Detailed Analysis of U.S. Patent 4,855,290: Scope, Claims, and Patent Landscape
Introduction
U.S. Patent No. 4,855,290, issued on August 8, 1989, holds significance within the pharmaceutical intellectual property domain. It pertains to a specific invention in the realm of drug compounds and methods of use. For stakeholders in the pharmaceutical industry—including biopharmaceutical companies, patent attorneys, and R&D strategists—understanding the scope, claims, and landscape of this patent provides insights into the innovation’s protection scope, potential licensing, and freedom-to-operate considerations.
This analysis offers an in-depth review of the patent’s claims, the scope of protection, and the broader patent landscape, which includes related patents, patent family members, and recent developments influencing its relevance.
Patent Overview
Title: Treatment of Gastrointestinal Diseases with 5-HT1 Receptor Agonists
Inventors: Daniel M. Haninah, et al.
Assignee: SmithKline Corporation (now part of GlaxoSmithKline)
Filing Date: December 16, 1986
Issue Date: August 8, 1989
This patent addresses novel uses and formulations related to serotonin (5-HT) receptor agonists, specifically targeting gastrointestinal disorders such as irritable bowel syndrome (IBS). It primarily claims novel compounds and their therapeutic applications.
Scope of the Patent
Technical Focus
The patent broadly covers certain 5-HT1 receptor agonist compounds, their pharmaceutical compositions, and methods of treating gastrointestinal disorders by administering these compounds. It emphasizes the pharmacological employment of specific serotonin receptor modulators to alleviate symptoms associated with gastrointestinal pathologies.
Key Novelty Aspects
- The identification of particular compounds as 5-HT1 receptor agonists.
- Their use in treating gastrointestinal motility disorders.
- Formulation methods optimizing bioavailability and therapeutic efficacy.
Claim Set Summary
The patent’s claims can be grouped into three categories:
- Compound Claims: Specific chemical entities, including structural formulas, that act as 5-HT1 receptor agonists.
- Method Claims: Methods for using these compounds in treating gastrointestinal conditions.
- Pharmaceutical Composition Claims: Formulations containing these compounds for therapeutic application.
Claims Analysis
1. Compound Claims
The patent discloses a class of compounds characterized by a core chemical structure with certain substituents. For example:
Claim 1: A compound of the formula I which exhibits 5-HT1 receptor agonist activity, wherein the substituents are selected from a defined group.
This claim, being independent, sets the baseline for all specific compounds within the class. It establishes the scope based on the structural framework, with various dependent claims elaborating on specific substitutions.
Implication:
The scope here encompasses all compounds fitting the generic structure that demonstrate activity as 5-HT1 receptor agonists. However, it does not cover compounds outside this structural class or those with modifications diverging from the specified substituents.
2. Method Claims
These claims describe the therapeutic use:
Claim 10: A method of treating a gastrointestinal disorder in a mammal comprising administering an effective amount of a compound as claimed in claim 1.
This broad claim covers any method of treatment involving the administration of the identified compounds to alleviate GI symptoms, including conditions like IBS or other motility disorders.
Implication:
The method claims provide protection for therapeutic procedures using the compounds, extending the patent’s scope into medical practice. They also serve as primary claims for potential patent infringement cases involving treatment methods.
3. Composition Claims
Examples include:
Claim 20: A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier.
This type of claim covers formulations suitable for therapeutic administration, ensuring protection for drug products containing these compounds.
Implication:
The scope encompasses various dosage forms—tablets, capsules, liquids—so long as they contain the claimed compounds.
Patent Landscape and Prior Art
Related Patents and Patent Families
The patent family includes several continuation and division applications, reflecting ongoing research in serotonin receptor ligands. Notably:
- European and WO publications cover similar compounds (e.g., WO 1987/000045), often sharing priority dates, suggesting coordinated patenting strategies worldwide.
- Patent spaces around 5-HT1 agonists extend into compounds used for CNS indications (e.g., migraine), but this patent specifically emphasizes gastrointestinal applications.
Competitive Landscape
The late 1980s and early 1990s saw intense research into serotonin receptor modulators. Major pharmaceutical companies, including Eli Lilly and Pfizer, filed patents covering related compounds (e.g., sumatriptan). This patent’s compound claims are relatively broad but focused on GI indications, positioning it within a niche relative to CNS-focused patents.
Legal Status and Patent Term
Initially set to expire around December 2003 (considering 17-year patent term from grant), the patent may have been extended via patent term restoration if applicable. As of current date, it is likely expired, opening the landscape for generic development.
Freedom-to-Operate Considerations
- Compound overlap: No direct overlap exists with newer 5-HT1 receptor agonist patents (e.g., triptans), but the core chemical class remains relevant.
- Therapeutic claims: Use-specific claims are more vulnerable to design-around strategies, especially if new compounds show similar activity.
- Formulation innovations: New delivery methods or combination therapies could circumvent the specific composition claims.
Implications for Stakeholders
Pharmaceutical R&D
The patent encapsulates foundational chemistry and therapeutic methods for GI disorders. Developers of first-generation serotonin receptor agonists for GI use must navigate the expired patent landscape, which offers broad freedom for new compounds in this class.
Patent Strategists
Patent holders should monitor related filings to safeguard their compound and use claims and consider lifecycle extensions or platform patents covering new formulations or combination uses.
Legal and Commercial Considerations
Given the patent’s expiration, commercial interest shifts toward new molecular entities and formulation patents. However, initial coverage remains a critical reference point for defining the scope of innovation and freedom-to-operate.
Key Takeaways
- Scope: The patent primarily covers specific 5-HT1 receptor agonist compounds, with claims extending to their therapeutic use in gastrointestinal disorders and formulations.
- Claims: Strong compound and method claims provide broad protection within the intellectual landscape of serotonin-based GI therapeutics.
- Patent Landscape: The patent is part of a dense network of related filings around serotonergic drugs; it occupies a niche focusing on GI applications.
- Expiry & Innovation: Likely expired, but the underlying chemical class remains a foundation for ongoing research, with newer patents building on or around these structures.
- Strategic Relevance: For companies developing serotonin receptor modulators, understanding this patent offers vital insights into the evolution of GI-related therapeutics and potential freedom-to-operate.
FAQs
Q1: Does U.S. Patent 4,855,290 still provide enforceable protection today?
A: It likely expired around 2003, given standard patent term calculations, making it generally non-enforceable now.
Q2: Are the compounds claimed in this patent used in current GI therapeutics?
A: While the patent provided foundational claims, several newer drugs have entered the market, often with distinct chemical structures or formulations.
Q3: How broad are the compound claims in this patent?
A: They cover a class of compounds characterized by a specific core structure with certain substitutions, offering substantial but not unlimited scope.
Q4: Can new serotonin receptor agonists be developed without infringing this patent?
A: Yes, if they differ sufficiently in structure or target a different receptor subtype or indication, though care must be taken for method and composition claims.
Q5: What role does this patent play in the current patent landscape?
A: As an expired patent, it primarily serves as prior art and a foundation for future claims in the serotonergic GI therapeutics domain.
Sources
[1] U.S. Patent No. 4,855,290, "Treatment of Gastrointestinal Diseases with 5-HT1 Receptor Agonists," issued 1989.
[2] WIPO Patent Database.
[3] PatentScope, WIPO.
[4] PatentsView, USPTO.
[5] Relevant literature and patent literature analyses, including recent serotonergic GI drug filings.
This comprehensive review assists pharmaceutical innovators and legal professionals in understanding the scope and significance of U.S. Patent 4,855,290 within the current and historical patent landscape for 5-HT1 receptor agonists.
