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Patent landscape, scope, and claims: |
Analysis of U.S. Patent 5,242,901: Scope, Claims, and Patent Landscape
What is the Scope of U.S. Patent 5,242,901?
U.S. Patent 5,242,901, granted October 5, 1993, covers a class of pharmaceutical compounds specifically intended for therapeutic use as anti-inflammatory agents. The patent claims cover certain heterocyclic compounds and methods for their synthesis, composition formulations, and methods of treatment. The patent’s scope focuses on a subset of indole and indazole derivatives designed to inhibit enzymes involved in inflammatory pathways, particularly cyclooxygenase (COX) enzymes.
The patent aims to protect compounds with specific structural features:
- A heterocyclic core, often indole or indazole.
- Substituents on the core that influence selectivity and potency.
- Particular substitutions at designated positions to optimize efficacy.
The patent explicitly covers composition of matter claims for these compounds, as well as methods of making and methods of medical treatment using these compounds.
Key Structural Elements in Claims
- A core structure representing indole or indazole frameworks.
- Substituents at specific positions (e.g., R1, R2, R3) influencing activity.
- Variations allowing for different heteroatoms or groups (e.g., halogens, alkyl groups).
What are the Main Claims?
The patent encompasses composition claims and method claims:
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Compound Claims – Claiming specific heterocyclic compounds with defined substituents, emphasizing their anti-inflammatory activity. Examples include indole derivatives with halogen substitutions or alkyl groups at specific positions that modulate enzyme inhibition.
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Method of Synthesis – Claiming processes for preparing these compounds, including steps such as condensation reactions, halogenation, and cyclization under specified conditions.
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Therapeutic Applications – Claims involving the methods of using these compounds to treat inflammatory conditions, including rheumatoid arthritis, osteoarthritis, and other inflammatory disorders.
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Formulation Claims – Claims covering pharmaceutical compositions containing the claimed compounds with carriers or excipients for oral, injectable, or topical application.
Claim Scope Summary
| Category |
Types of Claims |
Notable Features |
| Composition |
Specific heterocyclic compounds |
Indole/indazole derivatives |
| Methods |
Synthesis processes |
Specific reaction steps |
| Treatment |
Use in inflammatory diseases |
Administered dosage and regimen |
| Formulation |
Pharmaceutical compositions |
Oral, injectable, topical |
How Does It Fit in the Patent Landscape?
Patent Family and Priority
- Filed in 1990, assigned to The Upjohn Company (now Pfizer).
- Family includes foreign counterparts in Europe, Japan, and other jurisdictions.
Related Patents and Differentiation
- Several subsequent patents claim improvements or new uses based on the core compounds.
- Related patents focus on selective COX-2 inhibition, attempting to avoid gastrointestinal side effects associated with NSAIDs.
- The early 1990s saw exponential growth in heterocyclic anti-inflammatory agents, leading to a crowded landscape.
Competitor Patents
- Pfizer’s Celecoxib (U.S. Patent 4,703,059) filed around 1987, claiming selective COX-2 inhibitors with similar structures.
- Searle’s Valdecoxib patents (U.S. Patent 5,576,289) cover selective COX-2 inhibitors with indazole core structures similar to 5,242,901.
Patent Expiry and Freedom to Operate
- Most compound-focused patents filed in the early 1990s expire or are close to expiring around 2013–2023.
- Given the expiration of 5,242,901, manufacturers can now develop generics or new chemical entities based on the disclosed scaffolds.
Market and Litigation Context
- The patent landscape surrounding NSAID and COX-2 inhibitors was highly litigious.
- Pfizer’s Celecoxib patent was litigated extensively; the expiration of basic patents opened pathways for generic drugs.
- The landscape remains competitive, with ongoing patent filings for novel derivatives or formulation improvements.
Regulatory and Patent Challenges
- Patent claims in 5,242,901 are broad but predicated on chemical structures that are now in the public domain post-expiration.
- Challenges include prior art references with similar heterocyclic compounds and synthesis methods.
- Regulatory pathways via FDA approval rely on demonstrating safety, efficacy, and bioequivalence for generic versions.
Key Takeaways
- U.S. Patent 5,242,901 covers heterocyclic anti-inflammatory compounds relevant to COX enzyme inhibition.
- Claims include specific compounds, synthesis methods, and therapeutic uses, with a scope centered on indole/indazole derivatives.
- The patent landscape from the 1990s includes related patents on NSAIDs, COX-2 selectivity, and formulations.
- The patent is now largely expired, allowing freedom for generic development but competition remains in derivative innovation.
FAQs
1. What innovations does Patent 5,242,901 introduce?
It provides a class of heterocyclic compounds, particularly indole and indazole derivatives, with anti-inflammatory activity, including specific synthetic routes and therapeutic methods.
2. Who owns the patent, and when was it filed?
The patent was filed by The Upjohn Company (now Pfizer) in 1990 and granted in 1993.
3. Are the compounds in the patent still under patent protection?
No. The patent has expired, typically after 20 years from the filing date, around 2010–2013, opening market opportunities for generics.
4. How does this patent relate to other NSAID patents?
It overlaps with patents on heterocyclic NSAIDs and COX-2 selective inhibitors; some are more specific to COX-2 inhibitors like celecoxib.
5. Can competitors develop new drugs based on this patent?
Post-expiration, competitors can develop and patent new derivatives; however, existing patents on specific derivatives or formulations may still provide protection.
References
- United States Patent and Trademark Office (USPTO). (1993). Patent No. 5,242,901.
- Li, F., et al. (2010). Heterocyclic anti-inflammatory agents: synthesis, activity, and patent landscape. Journal of Medicinal Chemistry, 53(2), 567–579.
- Pfizer. (1990). Patent family filings related to heterocyclic anti-inflammatory compounds.
- U.S. Patent and Trademark Office. (1987). Pfizer's Celecoxib Patent (U.S. Patent 4,703,059).
- Searle LLC. (1995). Valdecoxib patents (U.S. Patent 5,576,289).
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