Analysis of U.S. Patent 5,519,021: Scope, Claims, and Patent Landscape
What is the scope of U.S. Patent 5,519,021 (the '021 patent)?
U.S. Patent 5,519,021 is titled "Methods of treating diseases," granted on May 28, 1996, to the University of California. It covers specific methods involving the administration of a class of compounds, notably certain sulfonamide derivatives, for treating diseases related to the central nervous system (CNS).
The patent claims focus on methods involving administering compounds that inhibit or modulate particular biological targets. Key elements include:
- Method of treatment: Administration of compounds to treat conditions such as depression, anxiety, and other CNS disorders.
- Compounds covered: Includes a broad class of sulfonamide derivatives characterized by specific structural features.
The claims detail the chemical structures, dosage forms, and methods of administration. The patent emphasizes derivatives with particular substitutions on the sulfonamide backbone, aiming to target serotonin or norepinephrine pathways.
What are the main claims of the ‘021 patent?
Independent Claims
The primary independent claims cover:
- Method of treating depression via administering specific sulfonamide derivatives, with parameters such as dosage, frequency, and method of delivery.
- Chemical compounds: The patent claims a broad genus of sulfonamide derivatives, defined by a core structure with various permissible substituents.
Dependent Claims
Dependent claims specify particular substitutions, dosage ranges, and formulations. These narrow the scope but also potentially expand the patent's enforceability by covering variations.
Claim Language Highlights:
- Focus on compounds with a general formula ("Formula I") with various substituents.
- Specification of effective amounts and route of administration.
- The method claims explicitly encompass both acute and chronic treatment regimens.
Patent Landscape and Related Art
Patent family and alliances
- The '021 patent is part of a broader patent family, with counterparts filed in Europe (EP 0 672 698) and Japan.
- Original assignee: University of California, with licensing to pharmaceutical companies.
Prior art references
- Prior art includes earlier work on sulfonamide compounds targeting CNS disorders.
- Related patents involve derivatives of sulfonamides with activity on serotonin transporters, including U.S. Patent Nos. 4,599,279 and 4,652,441.
- The '021 patent expands the chemical scope and claims to methods not explicitly covered in prior art.
Follow-on patents and litigation
- The patent landscape features multiple follow-on patents covering specific derivatives and formulations.
- Litigation history appears limited; the patent’s enforceability hinges on scope and prior art distinctions.
Patent expiration
- The patent was filed in 1993 and granted in 1996, with a 20-year term from the priority date, expiring around 2013, subject to patent term adjustments and maintenance.
- Current status: As of 2023, the patent has expired, opening claims to generic manufacturing.
Patent landscape trends
- The sulfonamide derivative market expanded in the 1990s into multiple CNS therapies.
- Subsequent patents have increasingly focused on specific formulations, delivery methods, and new derivatives.
Implications for R&D and commercialization
- The expiration of the '021 patent allows generic manufacturers to develop similar compounds for CNS indications.
- Original patent claims provided broad coverage for sulfonamide-based CNS therapies during its enforceable period.
- Competition in the space has shifted toward newer patents on derivatives and delivery devices.
Summary
Scope and Claims: The '021 patent covers methods for treating CNS disorders by administering broad classes of sulfonamide derivatives, with claims encompassing specific chemical structures, dosage forms, and treatment regimens. The language favors broad coverage but is limited by prior art references and the specific chemical genus defined.
Patent Landscape: The patent is part of a broader landscape of sulfonamide compounds targeting CNS activity. The patent expired in around 2013, permitting generic development. The landscape includes related patents on derivatives, formulations, and delivery methods issued subsequently.
Key Takeaways
- The '021 patent broadly covers sulfonamide derivatives for CNS treatment, focusing on method claims.
- Its effective life span has ended, reducing barriers for generics.
- The patent landscape features a dense cluster of related patents, especially on derivatives and formulations targeting CNS disorders.
- Companies with original rights may have pursued subsequent patents to extend patent protection.
FAQs
Q1. Are the chemical compounds claimed in the '021 patent still under patent protection?
No. The patent expired around 2013, opening the field to generic competition.
Q2. Does the '021 patent cover only a specific compound?
No. It claims a broad genus of sulfonamide derivatives with structural variations.
Q3. Can a company now manufacture and sell drugs based on the compounds described?
Yes, provided they do not infringe other active patents, especially later filings on derivatives or formulations.
Q4. Are there ongoing litigations related to this patent?
Available records do not indicate current litigations directly involving the '021 patent; enforcement period ended with the patent expiration.
Q5. How does the patent landscape influence drug development in this area?
The expiration led to increased generic activity; current development focuses on newer derivatives and delivery methods covered by newer patents.
References
- U.S. Patent 5,519,021. (1996). "Methods of treating diseases."
- European Patent No. 0 672 698. (Prior art related to sulfonamide compounds.)
- U.S. Patent Nos. 4,599,279; 4,652,441. (Related ex copious prior art on sulfonamide derivatives targeting CNS disorders.)
