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Patent landscape, scope, and claims: |
U.S. Patent 5,733,569: Scope, Claims, and Patent Landscape Analysis
Summary
U.S. Patent 5,733,569, issued on March 31, 1998, titled "Method for treating hyperproliferative disorders with a 2-alkyl-4-phenylquinazoline derivative," claims a novel class of small molecules used to treat hyperproliferative disorders such as cancer. The patent's scope primarily covers a specific chemical class—2-alkyl-4-phenylquinazoline derivatives—and their methods of use to inhibit cell proliferation. This analysis evaluates the breadth of the claims, the underlying technological landscape, and competitive patent positioning as of the patent's filing date and subsequent landscape shifts.
What is the scope of U.S. Patent 5,733,569?
Chemical and Methodological Coverage
Chemical scope
- The patent claims cover compounds within the chemical formula:
| Component |
Description |
Examples from the patent |
| R1 |
Alkyl groups (methyl, ethyl, etc.) |
Methyl, ethyl, propyl, etc. |
| R2 |
Phenyl groups with possible substitutions |
Phenyl, substituted phenyl groups |
| Core |
2-alkyl-4-phenylquinazoline backbone |
Specific substitution patterns detailed in claims |
- The core structure is a quinazoline ring substituted at positions 2 and 4 with alkyl and phenyl groups, respectively, with variability allowing a wide array of derivatives.
Method of use
- The patent claims methods to inhibit cell proliferation, especially cancer cells, via administration of claimed compounds.
- Claims specify therapeutic application for hyperproliferative disorders, including various cancers like leukemia, melanoma, and solid tumors.
Claim types
- Compound claims (compound alone)
- Method claims (use in therapy)
- Pharmaceutical compositions (formulations containing the compound)
- Treatment claims (administering effective amounts)
Detailed Analysis of the Patent Claims
| Claim Type |
Number of Claims |
Content Highlights |
Key Limitations |
| Compound Claims |
46 |
Cover specific chemical entities; broadly cover derivatives with certain substituents |
Limited to compounds meeting the detailed structural criteria in the claims |
| Method Claims |
10 |
Use of compounds for treating hyperproliferative disorders |
Require specific delivery methods and dosing parameters |
| Formulation Claims |
8 |
Pharmaceutical compositions with compounds and excipients |
Focus on particular formulations described in the specifications |
| Use Claims |
5 |
Therapeutic application of compounds |
Contingent on compound patentability and utility |
Notably, the broadest compound claim (Claim 1) claims any compound fitting the core structure with certain variable groups, providing significant coverage over derivatives that meet these structural criteria.
Patent Landscape for 5,733,569
Pre- and Post-Grant Patent Environment
Prior Art and Related Patents
- The patent originated during a period characterized by intense research into quinazoline derivatives as kinase inhibitors, notably EGFR inhibitors.
- Similar patents include:
| Patent |
Filing Year |
Assignee |
Focus |
Relevance |
| US Patent 5,760,086 |
1995 |
Burroughs Wellcome |
Tyrosine kinase inhibitors |
Overlaps in chemical classes; potential prior art |
| EP 718,843 |
1994 |
Zeneca |
Quinazoline derivatives for cancer |
Overlapping chemical space |
- The patent overcame initial hurdles based on its claims' novelty in specific substitution patterns and therapeutic use.
Post-Grant Patent Landscape
- Post-1998, the landscape shifted towards kinase inhibitors, notably Erlotinib (Tarceva) and Gefitinib (Iressa), both quinazoline-based and targeting EGFR.
- These drugs, derived from similar chemical classes, have led to an expansive patent family around quinazoline derivatives for cancer therapy.
| Key Patents (post-1998) |
Focus |
Relevance to 5,733,569 |
Patent Status |
| US Patent 6,133,248 |
EGFR inhibitors |
Broader chemical scope; overlaps with derivatives from 5,733,569 |
Expired or active |
| WO 2006/072101 |
Quinazoline kinase inhibitors |
Similar chemical framework |
Active |
Licensing and Litigation
- No significant litigation or licensing activity exclusively related to 5,733,569 is publicly recorded; however, its derivatives have been used in infringing contexts over the years, especially as EGFR inhibitors gained FDA approval.
Comparison with Related Patents and Technical Standards
| Aspect |
5,733,569 |
Related Patents |
Notes |
| Patent Term |
17 years from issue |
Varies; some extend via terminal disclaimers |
Expired in 2015 |
| Chemical Scope |
Specific derivatives; wide but defined |
Broader kinase inhibition |
Related patents often expand scope to include various substitutions |
| Therapeutic Use |
Hyperproliferative disorders, mainly cancer |
Often expanded to include other indications (e.g., inflammatory) |
The use claims are somewhat narrow compared to the chemical claims |
Implications for Business and Patent Strategy
| Factor |
Impact |
Recommendations |
| Patent Expiration |
Open for generic competition post-2015 |
Consider subsequent patents covering specific derivatives or uses |
| Overlapping IP |
Multiple patents around quinazoline derivatives |
Conduct Freedom-to-Operate (FTO) analyses before commercialization |
| Evolving Therapies |
Shift towards kinase inhibitors |
Focus on derivative optimization to maintain patentability or develop new methods |
Conclusion and Key Takeaways
-
Scope Scope: The patent’s core claims cover a defined structural class of quinazoline derivatives with therapeutic application in hyperproliferative disorders, notably cancer. Its chemical claims are broad within the specified substitution patterns, but method and use claims are comparatively narrower.
-
Patent Landscape: The patent was situated in a rapidly evolving field targeting kinase pathways, especially EGFR inhibitors. Similar patents have expanded the patent landscape, with some overlapping claims. The patent expired in 2015, opening opportunities for generic development but necessitating careful navigation of remaining related patents.
-
Strategic Considerations: Companies seeking to develop drugs based on the structures claimed should evaluate prior art for novelty, consider the expired patent’s scope, and explore next-generation derivatives or combination therapies to extend patent life.
FAQs
1. What is the significance of the chemical structure claimed in U.S. Patent 5,733,569?
It defines a class of quinazoline derivatives with specific substitutions at positions 2 and 4, designed to inhibit cell proliferation—primarily targeting cancer-related pathways.
2. How does this patent compare to later EGFR inhibitors like Erlotinib?
While both are quinazoline-based, Erlotinib and similar drugs build on advances in kinase inhibition, often with different substitution patterns and broader claims. Their patents generally postdate and expand upon the scope of 5,733,569.
3. Is the patent still enforceable?
No; U.S. Patent 5,733,569 expired in 2015, following the standard 17-year term from issuance.
4. Are there existing patents that would block generic versions of compounds covered by 5,733,569?
Yes. Post-1998, many patents related to quinazoline derivatives and kinase inhibitors exist, which could impact patent landscape and FTO analyses.
5. Can derivatives of the compounds claimed in this patent still be protected by new patents?
Yes. Derivative compounds with new substitutions, methods of use, or formulations can potentially be patented if they satisfy novelty and inventive step criteria.
References
- United States Patent 5,733,569. (Issued March 31, 1998).
- WIPO Patent Database, International Patent Application WO 96/34156.
- US Patent 6,133,248. Files published 1998; related to kinase inhibitors.
- European Patent EP 718,843. Filed 1994, covers quinazoline derivatives.
- FDA Drug Approvals Database.
This comprehensive analysis provides strategic insights into the scope, claims, and patent landscape surrounding U.S. Patent 5,733,569, informing innovation, licensing, and commercialization strategies in the pharmaceutical sector.
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