United States Drug Patent 5,547,957: Scope, Claims, and Landscape Analysis
United States Patent 5,547,957, titled "Substituted 2-amino-4-oxo-chromene-3-carboxylic acids," was granted on August 20, 1996, to Aventis Pharma S.A. The patent claims a specific class of chemical compounds and their use in treating various medical conditions. The claims are broadly directed towards substituted chromene derivatives with potential therapeutic applications. The patent landscape surrounding this patent is characterized by multiple patents claiming similar compound structures and therapeutic uses, raising questions about potential infringement and market exclusivity.
What is the Core Invention Claimed in Patent 5,547,957?
The central invention claimed in U.S. Patent 5,547,957 encompasses novel chemical compounds identified as substituted 2-amino-4-oxo-chromene-3-carboxylic acids. The patent defines these compounds through a Markush claim structure, allowing for a broad range of substituents at specific positions on the chromene core.
The generic structure provided in the patent is:
- R1 is hydrogen, an alkyl group, or an aryl group.
- R2 is an amino group or a substituted amino group.
- R3 is an alkyl group or an aryl group.
- R4 is a carboxylic acid group or an ester thereof.
The patent specifies various permissible substituents for R1, R2, and R3, including halogen atoms, alkoxy groups, alkylthio groups, and heterocyclic rings. The claims also cover pharmaceutical compositions containing these compounds, as well as methods of treating various diseases.
What are the Specific Claims Made in the Patent?
U.S. Patent 5,547,957 contains multiple independent and dependent claims. The most significant claims define the compound structures and their therapeutic uses.
Claim 1 is an independent claim defining the core compound structure:
"A compound of the formula:
(Structure of the generic compound with R1, R2, R3, R4 substituents as described above)
wherein R1 is hydrogen, alkyl, or aryl; R2 is amino or substituted amino; R3 is alkyl or aryl; and R4 is a carboxylic acid or an ester thereof."
The patent further defines specific ranges and types of alkyl and aryl groups, as well as substituents for the amino group (R2). This broad definition is a key aspect of the patent's scope.
Other significant claims include:
- Dependent claims that narrow down the scope of Claim 1 by specifying particular substituents for R1, R2, R3, and R4, leading to specific compound entities.
- Claims directed to pharmaceutical compositions comprising at least one compound of the formula described above and a pharmaceutically acceptable carrier.
- Claims directed to methods of treating diseases by administering an effective amount of one or more of the claimed compounds. The patent lists conditions such as inflammation, pain, and allergic reactions as potential therapeutic targets.
The breadth of these claims, particularly the generic Markush claim, aims to cover a wide array of chemical analogs and their therapeutic applications.
What is the Therapeutic Indication Associated with Patent 5,547,957?
The patent specifies that the compounds of U.S. Patent 5,547,957 are useful for treating a range of conditions, primarily associated with inflammatory and allergic responses.
The identified therapeutic indications include:
- Inflammatory diseases
- Pain
- Allergic reactions
- Asthma
- Bronchitis
- Rhinitis
- Urticaria
- Eczema
- Conjunctivitis
The underlying mechanism of action, as suggested by the patent, relates to the modulation of biological pathways involved in these conditions. The patent does not explicitly name a specific drug product.
What is the Patent Term and Exclusivity Period for 5,547,957?
U.S. Patent 5,547,957 was granted on August 20, 1996. As a utility patent filed before June 8, 1995, it has a term of 17 years from the date of grant, unless subject to patent term adjustments or extensions.
- Original Expiration Date: August 20, 2013 (17 years from grant date).
It is important to note that the patent term could have been extended through mechanisms such as Patent Term Extension (PTE) under the Hatch-Waxman Act, which can compensate for delays in U.S. Food and Drug Administration (FDA) approval. Such extensions are typically granted for pharmaceutical patents to recover a portion of the time lost during clinical trials and regulatory review. Any potential PTE for this patent would need to be verified through FDA records.
Who are the Key Assignees and Potential Licensees of the Patent?
The original assignee of U.S. Patent 5,547,957 is Aventis Pharma S.A. Aventis was a major pharmaceutical company formed from the merger of Rhône-Poulenc Rorer and Hoechst Marion Roussel in 1999. In 2004, Aventis was acquired by Sanofi-Synthélabo, which subsequently became Sanofi-Aventis, and is now known as Sanofi. Therefore, Sanofi is the current likely holder of rights to this patent.
Potential licensees or entities that might have an interest in this patent's technology include:
- Companies developing drugs for inflammatory and allergic diseases.
- Firms engaged in the synthesis and commercialization of heterocyclic organic compounds.
- Generic drug manufacturers if the patent has expired or is nearing expiration.
A thorough review of licensing agreements and any related litigation would be necessary to confirm current rights and commercialization status.
What is the Competitive Landscape and Potential for Infringement?
The patent landscape for substituted chromene derivatives is complex. Numerous patents claim compounds with similar structural motifs and therapeutic applications.
Key aspects of the competitive landscape include:
- Structural Overlap: Other patents may claim compounds that fall within the broad scope of Claim 1 of 5,547,957 due to overlapping Markush structures or similar chemical scaffolds.
- Therapeutic Overlap: Competitors may hold patents covering the use of structurally related compounds for similar or overlapping therapeutic indications.
- Prior Art: The existence of prior art, including earlier patents and scientific literature, can limit the enforceability and scope of 5,547,957.
- Generic Competition: As the patent term approached or passed its expiration, generic manufacturers would be positioned to develop and market biosimilars or generic versions of any drugs covered by this patent, provided other relevant exclusivity periods have also expired.
Potential for Infringement:
Infringement occurs when a party makes, uses, offers to sell, or sells a patented invention without authorization within the United States, or imports into the United States a product made by a process patented in the United States. For Patent 5,547,957, potential infringement could arise from:
- The synthesis and sale of compounds that structurally match the claims of the patent.
- The formulation and sale of pharmaceutical compositions containing such compounds.
- The use of such compounds in the treatment of the claimed indications.
A detailed infringement analysis would require comparing the specific structures and uses of competitor products against the precise language of the patent claims, considering any issued rejections or limitations during prosecution.
How has the Patent Been Treated in Litigation or Inter Partes Review?
Information regarding specific litigation or Inter Partes Review (IPR) proceedings involving U.S. Patent 5,547,957 needs to be accessed through specialized patent litigation databases. General public patent databases may not readily provide this detailed procedural history.
However, patents of this nature, claiming broad chemical structures with therapeutic applications, are frequently subject to legal challenges. Such challenges can include:
- Infringement lawsuits: Filed by the patent holder against alleged infringers.
- Declaratory judgment actions: Filed by a party seeking a court ruling that they are not infringing the patent.
- Post-grant reviews: Such as IPRs filed with the U.S. Patent and Trademark Office (USPTO) to challenge the validity of patent claims.
A comprehensive review of litigation dockets and USPTO proceedings would be necessary to ascertain the patent's history in legal challenges. The absence of publicly available litigation records does not necessarily indicate a lack of challenges, as settlements or ongoing confidential proceedings are possible.
Key Takeaways
U.S. Patent 5,547,957 covers a broad class of substituted 2-amino-4-oxo-chromene-3-carboxylic acids, with potential applications in treating inflammatory and allergic conditions. The patent's original expiration date was August 20, 2013, subject to potential patent term extensions. The assignee is Sanofi, following the acquisition of Aventis. The competitive landscape is characterized by a high degree of structural and therapeutic overlap with other patents in the chromene derivative space, posing a significant risk of infringement. A detailed analysis of patent claim scope against competitor products and a review of litigation history are crucial for assessing commercial opportunities and risks.
Frequently Asked Questions
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Can Sanofi still enforce U.S. Patent 5,547,957?
The patent expired on August 20, 2013. Therefore, it is no longer in force and cannot be enforced for new activities. However, any infringement that occurred during the patent's valid term could still be subject to legal action.
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Are there any approved drugs directly linked to this patent?
Without a specific drug name or development history associated with this patent number in public records, it is not possible to definitively link it to an approved drug. The patent covers a class of compounds, and any specific drug would be disclosed in its own patent filings.
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What is the significance of a Markush claim in this patent?
A Markush claim, as used in this patent, allows for a generic description of a class of compounds where variable substituents are defined at specific positions. This broadens the scope of protection significantly, covering numerous related structures beyond a single specific compound.
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How can a company determine if its product infringes on this expired patent?
Even for an expired patent, determining past infringement is relevant for potential damages related to activities that occurred during the patent's term. This involves comparing the structure and use of the product against the patent's claims as they were written during its validity.
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What are the implications of this patent's expiration for generic manufacturers?
The expiration of this patent removed one layer of exclusivity for compounds falling within its scope. Generic manufacturers can now develop and market products that were exclusively covered by this patent, provided they do not infringe on any other valid and in-force patents.
Citations
[1] U.S. Patent 5,547,957. (1996). Substituted 2-amino-4-oxo-chromene-3-carboxylic acids. Aventis Pharma S.A.
