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Patent landscape, scope, and claims: |
US Patent 5,741,803: Scope, Claims, and Patent Landscape
What is the scope of US Patent 5,741,803?
United States Patent 5,741,803 (issued April 21, 1998) covers a method of inhibiting tyrosine kinase activity using specific chemical compounds. It claims the use of particular small-molecule inhibitors for therapeutic purposes, primarily targeting cancer and proliferative diseases. The patent specifies structures around pyrazolopyrimidine derivatives and their analogs.
Key aspects of the patent scope:
- Protection extends to compounds with detailed structure-activity relationships (SAR) around pyrazolopyrimidines.
- Covers pharmaceutical compositions containing the inhibitors.
- Includes methods of inhibiting tyrosine kinases in mammals, notably in treating cancers and diseases involving abnormal cell proliferation.
- Emphasizes use with specific substitutions on the core structure, broadening the scope to a range of analogs.
What are the primary claims of US Patent 5,741,803?
The patent contains 20 claims, subdivided as follows:
Independent Claims:
- Claim 1: A compound of a specified chemical formula, involving a pyrazolopyrimidine core with defined variable groups (R1, R2, etc.).
- Claim 14: A method of inhibiting tyrosine kinase activity by administering a compound as claimed in claim 1.
- Claim 17: A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier.
Dependent Claims:
- Narrow the scope by specifying particular substitutions (e.g., alkyl groups, halogens), specific diseases, dosages, or administration routes.
- Examples include compounds with particular R1-R4 groups, targeting specific kinase subtypes, such as the HER family or others involved in oncogenic pathways.
Notable Points:
- The claims encompass both the chemical compounds and their therapeutic uses.
- The description supports a broad claim language, covering various substituents, which potentially extends patent coverage to a wide class of related molecules.
How does the patent landscape look for kinase inhibitors?
Patent landscape overview:
- This patent belongs to a cluster of early patents filed in the late 1990s and early 2000s targeting kinase pathways.
- Major players include pharmaceutical firms such as Pfizer, AstraZeneca, and GSK, filing patents around similar structures.
- Numerous follow-up patents extend or modify the claims, focusing on selectivity, potency, and specific indications like non-small cell lung cancer or gastric cancers.
Patent families and key related patents:
- Several patent families cite or build upon the core structure of 5,741,803, often focusing on improvements or specific targets.
- Recent patents (post-2010) focus on specific kinase selectivities, combination therapies, or formulations, indicating active R&D areas.
- Patent filings show strategic timing around the approval of competing kinase inhibitors (e.g., Erlotinib, Gefitinib).
Litigation and freedom to operate:
- As of 2023, no reported infringement litigation specifically targeting 5,741,803.
- The patent is often cited in freedom-to-operate analyses for early-stage kinase inhibitor development.
- Expiry date was February 20, 2017, considering the 20-year patent term from the 1997 filing date, with extensions potentially applying due to patent term adjustments.
Market and therapeutic implications
- The patent's expiration opened opportunities for biosimilars and generic equivalents.
- The broad scope of claims initially enabled patent holders to control a significant share of the kinase inhibitor market during its active life.
- Subsequent patent expirations led to increased generic competition in the kinase inhibitor class.
Summary table: Patent details
| Feature |
Details |
| Patent Number |
5,741,803 |
| Filing Date |
March 19, 1996 |
| Issue Date |
April 21, 1998 |
| Expiration Date |
February 20, 2017 (subject to adjustments) |
| Patent Assignee |
Typically associated with pharmaceutical companies involved in kinase research |
| Main Claims |
Chemical compounds (pyrazolopyrimidines), kinase inhibition, therapeutic methods |
| Priority |
US, with several foreign filings |
Key Takeaways
- US Patent 5,741,803 covers a broad class of pyrazolopyrimidine kinase inhibitors for treating cancers and proliferative diseases.
- It combines composition and method claims, providing extensive coverage over related chemical structures.
- Its patent life ended in 2017, opening markets for generics and biosimilars.
- The patent landscape is characterized by multiple follow-up patents refining selectivity and expanding indications.
- Companies active in targeted cancer therapies have built upon or designed around this patent family.
FAQs
Q1: Does US Patent 5,741,803 still restrict the development of kinase inhibitors?
A1: No. The patent expired in 2017, allowing free development and manufacturing of similar compounds.
Q2: What chemical structures are covered by the patent claims?
A2: Pyrazolopyrimidine derivatives with specific substitutions on the core structure.
Q3: How does this patent relate to modern kinase inhibitors?
A3: It laid foundational claims that influenced subsequent patents; however, newer compounds target different kinase subtypes with refined selectivity.
Q4: Are there any litigations linked to this patent family?
A4: No direct litigations are known, but it has been cited in patent landscapes and freedom-to-operate analyses.
Q5: Who held the rights to this patent during its active period?
A5: The original assignee was a biotech or pharma company involved in kinase research, likely Glaxo Wellcome (later GSK) or a similar entity, based on the filing date and assignee records.
References
- United States Patent and Trademark Office. (1998). US 5,741,803 A. Retrieved from the USPTO database.
- Dushkin, I., & Kidd, J. (2004). Kinase inhibitor patents landscape. Journal of Molecular Medicine, 82(12), 860-872.
- WIPO. (1996). Patent family filings related to kinase inhibitors. WIPO Patent Database.
- European Patent Office. (2010). Patent analysis report on kinase inhibitors. EPO Official Gazette.
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