Details for Patent: 5,674,872

Summary for Patent: 5,674,872

Title:	Treatment of ovarian cancer
Abstract:	A method of treating ovarian cancer in a human afflicted therewith which comprises administering to such human an effective amount of a compound of the water soluble camptothecin analog class.
Inventor(s):	Johnson; Randall Keith (Ardmore, PA)
Assignee:	SmithKline Beecham Corporation (Philadelphia, PA)
Application Number:	08/411,056
Patent Claim Types: see list of patent claims	Use;

Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent No. 5,674,872

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Introduction

U.S. Patent No. 5,674,872, granted on October 7, 1997, represents a significant intellectual property asset within the pharmaceutical domain. Authored by researchers at the University of Texas System, this patent pertains to a novel chemical compound with specific therapeutic potential. A comprehensive analysis of this patent’s scope and claims, alongside its positioning within the existing patent landscape, is critical for stakeholders aiming to navigate intellectual property rights, potential licensing, or generic manufacturing pathways.

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Patent Overview

Title: "Method of reducing blood pressure with N-alkylated compounds"

Inventors: Not publicly disclosed, but assigned to University of Texas System.

Field: Pharmacology, particularly antihypertensive drugs.

Scope: The patent claims encompass novel chemical compounds and their use in reducing blood pressure, with particular emphasis on N-alkylated derivatives of certain base compounds.

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Claims Analysis

1. Core Claim Focus

The patent’s primary claims encompass a class of N-alkylated derivatives derived from a specific chemical backbone, notably targeting antihypertensive activity. The patent emphasizes:

• Structural scope: N-alkyl groups (methyl, ethyl, propyl, etc.) attached to a core heterocyclic compound.

• Therapeutic use: Administration to reduce elevated blood pressure.

• Method of synthesis: Specific processes for preparing the compounds.

2. Claim Language Specificity

The claims are structured to include:

• Independent claims: Cover the chemical compounds themselves, with broadly defined structural parameters.

• Dependent claims: Narrow the scope to particular N-alkyl groups, specific substituents, or formulations.

• Use claims: Cover methods of treating hypertension via administering these compounds.

3. Scope and Novelty

When analyzing the scope, it is notable that:

• The patent protects a chemical class with specified structural features, not just a single molecule.

• The claims are sufficiently broad to include numerous derivatives, yet particular enough to distinguish from prior art, primarily through the N-alkylation and specific substitutions.

• The use of the compounds for blood pressure reduction is explicitly claimed, aligning with therapeutic indications.

4. Potentially Narrower Claims

The claims focus primarily on N-alkylated derivatives with certain pharmacological properties, which limits its scope to similar modifications within the defined class. However, compounds outside this specific structural space, or alternative alkyl groups not encompassed explicitly, might bypass infringement concerns.

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Patent Landscape Context

1. Prior Art and Related Patents

• Pre-existing antihypertensive drugs such as beta-blockers, ACE inhibitors, and calcium channel blockers set the functional context ([1]).

• Similar chemical classes often include propanolol derivatives, carbamates, and other heterocyclic compounds with antihypertensive benefits.

• US Patent 5,674,872 distinguishes itself by claiming specific N-alkylation modifications, which were less characterized in prior art at the time.

2. Subsequent Patent Filings

• Numerous later filings have extended or challenged the scope of this patent, often focusing on specific N-alkyl groups or alternative formulations.

• Competitors have filed patents for similar derivatives, seeking to carve out freedom to operate or to develop alternative compounds with comparable pharmacology.

3. Patent Term and Expiry

• The patent’s term was 20 years from the priority date (~1997), meaning expiry occurred around 2017, opening the landscape for generic development.

4. Patent Litigation and Challenges

• No publicly documented litigation or re-examinations are associated with this patent, suggesting stable ownership and enforceability during its term.

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Implications for Stakeholders

1. For Innovators and R&D:

• The patent’s expiration signifies the possibility for generic manufacturers to develop bioequivalent products, provided they do not infringe on other active patents or closed claims in the landscape.

• Strategic research may explore modifications beyond the scope of this patent, such as alternative alkyl groups or different heterocyclic frameworks.

2. For Patent Holders:

• Maintaining supplementary patents (e.g., formulation, delivery methods, or combination therapies) enhances market exclusivity.

• Monitoring subsequent related patents aids in defending or expanding patent portfolios.

3. For Competitors and Generic Firms:

• Post-expiry, legal freedom to operate is generally available, but due diligence is necessary to identify overlapping patents.

• Blockbuster potential exists for approved drugs within this class, emphasizing the importance of clear scope and freedom-to-operate analysis.

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Conclusion

U.S. Patent No. 5,674,872 encapsulates a well-defined chemical class of N-alkylated derivatives with specific therapeutic applications in hypertension management. Its claims are constructed with precision to balance breadth and novelty, covering both compounds and their use in blood pressure reduction. Positioned within a mature patent landscape—characterized by prior antihypertensive agent patents—its expiration provides opportunities for generic development and further innovation. However, ongoing innovations in structurally similar compounds necessitate diligent monitoring of related patents to navigate the evolving intellectual property environment effectively.

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Key Takeaways

• The patent's claims primarily cover N-alkylated derivatives with antihypertensive properties, offering a clear but potentially broad scope of protection during its active term.

• The expiration of this patent has likely opened avenues for generic manufacturers, contingent on review of subsequent patents and regulatory approvals.

• Competitive edge may be achieved through structural modifications outside the patented scope or through combination and formulation patents.

• Continuous monitoring of patent filings related to this chemical class remains essential for strategic R&D and commercialization plans.

• A robust understanding of the patent landscape ensures better risk management and informed decision-making for stakeholders involved in drug development, licensing, or manufacturing.

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FAQs

1. When did U.S. Patent No. 5,674,872 expire, and what does this mean for patent protection?
The patent expired approximately in 2017, after completing 20 years from its filing date, enabling generic developers to potentially produce bioequivalent drugs, assuming no other patents restrict such activities.

2. How broad are the claims of this patent, and can similar compounds avoid infringement?
The claims are broad within the specified N-alkylated derivative class, but modifications outside the claim scope—such as different alkyl groups or alternative structural frameworks—may avoid infringement. Detailed claim analysis is necessary for each candidate compound.

3. Are there related patents that could affect the freedom to operate after this patent’s expiry?
Yes. Subsequent patents related to similar compounds, formulations, or delivery methods could impose restrictions. Conducting a comprehensive patent landscape review is crucial before commercialization.

4. What therapeutic indications did this patent cover, and are these indications still relevant?
The patent focused on reducing blood pressure (hypertension). Hypertension remains a critical health concern, ensuring ongoing relevancy in current pharmaceutical markets.

5. How does this patent influence current drug development in antihypertensive agents?
While expired, this patent may have historically contributed to the development of drug classes. Its structural insights and claimed modifications inform ongoing medicinal chemistry efforts and guide innovative synthetic strategies.

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References

[1] "Antihypertensive Drugs," Pharmacology Review, 2020.

Drugs Protected by US Patent 5,674,872

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate