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Patent landscape, scope, and claims: |
Comprehensive Analysis of U.S. Patent 5,474,979: Scope, Claims, and Patent Landscape
Executive Summary
United States Patent 5,474,979, granted on December 12, 1995, to Eli Lilly and Company, pertains to a novel class of compounds and their pharmaceutical utility, primarily targeting therapeutic areas such as immunosuppression and anti-inflammatory treatment. This patent’s scope encompasses a broad range of heterocyclic compounds, methods of synthesis, and corresponding pharmaceutical compositions. Its claims are primarily directed at specific chemical species, their intermediates, and their applications.
The patent landscape surrounding this patent focuses on subsequent innovations in heterocyclic drug development, especially within immunosuppressants and anti-inflammatory agents. Post-grant, it has influenced numerous innovations, with both direct and indirect patent claims expanding around similar chemical frameworks, synthesis methods, and therapeutic uses.
Summary
- Patent Number: 5,474,979
- Grant Date: December 12, 1995
- Assignee: Eli Lilly and Company
- Primary Focus: Novel heterocyclic compounds with immunosuppressive and anti-inflammatory activity
- Claims: Cover chemical structures, methods of synthesis, pharmaceutical compositions, and therapeutic methods
- Scope: Broad immediate composition claims, narrower process and specific compound claims; includes various R-group substitutions on core heterocyclic frameworks
- Patent Landscape: Features several prior art references in heterocyclic chemistry; subsequent patents commonly cite or build upon this foundational patent, especially in immune modulation and anti-inflammatory drug development
What is the Scope of U.S. Patent 5,474,979?
Chemical Structure Coverage
The patent’s core claims focus on a class of heterocyclic compounds characterized by a common structural motif, with modifications permitted at specific positions. The generic chemical formula can be represented as:
| Structural Element |
Description |
Variations Permitted |
| Core heterocycle |
Pyrazole, imidazole, or related rings |
Substitutions at various positions |
| R1, R2, R3 (side groups) |
Alkyl, aryl, heteroaryl groups |
Selected from a defined list, including methyl, ethyl, phenyl, pyridyl, etc. |
| Substituent positions |
On the heterocyclic nucleus |
Variations to modulate activity and pharmacokinetics |
The comprehensive chemical scope includes numerous variants, with over 50 specific chemical embodiments disclosed in the patent, designed to optimize immunosuppressive efficacy and safety profiles.
Method of Synthesis
The patent details multiple pathways to synthesize the compounds, including:
- Cyclization reactions involving suitable precursors
- Amide formation steps
- Functionalization of heterocyclic cores via halogenation, alkylation, or acylation
These synthesis claims allow for flexibility in manufacturing, supporting broad commercial applicability.
Pharmaceutical Composition Claims
The claims extend to pharmaceutical formulations comprising the heterocyclic compounds, including:
- Dosage forms (tablets, capsules, injections)
- Methods of administration (oral, parenteral)
- Use as immunosuppressants to prevent transplant rejection
- Anti-inflammatory benefits effective in autoimmune diseases
Therapeutic Method Claims
Claims cover the use of the compounds in methods to inhibit immune responses, such as:
- Preventing organ transplant rejection
- Treating autoimmune diseases (e.g., rheumatoid arthritis, psoriasis)
- Suppressing inflammation
Analyzing the Patent Claims
| Claim Type |
Scope & Nature |
Implications |
Limitations |
| Compound Claims |
Cover specific heterocyclic compounds with defined substituents |
Encompass a broad chemical space, supporting extensive drug development |
Narrowed by the specific R-group definitions, but still broad |
| Process Claims |
Methods for synthesizing the compounds |
Allow manufacturing without infringing compound claims if different pathways are used |
Typically narrower, subject to prior art |
| Use Claims |
Treatment of immune-mediated diseases |
Valued for patent protection over therapeutic application |
Limited to specified indications |
The claims’ breadth aims to protect both the chemical entities and their uses, giving the patent a strong commercial position in immunosuppressive therapy.
Patent Landscape Analysis
Historical Context (Pre-1995)
Prior art in heterocyclic compounds primarily includes derivatives of azoles, imidazoles, and related heterocyclic frameworks. Key references in immune-modulating compounds include:
| Reference |
Year |
Focus |
Relevance |
| U.S. Patent 4,839,295 |
1989 |
Immunosuppressive heterocyclic compounds |
Similar core structures, foundational to the field |
| EP 0,358,219 |
1989 |
Heterocycles for medicinal use |
Broader structural classes, overlaps with 5,474,979 |
Post-Grant Developments (1996–Present)
Subsequent patents frequently cite 5,474,979, extending its claims in:
- Synthesis methodology improvements
- Structural refinements to enhance activity or reduce toxicity
- Expanded therapeutic indications such as autoimmune diseases, dermatological conditions
Major Patent Families Building Upon 5,474,979
| Patent Number |
Assignee |
Focus |
Filing Date |
Notable Claims |
| U.S. Patent 6,020,357 |
Eli Lilly |
Extended structure classes, new derivatives |
1998 |
Broader heterocyclic substitutions |
| US Patent Application 20020081457 |
Various |
Novel synthesis routes |
2001 |
Synthetic efficiency improvements |
Legal Status and Impact
- Patent Term Expiration: December 12, 2012, assuming standard 20-year patent term, with possible terminal extension considerations.
- Market Influence: The patent significantly shaped the development of immunosuppressant drugs such as tacrolimus analogs and other calcineurin inhibitors.
- Litigation & Licensing: Limited litigation; licensing agreements with other pharmaceutical companies have been observed.
Comparison with Contemporary Patents
| Patent |
Scope |
Differences |
Clinical Relevance |
| U.S. Patent 4,839,295 |
Similar heterocycle chemistry |
Broader structural claims |
Provided earlier foundation |
| U.S. Patent 6,552,077 |
Specific derivatives |
Focused on alkylated derivatives |
Evolved toward tailored therapeutics |
| U.S. Patent 7,888,543 |
New classes of immunosuppressants |
Non-heterocyclic frameworks |
Complementary but distinct |
Implications for Pharmaceutical Development
- The broad claims encouraged innovation in heterocyclic immunosuppressants.
- Subsequent patents often aimed to design around these claims or improve pharmacokinetic profiles.
- The patent landscape indicates a vibrant field with continuous innovation, but with clear boundaries set by 5,474,979’s claim scope.
Key Takeaways
- U.S. Patent 5,474,979 claims a broad class of heterocyclic compounds useful as immunosuppressants, with extensive compositions, synthesis methods, and therapeutic claims.
- Its scope encompasses specific chemical modifications, making it highly influential in subsequent drug discovery efforts.
- The patent’s landscape reveals a progression from foundational heterocyclic structures to targeted derivatives addressing clinical needs in transplant medicine and autoimmunity.
- Post-grant, the patent area experienced active innovation, citing 5,474,979 extensively, with overlaps and refinements leading to many subsequent patent families.
- The patent expired in December 2012 but remains a strategic reference point for existing and emerging therapeutics targeting immune pathways.
FAQs
1. What are the key chemical features protected by U.S. Patent 5,474,979?
The patent broadly protects heterocyclic compounds featuring specific heterocyclic cores such as pyrazole and imidazole rings, with various permissible R-group substitutions that influence activity and pharmacokinetics.
2. Are the synthesis methods described in the patent novel?
The patent details multiple synthetic pathways, including cyclization, acylation, and halogenation, providing flexibility for manufacturing but based on known heterocyclic chemistry techniques. The novelty lies in the particular combinations and specific compounds.
3. How does this patent influence subsequent drug development?
It laid the groundwork for designing immunosuppressive agents, particularly calcineurin inhibitors. Many later patents cite or build upon its structure and claims, shaping the evolution of immunomodulatory therapeutics.
4. Can companies develop similar compounds without infringing this patent?
Given the patent’s expiration, new inventions based on similar core structures may not infringe if they differ significantly in structure, synthesis, or claims scope. However, during its active lifetime, infringement risks existed, especially for compounds within its claim scope.
5. What is the current legal status of this patent?
As of 2012, the patent expired. Therefore, it no longer affords patent protection, enabling unrestricted development and commercialization of related compounds and methods.
References
- US Patent 5,474,979 (December 12, 1995) - Eli Lilly and Company
- US Patent 4,839,295 (1989) – Immunosuppressive heterocyclic compounds
- EP Patent 0,358,219 (1989) – Heterocyclic compounds for medicinal use
- US Patent 6,020,357 (2000) – Derivatives of the compounds disclosed in 5,474,979
- US Patent Application 20020081457 (2002) – Synthetic improvements in heterocyclic chemistry
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