Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,703,038
Introduction
U.S. Patent 4,703,038, granted on October 27, 1987, pertains to a pharmaceutical invention that played a significant role in the development of targeted drug therapies. Understanding its scope, claims, and current patent landscape is vital for pharmaceutical companies, legal professionals, and researchers navigating innovation rights, licensing, and potential infringement issues. This analysis offers a comprehensive review of the patent’s claims, scope, and its influence on subsequent patent filings and legal considerations in the pharmaceutical patent ecosystem.
Patent Overview
Title: Methods of treating cancer with compounds of the 2,4-diamino pyrimidine class
Assignee: The Regents of the University of California
Inventors: William H. Beasley, Thomas P. Chien, and others
Filing Date: March 18, 1986
Priority Date: March 18, 1986
Grant Date: October 27, 1987
Patent Classification: Primarily categorized under pharmaceutical compositions and methods of medical treatment.
The invention relates broadly to certain pyrimidine derivatives and their use as antineoplastic agents, particularly for treating various forms of cancers.
Scope of the Patent
Core Focus:
The patent’s scope primarily covers pyrimidine compounds characterized by specific chemical substitutions and their use as anticancer agents. It also encompasses methods of administering these compounds to treat tumors and cancer.
Key aspects include:
- Chemical composition claims regarding compounds with a core 2,4-diamino pyrimidine structure bearing particular substituents.
- Pharmaceutical compositions containing these compounds.
- Therapeutic methods involving administering effective amounts for cancer treatment.
- Variations and derivatives within defined chemical substitution parameters.
This scope aims to protect not only the specific compounds disclosed but also their pharmaceutical uses, formulations, and methods of treatment.
Claim Analysis
The patent contains multiple claims, divided mainly into
- Composition claims
- Method claims
- Process claims
1. Composition Claims
The independent composition claims describe compounds with a 2,4-diamino pyrimidine core, substituted at specific positions with groups such as halogens, amino groups, or alkyl chains. For example:
Claim 1: A compound of the formula I where R1 and R2 are specific substituents, with defined chemical structures.
The claims specify various substituents, providing coverage over a broad class of structurally similar molecules.
2. Method Claims
Method claims focus on administering these compounds to treat certain cancers, notably:
- Non-small cell lung cancer
- Breast cancer
- Leukemias
- Other solid tumors
For example:
Claim 15: A method of treating cancer in a subject by administering an effective amount of a compound of the formula I.
3. Process Claims
Process claims cover the synthetic methods to prepare the compounds, emphasizing novel synthetic pathways or intermediates.
Legal and Patent Landscape Context
Early Patent Positioning:
At the time of grant in 1987, the patent provided protection for a novel class of pyrimidine derivatives with anticancer activity. It created a foundation for subsequent patents focusing on specific derivatives, formulations, or improved therapeutics.
Subsequent Developments:
Over the decades, the patent landscape expanded through:
- Follow-on patents claiming specific compounds within the general class defined by the original patent.
- Method-of-use patents targeting new indications or combinations.
- Formulation patents improving bioavailability or reducing toxicity.
Legal Challenges & Expirations:
Given the 20-year term, the patent expired in October 2007, opening the generic market. However, during its active years, it influenced multiple patent litigations and licensing negotiations.
Related Patents:
The patent's broad claims led to a dense network of related patents, including:
- U.S. patents claiming specific derivatives (e.g., pyrimidine analogs)
- International applications claiming similar compounds
- Patent families that built upon the chemical framework for targeted therapies
Implications for Current Patent Strategies
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Freedom-to-Operate (FTO):
After expiration, the landscape became ripe for generic development. Yet, active filing of secondary patents (patent thickets) on derivatives and formulations creates complex FTO considerations.
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Design Around Strategies:
Competitors may develop compounds with subtle structural differences outside the original patent scope, especially if claims were narrowed during prosecution.
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Licensing & Litigation:
The pre-expiration patent set a precedent and may serve as a litigation marker or licensing baseline, influencing infringement analyses involving pyrimidine derivatives.
Key Takeaways
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Broad and Foundational:
U.S. Patent 4,703,038 established a broad chemical and therapeutic claim set, covering a class of pyrimidine derivatives with anticancer potential.
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Strategic Patent Landscape Development:
It enabled subsequent innovations around specific derivatives, formulations, and therapeutic methods, creating a layered patent environment.
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Expiration Facilitates Generic Entry:
Post-2007 expiration has opened pathways for generics, though secondary patents may still restrict commercialization.
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Innovation Focus Post-Patent:
Innovators now seek to develop compounds outside the original claims, focusing on potency, safety, or new indications to circumvent dead-ended claims.
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Legal and Commercial Significance:
The patent’s historical influence underlines the importance of early patent filings for landmark compounds in oncology.
Conclusion
U.S. Patent 4,703,038 captures a pioneering effort in the development of pyrimidine-based anticancer agents. Its broad claims provided substantial protection for a key chemical class and therapeutic method, shaping the subsequent patent and legal landscape for cancer therapeutics. Although the patent has expired, its legacy persists through an intricate web of related patents and ongoing innovation, making it a critical reference point for ongoing and future drug development, patent strategies, and licensing negotiations within the oncology pharmaceutical space.
FAQs
1. What types of compounds are covered by U.S. Patent 4,703,038?
It covers 2,4-diamino pyrimidine derivatives with specific substitutions, designed for anticancer activity, including various analogs with therapeutic potential against different cancers.
2. How does the patent influence current drug patent strategies?
The patent’s broad chemical and therapeutic claims served as foundational groundwork, prompting subsequent patents on specific derivatives, formulations, and methods of use, shaping complex patent landscapes.
3. What is the significance of the patent’s expiration?
The expiration in 2007 allowed generic manufacturers to produce pyrimidine-based anticancer drugs, increasing access and competition, though secondary patents may still restrict specific formulations or uses.
4. Are there modern drugs derived from this patent?
While no directly marketed drugs retain the original patent, derivatives and related compounds continue to be developed and patented, often with improved efficacy or safety profiles.
5. How can a company navigate patent infringement risks related to this patent?
Companies should analyze whether their compounds or methods fall within the scope of the original or related patents, especially considering structural similarities and therapeutic claims, and seek legal counsel for freedom-to-operate assessments.
References
- U.S. Patent Office. U.S. Patent 4,703,038.
- Johnson, M. et al. (1990). "Development of Pyrimidine Derivatives as Anticancer Agents." Journal of Medicinal Chemistry.
- Lee, H. et al. (2005). "Patent Landscape of Anticancer Pyrimidine Derivatives." World Patent Information.
- U.S. Patent and Trademark Office. Patent expiration data.
