United States Drug Patent 5,496,931: Scope, Claims, and Landscape Analysis

This report details United States Patent 5,496,931, granted on March 5, 1996, to Merck & Co., Inc. The patent covers certain pyrazolo[1,5-a]pyrimidine compounds and their use in treating inflammatory conditions, specifically those mediated by phosphodiesterase (PDE) enzymes. The patent's scope is defined by its claims, which delineate the exclusive rights granted. Understanding this patent's landscape is crucial for companies involved in the development or commercialization of PDE inhibitors for inflammatory diseases.

What is the Core Invention of Patent 5,496,931?

The invention described in US Patent 5,496,931 centers on a class of chemical compounds characterized by a pyrazolo[1,5-a]pyrimidine core structure. These compounds function as inhibitors of phosphodiesterase (PDE) enzymes, which are critical in regulating intracellular cyclic nucleotide levels. By inhibiting specific PDE isoforms, these compounds can modulate inflammatory pathways.

The patent's abstract highlights the utility of these compounds in treating conditions such as asthma, chronic obstructive pulmonary disease (COPD), and allergic rhinitis. The described mechanism of action involves increasing intracellular levels of cyclic adenosine monophosphate (cAMP) or cyclic guanosine monophosphate (cGMP), leading to the relaxation of airway smooth muscle and suppression of inflammatory cell activity.

What Specific Compounds Are Claimed?

Patent 5,496,931 includes several dependent and independent claims that define the scope of the protected invention.

Independent Claims

The primary independent claims define the core chemical structures and their intended use.

Claim 1: This is a foundational claim that defines a genus of pyrazolo[1,5-a]pyrimidine compounds. It specifies a general structural formula with various substituent possibilities. The core structure is a pyrazolo[1,5-a]pyrimidine ring system. The substituents (R1, R2, R3, R4, R5, R6, R7) are defined by a range of chemical groups, including alkyl, aryl, heteroaryl, halogen, alkoxy, and various functional groups. This broad claim establishes protection over a wide family of related molecules. [1]
Claim 2: This claim further refines Claim 1 by narrowing the definitions of certain substituents, thereby defining a more specific subclass of compounds within the broader genus. For example, it may specify particular types of aryl or heteroaryl groups, or restrict the chain lengths of alkyl substituents. [1]
Claims 3-14: These claims continue to narrow down the scope by imposing further limitations on the substituents defined in Claim 1, leading to progressively more specific compound structures. These claims define smaller, more concrete groups of compounds within the patented invention. [1]

Dependent Claims and Their Impact

Dependent claims add further limitations to the independent claims, specifying particular embodiments or preferred aspects of the invention. These claims are crucial for understanding specific examples of compounds that are explicitly covered and for assessing the patent's strength in protecting narrower chemical spaces.

Example of a Dependent Claim's Impact: If Claim 1 defines a general formula, a dependent claim might specify that R1 must be a phenyl group substituted with a halogen at the para position. This further restricts the chemical space, offering protection to a more defined set of molecules that meet this additional criterion. [1]

The claims collectively provide a tiered approach to protection, covering both broad chemical families and specific, preferred embodiments.

What is the Therapeutic Utility Claimed?

The patent explicitly claims the use of the defined pyrazolo[1,5-a]pyrimidine compounds for treating inflammatory diseases. The core therapeutic utility is based on their activity as phosphodiesterase (PDE) inhibitors.

Mechanism of Action: The compounds increase intracellular cyclic adenosine monophosphate (cAMP) and/or cyclic guanosine monophosphate (cGMP) levels. This elevation is a key mechanism for reducing inflammation and bronchodilation. [1]
Target Conditions: The patent lists specific inflammatory conditions, including but not limited to:
- Asthma
- Chronic Obstructive Pulmonary Disease (COPD)
- Allergic rhinitis
- Inflammatory bowel disease
- Rheumatoid arthritis
- Psoriasis [1]

The claims are directed towards the method of treating these conditions using the claimed compounds. This means that any entity that manufactures, uses, or sells these compounds for the purpose of treating these diseases would infringe the patent.

What is the Patent Landscape for Pyrazolo[1,5-a]pyrimidine PDE Inhibitors?

The patent landscape surrounding pyrazolo[1,5-a]pyrimidine PDE inhibitors is dynamic, with significant activity before and after the grant of US Patent 5,496,931. Analyzing this landscape involves identifying key players, patent filing trends, and the evolution of related technologies.

Key Players and Early Research

Merck & Co., Inc. was a significant early innovator in this field, as evidenced by this patent. Other pharmaceutical companies have also engaged in research and development of PDE inhibitors for inflammatory and other conditions. Early research often focused on understanding PDE enzyme isoforms and their specific roles in various physiological and pathological processes.

Patent Filing Trends

Following the grant of US Patent 5,496,931, there has been ongoing patent activity in related chemical classes and PDE inhibition. Companies have sought to:

Develop Second-Generation Compounds: Patents filed after 5,496,931 often claim structurally modified pyrazolo[1,5-a]pyrimidine derivatives with improved potency, selectivity for specific PDE isoforms, or better pharmacokinetic profiles.
Broaden Therapeutic Applications: Research has expanded to explore PDE inhibitors for a wider range of diseases beyond the initial indications, leading to patents covering new therapeutic uses.
Develop Different Chemical Scaffolds: While 5,496,931 focuses on a specific core, the broader field of PDE inhibitors includes numerous other chemical classes. Patents in these other classes may represent alternative approaches to PDE inhibition and potential future competition.

Dominant PDE Isoforms and Therapeutic Targets

The landscape has evolved with a deeper understanding of different PDE isoforms (PDE1-PDE11) and their distinct roles. While US Patent 5,496,931 is broad, subsequent research and patenting have often focused on isoform-specific inhibitors.

PDE4 Inhibitors: These have been a major focus for inflammatory diseases, particularly asthma and COPD. Compounds targeting PDE4 have been extensively patented.
PDE3 Inhibitors: Primarily associated with cardiovascular applications, but also have anti-inflammatory effects.
PDE5 Inhibitors: Widely known for erectile dysfunction, but also explored for pulmonary hypertension and other conditions.
Dual/Multi-Isoform Inhibitors: Some research has aimed to develop inhibitors that target multiple PDE isoforms, seeking synergistic effects or broader therapeutic benefits.

Key Patents and Their Relationships

While a comprehensive search is beyond the scope of this summary, it is important to note that:

Prior Art: US Patent 5,496,931 would have been examined against existing patents and scientific literature. Understanding this prior art is crucial for assessing its validity and inventiveness.
Subsequent Patents: Numerous patents likely claim compounds that are structurally similar to or achieve similar therapeutic effects as those claimed in 5,496,931. These subsequent patents could represent potential infringements or improvements upon the original invention.
Generics and Biosimilars: For any approved drugs derived from this patent family, the patent expiration date is critical for generic entry.

What Are the Implications for R&D and Investment?

The existence and scope of US Patent 5,496,931 have several implications for research and development and investment decisions.

Freedom to Operate (FTO)

Companies developing novel PDE inhibitors or treatments for inflammatory conditions must conduct thorough Freedom to Operate (FTO) analyses. This involves:

Identifying Relevant Patents: Determining if their proposed compounds or methods fall within the claims of 5,496,931 or its continuations, divisions, or related foreign patents.
Assessing Patent Expiration: US Patent 5,496,931 has an expiration date. Understanding this date is critical for planning generic market entry or for developing new patentable entities.
Navigating Subsequent Patents: Beyond the original patent, the broader patent landscape needs assessment for potential blocking patents, especially for compounds with similar mechanisms of action or chemical structures.

Drug Discovery and Development Strategies

Designing Around: Researchers may aim to design compounds that are structurally distinct from those explicitly claimed in 5,496,931 while still achieving the desired therapeutic effect through PDE inhibition. This requires a deep understanding of Markush structures and claim interpretation.
Targeting Different Isoforms: Focusing on PDE isoforms not effectively inhibited by the compounds claimed in 5,496,931, or exploring novel therapeutic applications not covered by the patent's claims.
Identifying Licensed Technologies: Companies might consider licensing the technology covered by 5,496,931 or seeking agreements with the patent holder if their development aligns with the patented scope.

Investment Considerations

Competitive Landscape: Investors must evaluate the competitive intensity within the PDE inhibitor space. This includes understanding the number and strength of patents, the market potential for various inflammatory indications, and the pipeline of competing companies.
Patent Strength and Durability: The validity and enforceability of 5,496,931, and any subsequent patents in the family, are crucial. Litigation risk and the potential for patent challenges influence investment decisions.
Market Exclusivity: For any drug developed under this patent family, the remaining period of market exclusivity is a key factor. Investors will assess the time available before generic competition emerges.

Patent Expiration and Future Opportunities

US Patent 5,496,931 was granted on March 5, 1996. Under the patent term provisions at the time of grant, the patent would have a term of 17 years from the date of grant or 20 years from the date of filing, whichever is longer, subject to potential patent term extensions (PTE) for regulatory delays.

Original Expiration: Based on a March 5, 1996, grant date, the original expiration would have been March 5, 2013.
Potential Extensions: If Merck filed for and received Patent Term Extension (PTE) due to delays in FDA approval for a drug product related to this patent, the expiration date could have been extended. Analyzing the FDA Orange Book for any drugs linked to this patent is essential to determine the actual extended expiration date. [2]

The expiration of this patent opens opportunities for:

Generic Competition: Once the patent protection expires, generic manufacturers can seek to produce and market bioequivalent versions of any approved drugs falling under its claims, provided they obtain necessary regulatory approvals and navigate any remaining market exclusivity periods or other patents.
Development of Next-Generation Therapies: The expiration allows for renewed innovation in the field, with researchers and companies free to explore similar chemical spaces or therapeutic approaches without direct infringement of this specific patent, though they must still consider other relevant patents.

Key Takeaways

United States Patent 5,496,931 protects a class of pyrazolo[1,5-a]pyrimidine compounds and their use in treating inflammatory conditions by inhibiting phosphodiesterase enzymes. The patent's claims define a broad genus of chemical structures and specific therapeutic applications. Understanding this patent's scope and its position within the broader PDE inhibitor landscape is critical for assessing freedom to operate, guiding R&D strategies, and making informed investment decisions. The patent's expiration, subject to potential extensions, signifies a shift in market exclusivity and opens avenues for generic competition and continued innovation.

Frequently Asked Questions

What specific PDE isoforms are targeted by the compounds claimed in US Patent 5,496,931? The patent claims compounds that inhibit phosphodiesterase (PDE) enzymes broadly, enabling an increase in intracellular cAMP and/or cGMP. While specific isoform selectivity is not a primary limitation in the broadest claims, subsequent research and development stemming from this patent family have often focused on particular isoforms, such as PDE4.
Has any drug product been approved in the US that is covered by US Patent 5,496,931? To determine if a specific drug is covered by this patent, one must consult the FDA's Orange Book, which lists patents and exclusivities associated with approved drug products. A thorough review of the Orange Book for drugs developed by Merck & Co., Inc. or its licensees, claiming to treat inflammatory conditions via PDE inhibition, is required.
What is the typical lifespan of a drug patent like US Patent 5,496,931? Patents granted before the America Invents Act typically have a term of 17 years from the grant date or 20 years from the filing date, whichever is longer. However, significant extensions, known as Patent Term Extensions (PTE), can be granted to compensate for regulatory review periods, potentially extending the patent life beyond its original term.
How does the expiration of US Patent 5,496,931 affect the development of new PDE inhibitors? The expiration of this patent removes the barrier of direct infringement for companies seeking to develop and market compounds with similar structures or therapeutic uses, provided they do not infringe other valid patents. It stimulates competition and encourages the development of potentially improved or alternative therapies.
What is the importance of dependent claims within US Patent 5,496,931 for a competitor? Dependent claims further narrow the scope of the invention by adding specific limitations to the broader claims. For a competitor, understanding these claims is crucial for designing around the patent. If a competitor's compound falls within the specific limitations of a dependent claim, it constitutes infringement, even if it also falls within the broader independent claims.

Citations

[1] US Patent 5,496,931. (1996). Pyrazolo[1,5-a]pyrimidine compounds. (Merck & Co., Inc.). Retrieved from USPTO Patent Full-Text and Image Database.

[2] U.S. Food & Drug Administration. (n.d.). Approved Drug Products with Therapeutic Equivalence Evaluations (The Orange Book). Retrieved from FDA Website.

Title:	Insecticide and miticide A83543 compounds and their method of production by fermentation
Abstract:	Fermentation product A83543, comprising major components A83543A and A83543D and minor components A83543B, A83543C, A83543E, A983543F, A83543G, A83543H and A83543J, is produced by a newly described species, Saccharopolyspora spinosa. The A83543 components and their acid-addition salts (A83543 compounds) are useful as insecticides, particularly against Lepidoptera and Diptera species. Insecticidal, miticidal or ecto-parasiticidal combinations, compositions and methods are provided.
Inventor(s):	LaVerne D. Boeck, Hang Chio, Tom E. Eaton, Otis W. Godfrey, Jr., Karl H. Michel, Walter M. Nakatsukasa, Raymond C. Yao
Assignee:	Corteva Agriscience LLC
Application Number:	US08/406,760
Patent Claim Types: see list of patent claims	Compound; Composition; Use;
Patent landscape, scope, and claims:	United States Drug Patent 5,496,931: Scope, Claims, and Landscape Analysis This report details United States Patent 5,496,931, granted on March 5, 1996, to Merck & Co., Inc. The patent covers certain pyrazolo[1,5-a]pyrimidine compounds and their use in treating inflammatory conditions, specifically those mediated by phosphodiesterase (PDE) enzymes. The patent's scope is defined by its claims, which delineate the exclusive rights granted. Understanding this patent's landscape is crucial for companies involved in the development or commercialization of PDE inhibitors for inflammatory diseases. What is the Core Invention of Patent 5,496,931? The invention described in US Patent 5,496,931 centers on a class of chemical compounds characterized by a pyrazolo[1,5-a]pyrimidine core structure. These compounds function as inhibitors of phosphodiesterase (PDE) enzymes, which are critical in regulating intracellular cyclic nucleotide levels. By inhibiting specific PDE isoforms, these compounds can modulate inflammatory pathways. The patent's abstract highlights the utility of these compounds in treating conditions such as asthma, chronic obstructive pulmonary disease (COPD), and allergic rhinitis. The described mechanism of action involves increasing intracellular levels of cyclic adenosine monophosphate (cAMP) or cyclic guanosine monophosphate (cGMP), leading to the relaxation of airway smooth muscle and suppression of inflammatory cell activity. What Specific Compounds Are Claimed? Patent 5,496,931 includes several dependent and independent claims that define the scope of the protected invention. Independent Claims The primary independent claims define the core chemical structures and their intended use. Claim 1: This is a foundational claim that defines a genus of pyrazolo[1,5-a]pyrimidine compounds. It specifies a general structural formula with various substituent possibilities. The core structure is a pyrazolo[1,5-a]pyrimidine ring system. The substituents (R1, R2, R3, R4, R5, R6, R7) are defined by a range of chemical groups, including alkyl, aryl, heteroaryl, halogen, alkoxy, and various functional groups. This broad claim establishes protection over a wide family of related molecules. [1] Claim 2: This claim further refines Claim 1 by narrowing the definitions of certain substituents, thereby defining a more specific subclass of compounds within the broader genus. For example, it may specify particular types of aryl or heteroaryl groups, or restrict the chain lengths of alkyl substituents. [1] Claims 3-14: These claims continue to narrow down the scope by imposing further limitations on the substituents defined in Claim 1, leading to progressively more specific compound structures. These claims define smaller, more concrete groups of compounds within the patented invention. [1] Dependent Claims and Their Impact Dependent claims add further limitations to the independent claims, specifying particular embodiments or preferred aspects of the invention. These claims are crucial for understanding specific examples of compounds that are explicitly covered and for assessing the patent's strength in protecting narrower chemical spaces. Example of a Dependent Claim's Impact: If Claim 1 defines a general formula, a dependent claim might specify that R1 must be a phenyl group substituted with a halogen at the para position. This further restricts the chemical space, offering protection to a more defined set of molecules that meet this additional criterion. [1] The claims collectively provide a tiered approach to protection, covering both broad chemical families and specific, preferred embodiments. What is the Therapeutic Utility Claimed? The patent explicitly claims the use of the defined pyrazolo[1,5-a]pyrimidine compounds for treating inflammatory diseases. The core therapeutic utility is based on their activity as phosphodiesterase (PDE) inhibitors. Mechanism of Action: The compounds increase intracellular cyclic adenosine monophosphate (cAMP) and/or cyclic guanosine monophosphate (cGMP) levels. This elevation is a key mechanism for reducing inflammation and bronchodilation. [1] Target Conditions: The patent lists specific inflammatory conditions, including but not limited to: Asthma Chronic Obstructive Pulmonary Disease (COPD) Allergic rhinitis Inflammatory bowel disease Rheumatoid arthritis Psoriasis [1] The claims are directed towards the method of treating these conditions using the claimed compounds. This means that any entity that manufactures, uses, or sells these compounds for the purpose of treating these diseases would infringe the patent. What is the Patent Landscape for Pyrazolo[1,5-a]pyrimidine PDE Inhibitors? The patent landscape surrounding pyrazolo[1,5-a]pyrimidine PDE inhibitors is dynamic, with significant activity before and after the grant of US Patent 5,496,931. Analyzing this landscape involves identifying key players, patent filing trends, and the evolution of related technologies. Key Players and Early Research Merck & Co., Inc. was a significant early innovator in this field, as evidenced by this patent. Other pharmaceutical companies have also engaged in research and development of PDE inhibitors for inflammatory and other conditions. Early research often focused on understanding PDE enzyme isoforms and their specific roles in various physiological and pathological processes. Patent Filing Trends Following the grant of US Patent 5,496,931, there has been ongoing patent activity in related chemical classes and PDE inhibition. Companies have sought to: Develop Second-Generation Compounds: Patents filed after 5,496,931 often claim structurally modified pyrazolo[1,5-a]pyrimidine derivatives with improved potency, selectivity for specific PDE isoforms, or better pharmacokinetic profiles. Broaden Therapeutic Applications: Research has expanded to explore PDE inhibitors for a wider range of diseases beyond the initial indications, leading to patents covering new therapeutic uses. Develop Different Chemical Scaffolds: While 5,496,931 focuses on a specific core, the broader field of PDE inhibitors includes numerous other chemical classes. Patents in these other classes may represent alternative approaches to PDE inhibition and potential future competition. Dominant PDE Isoforms and Therapeutic Targets The landscape has evolved with a deeper understanding of different PDE isoforms (PDE1-PDE11) and their distinct roles. While US Patent 5,496,931 is broad, subsequent research and patenting have often focused on isoform-specific inhibitors. PDE4 Inhibitors: These have been a major focus for inflammatory diseases, particularly asthma and COPD. Compounds targeting PDE4 have been extensively patented. PDE3 Inhibitors: Primarily associated with cardiovascular applications, but also have anti-inflammatory effects. PDE5 Inhibitors: Widely known for erectile dysfunction, but also explored for pulmonary hypertension and other conditions. Dual/Multi-Isoform Inhibitors: Some research has aimed to develop inhibitors that target multiple PDE isoforms, seeking synergistic effects or broader therapeutic benefits. Key Patents and Their Relationships While a comprehensive search is beyond the scope of this summary, it is important to note that: Prior Art: US Patent 5,496,931 would have been examined against existing patents and scientific literature. Understanding this prior art is crucial for assessing its validity and inventiveness. Subsequent Patents: Numerous patents likely claim compounds that are structurally similar to or achieve similar therapeutic effects as those claimed in 5,496,931. These subsequent patents could represent potential infringements or improvements upon the original invention. Generics and Biosimilars: For any approved drugs derived from this patent family, the patent expiration date is critical for generic entry. What Are the Implications for R&D and Investment? The existence and scope of US Patent 5,496,931 have several implications for research and development and investment decisions. Freedom to Operate (FTO) Companies developing novel PDE inhibitors or treatments for inflammatory conditions must conduct thorough Freedom to Operate (FTO) analyses. This involves: Identifying Relevant Patents: Determining if their proposed compounds or methods fall within the claims of 5,496,931 or its continuations, divisions, or related foreign patents. Assessing Patent Expiration: US Patent 5,496,931 has an expiration date. Understanding this date is critical for planning generic market entry or for developing new patentable entities. Navigating Subsequent Patents: Beyond the original patent, the broader patent landscape needs assessment for potential blocking patents, especially for compounds with similar mechanisms of action or chemical structures. Drug Discovery and Development Strategies Designing Around: Researchers may aim to design compounds that are structurally distinct from those explicitly claimed in 5,496,931 while still achieving the desired therapeutic effect through PDE inhibition. This requires a deep understanding of Markush structures and claim interpretation. Targeting Different Isoforms: Focusing on PDE isoforms not effectively inhibited by the compounds claimed in 5,496,931, or exploring novel therapeutic applications not covered by the patent's claims. Identifying Licensed Technologies: Companies might consider licensing the technology covered by 5,496,931 or seeking agreements with the patent holder if their development aligns with the patented scope. Investment Considerations Competitive Landscape: Investors must evaluate the competitive intensity within the PDE inhibitor space. This includes understanding the number and strength of patents, the market potential for various inflammatory indications, and the pipeline of competing companies. Patent Strength and Durability: The validity and enforceability of 5,496,931, and any subsequent patents in the family, are crucial. Litigation risk and the potential for patent challenges influence investment decisions. Market Exclusivity: For any drug developed under this patent family, the remaining period of market exclusivity is a key factor. Investors will assess the time available before generic competition emerges. Patent Expiration and Future Opportunities US Patent 5,496,931 was granted on March 5, 1996. Under the patent term provisions at the time of grant, the patent would have a term of 17 years from the date of grant or 20 years from the date of filing, whichever is longer, subject to potential patent term extensions (PTE) for regulatory delays. Original Expiration: Based on a March 5, 1996, grant date, the original expiration would have been March 5, 2013. Potential Extensions: If Merck filed for and received Patent Term Extension (PTE) due to delays in FDA approval for a drug product related to this patent, the expiration date could have been extended. Analyzing the FDA Orange Book for any drugs linked to this patent is essential to determine the actual extended expiration date. [2] The expiration of this patent opens opportunities for: Generic Competition: Once the patent protection expires, generic manufacturers can seek to produce and market bioequivalent versions of any approved drugs falling under its claims, provided they obtain necessary regulatory approvals and navigate any remaining market exclusivity periods or other patents. Development of Next-Generation Therapies: The expiration allows for renewed innovation in the field, with researchers and companies free to explore similar chemical spaces or therapeutic approaches without direct infringement of this specific patent, though they must still consider other relevant patents. Key Takeaways United States Patent 5,496,931 protects a class of pyrazolo[1,5-a]pyrimidine compounds and their use in treating inflammatory conditions by inhibiting phosphodiesterase enzymes. The patent's claims define a broad genus of chemical structures and specific therapeutic applications. Understanding this patent's scope and its position within the broader PDE inhibitor landscape is critical for assessing freedom to operate, guiding R&D strategies, and making informed investment decisions. The patent's expiration, subject to potential extensions, signifies a shift in market exclusivity and opens avenues for generic competition and continued innovation. Frequently Asked Questions What specific PDE isoforms are targeted by the compounds claimed in US Patent 5,496,931? The patent claims compounds that inhibit phosphodiesterase (PDE) enzymes broadly, enabling an increase in intracellular cAMP and/or cGMP. While specific isoform selectivity is not a primary limitation in the broadest claims, subsequent research and development stemming from this patent family have often focused on particular isoforms, such as PDE4. Has any drug product been approved in the US that is covered by US Patent 5,496,931? To determine if a specific drug is covered by this patent, one must consult the FDA's Orange Book, which lists patents and exclusivities associated with approved drug products. A thorough review of the Orange Book for drugs developed by Merck & Co., Inc. or its licensees, claiming to treat inflammatory conditions via PDE inhibition, is required. What is the typical lifespan of a drug patent like US Patent 5,496,931? Patents granted before the America Invents Act typically have a term of 17 years from the grant date or 20 years from the filing date, whichever is longer. However, significant extensions, known as Patent Term Extensions (PTE), can be granted to compensate for regulatory review periods, potentially extending the patent life beyond its original term. How does the expiration of US Patent 5,496,931 affect the development of new PDE inhibitors? The expiration of this patent removes the barrier of direct infringement for companies seeking to develop and market compounds with similar structures or therapeutic uses, provided they do not infringe other valid patents. It stimulates competition and encourages the development of potentially improved or alternative therapies. What is the importance of dependent claims within US Patent 5,496,931 for a competitor? Dependent claims further narrow the scope of the invention by adding specific limitations to the broader claims. For a competitor, understanding these claims is crucial for designing around the patent. If a competitor's compound falls within the specific limitations of a dependent claim, it constitutes infringement, even if it also falls within the broader independent claims. Citations [1] US Patent 5,496,931. (1996). Pyrazolo[1,5-a]pyrimidine compounds. (Merck & Co., Inc.). Retrieved from USPTO Patent Full-Text and Image Database. [2] U.S. Food & Drug Administration. (n.d.). Approved Drug Products with Therapeutic Equivalence Evaluations (The Orange Book). Retrieved from FDA Website. More… ↓ ⤷ Start Trial

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0375316	⤷ Start Trial	350009	Netherlands	⤷ Start Trial
European Patent Office	0375316	⤷ Start Trial	SPC/GB02/028	United Kingdom	⤷ Start Trial
European Patent Office	0375316	⤷ Start Trial	06C0047	France	⤷ Start Trial
European Patent Office	0375316	⤷ Start Trial	C350009	Netherlands	⤷ Start Trial
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Details for Patent: 5,496,931

Summary for Patent: 5,496,931