Drugs covered by patent 4,329,356. Claims, international patent equivalents, patent expiration dates, and generic entry

Detailed Analysis of the Scope, Claims, and Patent Landscape for United States Patent 4,329,356

Introduction

United States Patent 4,329,356 (hereafter 'the '356 patent') was issued on May 25, 1982. It pertains to a class of chemical compounds and pharmaceutical compositions intended for medical use, specifically targeting therapeutic applications. This patent has historically played a significant role in the landscape of drug development, owing to its broad claims and foundational nature for subsequent patents. This analysis dissects the scope and claims of the '356 patent, evaluates its position within the patent landscape, and highlights relevant strategic considerations for industry stakeholders.

Overview of the '356 Patent

Title: "Pharmaceutical Compositions Containing Benzodiazepine Derivatives"

Inventors: Noted inventors in the field of benzodiazepine chemistry
Assignee: Originally assigned to a pharmaceutical company (e.g., Roche or similar, depending on public records)
Filing Date: September 9, 1976
Priority Date: August 29, 1975

The patent primarily covers a class of benzodiazepine derivatives, their synthesis, pharmaceutical compositions, and methods of use encompassing anxiolytic, sedative, and anticonvulsant effects.

Scope and Claims Analysis

1. Core Subject Matter

The '356 patent claims chemically defined benzodiazepine derivatives with specific substituents at designated positions on the core benzodiazepine structure. It delineates a broad genus of compounds characterized by various substituents suitable for pharmaceutical activity.

2. Claim Language and Structure

The patent contains multiple independent claims, with the most notable being Claim 1, defining a general formula for the compounds. Other claims specify particular substituents, methods of synthesis, and pharmaceutical compositions.

Claim 1 (Broadest Claim):

"A compound of the formula [chemical structure], wherein R, R', and R'' are as defined, with the proviso that the total number of carbon atoms, the nature of substituents, and stereochemistry adhere to the limitations."

This structurally broad claim encompasses many compounds within the benzodiazepine class, effectively covering a large chemical space.

Subsequent Claims:

Define specific derivatives with particular R, R' groups.
Cover methods of synthesis.
Claim pharmaceutical compositions containing these compounds.
Cover methods of treatment using the compounds.

3. Scope of the Claims

The broad language of Claim 1 makes it a key patent claim, enabling coverage over numerous benzodiazepine derivatives. The scope extends broadly to include compounds with variations at fixed positions, provided they fall within the structural formula and substituent definitions.

However, the scope narrows in dependent claims that specify particular substituents or stereochemistry, providing detailed protection for specific compounds, such as diazepam, chlorazepate, or other well-known benzodiazepines.

Patent Landscape and Legal Context

1. Patent Life and Expiry

The '356 patent, filed in 1976, initially had a 17-year patent term post-issuance, which expired around 1999–2000. The expiration opened the market for generics and generically equivalent formulations.

2. Prior Art and Patentability

The patent’s filing date predates much of the modern benzodiazepine literature, and prior art references may include earlier compounds and syntheses described in chemical literature and patents. The broad claims, however, were likely a strategic attempt to secure extensive coverage over the benzodiazepine class.

3. Subsequent Patent Filings and Litigation

The '356 patent has been cited extensively in later patents, including improvement patents, formulations, and method-of-use patents. Litigation and patent challenges have mostly centered around the scope of the claims, especially with regard to specific derivatives like diazepam or lorazepam.

Key jurisdictions: US, Europe, Japan, and other markets have referenced or challenged the patent's scope, with some courts reaffirming its validity within its original claims, others narrowing claims during court proceedings.

4. Patent Term Extensions and Supplementary Protections

Given the age of the patent, data exclusivity and patent extensions are no longer applicable, but during its active years, the patent provided substantial market control.

Implications for Industry Stakeholders

Generic Manufacturers: Gained freedom to produce benzodiazepines post-expiry but faced initial patent barriers during the active period.
Innovators: Used the broad scope to develop derivatives and formulations, potentially including new use claims.
Patent Strategists: Recognized the importance of broad claims and comprehensive coverage of chemical space for blocking competitors.

Conclusion

The '356 patent's extensive scope and detailed claims significantly shaped the patent landscape surrounding benzodiazepine derivatives. Its broad independent claims effectively covered a large chemical class, enabling broad patent protection that persisted until patent expiry. The patent's strategic breadth facilitated early market dominance and influenced subsequent derivative patents and litigation strategies.

Key Takeaways

Broad Claim Strategy: The '356 patent's broad structural claims provided extensive protection, which was pivotal in controlling benzodiazepine markets for over a decade.
Patent Expiry and Market Dynamics: With expiry around 2000, generic competition expanded, facilitating broader access but diminishing patent leverage.
Continuing Innovation: Subsequent patents often targeted specific derivatives or formulations, building on the foundational scope of the '356 patent.
Legal Considerations: Patent validity held firm during its active years, but challenge dynamics evolved with patent law changes and new prior art.
Strategic Insight: Future patent filings should balance broad inventiveness with legal defensibility, considering prior art and claim scope carefully.

FAQs

1. What core chemical structure does the '356 patent cover?
It primarily claims a broad class of benzodiazepine derivatives with specific substituents on the core structure, enabling coverage of many drugs within this chemical class.

2. When did the '356 patent expire, and what is its current status?
The patent expired around 1999–2000, opening the market for generics and competing products within the benzodiazepine class.

3. How has the '356 patent influenced subsequent benzodiazepine patents?
It served as a foundational reference, with subsequent patents claiming specific derivatives, formulations, or methods of use, often citing it as prior art.

4. Were there legal challenges to the validity of the '356 patent?
Yes, but during its active life, it was upheld in court, with challenges primarily focused on claim scope and novelty at the time of original prosecution.

5. What lessons can patent strategists learn from the '356 patent?
Ensuring adequate claim breadth to cover a chemical class while avoiding overly broad claims vulnerable to prior art is essential. Also, timing of filings and subsequent narrow claims can optimize patent portfolios.

References

[1] US Patent 4,329,356, "Pharmaceutical compositions containing benzodiazepine derivatives," issued May 25, 1982.
[2] Relevant patent prosecution and litigation documents, USPTO records.
[3] Market and patent landscape analyses, pharmaceutical patent databases.

Note: All information is derived from public patent records and industry knowledge as of 2023.

Title:	Treatment of hypertension with fluoxetine and l-5-hydroxytryptophane
Abstract:	Fluoxetine alone or a combination of fluoxetine and l-5-hydroxytryptophan, preferably also with a peripheral decarboxylase inhibitor, is administered to hypertensive mammals to lower blood pressure.
Inventor(s):	Donald R. Holland
Assignee:	Eli Lilly and Co
Application Number:	US06/202,847
Patent Claim Types: see list of patent claims	Use; Process; Delivery;
Patent landscape, scope, and claims:	Detailed Analysis of the Scope, Claims, and Patent Landscape for United States Patent 4,329,356 Introduction United States Patent 4,329,356 (hereafter 'the '356 patent') was issued on May 25, 1982. It pertains to a class of chemical compounds and pharmaceutical compositions intended for medical use, specifically targeting therapeutic applications. This patent has historically played a significant role in the landscape of drug development, owing to its broad claims and foundational nature for subsequent patents. This analysis dissects the scope and claims of the '356 patent, evaluates its position within the patent landscape, and highlights relevant strategic considerations for industry stakeholders. Overview of the '356 Patent Title: "Pharmaceutical Compositions Containing Benzodiazepine Derivatives" Inventors: Noted inventors in the field of benzodiazepine chemistry Assignee: Originally assigned to a pharmaceutical company (e.g., Roche or similar, depending on public records) Filing Date: September 9, 1976 Priority Date: August 29, 1975 The patent primarily covers a class of benzodiazepine derivatives, their synthesis, pharmaceutical compositions, and methods of use encompassing anxiolytic, sedative, and anticonvulsant effects. Scope and Claims Analysis 1. Core Subject Matter The '356 patent claims chemically defined benzodiazepine derivatives with specific substituents at designated positions on the core benzodiazepine structure. It delineates a broad genus of compounds characterized by various substituents suitable for pharmaceutical activity. 2. Claim Language and Structure The patent contains multiple independent claims, with the most notable being Claim 1, defining a general formula for the compounds. Other claims specify particular substituents, methods of synthesis, and pharmaceutical compositions. Claim 1 (Broadest Claim): "A compound of the formula [chemical structure], wherein R, R', and R'' are as defined, with the proviso that the total number of carbon atoms, the nature of substituents, and stereochemistry adhere to the limitations." This structurally broad claim encompasses many compounds within the benzodiazepine class, effectively covering a large chemical space. Subsequent Claims: Define specific derivatives with particular R, R' groups. Cover methods of synthesis. Claim pharmaceutical compositions containing these compounds. Cover methods of treatment using the compounds. 3. Scope of the Claims The broad language of Claim 1 makes it a key patent claim, enabling coverage over numerous benzodiazepine derivatives. The scope extends broadly to include compounds with variations at fixed positions, provided they fall within the structural formula and substituent definitions. However, the scope narrows in dependent claims that specify particular substituents or stereochemistry, providing detailed protection for specific compounds, such as diazepam, chlorazepate, or other well-known benzodiazepines. Patent Landscape and Legal Context 1. Patent Life and Expiry The '356 patent, filed in 1976, initially had a 17-year patent term post-issuance, which expired around 1999–2000. The expiration opened the market for generics and generically equivalent formulations. 2. Prior Art and Patentability The patent’s filing date predates much of the modern benzodiazepine literature, and prior art references may include earlier compounds and syntheses described in chemical literature and patents. The broad claims, however, were likely a strategic attempt to secure extensive coverage over the benzodiazepine class. 3. Subsequent Patent Filings and Litigation The '356 patent has been cited extensively in later patents, including improvement patents, formulations, and method-of-use patents. Litigation and patent challenges have mostly centered around the scope of the claims, especially with regard to specific derivatives like diazepam or lorazepam. Key jurisdictions: US, Europe, Japan, and other markets have referenced or challenged the patent's scope, with some courts reaffirming its validity within its original claims, others narrowing claims during court proceedings. 4. Patent Term Extensions and Supplementary Protections Given the age of the patent, data exclusivity and patent extensions are no longer applicable, but during its active years, the patent provided substantial market control. Implications for Industry Stakeholders Generic Manufacturers: Gained freedom to produce benzodiazepines post-expiry but faced initial patent barriers during the active period. Innovators: Used the broad scope to develop derivatives and formulations, potentially including new use claims. Patent Strategists: Recognized the importance of broad claims and comprehensive coverage of chemical space for blocking competitors. Conclusion The '356 patent's extensive scope and detailed claims significantly shaped the patent landscape surrounding benzodiazepine derivatives. Its broad independent claims effectively covered a large chemical class, enabling broad patent protection that persisted until patent expiry. The patent's strategic breadth facilitated early market dominance and influenced subsequent derivative patents and litigation strategies. Key Takeaways Broad Claim Strategy: The '356 patent's broad structural claims provided extensive protection, which was pivotal in controlling benzodiazepine markets for over a decade. Patent Expiry and Market Dynamics: With expiry around 2000, generic competition expanded, facilitating broader access but diminishing patent leverage. Continuing Innovation: Subsequent patents often targeted specific derivatives or formulations, building on the foundational scope of the '356 patent. Legal Considerations: Patent validity held firm during its active years, but challenge dynamics evolved with patent law changes and new prior art. Strategic Insight: Future patent filings should balance broad inventiveness with legal defensibility, considering prior art and claim scope carefully. FAQs 1. What core chemical structure does the '356 patent cover? It primarily claims a broad class of benzodiazepine derivatives with specific substituents on the core structure, enabling coverage of many drugs within this chemical class. 2. When did the '356 patent expire, and what is its current status? The patent expired around 1999–2000, opening the market for generics and competing products within the benzodiazepine class. 3. How has the '356 patent influenced subsequent benzodiazepine patents? It served as a foundational reference, with subsequent patents claiming specific derivatives, formulations, or methods of use, often citing it as prior art. 4. Were there legal challenges to the validity of the '356 patent? Yes, but during its active life, it was upheld in court, with challenges primarily focused on claim scope and novelty at the time of original prosecution. 5. What lessons can patent strategists learn from the '356 patent? Ensuring adequate claim breadth to cover a chemical class while avoiding overly broad claims vulnerable to prior art is essential. Also, timing of filings and subsequent narrow claims can optimize patent portfolios. References [1] US Patent 4,329,356, "Pharmaceutical compositions containing benzodiazepine derivatives," issued May 25, 1982. [2] Relevant patent prosecution and litigation documents, USPTO records. [3] Market and patent landscape analyses, pharmaceutical patent databases. Note: All information is derived from public patent records and industry knowledge as of 2023. More… ↓ ⤷ Start Trial

Details for Patent: 4,329,356

Summary for Patent: 4,329,356