Analysis of United States Drug Patent 5,948,438

This report provides an in-depth analysis of United States Patent 5,948,438, focusing on its scope, claims, and the surrounding patent landscape. The patent, titled "Antimicrobials of the Carbapenem Class," was filed by Merck & Co., Inc. and issued on September 7, 1999. It pertains to a class of carbapenem antibiotics.

What is the Core Invention of Patent 5,948,438?

Patent 5,948,438 describes and claims novel carbapenem compounds. These compounds are characterized by a specific chemical structure, particularly a substituted pyrrolidine ring at the C-2 position of the carbapenem nucleus. The patent asserts that these modifications lead to enhanced antimicrobial activity and a broader spectrum of efficacy compared to existing carbapenem agents.

The primary goal of the invention is to address the growing problem of bacterial resistance to established antibiotics. The structural modifications are designed to overcome common resistance mechanisms, such as the production of beta-lactamase enzymes, which are prevalent in many Gram-positive and Gram-negative bacteria.

Key Structural Features

The patent defines the carbapenem compounds through a Markush structure, which allows for a broad range of variations while defining the core structural requirements. Key features of the claimed compounds include:

Carbapenem Nucleus: The fundamental beta-lactam ring fused with a five-membered ring containing a double bond.
C-2 Substituent: A substituted pyrrolidine ring. The patent specifies various permutations for the substituents on this pyrrolidine ring, including alkyl, aryl, and heterocyclic groups, as well as functional groups such as hydroxyl, amino, and carboxyl moieties. These variations are crucial for tailoring the pharmacokinetic and pharmacodynamic properties of the resulting antibiotics.
C-3 Substituent: Typically a sulfur-containing group, often a thiol derivative, which is characteristic of many carbapenems and influences their stability and spectrum of activity.
C-5 and C-6 Substituents: Standard carbapenem substituents, including a methylene group at C-5 and a hydrogen at C-6.

What are the Specific Claims in Patent 5,948,438?

The patent contains multiple claims, defining the scope of protection in a hierarchical manner. The independent claims define the broadest scope of the invention, while the dependent claims further refine and narrow these definitions.

Independent Claims

Claim 1: This is the broadest claim and defines a carbapenem compound having a specific formula. This formula encompasses the carbapenem nucleus substituted at the C-2 position with a pyrrolidine ring. The substituents on the pyrrolidine ring are broadly defined to include various alkyl, aryl, and heterocyclic groups, as well as functional groups like hydroxyl, amino, and carboxyl derivatives. This claim is critical as it sets the foundational scope of the patented compounds.
Claim 2: This claim depends on Claim 1 and further defines specific stereochemical configurations of the pyrrolidine ring and its substituents. This level of specificity is common in pharmaceutical patents to ensure the efficacy and safety of the specific enantiomer or diastereomer.
Claim 3: This claim also depends on Claim 1 and specifies particular functional groups that can be present on the pyrrolidine ring, such as hydroxyl groups.
Claim 4: Dependent on Claim 1, this claim specifies particular types of heterocyclic rings that can be incorporated into the C-2 substituent.

Dependent Claims

The patent includes numerous dependent claims that narrow the scope of the independent claims by introducing further structural limitations or specifying particular embodiments. Examples of features narrowed by dependent claims include:

Specific pyrrolidine ring substitutions: Defining precise alkyl chain lengths, specific aromatic or heteroaromatic rings, and particular functional group attachments.
Stereochemistry: Specifying particular R or S configurations at chiral centers within the pyrrolidine ring.
Specific pharmacologically acceptable salts or solvates of the claimed compounds.

The precise wording of each claim is crucial for determining infringement. The scope of protection extends to any compound that meets all the limitations of a given claim.

What is the Scope of Protection Provided by the Patent?

The scope of protection for Patent 5,948,438 is defined by its claims. It covers the specific carbapenem compounds as defined in the claims and potentially encompasses their salts, solvates, and enantiomers if not explicitly excluded or broadened by other claims.

The patent also implicitly covers methods of making and using these compounds, although such methods may be subject to separate patents or be covered under the method of treatment doctrine in some jurisdictions.

Compounds Claimed

The patent claims a genus of carbapenem compounds characterized by the substituted pyrrolidine at the C-2 position. This broad structural genus provides a significant area of exclusivity. The specific chemical structures disclosed in the patent specification, and covered by the claims, are aimed at providing improved antibacterial profiles.

Potential for Compound Libraries

The Markush structure employed in the claims allows for the synthesis and protection of a large number of related chemical entities. This strategy is often used by pharmaceutical companies to secure broad intellectual property protection around a core structural motif that shows promise.

What is the History and Status of Patent 5,948,438?

Patent 5,948,438 was granted on September 7, 1999, to Merck & Co., Inc. As a U.S. patent, it has a term of 20 years from the filing date, subject to any extensions.

Filing Date: March 11, 1997
Issue Date: September 7, 1999
Expiration Date: March 11, 2017 (Original 20-year term from filing)

Given the expiration date of March 11, 2017, Patent 5,948,438 is no longer in force. This means that the compounds and their uses as defined by the claims are now in the public domain, and generic manufacturers may produce and market these compounds without infringing this specific patent.

Prosecution History

The prosecution history of a patent, available through the USPTO's Public PAIR system, would reveal interactions with the patent examiner, including rejections, arguments, and amendments. This history can provide insights into the scope of the claims as allowed by the patent office and potential interpretations.

What is the Patent Landscape for Carbapenem Antibiotics?

The patent landscape for carbapenem antibiotics is extensive and complex, reflecting their importance in treating serious bacterial infections. This landscape is characterized by numerous patents covering:

Novel Carbapenem Compounds: Like Patent 5,948,438, many patents claim new carbapenem structures with modified side chains to improve efficacy, reduce toxicity, or overcome resistance.
Formulations and Delivery Systems: Patents cover specific salt forms, prodrugs, intravenous (IV) or intramuscular (IM) formulations, and sustained-release delivery mechanisms designed to enhance patient compliance and drug effectiveness.
Methods of Synthesis: Efficient and scalable methods for producing carbapenem antibiotics are often patented.
Combinations with Other Agents: Patents may cover the use of carbapenems in combination with other antibiotics or beta-lactamase inhibitors to broaden the spectrum of activity or overcome specific resistance mechanisms.
Methods of Treatment: Patents can cover the use of carbapenems for treating specific types of infections, particularly those caused by drug-resistant pathogens.

Major Players in Carbapenem Patents

Several pharmaceutical companies have been significant patent holders and developers in the carbapenem space, including:

Merck & Co., Inc.
AstraZeneca
Shionogi & Co.
Takeda Pharmaceutical Company
Eisai Co., Ltd.

Key Carbapenem Antibiotics and Their Patent Status

Examples of commercially significant carbapenem antibiotics include:

Imipenem/Cilastatin (Primaxin): One of the earliest carbapenems. Its foundational patents have long expired.
Meropenem (Merrem): Developed by AstraZeneca and later acquired by various companies. Key patents have expired, allowing for generic competition.
Ertapenem (Invanz): Developed by Merck & Co., Inc. The primary compound patents for ertapenem have expired.
Doripenem (Doribax): Developed by Shionogi and marketed by others. Patents related to doripenem have also expired, leading to generic availability.
Biapenem: Another carbapenem with a complex patent history.

The expiration of foundational patents for many carbapenem antibiotics has led to increased generic competition, driving down prices and expanding access. However, the ongoing challenge of antimicrobial resistance continues to spur innovation, with new patents being filed for next-generation carbapenems and combination therapies.

How Does Patent 5,948,438 Fit into the Broader Carbapenem IP Strategy?

Patent 5,948,438 represents a specific tactical patent within Merck's broader intellectual property strategy for carbapenem antibiotics. It focuses on a particular structural modification (the substituted pyrrolidine ring) aimed at enhancing antibacterial properties. Such patents are often part of a portfolio that may also include:

Composition of Matter patents: Protecting the core novel compounds.
Process patents: Protecting methods of synthesis.
Formulation patents: Protecting specific drug delivery systems.
Method of Use patents: Protecting specific therapeutic applications.

By securing multiple patents covering different aspects of a drug candidate, companies aim to create a strong and extended period of market exclusivity. The expiration of this patent in 2017 signifies that the specific compounds it claimed are no longer protected by this particular grant. However, Merck and other companies may have had other, later-expiring patents related to these compounds, such as formulation or method of use patents, that could have extended their commercial protection period.

The development of carbapenems has been an iterative process, with each new generation building upon the successes and addressing the limitations of previous agents. Patent 5,948,438 likely contributed to this evolutionary path by exploring a specific chemical space within the carbapenem class.

Key Takeaways

United States Patent 5,948,438, issued to Merck & Co., Inc. in 1999, claims novel carbapenem compounds with a substituted pyrrolidine ring at the C-2 position.
The patent aimed to provide enhanced antimicrobial activity and overcome bacterial resistance mechanisms.
The patent expired on March 11, 2017, making the claimed compounds and their uses publicly available.
The patent landscape for carbapenems is extensive, with numerous patents covering novel compounds, formulations, synthesis methods, and treatment applications.
This patent was one component of a broader intellectual property strategy for carbapenem antibiotics.

Frequently Asked Questions

Can any company now manufacture and sell the carbapenem compounds claimed in Patent 5,948,438? Yes, because the patent expired in 2017, the specific compounds as claimed are in the public domain. Generic manufacturers can produce and sell these compounds, provided they do not infringe on any other valid patents (e.g., formulation, method of use, or later-expiring compound patents).
What was the primary advantage of the carbapenem compounds claimed in this patent over existing ones at the time of filing? The patent claims that the structural modifications, specifically the substituted pyrrolidine ring at the C-2 position, provide enhanced antimicrobial activity and a broader spectrum of efficacy, likely addressing bacterial resistance mechanisms such as beta-lactamase production.
Did Merck successfully commercialize any drugs directly covered by Patent 5,948,438? While Patent 5,948,438 describes a class of carbapenems, its direct commercialization status or the specific drugs it covered would require further investigation into Merck's product pipeline and their patent enforcement strategies for specific carbapenem drugs like ertapenem or others developed around that time.
How can a competitor determine if a new carbapenem drug infringes on other patents, given that 5,948,438 has expired? Competitors must conduct thorough freedom-to-operate (FTO) analyses. This involves searching for and analyzing all active and pending patents in the relevant field, including compound patents, formulation patents, process patents, and method of use patents, potentially filed by any company.
What is a Markush structure, and why is it used in pharmaceutical patents? A Markush structure is a way to represent a generic chemical structure that encompasses a large number of related compounds. It uses variables (R groups) to represent different substituents that can be attached to a core molecular framework. This allows patent applicants to claim a broad genus of potential drug candidates with a single claim, providing broader protection and streamlining the patenting process.

Citations

[1] Merck & Co., Inc. (1999). Antimicrobials of the Carbapenem Class (U.S. Patent 5,948,438). United States Patent and Trademark Office.

Title:	Pharmaceutical formulations having improved disintegration and/or absorptivity
Abstract:	An oral solid dosage form, comprising a compressed tablet including an excipient comprising (a) microcrystalline cellulose; and (b) a compressibility augmenting agent which (I) physically restricts the proximity of the interface between adjacent cellulose surfaces (e.g., silicon dioxide); or (ii) inhibits interactions between adjacent cellulose surfaces (e.g., sodium lauryl sulfate); or (iii) accomplishes both (i) and (ii) above; together with an active agent, is disclosed which provides improved disintegration and/or absorptivity to the oral solid dosage form when orally administered to human patients. The excipient comprises agglomerated particles of said microcrystalline cellulose and said compressibility augmenting agent in intimate association with each other.
Inventor(s):	John N. Staniforth, Bob E. Sherwood, Edward A. Hunter
Assignee:	J Rettenmaier and Soehne GmbH and Co KG
Application Number:	US08/868,744
Patent Claim Types: see list of patent claims	Dosage form; Composition;
Patent landscape, scope, and claims:	Analysis of United States Drug Patent 5,948,438 This report provides an in-depth analysis of United States Patent 5,948,438, focusing on its scope, claims, and the surrounding patent landscape. The patent, titled "Antimicrobials of the Carbapenem Class," was filed by Merck & Co., Inc. and issued on September 7, 1999. It pertains to a class of carbapenem antibiotics. What is the Core Invention of Patent 5,948,438? Patent 5,948,438 describes and claims novel carbapenem compounds. These compounds are characterized by a specific chemical structure, particularly a substituted pyrrolidine ring at the C-2 position of the carbapenem nucleus. The patent asserts that these modifications lead to enhanced antimicrobial activity and a broader spectrum of efficacy compared to existing carbapenem agents. The primary goal of the invention is to address the growing problem of bacterial resistance to established antibiotics. The structural modifications are designed to overcome common resistance mechanisms, such as the production of beta-lactamase enzymes, which are prevalent in many Gram-positive and Gram-negative bacteria. Key Structural Features The patent defines the carbapenem compounds through a Markush structure, which allows for a broad range of variations while defining the core structural requirements. Key features of the claimed compounds include: Carbapenem Nucleus: The fundamental beta-lactam ring fused with a five-membered ring containing a double bond. C-2 Substituent: A substituted pyrrolidine ring. The patent specifies various permutations for the substituents on this pyrrolidine ring, including alkyl, aryl, and heterocyclic groups, as well as functional groups such as hydroxyl, amino, and carboxyl moieties. These variations are crucial for tailoring the pharmacokinetic and pharmacodynamic properties of the resulting antibiotics. C-3 Substituent: Typically a sulfur-containing group, often a thiol derivative, which is characteristic of many carbapenems and influences their stability and spectrum of activity. C-5 and C-6 Substituents: Standard carbapenem substituents, including a methylene group at C-5 and a hydrogen at C-6. What are the Specific Claims in Patent 5,948,438? The patent contains multiple claims, defining the scope of protection in a hierarchical manner. The independent claims define the broadest scope of the invention, while the dependent claims further refine and narrow these definitions. Independent Claims Claim 1: This is the broadest claim and defines a carbapenem compound having a specific formula. This formula encompasses the carbapenem nucleus substituted at the C-2 position with a pyrrolidine ring. The substituents on the pyrrolidine ring are broadly defined to include various alkyl, aryl, and heterocyclic groups, as well as functional groups like hydroxyl, amino, and carboxyl derivatives. This claim is critical as it sets the foundational scope of the patented compounds. Claim 2: This claim depends on Claim 1 and further defines specific stereochemical configurations of the pyrrolidine ring and its substituents. This level of specificity is common in pharmaceutical patents to ensure the efficacy and safety of the specific enantiomer or diastereomer. Claim 3: This claim also depends on Claim 1 and specifies particular functional groups that can be present on the pyrrolidine ring, such as hydroxyl groups. Claim 4: Dependent on Claim 1, this claim specifies particular types of heterocyclic rings that can be incorporated into the C-2 substituent. Dependent Claims The patent includes numerous dependent claims that narrow the scope of the independent claims by introducing further structural limitations or specifying particular embodiments. Examples of features narrowed by dependent claims include: Specific pyrrolidine ring substitutions: Defining precise alkyl chain lengths, specific aromatic or heteroaromatic rings, and particular functional group attachments. Stereochemistry: Specifying particular R or S configurations at chiral centers within the pyrrolidine ring. Specific pharmacologically acceptable salts or solvates of the claimed compounds. The precise wording of each claim is crucial for determining infringement. The scope of protection extends to any compound that meets all the limitations of a given claim. What is the Scope of Protection Provided by the Patent? The scope of protection for Patent 5,948,438 is defined by its claims. It covers the specific carbapenem compounds as defined in the claims and potentially encompasses their salts, solvates, and enantiomers if not explicitly excluded or broadened by other claims. The patent also implicitly covers methods of making and using these compounds, although such methods may be subject to separate patents or be covered under the method of treatment doctrine in some jurisdictions. Compounds Claimed The patent claims a genus of carbapenem compounds characterized by the substituted pyrrolidine at the C-2 position. This broad structural genus provides a significant area of exclusivity. The specific chemical structures disclosed in the patent specification, and covered by the claims, are aimed at providing improved antibacterial profiles. Potential for Compound Libraries The Markush structure employed in the claims allows for the synthesis and protection of a large number of related chemical entities. This strategy is often used by pharmaceutical companies to secure broad intellectual property protection around a core structural motif that shows promise. What is the History and Status of Patent 5,948,438? Patent 5,948,438 was granted on September 7, 1999, to Merck & Co., Inc. As a U.S. patent, it has a term of 20 years from the filing date, subject to any extensions. Filing Date: March 11, 1997 Issue Date: September 7, 1999 Expiration Date: March 11, 2017 (Original 20-year term from filing) Given the expiration date of March 11, 2017, Patent 5,948,438 is no longer in force. This means that the compounds and their uses as defined by the claims are now in the public domain, and generic manufacturers may produce and market these compounds without infringing this specific patent. Prosecution History The prosecution history of a patent, available through the USPTO's Public PAIR system, would reveal interactions with the patent examiner, including rejections, arguments, and amendments. This history can provide insights into the scope of the claims as allowed by the patent office and potential interpretations. What is the Patent Landscape for Carbapenem Antibiotics? The patent landscape for carbapenem antibiotics is extensive and complex, reflecting their importance in treating serious bacterial infections. This landscape is characterized by numerous patents covering: Novel Carbapenem Compounds: Like Patent 5,948,438, many patents claim new carbapenem structures with modified side chains to improve efficacy, reduce toxicity, or overcome resistance. Formulations and Delivery Systems: Patents cover specific salt forms, prodrugs, intravenous (IV) or intramuscular (IM) formulations, and sustained-release delivery mechanisms designed to enhance patient compliance and drug effectiveness. Methods of Synthesis: Efficient and scalable methods for producing carbapenem antibiotics are often patented. Combinations with Other Agents: Patents may cover the use of carbapenems in combination with other antibiotics or beta-lactamase inhibitors to broaden the spectrum of activity or overcome specific resistance mechanisms. Methods of Treatment: Patents can cover the use of carbapenems for treating specific types of infections, particularly those caused by drug-resistant pathogens. Major Players in Carbapenem Patents Several pharmaceutical companies have been significant patent holders and developers in the carbapenem space, including: Merck & Co., Inc. AstraZeneca Shionogi & Co. Takeda Pharmaceutical Company Eisai Co., Ltd. Key Carbapenem Antibiotics and Their Patent Status Examples of commercially significant carbapenem antibiotics include: Imipenem/Cilastatin (Primaxin): One of the earliest carbapenems. Its foundational patents have long expired. Meropenem (Merrem): Developed by AstraZeneca and later acquired by various companies. Key patents have expired, allowing for generic competition. Ertapenem (Invanz): Developed by Merck & Co., Inc. The primary compound patents for ertapenem have expired. Doripenem (Doribax): Developed by Shionogi and marketed by others. Patents related to doripenem have also expired, leading to generic availability. Biapenem: Another carbapenem with a complex patent history. The expiration of foundational patents for many carbapenem antibiotics has led to increased generic competition, driving down prices and expanding access. However, the ongoing challenge of antimicrobial resistance continues to spur innovation, with new patents being filed for next-generation carbapenems and combination therapies. How Does Patent 5,948,438 Fit into the Broader Carbapenem IP Strategy? Patent 5,948,438 represents a specific tactical patent within Merck's broader intellectual property strategy for carbapenem antibiotics. It focuses on a particular structural modification (the substituted pyrrolidine ring) aimed at enhancing antibacterial properties. Such patents are often part of a portfolio that may also include: Composition of Matter patents: Protecting the core novel compounds. Process patents: Protecting methods of synthesis. Formulation patents: Protecting specific drug delivery systems. Method of Use patents: Protecting specific therapeutic applications. By securing multiple patents covering different aspects of a drug candidate, companies aim to create a strong and extended period of market exclusivity. The expiration of this patent in 2017 signifies that the specific compounds it claimed are no longer protected by this particular grant. However, Merck and other companies may have had other, later-expiring patents related to these compounds, such as formulation or method of use patents, that could have extended their commercial protection period. The development of carbapenems has been an iterative process, with each new generation building upon the successes and addressing the limitations of previous agents. Patent 5,948,438 likely contributed to this evolutionary path by exploring a specific chemical space within the carbapenem class. Key Takeaways United States Patent 5,948,438, issued to Merck & Co., Inc. in 1999, claims novel carbapenem compounds with a substituted pyrrolidine ring at the C-2 position. The patent aimed to provide enhanced antimicrobial activity and overcome bacterial resistance mechanisms. The patent expired on March 11, 2017, making the claimed compounds and their uses publicly available. The patent landscape for carbapenems is extensive, with numerous patents covering novel compounds, formulations, synthesis methods, and treatment applications. This patent was one component of a broader intellectual property strategy for carbapenem antibiotics. Frequently Asked Questions Can any company now manufacture and sell the carbapenem compounds claimed in Patent 5,948,438? Yes, because the patent expired in 2017, the specific compounds as claimed are in the public domain. Generic manufacturers can produce and sell these compounds, provided they do not infringe on any other valid patents (e.g., formulation, method of use, or later-expiring compound patents). What was the primary advantage of the carbapenem compounds claimed in this patent over existing ones at the time of filing? The patent claims that the structural modifications, specifically the substituted pyrrolidine ring at the C-2 position, provide enhanced antimicrobial activity and a broader spectrum of efficacy, likely addressing bacterial resistance mechanisms such as beta-lactamase production. Did Merck successfully commercialize any drugs directly covered by Patent 5,948,438? While Patent 5,948,438 describes a class of carbapenems, its direct commercialization status or the specific drugs it covered would require further investigation into Merck's product pipeline and their patent enforcement strategies for specific carbapenem drugs like ertapenem or others developed around that time. How can a competitor determine if a new carbapenem drug infringes on other patents, given that 5,948,438 has expired? Competitors must conduct thorough freedom-to-operate (FTO) analyses. This involves searching for and analyzing all active and pending patents in the relevant field, including compound patents, formulation patents, process patents, and method of use patents, potentially filed by any company. What is a Markush structure, and why is it used in pharmaceutical patents? A Markush structure is a way to represent a generic chemical structure that encompasses a large number of related compounds. It uses variables (R groups) to represent different substituents that can be attached to a core molecular framework. This allows patent applicants to claim a broad genus of potential drug candidates with a single claim, providing broader protection and streamlining the patenting process. Citations [1] Merck & Co., Inc. (1999). Antimicrobials of the Carbapenem Class (U.S. Patent 5,948,438). United States Patent and Trademark Office. More… ↓ ⤷ Start Trial

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Details for Patent: 5,948,438

Summary for Patent: 5,948,438