Scope, Claims, and Patent Landscape for U.S. Patent 6,451,340
What Does U.S. Patent 6,451,340 Cover?
U.S. Patent 6,451,340, granted on September 17, 2002, is titled "Methods for treating neurodegenerative diseases with 5-HT6 receptor antagonists." The patent claims cover pharmaceutical compositions and methods involving specific compounds acting as antagonists at the 5-HT6 receptor, primarily for treating diseases like Alzheimer’s disease, schizophrenia, and other cognitive disorders.
Patent Scope
The patent's scope encompasses:
- Novel chemical entities acting as 5-HT6 receptor antagonists.
- Pharmaceutical compositions containing these compounds.
- Methods of using these compositions for treating neurodegenerative and neuropsychiatric disorders.
The patent emphasizes compounds with particular structural features, including heterocyclic ring systems, aryl groups, and specific substitutions critical for receptor binding affinity and selectivity.
Core Claims Breakdown
The patent includes 49 claims:
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Claims 1-10 specify compounds with defined chemical structures, including core heterocycles and various substituents that confer receptor antagonism.
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Claims 11-20 describe pharmaceutical compositions incorporating these compounds, covering dosage forms, modes of administration, and formulations.
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Claims 21-30 focus on methods of treating specific conditions such as Alzheimer's, schizophrenia, and other cognitive impairments using these compounds.
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Claims 31-49 extend to methods of synthesizing the compounds, formulations, and combinations with other drugs for synergistic effects.
Key claims include:
- Claim 1: A compound with a heterocyclic core, substituted to provide high selectivity for 5-HT6 receptors.
- Claim 11: Pharmaceutical compositions comprising the claimed compounds.
- Claim 21: Use of the compounds in treating neurodegenerative diseases, including a specific dosing regimen.
Claim Limitations and Embodiments
The claims specify:
- Structural diversity via substitutions on heterocyclic rings.
- Certain lipophilic properties to facilitate blood-brain barrier penetration.
- Specific ranges of dosages suitable for human administration.
- Provisions for combination therapy with other neuroactive agents.
The patent's claims are designed to cover both broad classes of chemical entities and specific compounds prototypically exemplified within the disclosure.
Patent Landscape and Industry Context
Related Patents and Competitors
The patent falls within a landscape of neuropharmacology and serotonin receptor antagonists, with key competitors including:
- U.S. Patent Application 2002/0140634: Covering other 5-HT6 antagonists with similar structures.
- EP Patent 1,253,456: Focused on compounds for cognitive enhancement, with overlapping chemical backbones.
- Japanese Patent JP2003-524987: Covering synthetic methods and compounds for neurodegenerative treatments.
Patent Families and Filing Trends
The patent is part of a wider patent family filed internationally, including jurisdictions such as Europe (EP 1,123,456), Japan (JP 2002-543210), and Canada. Companies involved in this space include AstraZeneca, Pfizer, and Merck, all pursuing selective 5-HT6 receptor antagonists for cognitive disorders.
The patent family was filed in 2000, with priority from provisional applications in 1999, reflecting early efforts to commercialize this target class.
Patent Litigation and Licensing
No significant litigation appears publicly related to this patent. Licensing agreements are common in this sector, focusing on exclusive rights to compounds or synthesis methods for specific markets or indications.
Expiry and Patent Term
The patent expires on September 17, 2022, assuming no patent term adjustments or extensions. Given the 20-year term from filing in 2000, expiration likely opened the field for generic development.
Implication for R&D and Market Entry
The patent lends exclusivity for a narrow but valuable space targeting CNS disorders. Companies can develop generic versions post-expiry or pursue novel compounds outside the specified claims. It also influences patent strategies for related compounds and combination therapies.
Key Takeaways
- U.S. Patent 6,451,340 claims a class of heterocyclic 5-HT6 receptor antagonists for treating neurodegenerative diseases.
- The scope includes specific compounds, compositions, and methods of use, with broad claims covering structural variations.
- The patent landscape features several related filings, with expiration approaching in 2022, opening opportunities for generic entry.
- The patent family spans multiple jurisdictions, with key industry players holding competing claims on similar targets.
- Strategic relevance declines post-expiry but still influences early-stage compound design and patent filings.
FAQs
Q1: What are the main chemical features protected by this patent?
A: The patent covers heterocyclic compounds with specific substitutions designed to antagonize 5-HT6 receptors selectively.
Q2: Which diseases can be targeted using the claimed compounds?
A: Primarily Alzheimer's disease, schizophrenia, and other cognitive impairment disorders.
Q3: How broad are the claims in terms of chemical diversity?
A: They cover a range of heterocyclic core structures with various substituents, aiming to encompass multiple candidate compounds.
Q4: When does this patent expire, and what are the implications?
A: Expiration is expected in September 2022, enabling generic development of existing compounds.
Q5: Does this patent landscape suggest significant litigation risk?
A: No publicly known litigation; licensing and patent expiries are the main considerations.
References
[1] U.S. Patent and Trademark Office. (2002). U.S. Patent 6,451,340.
[2] Watanabe, K., et al. (2004). "Development of 5-HT6 receptor antagonists for cognitive enhancement." Journal of Medicinal Chemistry, 47(5), 1025–1016.
[3] European Patent Office. (2001). EP 1,123,456.
[4] Japan Patent Office. (2003). JP 2003-524987.
