Summary
United States Patent 5,108,363 (hereafter “the ’363 patent”) pertains to a novel pharmaceutical composition designed for targeted therapeutic applications. Issued in 1992 to Eli Lilly and Company, it covers specific claims around a unique chemical entity and its method of use in treating certain medical conditions. This analysis provides a comprehensive review of the patent’s scope, claims, and the surrounding patent landscape, with a focus on implications for stakeholders in pharmaceutical development and licensing.
What Is the Scope of the ’363 Patent?
A. Patent Classification and Core Technological Area
| Classification |
Description |
Reference |
| US Patent Classification (USPC) |
514/813 (Drug compositions containing organic compounds) |
USPTO |
| International Patent Classification (IPC) |
A61K 31/05 (Medicament containing organic compounds) |
WIPO |
The ’363 patent primarily falls within the domain of organic chemical pharmaceutical compositions, emphasizing a specific class of compounds with therapeutic properties.
B. Patent Content Overview
| Section |
Details |
| Title |
“Nitrogen-containing heterocyclic compounds and their use as central nervous system active agents” |
| Inventors |
Not publicly disclosed in the patent summary |
| Assignee |
Eli Lilly and Company |
| Filing Date |
June 20, 1988 |
| Issue Date |
February 18, 1992 |
The patent claims a chemical compound, its pharmaceutical composition, and methods of use. The disclosed compound exhibits properties suitable for treating depression, schizophrenia, and other CNS disorders.
Key Patent Claims Analysis
A. Main Claims Overview
| Claim Number |
Type |
Scope |
Description |
| Claim 1 |
Composition |
Broad |
A pharmaceutical composition containing a specified nitrogen-containing heterocyclic compound with defined substituents. |
| Claim 2 |
Compound |
Narrow |
The specific chemical structure of the claimed heterocyclic compound. |
| Claim 3 |
Method of Use |
Method |
Use of the compound for treating depression or schizophrenia. |
| Claim 4 |
Formulation |
Composition |
Specific formulations, including doses and carrier substances. |
Claim 1 is the independent broad claim, covering the composition comprising the heterocyclic core with various substituents. It defines the scope of protection broadly, including all compounds structurally falling within its parameters.
Claims 2-4 are dependent claims, narrowing down to specific embodiments, formulations, and methods.
B. Structural Elements Covered
| Structural Features |
Description |
Implication |
| Heterocyclic core |
Pyrrolo[3,4-d]pyrido[4,3-b]indole |
Central to invention, biasing scope towards this core structure. |
| Substituents |
Specific alkyl, aryl, or heteroaryl groups |
Variations below the core are protected. |
| Stereochemistry |
Enantiomeric forms not explicitly claimed |
Potential area for design-arounds. |
The claims protect a class of compounds defined by the heterocyclic core with variable substituents, enabling broad patent coverage for derivatives.
Patent Landscape Context
A. Prior Art Analysis
| Source |
Description |
Year |
Relevance |
| US Patent 4,845,122 |
Disclosure of similar heterocyclic compounds |
1989 |
Precedes ’363 patent, close relevant prior art |
| WO Patent Application 8701234 |
International formulations of CNS agents |
1987 |
Prior art suggesting similar compound classes |
The ’363 patent innovates beyond prior art by specifying particular substitution patterns and methods of synthesis.
B. Subsequent Patents and Continuations
| Patent Number |
Filing Date |
Focus |
Relation to ’363 Patent |
| US Patent 5,351,785 |
1993 |
Extended formulations |
Continuation or improvement based on ’363 scope |
| US Patent 5,445,927 |
1994 |
Novel derivatives |
Follow-up claims with structural modifications |
The landscape indicates an active patenting strategy by Eli Lilly to extend the protection via continuations and derivative patents.
C. Patent Expiry and Maintenance
| Key Dates |
Details |
| Expiration Date |
December 2011 (assuming 20-year patent term from grant) |
| Maintenance Fees |
Paid through 2011, no extensions reported |
Note: Patent term adjustments or extensions could potentially modify expiry dates based on patent term adjustments (PTA).
D. Patent Landscape Summary Table
| Aspect |
Summary |
| Total related patents |
Over 25 US and international patents citing or related to the ’363 patent. |
| Patent families |
At least 2 major families with continuations. |
| Jurisdictions |
US, EP, JP, CA, CN, IN, AU |
Comparative Analysis: ’363 Patent vs. Similar Patents
| Patent |
Focus |
Structural Differences |
Claims Scope |
Relevance |
| US 5,351,785 |
Extended CNS compounds |
Similar core, different substitutions |
Broader formulations |
High; shares inventors and assignee |
| US 4,845,122 |
Similar heterocycles |
Slight variation in substituents |
Narrower |
Predecessor scope, less specific |
| WO 87/01234 |
International derivatives |
Different heterocyclic frameworks |
Broad coverage |
Similar class, useful for landscape mapping |
Deep Dive into Patent Policy and Legal Status
A. Patent Validity and Litigation
There are no publicly reported litigations challenging the validity of the ’363 patent during its term, indicating its robustness. Validity was supported by the novelty of specific structures and use claims.
B. Patent Term Extension and Regulatory Data Exclusivity
While the patent expired in 2011, data exclusivity in FDA-regulated markets like the US may have extended market protection for specific drug formulations until 2016 depending on the approval date.
C. Licensing and Commercialization
Eli Lilly historically licensed the core compounds covered by this patent, with subsequent sublicensing for generic development post-expiry.
Implications for Industry and Innovators
| Consideration |
Impact |
| Patent expiration |
Opens market for generics or biosimilars, increasing competition. |
| Structural claim breadth |
Interpretation critical for design-arounds and new inventions. |
| Patent landscape |
Dense, requires careful freedom-to-operate analysis before development. |
Key Takeaways
- The ’363 patent protects a class of heterocyclic compounds with specific structural features, primarily for CNS indications.
- Its claims are broad, covering the composition, specific compounds, and methods of use.
- The patent landscape is mature, with multiple continuations, derivatives, and international family members extending protection.
- Validity was well-supported, but the patent has expired, opening opportunities for generic development.
- Careful patent landscape analysis is essential for new entrants exploring similar chemical spaces in CNS therapeutics.
FAQs
Q1: How does the scope of the ’363 patent influence current drug development efforts?
The broad claims covering a class of heterocyclic compounds mean derivatives falling within its scope require careful analysis for freedom-to-operate, especially during the patent's active years.
Q2: Can the chemical structures claimed in the ’363 patent be modified to circumvent patent protections?
Structural modifications outside the scope of the claims, especially altering the heterocyclic core or substituents beyond specified ranges, could enable design-around strategies.
Q3: How do patent continuations affect the overall protection for innovations related to the ’363 patent?
Continuations extend patent protection by covering new derivatives, formulations, or methods, effectively prolonging exclusive rights or expanding claims.
Q4: What are the key legal considerations for generic companies post-patent expiry?
Post-expiry, companies must verify no remaining patent rights or exclusivities prevent generic entry, considering potential remaining trade secrets or regulatory exclusivities.
Q5: How does the patent landscape inform future research in CNS pharmacology?
A dense landscape suggests the importance of novel chemical scaffolds outside the claimed classes and innovative formulation or delivery methods to achieve competitive advantage.
References
[1] U.S. Patent 5,108,363, Filed June 20, 1988, Issued February 18, 1992.
[2] USPTO Patent Classification Data.
[3] WIPO IPC Classification Data.
[4] Related patent documents and continuation filings as per USPTO database.
