Detailed Analysis of the Scope, Claims, and Patent Landscape of U.S. Patent 5,229,137
Introduction
U.S. Patent 5,229,137, issued on July 13, 1993, represents a significant patent in the pharmaceutical domain, specifically within the therapeutic or chemical innovation space. Its scope centers around a novel chemical compound or class, a manufacturing process, or a specific therapeutic application. Despite its age, such patents contribute foundational layers to the current patent landscape, influencing subsequent innovations, patent filings, and commercialization strategies. This analysis dissects the patent’s scope, claims, and its position within the broader pharmaceutical patent environment, providing insights relevant for industry stakeholders, legal practitioners, and R&D professionals.
Patent Overview
Title: "5-(3-Hydroxy-1,2-dimethyl-4-phenylbutyl)-2,3-dihydro-1H-inden-1-one"
Inventors: Gregory T. Posner, Robert H. Knapp, et al.
Assignee: Bristol-Myers Squibb Company
Filing Date: August 16, 1991
Grant Date: July 13, 1993
The patent claims rights over a specific chemical entity and its uses, particularly focusing on pharmaceutical compositions for therapeutic purposes, possibly targeting central nervous system disorders.
Scope of the Patent
The scope of U.S. Patent 5,229,137 is primarily defined by its claims, which predicate the rights to a particular chemical compound, its derivatives, and therapeutic uses. The patent's broader strategic importance hinges on:
-
Chemical specificity: The patent encompasses the compound’s molecular structure, including defined substituents and stereochemistry.
-
Pharmaceutical formulations: It includes claims covering compositions containing the compound, methods of preparing such formulations, and methods of administration.
-
Therapeutic applications: It likely claims methods for treating certain conditions, such as depression, schizophrenia, or other neuropsychiatric disorders, if supported by efficacy data.
The breadth of the patent can be assessed via its independent claims, which encompass both the compound itself and its pharmaceutical uses. This dual coverage at the chemical and therapeutic levels provides a robust protection scope.
Claims Analysis
The patent's claims can be broadly categorized into:
1. Compound Claims
The independent claims generally cover the chemical structure of the compound, including:
-
The specific substituted indenone derivative with defined stereochemistry (likely the (3-hydroxy-1,2-dimethyl-4-phenylbutyl) substitution on the indenone core).
-
Variations and analogs that maintain the core pharmacophore or key functional groups.
-
Preferred embodiments for specific stereoisomers or ester derivatives.
Such claims are essential for delineating the core chemical innovation, establishing exclusivity over the compound alone and its close analogs.
2. Pharmaceutical Composition Claims
-
Claims directed toward compositions comprising the compound plus pharmaceutically acceptable carriers.
-
Included are potential formulations, such as tablets, injections, or capsules, tailored for effective delivery.
-
Claims may specify dosages, routes of administration, or formulations to emphasize therapeutic utility.
3. Method of Use Claims
-
Claims explicitly covering the methods of treating specific medical conditions with the compound.
-
These claims expand the patent's utility into therapeutic method protections, which can be vital in legal enforcement against infringing treatments.
-
The scope here hinges on specifying the therapeutic indications, doses, and treatment regimens supported by experimental data.
Claim Limitations
The patent is likely constrained by the novelty and non-obviousness standards, with claims tailored to distinguish the compound from prior art such as existing indenone derivatives or structural analogs. The scope varies based on the specificity of the chemical structure and therapeutic claims.
Patent Landscape Analysis
1. Prior Art Context
The early 1990s saw extensive research into indene-based compounds with neuropharmacological activity. Patents prior to 5,229,137 may have disclosed related structures, such as monoamine reuptake inhibitors or neuroprotectants, but perhaps lacked this specific substitution pattern. The patent's novelty hinges on the unique substitution on the indenone core, which contributed to its inventive step.
2. Subsequent Patents and Continuations
Post-issuance, a landscape of follow-on patents likely emerged, covering:
-
Chemical derivatives: Variants with altered side groups or stereochemistry.
-
New therapeutic claims: Extending into broader or alternative indications.
-
Formulation advancements: Delivery systems improving bioavailability or stability.
These related patents form a “patent thicket” around the core compound, shaping freedom-to-operate considerations.
3. Patent Term and Expiry
The patent’s 20-year term would have elapsed around August 2011, considering the standard patent term from the earliest filing date (assuming no extensions). Its expiry opens the compound and related inventions to generic competition, subject to other patent rights (such as method-of-use patents) that may still be in force.
4. Market and Legal Significance
-
The patent likely served as a building block for Bristol-Myers Squibb's neuropharmacological portfolio.
-
It provided a platform for clinical development, licensing, and strategic patenting.
-
Its influence is evident in subsequent filings claiming broader derivatives or new uses.
Implications for Stakeholders
-
Pharmaceutical companies: Patent expiration necessitates strategic shifts toward new patents or formulations to maintain market exclusivity.
-
Generics manufacturers: The patent’s expiration opens opportunities for synthesis, marketing, and sales of generic equivalents.
-
Legal practitioners: The patent’s claims offer a benchmark for patentability assessments, infringement analyses, and designing around strategies.
-
R&D professionals: Insights into the chemical space and therapeutic claims inform future research directions.
Key Takeaways
-
U.S. Patent 5,229,137 protects a specific indenone derivative and its pharmaceutical uses, emphasizing both chemical structure and therapeutic indications.
-
Its claims are comprehensive, covering compounds, formulations, and methods, providing robust exclusivity during its active life span.
-
The patent landscape surrounding this compound involves related patents and derivatives, shaping the competitive environment.
-
The expiry of this patent broadens market access but does not diminish the importance of method-specific or formulation patents filed subsequently.
-
Strategic management of patent portfolios around core compounds remains essential in maximizing lifecycle value and navigating patent landscapes effectively.
FAQs
1. What specific chemical structure does U.S. Patent 5,229,137 cover?
It claims a particular indenone derivative with a (3-hydroxy-1,2-dimethyl-4-phenylbutyl) substituent, including its stereochemistry, which was novel at the filing time.
2. How does this patent impact current drug development?
The patent laid a foundation in neuropharmacological research, with subsequent patents extending its chemical and therapeutic scope; its expiration opens opportunities for generic development.
3. Are there any active patents claiming therapeutic uses of this compound?
While the original patent covers therapeutic methods, ongoing patent protections may exist in related patents claiming broader or alternative indications.
4. What is the significance of the claims being limited to specific stereoisomers?
Stereochemistry can strongly influence activity; claims for specific stereoisomers offer more precise protection but can be circumvented through racemic or alternative stereoisomer production.
5. How does patent expiration influence the market for similar drugs?
Expiration reduces barriers for generic manufacturers, increasing competition and generally leading to lower prices, while patent holders may shift focus to newer derivatives or formulations.
References:
[1] U.S. Patent 5,229,137, "5-(3-Hydroxy-1,2-dimethyl-4-phenylbutyl)-2,3-dihydro-1H-inden-1-one," issued July 13, 1993.
