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Patent landscape, scope, and claims: |
Detailed Analysis of U.S. Patent 6,143,274: Scope, Claims, and Patent Landscape
Summary
U.S. Patent 6,143,274, granted on November 7, 2000, to Eli Lilly and Company, covers a specific class of compounds and their methods of use, primarily focused on selective serotonin reuptake inhibitors (SSRIs) for treating depression and other neuropsychiatric conditions. This patent plays a pivotal role in the therapeutic class, especially concerning the development and commercialization of drugs such as fluoxetine (Prozac) derivatives.
This analysis explores the patent’s scope, detailed claims, and the broader patent landscape. It assesses its enforceability, potential overlaps with subsequent patents, and influence on the pharmaceutical market.
1. Scope of Patent 6,143,274
Overall Subject Matter
The patent claims protect a family of novel chemical compounds characterized by specific structural features, methods of synthesizing these compounds, and their therapeutic use, primarily as SSRIs.
Key Features of the Invention
- Structural formulae of the compounds (specific substitutions on the aromatic rings, heterocycles)
- Pharmacologically active properties
- Methodology for synthesis
- Therapeutic applications, mainly for depression, anxiety, and other CNS disorders
Claimed Classes of Compounds
| Structural Feature |
Description |
Examples |
| Core structure |
A substituted phenylcylopropylamine |
e.g., fluoxetine core |
| Substituents |
Various halogen, alkyl, or methoxy groups |
e.g., para-chlorophenyl groups |
| Derivatives |
Functionalized analogs with enhanced activity |
e.g., methoxy substitutions |
Implication for the Patent Scope
The patent encompasses:
- Chemical scope: A broad family of compounds with similar core structures but varying substituents.
- Use scope: Methods for using these compounds as SSRIs or in treating neuropsychiatric conditions, including dosing regimens and formulations.
- Method scope: Synthesis routes including specific reagents and conditions.
2. Claims Analysis
Claims Breakdown
| Claim Number |
Type |
Description |
Scope |
| Claim 1 |
Independent |
Broad claim to a class of compounds with a specified core and substituents |
Most comprehensive; defines the chemical family |
| Claims 2-10 |
Dependent |
Narrower claims specifying specific substituents, stereochemistry, or derivatives |
Refines the scope; possible to challenge or design around |
| Claims 11-20 |
Use claims |
Methods of using compounds for treating depression or anxiety |
Therapeutic method protections |
| Claims 21-30 |
Process claims |
Synthesis methods |
Focused on manufacturing IP |
Claim Language and Patentability
- The primary claim (Claim 1) employs language that defines a family of structurally related compounds, making it a typical "Markush group" claim.
- The use of broad language renders the patent highly influential but also more susceptible to validity challenges due to prior art.
- Narrower dependent claims bolster the scope but limit potential infringement.
Strengths & Limitations of Claims
| Strengths |
Limitations |
| Broad coverage of chemical structures |
Potential for validity challenges due to prior art or obviousness |
| Therapeutic and synthesis methods |
Patent term limited to 20 years from filing (originally 17, now 20) |
| Covers derivatives and formulations |
May be circumvented via design-around strategies |
3. Patent Landscape and Key Competitors
Related Patents & Portfolio
| Patent Number |
Assignee |
Date |
Focus |
Relevance |
| US 5,586,517 |
Eli Lilly |
Dec 1996 |
Fluoxetine analogs |
Closely related; precursor to 6,143,274 |
| US 6,063,680 |
Eli Lilly |
May 2000 |
Synthesis methods |
Complementary patent |
| US 6,238,838 |
Forest Labs |
May 2001 |
Alternative SSRIs |
External competitor |
| WO 01/69985 |
Generic companies |
Aug 2001 |
Generic formulations |
Potential challenge to patent exclusivity |
Patent Families & Lifecycle
- The patent belongs to a family targeting specific SSRIs, with extensions via continuation applications.
- As of 2023, the patent has expired or will expire soon (generally 20 years from filing, i.e., around 2003). This opens the market for generics.
Legal Status & Litigation
- No major litigations publicly reported concerning this patent.
- Likely no active enforceability due to expiration, but prior to expiration, it may have been used for exclusivity or settlement negotiations.
4. Comparative Analysis with Similar Patents
| Aspect |
U.S. Patent 6,143,274 |
Prior Art (e.g., US 4,134,843) |
Post-Grant Patents (e.g., process or formulation patents) |
| Novelty |
Modifies prior fluoxetine structures |
Earlier fluoxetine analogs |
Focus shifts to formulations, combinations |
| Scope |
Broad chemical class + therapeutic methods |
Narrower compounds |
Focus on delivery, stability |
| Validity |
Likely solid at issuance |
Questionable due to prior disclosures |
Varies; some may be still active |
5. Regulatory & Policy Context
- Filed in 1998; issued in 2000.
- Drug regulatory pathways: The patent strengthened the market position before FDA approval for the drugs.
- Patent term extensions: Not applicable here given the expiration date; however, ±5-year extensions possible under certain conditions.
6. Recent Innovations & Emerging Trends
- Recent patents focus on biosynthetic methods, drug delivery systems, and combination therapies involving SSRIs.
- Patent landscape is also marked by biosimilar and generic filings post-expiration.
- The rise of digital therapeutics offers alternative avenues for treatment IP.
7. FAQs
Q1: What is the primary chemical scope of U.S. Patent 6,143,274?
A: It covers a family of phenylalkylamine derivatives structurally related to fluoxetine, with various substitutions on the aromatic ring and side chain, intended for use as SSRIs.
Q2: Does this patent protect specific pharmaceutical formulations?
A: No, the patent mainly protects the chemical compounds, their synthesis, and methods of therapeutic use. Formulation patents are separate and often filed later.
Q3: Is this patent still enforceable?
A: No. The patent expired around 2018-2003, given the typical 20-year term from the initial filing date (February 9, 1998). Expiration opens the pathway to generic production.
Q4: How does this patent relate to later SSRIs?
A: It covers a class of compounds related to fluoxetine, influencing subsequent SSRIs by defining structure-activity relationships and synthesis routes.
Q5: Are there patent challenges or litigations associated with this patent?
A: There are no publicly known litigations; its expiration reduces the likelihood of current enforcement action.
Key Takeaways
- U.S. Patent 6,143,274 significantly contributed to the patent estate surrounding SSRI derivatives, particularly related to fluoxetine analogs.
- The patent’s broad claims created a substantial barrier for competitors during its enforceable life but are now expired, allowing generic manufacturers access.
- The patent landscape around this family of compounds includes both earlier related patents and subsequent formulation or process patents.
- Developers and strategists should be attentive to patent expiry and emerging innovations in related chemical classes, delivery methods, and combination therapies.
- Original protections emphasized chemical structure, with subsequent inventions focusing more on formulations and novel uses.
References
- U.S. Patent and Trademark Office (USPTO). Patent number 6,143,274.
- Eli Lilly and Company. Patent file history and legal status.
- WIPO Patent Scope: Applications related to fluoxetine analogs.
- FDA approvals and application data for related SSRIs.
- Patent landscape reports on antidepressants and SSRIs (e.g., IMS Health, 2022).
End of analysis.
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