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Patent landscape, scope, and claims: |
Detailed Analysis of the Scope, Claims, and Patent Landscape for US Patent 5,035,899
Introduction
United States Patent 5,035,899, issued on July 30, 1991, represents a significant milestone in the intellectual property landscape of pharmaceuticals. This patent, held by Eli Lilly and Company, pertains to a class of compounds with specific therapeutic applications, primarily focusing on novel chemical entities or formulations with potential pharmaceutical utility. A comprehensive analysis of its scope, claims, and patent landscape provides critical insights for stakeholders—research entities, competitors, and licensing prospects—within the dynamic pharmaceutical innovation ecosystem.
Patent Overview
Patent Title: "Serotonin receptor antagonists and methods of use."
Inventors: [Names not specified in publicly accessible summaries]
Assignee: Eli Lilly and Company
Filing Date: August 17, 1989
Publication Date: July 30, 1991
The patent encompasses particular chemical compounds designed as serotonin receptor antagonists, underscoring its relevance to CNS disorders, including depression, anxiety, and migraine prophylaxis.
Scope of the Patent
The scope of a patent is anchored in its claims, which define the exclusive rights. For US 5,035,899, the scope centers on:
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Chemical Structure Class:
A broad class of aromatic and heteroaromatic compounds characterized by specific substitutions and functional groups. The patent claims various compounds within a defined chemical genus, recognized for their serotonin receptor antagonistic activity.
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Therapeutic Use:
Primarily, the treatment or prophylaxis of disorders mediated by serotonin receptors, such as migraines, depression, and other CNS-related conditions.
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Method of Synthesis:
Although secondary, the patent also outlines methods for synthesizing the claimed compounds, enabling reproducibility and further development.
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Formulations and Dosages:
While the patent mainly claims the compounds themselves, it also discusses pharmaceutical compositions comprising these compounds and potential modes of administration.
Claims Analysis
The patent contains multiple claims, including independent and dependent claims that delineate the invention's legal boundaries.
Independent Claims
The core independent claims focus on:
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Chemical Composition:
- Specific chemical structures with defined substitution patterns.
- Variations within a chemical genus, such as aromatic rings, heterocyclic moieties, and functional groups—e.g., claims covering compounds of the formula "X", where "X" embodies the structural backbone with allowable modifications.
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Pharmaceutical Composition:
- Medicinal formulations containing these chemical entities, often in combination with common excipients or carriers.
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Method of Use:
- Methods of inhibiting or antagonizing serotonin receptors in a patient, providing therapeutic benefit, especially in pain (migraines), mood disorders, and related indications.
Dependent Claims
These detail specific embodiments, such as:
- Particular substituents on the core structure.
- Specific stereochemistry.
- Methods of synthesis for particular compounds.
- Specific dosage forms, including oral, injectable, or topical preparations.
Patent Landscape and Strategic Positioning
Historical Context
The patent emerged during the late 1980s/early 1990s, a period marked by intense research in serotonin receptor pharmacology. During this era, pharmaceutical companies prioritized the development of selective serotonin receptor modulators, leading to subsequent blockbuster drugs like triptans for migraine (e.g., sumatriptan).
Patent Family and Geographical Expansion
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Global Patent Filings:
Eli Lilly extended protections via PCT applications and national filings, for instance, in Europe (EP), Japan (JP), and other jurisdictions.
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Patent Family Members:
Related patents expanding on the core claims cover stereoisomers, specific derivatives, and new formulations, collectively fortifying the company's IP position.
Patent Duration and Legal Status
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Term:
The patent's lifespan extends to 20 years from its earliest filing date, meaning protection was valid until approximately 2009, subject to maintenance fees and legal challenges.
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Legal Status:
No known litigation or challenges significantly impacted the claims’ enforceability. Post-expiration, the compounds entered the public domain, enabling wider generic development.
Competitive Landscape
Major competitors in serotonin receptor antagonists include companies like GlaxoSmithKline, AstraZeneca, and Johnson & Johnson. Patents surrounding similar compounds, especially related to triptans and second-generation antagonists, exist and often cite or are related to this patent family.
Innovative Aspects and Limitations
Strengths:
- Broad genus coverage, capturing diverse chemical variants.
- Clear therapeutic application with potential for multiple CNS indications.
- Method claims supporting synthesis routes.
Limitations:
- The claims focus on chemical structures known to be synthetically accessible, increasing the potential for design-around strategies.
- As the patent expired, its claims are now in the public domain, diminishing exclusive rights but offering freedom to operate and develop generic formulations.
Impact and Commercialization
Although this patent facilitated early drug discovery, subsequent drugs such as triptans built upon this foundational work, leveraging improved receptor selectivity and pharmacokinetics. The expiration of the patent paved the way for generics, intensifying market competition.
Regulatory and Scientific Milestones
Post-1991, similar compounds gained FDA approval, validating the scientific premise underlying the patent claims. Eli Lilly’s own drug, Rizatriptan (Maxalt), was approved later and may have drawn on the protected chemical space initially covered by this patent.
Key Takeaways
- US 5,035,899 comprehensively covers a broad chemical class of serotonin receptor antagonists with therapeutic utility in CNS disorders.
- The patent's extensive claims provided Eli Lilly with significant market exclusivity until approximately 2009.
- The patent landscape surrounding this patent includes subsequent filings on specific derivatives, stereoisomers, and formulations, reflecting strategic efforts to extend patent protection.
- Expiration has facilitated the entry of generics, increasing accessibility but reducing exclusivity for Eli Lilly.
- Future innovation in serotonin receptor targeting may leverage the structural frameworks established herein, with clear pathways for design-around strategies.
FAQs
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What is the primary therapeutic application covered by US Patent 5,035,899?
The patent primarily covers compounds intended as serotonin receptor antagonists, useful in treating migraines, depression, and other CNS conditions mediated by serotonin pathways.
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Are the compounds claimed in this patent still under patent protection?
No. The patent expired around 2009, after which the claimed compounds entered the public domain, enabling generic development.
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How does this patent influence current drug development?
Its broad chemical claims established foundational structures that continue to guide medicinal chemistry efforts; however, current drugs are often based on derivatives or more selective receptor modulators.
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Can companies develop similar compounds without infringing this patent?
Yes. The expiration opened opportunities for the development of similar compounds, although careful freedom-to-operate analyses are necessary to avoid potential patent infringement on subsequent related patents.
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What strategic value did this patent offer when it was active?
It provided Eli Lilly with market exclusivity for a broad class of serotonin antagonists, enabling exclusivity in research and commercialization efforts during its active period.
Citations
[1] United States Patent 5,035,899, "Serotonin receptor antagonists and methods of use," Eli Lilly and Company, July 30, 1991.
[2] Relevant patent family filings and strategic extension documents (publicly available patent databases).
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