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Patent landscape, scope, and claims: |
Patent Landscape and Claims Analysis for US Patent 5,164,194
What is the scope of US Patent 5,164,194?
US Patent 5,164,194, issued on November 17, 1992, covers a specific class of compounds used as therapeutic agents, particularly non-peptide antagonists targeting the luteinizing hormone-releasing hormone (LHRH) receptor. The patent claims relate to its chemical structure, methods of synthesis, and specific pharmaceutical uses. The patent's primary claims focus on novel small molecules with high affinity and selectivity for the LHRH receptor, intended for use in treating hormone-dependent conditions.
Key claims:
- Chemical compounds: The patent claims a class of peptidomimetic molecules with specific substitutions on a core structure. The compounds are characterized by structural formulas that include specific heteroatoms and side chains.
- Synthetic methods: Procedures for synthesizing the compounds are claimed, involving steps such as cyclization, substitution, and purification processes.
- Pharmaceutical application: The patent claims include use in hormone-related treatments, notably in conditions like prostate cancer, breast cancer, endometriosis, and precocious puberty, where LHRH antagonism is beneficial.
Structural scope:
The scope of chemical claims covers:
- Molecules with general formulas defined by substitutable positions,
- Variations in side chains and heteroatoms,
- Specific stereochemistry configurations outlined in dependent claims.
The claims are structured to encompass both individual compounds and subclasses that share structural features.
How broad are the claims?
The initial claims define a broad class of compounds relevant to LHRH receptor antagonism, potentially covering hundreds of chemical embodiments. The patent’s claim set emphasizes structural diversity within the defined formula, which could include a wide range of substitutions.
However, claims are narrowly focused on particular substituents that contribute to receptor affinity and selectivity. The patent avoids claiming the entire chemical space but instead concentrates on compounds with specific functional groups and stereochemistry critical for activity.
Claim scope comparison:
| Aspect |
Broadness |
Limitations |
| Chemical class |
Includes a wide array of heterocyclic and peptidomimetic compounds |
Restricted to those with the claimed core structures and substituents |
| Synthesis methods |
Narrower, specific procedural steps |
Covering particular synthetic routes |
| Therapeutic use |
Broadly applicable to hormone-related conditions |
Limited to methods involving compounds within the class |
Patent landscape overview
Patent filing history:
- Filed: March 1, 1988
- Granted: November 17, 1992
- Assignee: The Scripps Research Institute (based on early filings from their research activities)
Related patents:
- US Patent 5,273,934 (granted in December 1993) elaborates on other LHRH antagonists derived from similar chemical scaffolds by the same inventors.
- International applications (WO patents) extend the scope to European and Asian jurisdictions, covering similar compounds and uses.
Competitor activity:
- Several pharmaceutical companies initiated patent applications for LHRH receptor antagonists following the issuance, including Sanofi-Aventis and Valeant Pharmaceuticals.
- Subsequent patents often build on the chemical framework established in US 5,164,194, with narrower claims targeting specific compounds or formulations.
Patent expiry and freedom to operate:
- The patent expiration date: November 17, 2012, with possibility of patent term extensions for regulatory delays.
- Post-expiration, the compounds entered public domain, increasing R&D freedom for biosimilars and generic alternatives.
Key patent citations:
- Cited patents relate to earlier hormone receptor modulators, such as US 4,860,938 (LHRH analogs) and US 4,562,272 (peptide antagonists).
- Subsequent patents cite US 5,164,194 as foundational, focusing on structural modifications and specific uses.
Litigation and patent challenges:
- No publicly recorded litigations directly contesting US 5,164,194.
- Patent crests over the core structural features are generally viewed as robust, with narrow claims limiting scope for challenge.
Summary of claims strengths and vulnerabilities
Strengths:
- Early patent protection on a broad class of non-peptide LHRH antagonists.
- Covering a wide chemical space with core structural features linked to receptor activity.
- Established synthetic routes support robust claim enforcement.
Vulnerabilities:
- Narrowed claims in later patents have reduced scope.
- The expired patent leaves room for biosimilars and generics.
- Structural similarities to prior art (peptide analogs) could pose obviousness arguments if challenged pre-issue, but current enforcement appears strong due to specific modifications.
Key Takeaways
- US Patent 5,164,194's backbone covers a broad chemical class of LHRH antagonists, positioning the patent as foundational for related drug development.
- Its claims emphasize structural features conducive to high affinity and selectivity.
- Patent expiry has opened opportunities for generic development.
- Follow-on patents and research build selectively on the original scope, often focusing on particular compounds or formulations.
- The patent landscape reflects active engagement by pharma players but remains non-controversial in litigation.
FAQs
1. How does the scope of US 5,164,194 compare to later patents?
Later patents tend to focus on narrower subclasses or specific compounds, often modifying the original core structure. US 5,164,194's broad claims establish foundational coverage, but subsequent patents can limit or specify the scope.
2. Are the patent claims enforceable today?
The patent expired on November 17, 2012, removing enforceability but allowing others to commercialize compounds within the originally claimed chemical class.
3. What therapeutic areas do the claims primarily target?
The claims are primarily for compounds used in hormone-dependent conditions such as prostate cancer, breast cancer, endometriosis, and precocious puberty.
4. What are the main vulnerabilities of these claims?
The main vulnerabilities involve the availability of prior art at the time of filing, narrow claim scope in later patents, and patent expiration.
5. How does the chemical scope impact generic drug development?
With the patent expired, generic manufacturers can develop and sell LHRH antagonists covering similar chemical classes without infringement, provided they do not infringe other active patents.
References
- U.S. Patent 5,164,194. (1992). Beta-hairpin peptides as gonadotropin-releasing hormone antagonists.
- SciFinder. (2023). Patent family and citation data.
- European Patent Office. (2023). Patent applications related to LHRH antagonists.
- FDA Orange Book. (2023). Approved drugs and patent statuses.
- WIPO. (2023). International patent filings extending US 5,164,194 concepts.
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