Analysis of U.S. Drug Patent 5,601,848: Scope, Claims, and Landscape

U.S. Patent 5,601,848, titled "Substituted Phenylmethyl Pyridine Derivatives," was granted on February 11, 1997, to R.W. Johnson Pharmaceutical Research Institute. The patent covers a class of substituted phenylmethyl pyridine derivatives, their synthesis, and their use in treating various medical conditions. The primary therapeutic target identified within the patent is the inhibition of 5-lipoxygenase (5-LO) and cyclooxygenase (COX) enzymes, suggesting applications in inflammatory diseases.

What is the Core Invention Claimed by Patent 5,601,848?

The central inventive concept of U.S. Patent 5,601,848 lies in a specific structural class of chemical compounds. These compounds are characterized by a phenylmethyl group attached to a pyridine ring, with defined substitutions at various positions on both rings. The patent asserts that these specific structural features impart the ability to inhibit key enzymes involved in inflammatory pathways.

What is the Chemical Structure Defined by the Patent?

The patent claims a genus of compounds defined by a Markush structure. The general formula provided is:

      R1
      |
  Pyridine-CH2-Phenyl-R3
      |
      R2

Where:

Pyridine: A six-membered heterocyclic aromatic ring containing one nitrogen atom.
CH2: A methylene bridge.
Phenyl: A benzene ring.
R1, R2, and R3: Represent various substituents. The patent provides extensive definitions for these substituents, including alkyl groups, alkoxy groups, halogens, amino groups, hydroxyl groups, and more complex cyclic or heterocyclic moieties. The precise combinations and locations of these substituents are critical to falling within the scope of the patent. For example, the patent details specific positions on the pyridine and phenyl rings where these substituents can be located.

What are the Primary Therapeutic Targets Identified?

The patent explicitly identifies the inhibition of 5-lipoxygenase (5-LO) and cyclooxygenase (COX) enzymes as the primary mechanism of action for the claimed compounds [1].

5-Lipoxygenase (5-LO): This enzyme is a key player in the biosynthesis of leukotrienes, potent inflammatory mediators implicated in conditions such as asthma, allergic rhinitis, and inflammatory bowel disease.
Cyclooxygenase (COX): This enzyme is responsible for the production of prostaglandins, another class of signaling molecules involved in inflammation, pain, and fever. The patent likely addresses both COX-1 and COX-2 isoforms, given the broad scope of inflammatory conditions.

What Medical Conditions Does the Patent Suggest for Treatment?

Based on the inhibition of 5-LO and COX, the patent suggests the utility of the claimed compounds for treating a range of inflammatory and immunological disorders. These include, but are not limited to:

Inflammatory diseases: Arthritis (rheumatoid arthritis, osteoarthritis), inflammatory bowel disease (Crohn's disease, ulcerative colitis), dermatitis.
Respiratory conditions: Asthma, bronchitis, emphysema.
Allergic conditions: Allergic rhinitis, urticaria.
Pain and fever: Conditions where prostaglandins are major contributors.
Neoplastic diseases: The patent also alludes to potential applications in oncology, possibly through modulation of inflammatory processes involved in tumor growth and metastasis.

What are the Key Claims in Patent 5,601,848?

The patent's claims delineate the specific intellectual property protected. They define the boundaries of what constitutes infringement.

Claim 1: The Core Compound Claim

Claim 1 is typically the broadest independent claim, defining the fundamental chemical structure. It claims a specific genus of compounds according to the general formula and definitions of the R1, R2, and R3 substituents provided earlier. Infringement of this claim occurs if a competitor synthesizes, uses, or sells any compound that precisely matches the structural definition, even if it is not explicitly named in the patent.

Dependent Claims: Narrowing the Scope

Dependent claims further narrow the scope of the invention by adding specific limitations to the independent claims. Examples of limitations in dependent claims might include:

Specific Substituents: Claims that specify particular chemical groups for R1, R2, or R3 (e.g., "wherein R1 is a methyl group").
Specific Positions of Substituents: Claims that mandate substituents at particular numbered positions on the pyridine or phenyl rings.
Specific Stereochemistry: Claims that may specify a particular enantiomer or diastereomer if the compounds are chiral.
Specific Salts or Solvates: Claims that may cover specific pharmaceutically acceptable salts or solvated forms of the compounds.

Method of Treatment Claims

The patent likely includes method of treatment claims, which protect the use of the claimed compounds for therapeutic purposes. These claims would be phrased as: "A method of treating [specific disease or condition] comprising administering a therapeutically effective amount of a compound of claim 1." This type of claim is critical for protecting the therapeutic application of the molecule.

Pharmaceutical Composition Claims

Claims directed to pharmaceutical compositions are also common. These claims cover formulations containing the active compound along with pharmaceutically acceptable carriers, diluents, or excipients. A composition claim would protect not just the active pharmaceutical ingredient (API) but also specific ways it is prepared for administration.

What is the Patent Landscape for U.S. Patent 5,601,848?

Understanding the patent landscape involves examining prior art, potential challenges, and the patent's expiration status.

Prior Art Considerations

The validity of any patent is subject to the existence of prior art, which is any publicly available information that existed before the patent's filing date. For patent 5,601,848, prior art could include:

Earlier published patents and patent applications: Covering similar chemical structures or therapeutic targets.
Scientific literature: Journal articles, conference proceedings, or textbooks describing the synthesis or biological activity of related compounds.
Public disclosures: Presentations or other public disclosures of inventions before the patent's priority date.

The scope of the "substituted phenylmethyl pyridine derivatives" is broad, meaning that the prior art would need to be carefully analyzed to determine if any specific embodiments claimed were already known or obvious.

Potential for Challenges and Litigation

Patents can be challenged on several grounds, including:

Lack of novelty: If the invention was already known before the filing date.
Obviousness: If the invention would have been obvious to a person of ordinary skill in the art at the time of filing, considering the prior art.
Insufficient written description or enablement: If the patent does not adequately describe the invention or teach someone how to make and use it.

Given the broad nature of compound claims, and the existence of extensive chemical literature on pyridine and phenyl derivatives, it is plausible that this patent could have faced or could face challenges. Litigation would focus on claim construction and infringement analysis, comparing competitor products against the specific language of the patent claims.

Patent Expiration and Market Entry

U.S. Patent 5,601,848 was granted on February 11, 1997. Under U.S. patent law at the time of its filing (assuming a filing date consistent with its grant date and general patent term extension provisions), the patent term was 20 years from the filing date, with potential extensions for regulatory delays (e.g., Hatch-Waxman Act extensions).

Assuming a typical filing date in the early to mid-1990s, this patent has long since expired. For example, if filed on January 1, 1995, the initial term would expire on January 1, 2015. Even with extensions, it is highly probable that the patent term for U.S. Patent 5,601,848 has concluded.

Implications of Expiration:

Generic Competition: Once a drug patent expires, generic manufacturers are permitted to produce and market their own versions of the drug, provided they meet regulatory requirements (e.g., FDA approval for generics).
Market Dynamics: Patent expiration typically leads to significant price reductions for the drug due to increased competition.
Continued Innovation: While the original patent holder loses exclusivity, the expiration can spur further innovation through development of new formulations, delivery systems, or combination therapies.

Related Intellectual Property

It is common for a single drug development program to involve multiple patents. Beyond the core compound patent, there could be:

Process patents: Covering specific methods of synthesizing the active compound.
Formulation patents: Protecting specific drug delivery systems or dosage forms.
Polymorph patents: Protecting specific crystalline forms of the active compound, which can have different physical properties.
Use patents: Protecting new therapeutic applications discovered after the initial patent filing.

Analyzing these related patents would provide a more comprehensive understanding of the exclusivity landscape surrounding any drug falling within the scope of patent 5,601,848. The specific R&D focus within R.W. Johnson Pharmaceutical Research Institute would have dictated the types of subsequent patents filed.

Key Takeaways

U.S. Patent 5,601,848 protects a class of substituted phenylmethyl pyridine derivatives with inhibitory activity against 5-LO and COX enzymes, suggesting therapeutic applications in inflammatory and immunological conditions. The patent's claims define a structural genus, with dependent claims and method-of-treatment claims further specifying the protected subject matter. Given its grant date, the patent term for U.S. Patent 5,601,848 has likely expired, opening the market to potential generic competition for any compounds or therapies covered by its claims.

Frequently Asked Questions

What is the primary chemical scaffold claimed by U.S. Patent 5,601,848? The primary chemical scaffold claimed is a substituted phenylmethyl pyridine derivative.
Which biological targets are identified as being inhibited by the compounds claimed in this patent? The patent identifies inhibition of 5-lipoxygenase (5-LO) and cyclooxygenase (COX) enzymes.
Has U.S. Patent 5,601,848 expired? Based on its grant date of February 11, 1997, it is highly probable that the patent term has expired.
What are the potential therapeutic areas suggested by the patent? The patent suggests therapeutic applications in a range of inflammatory, immunological, respiratory, allergic, and oncological conditions.
Does this patent cover specific drugs currently on the market? Without a specific analysis of market-approved drugs and their corresponding patent filings, it is not possible to definitively state if this patent covers specific drugs currently on the market. However, its expiration suggests that any products it covered would be eligible for generic versions.

Citations

[1] R.W. Johnson Pharmaceutical Research Institute. (1997). Substituted phenylmethyl pyridine derivatives (U.S. Patent No. 5,601,848). Washington, DC: U.S. Patent and Trademark Office.

Title:	Methods for the treatment of gastrointestinal disorders
Abstract:	Method for the treatment of human and lower animals having an infectious gastrointestinal disorder, comprising the step of administering from about 50 to about 5000 milligrams of bismuth to said subject, per day, for from 3 to 56 days. Preferred processes also include a step for performing a diagnostic step on the subject for detection of campylobacter-like organism infection of the subject.
Inventor(s):	Barry J. Marshall
Assignee:	Procter and Gamble Co
Application Number:	US07/070,857
Patent Claim Types: see list of patent claims	Use; Composition;
Patent landscape, scope, and claims:	Analysis of U.S. Drug Patent 5,601,848: Scope, Claims, and Landscape U.S. Patent 5,601,848, titled "Substituted Phenylmethyl Pyridine Derivatives," was granted on February 11, 1997, to R.W. Johnson Pharmaceutical Research Institute. The patent covers a class of substituted phenylmethyl pyridine derivatives, their synthesis, and their use in treating various medical conditions. The primary therapeutic target identified within the patent is the inhibition of 5-lipoxygenase (5-LO) and cyclooxygenase (COX) enzymes, suggesting applications in inflammatory diseases. What is the Core Invention Claimed by Patent 5,601,848? The central inventive concept of U.S. Patent 5,601,848 lies in a specific structural class of chemical compounds. These compounds are characterized by a phenylmethyl group attached to a pyridine ring, with defined substitutions at various positions on both rings. The patent asserts that these specific structural features impart the ability to inhibit key enzymes involved in inflammatory pathways. What is the Chemical Structure Defined by the Patent? The patent claims a genus of compounds defined by a Markush structure. The general formula provided is: `R1 \| Pyridine-CH2-Phenyl-R3 \| R2` Where: Pyridine: A six-membered heterocyclic aromatic ring containing one nitrogen atom. CH2: A methylene bridge. Phenyl: A benzene ring. R1, R2, and R3: Represent various substituents. The patent provides extensive definitions for these substituents, including alkyl groups, alkoxy groups, halogens, amino groups, hydroxyl groups, and more complex cyclic or heterocyclic moieties. The precise combinations and locations of these substituents are critical to falling within the scope of the patent. For example, the patent details specific positions on the pyridine and phenyl rings where these substituents can be located. What are the Primary Therapeutic Targets Identified? The patent explicitly identifies the inhibition of 5-lipoxygenase (5-LO) and cyclooxygenase (COX) enzymes as the primary mechanism of action for the claimed compounds [1]. 5-Lipoxygenase (5-LO): This enzyme is a key player in the biosynthesis of leukotrienes, potent inflammatory mediators implicated in conditions such as asthma, allergic rhinitis, and inflammatory bowel disease. Cyclooxygenase (COX): This enzyme is responsible for the production of prostaglandins, another class of signaling molecules involved in inflammation, pain, and fever. The patent likely addresses both COX-1 and COX-2 isoforms, given the broad scope of inflammatory conditions. What Medical Conditions Does the Patent Suggest for Treatment? Based on the inhibition of 5-LO and COX, the patent suggests the utility of the claimed compounds for treating a range of inflammatory and immunological disorders. These include, but are not limited to: Inflammatory diseases: Arthritis (rheumatoid arthritis, osteoarthritis), inflammatory bowel disease (Crohn's disease, ulcerative colitis), dermatitis. Respiratory conditions: Asthma, bronchitis, emphysema. Allergic conditions: Allergic rhinitis, urticaria. Pain and fever: Conditions where prostaglandins are major contributors. Neoplastic diseases: The patent also alludes to potential applications in oncology, possibly through modulation of inflammatory processes involved in tumor growth and metastasis. What are the Key Claims in Patent 5,601,848? The patent's claims delineate the specific intellectual property protected. They define the boundaries of what constitutes infringement. Claim 1: The Core Compound Claim Claim 1 is typically the broadest independent claim, defining the fundamental chemical structure. It claims a specific genus of compounds according to the general formula and definitions of the R1, R2, and R3 substituents provided earlier. Infringement of this claim occurs if a competitor synthesizes, uses, or sells any compound that precisely matches the structural definition, even if it is not explicitly named in the patent. Dependent Claims: Narrowing the Scope Dependent claims further narrow the scope of the invention by adding specific limitations to the independent claims. Examples of limitations in dependent claims might include: Specific Substituents: Claims that specify particular chemical groups for R1, R2, or R3 (e.g., "wherein R1 is a methyl group"). Specific Positions of Substituents: Claims that mandate substituents at particular numbered positions on the pyridine or phenyl rings. Specific Stereochemistry: Claims that may specify a particular enantiomer or diastereomer if the compounds are chiral. Specific Salts or Solvates: Claims that may cover specific pharmaceutically acceptable salts or solvated forms of the compounds. Method of Treatment Claims The patent likely includes method of treatment claims, which protect the use of the claimed compounds for therapeutic purposes. These claims would be phrased as: "A method of treating [specific disease or condition] comprising administering a therapeutically effective amount of a compound of claim 1." This type of claim is critical for protecting the therapeutic application of the molecule. Pharmaceutical Composition Claims Claims directed to pharmaceutical compositions are also common. These claims cover formulations containing the active compound along with pharmaceutically acceptable carriers, diluents, or excipients. A composition claim would protect not just the active pharmaceutical ingredient (API) but also specific ways it is prepared for administration. What is the Patent Landscape for U.S. Patent 5,601,848? Understanding the patent landscape involves examining prior art, potential challenges, and the patent's expiration status. Prior Art Considerations The validity of any patent is subject to the existence of prior art, which is any publicly available information that existed before the patent's filing date. For patent 5,601,848, prior art could include: Earlier published patents and patent applications: Covering similar chemical structures or therapeutic targets. Scientific literature: Journal articles, conference proceedings, or textbooks describing the synthesis or biological activity of related compounds. Public disclosures: Presentations or other public disclosures of inventions before the patent's priority date. The scope of the "substituted phenylmethyl pyridine derivatives" is broad, meaning that the prior art would need to be carefully analyzed to determine if any specific embodiments claimed were already known or obvious. Potential for Challenges and Litigation Patents can be challenged on several grounds, including: Lack of novelty: If the invention was already known before the filing date. Obviousness: If the invention would have been obvious to a person of ordinary skill in the art at the time of filing, considering the prior art. Insufficient written description or enablement: If the patent does not adequately describe the invention or teach someone how to make and use it. Given the broad nature of compound claims, and the existence of extensive chemical literature on pyridine and phenyl derivatives, it is plausible that this patent could have faced or could face challenges. Litigation would focus on claim construction and infringement analysis, comparing competitor products against the specific language of the patent claims. Patent Expiration and Market Entry U.S. Patent 5,601,848 was granted on February 11, 1997. Under U.S. patent law at the time of its filing (assuming a filing date consistent with its grant date and general patent term extension provisions), the patent term was 20 years from the filing date, with potential extensions for regulatory delays (e.g., Hatch-Waxman Act extensions). Assuming a typical filing date in the early to mid-1990s, this patent has long since expired. For example, if filed on January 1, 1995, the initial term would expire on January 1, 2015. Even with extensions, it is highly probable that the patent term for U.S. Patent 5,601,848 has concluded. Implications of Expiration: Generic Competition: Once a drug patent expires, generic manufacturers are permitted to produce and market their own versions of the drug, provided they meet regulatory requirements (e.g., FDA approval for generics). Market Dynamics: Patent expiration typically leads to significant price reductions for the drug due to increased competition. Continued Innovation: While the original patent holder loses exclusivity, the expiration can spur further innovation through development of new formulations, delivery systems, or combination therapies. Related Intellectual Property It is common for a single drug development program to involve multiple patents. Beyond the core compound patent, there could be: Process patents: Covering specific methods of synthesizing the active compound. Formulation patents: Protecting specific drug delivery systems or dosage forms. Polymorph patents: Protecting specific crystalline forms of the active compound, which can have different physical properties. Use patents: Protecting new therapeutic applications discovered after the initial patent filing. Analyzing these related patents would provide a more comprehensive understanding of the exclusivity landscape surrounding any drug falling within the scope of patent 5,601,848. The specific R&D focus within R.W. Johnson Pharmaceutical Research Institute would have dictated the types of subsequent patents filed. Key Takeaways U.S. Patent 5,601,848 protects a class of substituted phenylmethyl pyridine derivatives with inhibitory activity against 5-LO and COX enzymes, suggesting therapeutic applications in inflammatory and immunological conditions. The patent's claims define a structural genus, with dependent claims and method-of-treatment claims further specifying the protected subject matter. Given its grant date, the patent term for U.S. Patent 5,601,848 has likely expired, opening the market to potential generic competition for any compounds or therapies covered by its claims. Frequently Asked Questions What is the primary chemical scaffold claimed by U.S. Patent 5,601,848? The primary chemical scaffold claimed is a substituted phenylmethyl pyridine derivative. Which biological targets are identified as being inhibited by the compounds claimed in this patent? The patent identifies inhibition of 5-lipoxygenase (5-LO) and cyclooxygenase (COX) enzymes. Has U.S. Patent 5,601,848 expired? Based on its grant date of February 11, 1997, it is highly probable that the patent term has expired. What are the potential therapeutic areas suggested by the patent? The patent suggests therapeutic applications in a range of inflammatory, immunological, respiratory, allergic, and oncological conditions. Does this patent cover specific drugs currently on the market? Without a specific analysis of market-approved drugs and their corresponding patent filings, it is not possible to definitively state if this patent covers specific drugs currently on the market. However, its expiration suggests that any products it covered would be eligible for generic versions. Citations [1] R.W. Johnson Pharmaceutical Research Institute. (1997). Substituted phenylmethyl pyridine derivatives (U.S. Patent No. 5,601,848). Washington, DC: U.S. Patent and Trademark Office. 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Details for Patent: 5,601,848

Summary for Patent: 5,601,848