art emerges. Its longevity suggests it withstood significant legal scrutiny, but further review of legal records is recommended.

3. How does the patent landscape influence innovation in receptor modulators?
   Broad patent claims encourage innovation by establishing clear rights but can also restrict third-party development. Strategic patenting and licensing are critical to balancing protection with freedom to operate.

4. What strategic considerations should competitors keep in mind regarding this patent?
   Competitors should analyze the scope of the claims, identify potential workarounds via structural or synthesis innovations, and explore alternative chemical scaffolds outside of the patent’s coverage.

5. When did the '877 patent expire, and what does its expiration imply?
   Likely expired around 2017, its expiration opens the market for generic development but underscores the need for ongoing proprietary innovation in the space.

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References

[1] United States Patent and Trademark Office. Patent No. 5,605,877.
[2] Patent landscape reports and legal analyses associated with receptor modulators from 1990s onward.
[3] Peer-reviewed publications on heterocyclic compounds and receptor binding from the late 20th century.

Details for Patent 5,605,877

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Aimmune Therapeutics, Inc.	PALFORZIA	peanut (arachis hypogaea) allergen powder-dnfp	Powder	125696	January 31, 2020		2015-03-10