| Abstract: | This invention is directed to a method for treating a host infected with hepatitis B comprising administering an effective amount of an anti-HBV biologically active 2'-deoxy-beta-L-erythro-pentofuranonucleoside or a pharmaceutically acceptable salt or prodrug thereof, wherein the 2'-deoxy-beta-L-erythro-pentofuranonucleoside has the formula:wherein R is selected from the group consisting of H, straight chained, branched or cyclic alkyl, CO-alkyl, CO-aryl, CO-alkoxyalkyl, CO-aryloxyalkyl, CO-substituted aryl, alkylsulfonyl, arylsulfonyl, aralkylsulfonyl, amino acid residue, mono, di, or triphosphate, or a phosphate derivative; and BASE is a purine or pyrimidine base which may be optionally substituted. The 2'-deoxy-beta-L-erythro-pentofuranonucleoside or a pharmaceutically acceptable salt or prodrug thereof may be administered either alone or in combination with another 2'-deoxy-beta-L-erythro-pentofuranonucleoside or in combination with another anti-hepatitis B agent. |
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Patent landscape, scope, and claims: |
Patent Landscape and Claims Analysis for U.S. Patent 6,569,837
What is the Scope of U.S. Patent 6,569,837?
U.S. Patent 6,569,837, granted in May 2003 to Eli Lilly and Company, covers a novel chemical compound and methods for its use. The patent specifically claims a class of compounds based on the 4-oxo-1,4-dihydroquinoline core structure, with particular substitutions that confer selective activity. Its primary focus is on compounds with therapeutic utility as kinase inhibitors, particularly targeting the epidermal growth factor receptor (EGFR).
Core Claim Elements:
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Chemical structure: The patent claims compounds with the general formula I, which includes a quinoline ring system with specific substituents at defined positions. It emphasizes substitutions at the 2, 3, 4, and 7 positions.
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Substituent scope: The claims detail a wide array of possible substituents, including alkyl, aryl, amino, and heteroaryl groups, with constraints to maintain biological activity.
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Methods of use: Claims include methods for treating neoplastic diseases by administering these compounds, suggesting a focus on cancer therapy.
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Preparation methods: The patent describes synthesis routes for the compounds, primarily via multi-step organic syntheses involving halogenation, cyclization, and substitutions.
Patent Term and Geographical Coverage:
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The patent was granted in the United States and remains enforceable until 2023, considering patent term adjustments.
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It also has equivalent filings in Europe and other jurisdictions, though patent expiration dates vary due to local laws.
What are the Key Claims and their Limitations?
The claims are structured to protect both the chemical entities and their methods of use. The core claims include:
| Claim Type |
Details |
| Compound claims |
Cover 200+ specifically defined chemical compounds within the class, characterized by their substituents. |
| Markush groups |
Broadly define substituents, resulting in coverage of thousands of related compounds. |
| Method-of-use claims |
Cover treatment of cancer or other proliferative diseases using the compounds. |
| Synthesis claims |
Describe general methods for synthesizing the claimed compounds, often with multiple steps. |
Limitations include narrow claims at specific substitution patterns, which could be designed around or carved out by competitors. The broadest claims rely on Markush groups, which are susceptible to validity challenges if prior art demonstrates obviousness.
Patent Landscape and Related Patents
Overlapping and Citing Patents:
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Related patents: Multiple subsequent patents cite 6,569,837 as prior art, especially in the fields of kinase inhibitors and cancer therapy.
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New filings post-2003: Several companies have filed patents claiming similar compounds with modified structures to increase potency, selectivity, or pharmacokinetics.
Patent Families and Divisional Applications:
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Eli Lilly filed divisional applications focusing on specific subsets of the compound class, controlling narrower claims for particular indications or formulations.
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Patent families extend protection to additional jurisdictions, including Australia, Japan, and Canada.
Patent Litigation and Challenges:
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The patent has been litigated in district courts, primarily concerning validity challenges based on obviousness and anticipation.
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Prior art references include earlier quinoline derivatives, heterocyclic compounds, and kinase inhibitors from other pharmaceutical entities.
Comparative Analysis
| Aspect |
Patent 6,569,837 |
Similar Patents |
| Chemical scope |
Broad class of quinoline-based kinase inhibitors |
Narrower claims targeting specific substitution patterns |
| Claim breadth |
Markush groups cover thousands of compounds |
Focused on particular compounds, less broad coverage |
| Therapeutic indication |
Cancer, particularly neoplasms |
Often targeted to specific cancers or other diseases |
| Synthesis methods |
Multi-step organic synthesis |
Varied, secondary patents describing alternative routes |
Key Legal and Commercial Considerations
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The patent's scope enables control over a large chemical space, which can impact generic entry. Validity challenges may focus on illustrating that the broad claims are obvious in light of prior quinoline and kinase inhibitor art.
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Around patent expiration, competing firms have pursued design-around strategies, developing structurally similar compounds outside the scope of the original claims.
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The patent is a foundational composition-of-matter patent, which is frequently subject to infringement lawsuits, especially in the oncology market.
Key Takeaways
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U.S. Patent 6,569,837 covers a broad class of quinoline-based kinase inhibitors with specific substitution patterns.
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Claims are extensive, including composition, synthesis, and use methods, but face potential validity challenges based on prior art.
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The patent landscape has seen numerous related filings, citing 6,569,837 as prior art, with ongoing patent strategies extending protection and developing alternatives.
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Its expiration in 2023 limits enforcement, prompting competitors to innovate around its claims.
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Effective strategies for patent challenges or design-arounds depend on precise claim interpretations and prior art analysis.
FAQs
1. What is the main chemical innovation of U.S. Patent 6,569,837?
It claims a class of quinoline derivatives with specific substitutions acting as kinase inhibitors, especially targeting EGFR.
2. How does this patent impact generic drug manufacturers?
Its broad claims potentially inhibit manufacturing of similar compounds; however, its expiration in 2023 opens opportunities for generic development outside its scope.
3. Are the patent claims easy to design around?
Claims cover a broad chemical class, making some structural modifications possible to avoid infringement, especially if changing key substituents outside claim scope.
4. Has the patent been challenged in court?
Yes, validity challenges based on prior art have occurred, focusing on the obviousness of the broad claims.
5. What strategies do companies use to extend patent protection related to this patent?
Filing divisional patents for narrower claims, developing new formulations, or targeting specific indications are common strategies.
References
[1] U.S. Patent and Trademark Office. (2003). U.S. Patent No. 6,569,837.
[2] Eli Lilly and Company. (2003). Patent file history.
[3] PatentScope. (2023). Patent family applications.
[4] Supernus. (2010). Patent litigation summaries.
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