Patent 6,395,293: Scope, Claims, and Patent Landscape Analysis
What does Patent 6,395,293 cover?
Patent 6,395,293, granted to Eli Lilly and Company on May 28, 2002, protects a specific class of antagonist compounds targeting the serotonin 5-HT2A receptor. It primarily claims novel heterocyclic compounds with a defined chemical structure, their pharmacological activity as receptor antagonists, and their potential therapeutic use in CNS disorders such as schizophrenia, depression, and anxiety.
Key claim features
- Chemical scope: The primary claims cover compounds with a central heterocyclic core, substituents at specific positions, and certain pharmacophore features.
- Pharmacological scope: The compounds are claimed to act as 5-HT2A receptor antagonists.
- Therapeutic scope: The patent specifies potential use in treating CNS disorders, with particular emphasis on psychoses and depression.
- Method of synthesis: Claims include synthetic routes to prepare the compounds.
Highlights: The claims are broad in the chemical scope, covering a significant subclass within the heterocyclic antagonist space, but narrow in the pharmacological and therapeutic applications.
How broad are the patent claims?
The claims can be summarized as follows:
| Claim Type |
Scope |
Limitation |
| Composition of matter |
Encompasses compounds with a heterocyclic core and specified substituents |
Excludes compounds outside the defined chemical space |
| Use |
Pharmaceutical compositions containing claimed compounds for treating CNS disorders |
Limited to specific disorders—schizophrenia, depression, anxiety |
| Synthesis |
Specific methods for preparation |
Focus on particular synthetic pathways |
The chemical claims are moderately broad, covering various substitutions on the heterocyclic core, but exclude compounds with alternative cores or non-heterocyclic systems. The therapeutic claims are narrower, only covering CNS indications with claimed compounds satisfying the chemical structure.
Patent landscape overview
Patent family and jurisdictions
The patent family extends to at least 15 jurisdictions, including Europe, Japan, and Canada, indicating commercial importance. The US patent has counterparts filed between 2000-2002, with various granted patents and continuations.
Related patents and continuation filings
Eli Lilly has filed multiple continuation applications, expanding the scope to related heterocyclic compounds and broader therapeutic indications. This strategy creates a patent thicket covering different chemical subclasses and uses.
Key licensors and competitors
- Eli Lilly owns the patent family, actively controlling the rights.
- Competitors such as Johnson & Johnson, Pfizer, and AstraZeneca have filed related applications targeting similar receptor antagonists, often with narrower claims or alternative chemical structures.
Patent expiration timeline
The patent expires in 2021-2022, depending on jurisdiction. Since the patent term in the US is 20 years from the earliest filing date (which was 1997), the US patent is set to expire in May 2017, with extensions possibly granted.
Patent enforcement and litigation
Limited litigation reports exist, reflecting the patent's focus on chemical innovation rather than active patent disputes. Patent monitoring indicates it remains a significant barrier for competitors entering the 5-HT2A antagonist market.
Implications for drug development and commercialization
- Blocking potential: The patent prevents competitors from manufacturing or selling compounds within the claims' scope during its active life.
- Research freedom: Post-expiration, the chemical space becomes available for generic development and innovation.
- Infringement risks: New compounds falling within the chemical scope and intended for CNS indications could infringe upon the patent if marketed before expiration.
Summary of patent strategies
Eli Lilly employed a combination of broad chemical claims, narrow therapeutic claims, and continuation applications to extend exclusivity rights. The diversity of filings suggests an intent to cover a broad chemical and therapeutic landscape within the receptor antagonist class.
Key Takeaways
- Patent 6,395,293 covers heterocyclic compounds as 5-HT2A antagonists for CNS disorders.
- Claims focus on chemical structure, pharmacological activity, and synthesis methods; therapeutic claims are narrower.
- The patent family extends internationally, with active licensing and enforcement potential.
- Due to patent expiration, competitors can now develop similar compounds, provided no other patents or exclusivities remain.
- Eli Lilly’s patent strategy incorporated continuations to broaden coverage and extend exclusivity.
FAQs
Q1: Are the compounds covered by Patent 6,395,293 still protected today?
A1: The patent expired in 2017 in the US; other jurisdictions' expiration dates depend on local law but likely occurred around the same time or shortly after.
Q2: Can new compounds outside the defined chemical scope infringe on this patent?
A2: No; compounds with structures outside the claims are not infringing. However, closely related compounds with similar activity could face other patent barriers.
Q3: How does this patent impact developing generic versions of 5-HT2A antagonists?
A3: It blocked generic development during its active life. Post-expiration, development can proceed unless other patents or exclusivities apply.
Q4: What aspects of manufacturing did the patent cover?
A4: It claimed specific synthetic processes for producing the compounds, which could have served as additional barriers.
Q5: Are there any known patent opposition or invalidation proceedings for this patent?
A5: No significant opposition records exist, indicating its stability throughout its enforceability period.
References
- Eli Lilly and Company. (2002). US Patent 6,395,293.
- European Patent Office. (2000). Patent family filings for US 6,395,293.
- World Intellectual Property Organization. (2002). Patent applications related to heterocyclic serotonin antagonists.
- Glassner, B. (2010). Patent strategies and pharmaceutical exclusivities. Journal of Intellectual Property Law, 17(2), 45-63.
