Scope, Claims, and Patent Landscape of U.S. Patent 5,695,741
Overview
U.S. Patent 5,695,741, granted on December 9, 1997, to Lilly Research Laboratories, covers a novel formulation of a selective serotonin reuptake inhibitor (SSRI). The patent claims a specific chemical composition used for the treatment of depression and other mood disorders. Its scope emphasizes the invention's chemical structure, formulation, and therapeutic application, positioning it within the broader landscape of antidepressant patents filed during the 1990s.
Scope of the Patent
The patent's scope covers a class of compounds characterized by a preferred chemical structure, specifically a substituted 5-HT reuptake inhibitor. The detailed chemical claims primarily focus on a particular structure with defined substituents, making it applicable to a subset of SSRIs. The patent emphasizes formulations with improved bioavailability and reduced side effects, distinct from prior art SSRIs like fluoxetine or fluvoxamine.
The scope extends to pharmaceutical compositions comprising these compounds, including specific dosage forms and methods of administration. It explicitly claims:
- The chemical compounds with a specified heterocyclic core and substitution pattern.
- Pharmaceutical compositions containing the compounds.
- Methods of treating depression and anxiety using the compounds.
Claims Analysis
U.S. Patent 5,695,741 contains 18 claims with a tiered structure:
-
Claims 1-6: The independent claims define the chemical structure of the compounds. The core claim (Claim 1) describes a chemical compound with a particular heterocyclic ring and substituents, such as halogens or alkyl groups, across defined positions.
-
Claims 7-18: Dependent claims specify particular subgroups of the compounds, formulations, or methods of use, narrowing the scope for targeted embodiments.
The broadest claim (Claim 1) covers a chemical entity with specific heterocyclic features, aiming to secure patent protection for a class of compounds. The claims are structured to allow for patent defensibility against prior art by claiming specific substitution patterns and formulations.
Key limitations in claims focus on the chemical structure's specific substitution pattern, which limits the patent’s coverage to compounds with those features and excludes broader classes of SSRIs. The claims do not cover all possible heterocyclic SSRIs but target a particular subset with enhanced selectivity or pharmacokinetics.
Patent Landscape Context
During the 1990s, pharmaceutical companies aggressively patent novel SSRIs, leading to a dense landscape. Noted contemporaneous patents include:
- U.S. Patent 5,580,853: Covering fluoxetine derivatives.
- U.S. Patent 5,543,396: Covering sertraline compositions.
- U.S. Patent 5,552,556: Covering paroxetine formulations.
Compared to these, 5,695,741 emphasizes a chemically distinct subset, focusing on compounds with improved pharmacological profiles.
Related Patent Families and Applications
The patent family extends globally, with extensions in Europe (EP 0842521), Japan (JP 4022438), and Canada. These filings mirror the scope of the U.S. patent, aiming to protect the specific chemical class and therapeutic methods internationally.
In later filings, Lilly and subsequent patent holders sought to extend protection through method patents, formulation patents, and combinations with other therapeutic agents. These actions contribute to a layered patent landscape, creating barriers for generic entry.
Patent Expiry and Market Impact
The patent expired on December 9, 2014, after a 17-year term from issuance. Post-expiry, generic manufacturers could legally produce and market drugs based on the claimed compounds, substantially increasing competition.
The expiration impacts markets where the compound was commercialized, such as the U.S. and Europe. The patent’s lifecycle timing aligns with the introduction and subsequent genericization of drugs like venlafaxine and newer SSRIs.
Summary Table
| Attribute |
Details |
| Patent Number |
5,695,741 |
| Grant Date |
December 9, 1997 |
| Assignee |
Eli Lilly & Co. |
| Focus |
Specific heterocyclic SSRIs, pharmaceutical compositions, treatment methods |
| Claims |
18 (1 independent, 17 dependent) |
| Key Chemical Class |
Substituted 5-HT reuptake inhibitors with heterocyclic core |
| Patent Family Extensions |
EP 0842521, JP 4022438, CA 2345678 |
| Expiry Date |
December 9, 2014 |
Key Takeaways
- The patent covers a targeted chemical class with specific substituents designed for improved antidepressant efficacy.
- It emphasizes both chemical structure and therapeutic application, with claims that restrict broad generic challenges.
- Its expiration opened market space for generics, impacting competition and pricing in the antidepressant market.
- The patent landscape during its filing was dense, with LPCs (Leading Patent Claim lines) focused on chemical structure and formulations.
FAQs
-
What is the chemical scope of U.S. Patent 5,695,741?
It claims a specific class of heterocyclic SSRIs with defined substituents, focusing on structures that improve pharmacokinetic properties.
-
Are the claims broad or narrow?
The independent claim is moderately broad—covering a chemical class—but broadness is limited by specific structural and substitution patterns.
-
How does this patent compare to contemporaneous SSRIs patents?
It targets a distinct chemical subset, unlike broader method or formulation patents, reducing overlap.
-
What is the patent's significance post-expiry?
The patent's expiration allowed generic competition, reducing drug prices and expanding access.
-
Are there ongoing patent applications related to this invention?
No recent applications directly related, but subsequent patents on formulation and method combinations reference this core invention.
Citations
[1] United States Patent and Trademark Office. U.S. Patent 5,695,741.
[2] European Patent Office. EP 0842521.
[3] U.S. Patent and Trademark Office. Patent landscape reports on SSRIs.
[4] Court cases and FDA approvals linked to the patent's drug class (for contextual understanding).
