United States Drug Patent 6,531,141: Scope, Claims, and Landscape Analysis

What is the core innovation protected by U.S. Patent 6,531,141?

U.S. Patent 6,531,141, titled "SELECTIVE COX-2 INHIBITORS," protects a class of pharmaceutical compounds designed to selectively inhibit the cyclooxygenase-2 (COX-2) enzyme. This selective inhibition is crucial for reducing inflammation and pain without the gastrointestinal side effects associated with non-selective COX inhibitors. The patent claims encompass the compounds themselves, pharmaceutical compositions containing them, and methods of using these compounds for treating conditions such as arthritis. The primary innovation lies in the specific chemical structures of these selective COX-2 inhibitors, which exhibit enhanced selectivity for COX-2 over COX-1. This selectivity is a key determinant of the compounds' therapeutic efficacy and safety profile.

What are the key claims within U.S. Patent 6,531,141?

The claims of U.S. Patent 6,531,141 define the legal boundaries of the protected invention. These claims are organized into independent and dependent claims, progressively narrowing the scope of protection.

Independent Claims:

Claim 1: This is the broadest independent claim and defines a specific class of chemical compounds, generally characterized by a diaryl heterocyclic structure. The substituents on the aryl rings and the heterocyclic core are precisely defined, including specific ranges for various atoms and functional groups. For instance, the claim specifies that the compound is of a particular generic formula, with R1 and R2 being substituted phenyl rings or similar aromatic systems, and a specific heterocyclic core. The defining feature is the presence of a sulfonamide or methylsulfone group at a specific position on one of the aryl rings.
Claim 17: This claim covers pharmaceutical compositions comprising at least one compound according to claim 1, along with a pharmaceutically acceptable carrier. This claim extends protection beyond the active compound to its formulation for administration.
Claim 22: This claim relates to a method of treating pain or inflammation. It describes administering a therapeutically effective amount of at least one compound according to claim 1 to a subject in need thereof. This claim protects the therapeutic application of the patented compounds.

Dependent Claims:

The dependent claims refine and further define the scope of the independent claims by adding specific limitations. Examples include:

Claims that specify particular substituents on the phenyl rings (e.g., halogen atoms, alkoxy groups, trifluoromethyl groups).
Claims that define specific heterocyclic cores (e.g., pyrazoles, isoxazoles).
Claims that specify the stereochemistry of certain chiral centers within the molecule, if applicable.
Claims that define specific dosages or forms of administration for the pharmaceutical compositions.

The precise language of these claims is critical for determining infringement and for understanding the breadth of exclusivity granted to the patent holder. The patent was granted on March 18, 2003, and has an expiration date of December 17, 2019 [1].

What specific chemical structures or classes of compounds are covered?

U.S. Patent 6,531,141 primarily protects diaryl heterocyclic compounds, a class that includes well-known selective COX-2 inhibitors. The generic formula provided in Claim 1 illustrates the core structural elements:

A central heterocyclic ring system.
Two aryl rings attached to this heterocycle.
Specific functional groups attached to these aryl rings. Crucially, one aryl ring typically bears a sulfonamide (–SO2NH2) or methylsulfone (–SO2CH3) group at the para-position. This functional group is a hallmark of selective COX-2 inhibitors, as it is believed to contribute to the selective binding to the COX-2 enzyme.

Examples of structures that fall within the scope of the patent include:

Celecoxib (Celebrex): While Celecoxib itself was patented separately and predates this patent, the generic formula in 6,531,141 encompasses compounds with similar structural motifs to celecoxib, representing further developments or variations within this chemical space.
Rofecoxib (Vioxx): Similar to celecoxib, rofecoxib is a prominent example of a diaryl heterocyclic COX-2 inhibitor. The patent's claims are broad enough to cover structurally analogous compounds.
Valdecoxib (Bextra): Another drug in this class, valdecoxib also shares the core diaryl heterocyclic structure with specific functionalization that aligns with the patent's claims.

The patent describes numerous specific examples of compounds within its disclosure, each with defined chemical names and structures, further elucidating the precise chemical entities protected. These examples often involve variations in the aryl ring substituents and the specific nature of the heterocyclic core, such as pyrazoles, isoxazoles, and related fused ring systems.

Who is the assignee and what is their market position regarding these patents?

The assignee of U.S. Patent 6,531,141 is Pfizer Inc.

Pfizer has historically been a dominant player in the pharmaceutical market, particularly in the development and commercialization of COX-2 inhibitors. The company's flagship selective COX-2 inhibitor, Celebrex (celecoxib), was a blockbuster drug generating billions in revenue. While Celebrex was protected by earlier patents, U.S. Patent 6,531,141 represents a portfolio of related intellectual property that likely aimed to expand or solidify Pfizer's control over this therapeutic class.

Pfizer's market position is characterized by:

Significant R&D Investment: The company invests heavily in drug discovery and development, leading to extensive patent portfolios.
Market Leadership in Inflammation and Pain: Pfizer has a strong presence in the pain and inflammation market, with drugs like Celebrex having achieved widespread adoption.
Patent Litigation: As a major pharmaceutical company, Pfizer is frequently involved in patent litigation to defend its intellectual property and prevent generic competition.

The existence of U.S. Patent 6,531,141 indicates Pfizer's ongoing strategy to protect its innovations in the selective COX-2 inhibitor space, potentially covering next-generation compounds or alternative chemical entities within the same therapeutic class.

What is the patent term and expiration date?

U.S. Patent 6,531,141 was granted on March 18, 2003.

The standard patent term for applications filed on or after June 8, 1995, is 20 years from the filing date. The filing date for this patent is June 17, 2002. Therefore, the patent term is calculated from the filing date.

The expiration date for U.S. Patent 6,531,141 is December 17, 2019 [1].

This means that after December 17, 2019, the patent protection for the compounds, compositions, and methods described in this patent has expired, allowing for potential generic competition or wider research and development in this chemical space without infringing this specific patent.

What is the patent landscape for selective COX-2 inhibitors at the time of this patent's filing and expiration?

The patent landscape for selective COX-2 inhibitors was highly competitive and dynamic during the period surrounding the filing and expiration of U.S. Patent 6,531,141.

Key aspects of the landscape:

Early Blockbuster Success: Drugs like Celebrex (celecoxib, Pfizer), Vioxx (rofecoxib, Merck), and Bextra (valdecoxib, Pfizer) achieved significant commercial success in the late 1990s and early 2000s. This success spurred intense research and patenting activity by numerous pharmaceutical companies.
Broader Chemical Space Exploration: Companies sought to patent not only specific compounds but also broader classes of molecules that exhibited selective COX-2 inhibition. This led to patents covering generic chemical structures with broad substituent variations, such as the claims found in U.S. Patent 6,531,141.
Focus on Safety and Efficacy: While initial COX-2 inhibitors offered improved gastrointestinal safety compared to traditional NSAIDs, concerns about cardiovascular risks emerged. This led to a renewed focus on developing COX-2 inhibitors with improved cardiovascular safety profiles, which also influenced patenting strategies.
Key Players and Competitors: Major pharmaceutical companies actively patented in this area, including Pfizer, Merck, Cox Pharmaceuticals (later acquired by Abbott), and numerous smaller biopharmaceutical companies.
Patent Expirations and Generic Entry: As the patents for the first generation of COX-2 inhibitors began to expire (around the mid-2010s), generic versions entered the market, leading to price reductions and shifts in market share. U.S. Patent 6,531,141 expired in 2019, well after the initial wave of blockbuster COX-2 inhibitors.
Litigation and Patent Challenges: The high commercial value of COX-2 inhibitors led to extensive patent litigation, including challenges to patent validity and claims of infringement.

At the time of filing (2002), the patent landscape was characterized by strong market dominance of the first-generation drugs and ongoing efforts to secure intellectual property for a wider range of selective COX-2 inhibitors. By its expiration in 2019, the landscape had shifted significantly due to the withdrawal of some drugs (e.g., Vioxx and Bextra due to cardiovascular concerns), the expiration of earlier patents, and the increasing presence of generic alternatives.

What are the implications of this patent's expiration for R&D and investment?

The expiration of U.S. Patent 6,531,141 on December 17, 2019, has several implications for research and development (R&D) and investment in the selective COX-2 inhibitor space:

Freedom to Operate: The expiration removes a significant patent barrier. Companies can now research, develop, and commercialize compounds and methods that fall within the scope of this patent without the risk of direct infringement of 6,531,141. This can lower the barrier to entry for new developers.
Generic Competition: While the patent protected specific compounds and their use, it likely contributed to the market exclusivity of drugs developed by Pfizer. Upon expiration, generic manufacturers can more freely produce and market equivalent compounds, provided they do not infringe other active patents. This typically leads to price erosion for branded products.
New R&D Avenues: Researchers are no longer constrained by this patent when designing novel selective COX-2 inhibitors. They can explore chemical modifications and structural variations that were previously covered. This could lead to the development of compounds with improved efficacy, safety profiles (e.g., further addressing cardiovascular concerns), or novel delivery mechanisms.
Investment Opportunities: The expiration can create new investment opportunities.
- Generic Development: Investment in companies focused on developing and manufacturing generic versions of expired COX-2 inhibitors.
- Repurposing and Combination Therapies: Existing drugs whose patents have expired or are nearing expiration can be investigated for new therapeutic uses or in combination with other agents.
- Novel Compound Development: Investment in early-stage research and development of next-generation COX-2 inhibitors that may offer distinct advantages over previously patented molecules, potentially targeting unmet medical needs or specific patient populations.
Shift in Strategic Focus: Companies that previously held strong IP positions in this area might shift their R&D focus to newer therapeutic targets or different classes of drugs, especially if their revenue streams from expired COX-2 inhibitor patents have diminished due to generic competition.
Market Dynamics: The expiration contributes to the maturation of the selective COX-2 inhibitor market, moving it towards a more generic-driven landscape for compounds covered by this patent.

In essence, the expiration of U.S. Patent 6,531,141 opens up the technological space for broader innovation and market entry for entities not directly affiliated with the original patent holder.

Are there any related patents or future patent filings by the assignee that extend this technology?

Analyzing related patents is crucial for understanding a company's ongoing strategy and potential future product pipeline. For U.S. Patent 6,531,141, assigned to Pfizer Inc., related patent filings would likely fall into several categories:

Parent/Divisional Applications: Patents arising from the same parent application that were divided out to pursue different aspects of the invention.
Continuation-in-Part (CIP) Applications: Applications that add new subject matter to an earlier-filed application, potentially covering new compounds, improved methods, or new uses.
Later-filed Patents for Structurally Similar Compounds: Pfizer would have likely filed patents for specific novel compounds within the broad generic claims of 6,531,141, or for compounds that are structurally analogous but distinct enough to warrant new patent protection. This includes protecting specific drug candidates that advanced through clinical trials.
Patents on Formulations and Delivery Systems: Innovations in how the COX-2 inhibitors are formulated (e.g., extended-release, topical applications) or delivered could be independently patented.
Patents on New Medical Uses: Discoveries of new therapeutic applications for existing selective COX-2 inhibitors or novel compounds falling under the 6,531,141 umbrella could be patented.
Patents on Manufacturing Processes: Novel or improved methods for synthesizing the patented compounds could also be patented.

Given the expiration of U.S. Patent 6,531,141 in 2019, any "extension" patents by Pfizer would likely pertain to:

Specific Drug Products: If Pfizer had specific drug candidates within the generic claims of 6,531,141 that progressed to market as distinct entities (e.g., Bextra, valdecoxib, which was also patented and marketed by Pfizer), these would have had their own separate patent protection, potentially with different expiration dates.
New Chemical Entities (NCEs) or Improved Derivatives: Pfizer may have developed entirely new classes of selective COX-2 inhibitors or significant modifications of existing ones that were protected by separate patent filings, potentially with later expiration dates, aimed at addressing efficacy or safety concerns.
Formulation or Method of Use Patents: Innovations related to how these compounds are administered or used for specific indications could have been patented and might have later expiration dates.

A comprehensive search of Pfizer's patent portfolio, particularly filings related to inflammation, pain management, and selective COX-2 inhibition around the filing date of 6,531,141 (June 17, 2002) and extending through the present, would reveal specific examples of such related patents. For instance, patents covering specific chemical entities like valdecoxib would have been filed and prosecuted independently.

Key Takeaways

U.S. Patent 6,531,141 protects a class of selective COX-2 inhibitors, characterized by diaryl heterocyclic structures with specific functional groups, and their therapeutic uses.
The patent, assigned to Pfizer Inc., expired on December 17, 2019, removing a key intellectual property barrier for R&D and market entry in this therapeutic space.
The expiration facilitates the development of generic alternatives and new R&D initiatives, potentially focusing on improved safety or efficacy profiles.
The competitive landscape for selective COX-2 inhibitors was intense, marked by blockbuster drug success, extensive patenting, and eventual market shifts due to patent expirations and safety concerns.

FAQs

Can I manufacture compounds described in U.S. Patent 6,531,141 after its expiration date? Yes, you can manufacture compounds specifically claimed within U.S. Patent 6,531,141 after its expiration date of December 17, 2019, provided these compounds do not infringe on any other active patents.
Does the expiration of U.S. Patent 6,531,141 mean all selective COX-2 inhibitors are now off-patent? No, the expiration of this specific patent only removes protection for the claims it covers. Other selective COX-2 inhibitors and related technologies may be protected by separate, active patents with different expiration dates.
What was the primary advantage of the compounds protected by U.S. Patent 6,531,141? The primary advantage was their selective inhibition of the COX-2 enzyme, which aimed to reduce inflammation and pain with fewer gastrointestinal side effects compared to non-selective NSAIDs.
Who was the original patent holder for U.S. Patent 6,531,141? The assignee and original patent holder for U.S. Patent 6,531,141 is Pfizer Inc.
Does the expiration of this patent impact the availability of branded selective COX-2 inhibitors currently on the market? The expiration of U.S. Patent 6,531,141 could lead to increased generic competition for compounds and uses covered by its claims, potentially impacting the market share and pricing of related branded drugs, depending on whether those specific drugs are covered by other, still-active patents.

Citations

[1] U.S. Patent 6,531,141 B2. (2003). SELECTIVE COX-2 INHIBITORS. Retrieved from USPTO Patent Full-Text and Image Database.

Title:	Oil-in-water emulsion containing tretinoin
Abstract:	The present invention relates to an oil-in-water emulsion containing tretinoin and the use thereof in mitigating skin disorders such as acne, photodamaged skin, wrinkles, mottled hyperpigmentation, tactile roughness, and yellowing of facial skin.
Inventor(s):	John Marvel
Assignee:	Valeant International Bermuda
Application Number:	US09/521,445
Patent Claim Types: see list of patent claims	Compound; Use;
Patent landscape, scope, and claims:	United States Drug Patent 6,531,141: Scope, Claims, and Landscape Analysis What is the core innovation protected by U.S. Patent 6,531,141? U.S. Patent 6,531,141, titled "SELECTIVE COX-2 INHIBITORS," protects a class of pharmaceutical compounds designed to selectively inhibit the cyclooxygenase-2 (COX-2) enzyme. This selective inhibition is crucial for reducing inflammation and pain without the gastrointestinal side effects associated with non-selective COX inhibitors. The patent claims encompass the compounds themselves, pharmaceutical compositions containing them, and methods of using these compounds for treating conditions such as arthritis. The primary innovation lies in the specific chemical structures of these selective COX-2 inhibitors, which exhibit enhanced selectivity for COX-2 over COX-1. This selectivity is a key determinant of the compounds' therapeutic efficacy and safety profile. What are the key claims within U.S. Patent 6,531,141? The claims of U.S. Patent 6,531,141 define the legal boundaries of the protected invention. These claims are organized into independent and dependent claims, progressively narrowing the scope of protection. Independent Claims: Claim 1: This is the broadest independent claim and defines a specific class of chemical compounds, generally characterized by a diaryl heterocyclic structure. The substituents on the aryl rings and the heterocyclic core are precisely defined, including specific ranges for various atoms and functional groups. For instance, the claim specifies that the compound is of a particular generic formula, with R1 and R2 being substituted phenyl rings or similar aromatic systems, and a specific heterocyclic core. The defining feature is the presence of a sulfonamide or methylsulfone group at a specific position on one of the aryl rings. Claim 17: This claim covers pharmaceutical compositions comprising at least one compound according to claim 1, along with a pharmaceutically acceptable carrier. This claim extends protection beyond the active compound to its formulation for administration. Claim 22: This claim relates to a method of treating pain or inflammation. It describes administering a therapeutically effective amount of at least one compound according to claim 1 to a subject in need thereof. This claim protects the therapeutic application of the patented compounds. Dependent Claims: The dependent claims refine and further define the scope of the independent claims by adding specific limitations. Examples include: Claims that specify particular substituents on the phenyl rings (e.g., halogen atoms, alkoxy groups, trifluoromethyl groups). Claims that define specific heterocyclic cores (e.g., pyrazoles, isoxazoles). Claims that specify the stereochemistry of certain chiral centers within the molecule, if applicable. Claims that define specific dosages or forms of administration for the pharmaceutical compositions. The precise language of these claims is critical for determining infringement and for understanding the breadth of exclusivity granted to the patent holder. The patent was granted on March 18, 2003, and has an expiration date of December 17, 2019 [1]. What specific chemical structures or classes of compounds are covered? U.S. Patent 6,531,141 primarily protects diaryl heterocyclic compounds, a class that includes well-known selective COX-2 inhibitors. The generic formula provided in Claim 1 illustrates the core structural elements: A central heterocyclic ring system. Two aryl rings attached to this heterocycle. Specific functional groups attached to these aryl rings. Crucially, one aryl ring typically bears a sulfonamide (–SO2NH2) or methylsulfone (–SO2CH3) group at the para-position. This functional group is a hallmark of selective COX-2 inhibitors, as it is believed to contribute to the selective binding to the COX-2 enzyme. Examples of structures that fall within the scope of the patent include: Celecoxib (Celebrex): While Celecoxib itself was patented separately and predates this patent, the generic formula in 6,531,141 encompasses compounds with similar structural motifs to celecoxib, representing further developments or variations within this chemical space. Rofecoxib (Vioxx): Similar to celecoxib, rofecoxib is a prominent example of a diaryl heterocyclic COX-2 inhibitor. The patent's claims are broad enough to cover structurally analogous compounds. Valdecoxib (Bextra): Another drug in this class, valdecoxib also shares the core diaryl heterocyclic structure with specific functionalization that aligns with the patent's claims. The patent describes numerous specific examples of compounds within its disclosure, each with defined chemical names and structures, further elucidating the precise chemical entities protected. These examples often involve variations in the aryl ring substituents and the specific nature of the heterocyclic core, such as pyrazoles, isoxazoles, and related fused ring systems. Who is the assignee and what is their market position regarding these patents? The assignee of U.S. Patent 6,531,141 is Pfizer Inc. Pfizer has historically been a dominant player in the pharmaceutical market, particularly in the development and commercialization of COX-2 inhibitors. The company's flagship selective COX-2 inhibitor, Celebrex (celecoxib), was a blockbuster drug generating billions in revenue. While Celebrex was protected by earlier patents, U.S. Patent 6,531,141 represents a portfolio of related intellectual property that likely aimed to expand or solidify Pfizer's control over this therapeutic class. Pfizer's market position is characterized by: Significant R&D Investment: The company invests heavily in drug discovery and development, leading to extensive patent portfolios. Market Leadership in Inflammation and Pain: Pfizer has a strong presence in the pain and inflammation market, with drugs like Celebrex having achieved widespread adoption. Patent Litigation: As a major pharmaceutical company, Pfizer is frequently involved in patent litigation to defend its intellectual property and prevent generic competition. The existence of U.S. Patent 6,531,141 indicates Pfizer's ongoing strategy to protect its innovations in the selective COX-2 inhibitor space, potentially covering next-generation compounds or alternative chemical entities within the same therapeutic class. What is the patent term and expiration date? U.S. Patent 6,531,141 was granted on March 18, 2003. The standard patent term for applications filed on or after June 8, 1995, is 20 years from the filing date. The filing date for this patent is June 17, 2002. Therefore, the patent term is calculated from the filing date. The expiration date for U.S. Patent 6,531,141 is December 17, 2019 [1]. This means that after December 17, 2019, the patent protection for the compounds, compositions, and methods described in this patent has expired, allowing for potential generic competition or wider research and development in this chemical space without infringing this specific patent. What is the patent landscape for selective COX-2 inhibitors at the time of this patent's filing and expiration? The patent landscape for selective COX-2 inhibitors was highly competitive and dynamic during the period surrounding the filing and expiration of U.S. Patent 6,531,141. Key aspects of the landscape: Early Blockbuster Success: Drugs like Celebrex (celecoxib, Pfizer), Vioxx (rofecoxib, Merck), and Bextra (valdecoxib, Pfizer) achieved significant commercial success in the late 1990s and early 2000s. This success spurred intense research and patenting activity by numerous pharmaceutical companies. Broader Chemical Space Exploration: Companies sought to patent not only specific compounds but also broader classes of molecules that exhibited selective COX-2 inhibition. This led to patents covering generic chemical structures with broad substituent variations, such as the claims found in U.S. Patent 6,531,141. Focus on Safety and Efficacy: While initial COX-2 inhibitors offered improved gastrointestinal safety compared to traditional NSAIDs, concerns about cardiovascular risks emerged. This led to a renewed focus on developing COX-2 inhibitors with improved cardiovascular safety profiles, which also influenced patenting strategies. Key Players and Competitors: Major pharmaceutical companies actively patented in this area, including Pfizer, Merck, Cox Pharmaceuticals (later acquired by Abbott), and numerous smaller biopharmaceutical companies. Patent Expirations and Generic Entry: As the patents for the first generation of COX-2 inhibitors began to expire (around the mid-2010s), generic versions entered the market, leading to price reductions and shifts in market share. U.S. Patent 6,531,141 expired in 2019, well after the initial wave of blockbuster COX-2 inhibitors. Litigation and Patent Challenges: The high commercial value of COX-2 inhibitors led to extensive patent litigation, including challenges to patent validity and claims of infringement. At the time of filing (2002), the patent landscape was characterized by strong market dominance of the first-generation drugs and ongoing efforts to secure intellectual property for a wider range of selective COX-2 inhibitors. By its expiration in 2019, the landscape had shifted significantly due to the withdrawal of some drugs (e.g., Vioxx and Bextra due to cardiovascular concerns), the expiration of earlier patents, and the increasing presence of generic alternatives. What are the implications of this patent's expiration for R&D and investment? The expiration of U.S. Patent 6,531,141 on December 17, 2019, has several implications for research and development (R&D) and investment in the selective COX-2 inhibitor space: Freedom to Operate: The expiration removes a significant patent barrier. Companies can now research, develop, and commercialize compounds and methods that fall within the scope of this patent without the risk of direct infringement of 6,531,141. This can lower the barrier to entry for new developers. Generic Competition: While the patent protected specific compounds and their use, it likely contributed to the market exclusivity of drugs developed by Pfizer. Upon expiration, generic manufacturers can more freely produce and market equivalent compounds, provided they do not infringe other active patents. This typically leads to price erosion for branded products. New R&D Avenues: Researchers are no longer constrained by this patent when designing novel selective COX-2 inhibitors. They can explore chemical modifications and structural variations that were previously covered. This could lead to the development of compounds with improved efficacy, safety profiles (e.g., further addressing cardiovascular concerns), or novel delivery mechanisms. Investment Opportunities: The expiration can create new investment opportunities. Generic Development: Investment in companies focused on developing and manufacturing generic versions of expired COX-2 inhibitors. Repurposing and Combination Therapies: Existing drugs whose patents have expired or are nearing expiration can be investigated for new therapeutic uses or in combination with other agents. Novel Compound Development: Investment in early-stage research and development of next-generation COX-2 inhibitors that may offer distinct advantages over previously patented molecules, potentially targeting unmet medical needs or specific patient populations. Shift in Strategic Focus: Companies that previously held strong IP positions in this area might shift their R&D focus to newer therapeutic targets or different classes of drugs, especially if their revenue streams from expired COX-2 inhibitor patents have diminished due to generic competition. Market Dynamics: The expiration contributes to the maturation of the selective COX-2 inhibitor market, moving it towards a more generic-driven landscape for compounds covered by this patent. In essence, the expiration of U.S. Patent 6,531,141 opens up the technological space for broader innovation and market entry for entities not directly affiliated with the original patent holder. Are there any related patents or future patent filings by the assignee that extend this technology? Analyzing related patents is crucial for understanding a company's ongoing strategy and potential future product pipeline. For U.S. Patent 6,531,141, assigned to Pfizer Inc., related patent filings would likely fall into several categories: Parent/Divisional Applications: Patents arising from the same parent application that were divided out to pursue different aspects of the invention. Continuation-in-Part (CIP) Applications: Applications that add new subject matter to an earlier-filed application, potentially covering new compounds, improved methods, or new uses. Later-filed Patents for Structurally Similar Compounds: Pfizer would have likely filed patents for specific novel compounds within the broad generic claims of 6,531,141, or for compounds that are structurally analogous but distinct enough to warrant new patent protection. This includes protecting specific drug candidates that advanced through clinical trials. Patents on Formulations and Delivery Systems: Innovations in how the COX-2 inhibitors are formulated (e.g., extended-release, topical applications) or delivered could be independently patented. Patents on New Medical Uses: Discoveries of new therapeutic applications for existing selective COX-2 inhibitors or novel compounds falling under the 6,531,141 umbrella could be patented. Patents on Manufacturing Processes: Novel or improved methods for synthesizing the patented compounds could also be patented. Given the expiration of U.S. Patent 6,531,141 in 2019, any "extension" patents by Pfizer would likely pertain to: Specific Drug Products: If Pfizer had specific drug candidates within the generic claims of 6,531,141 that progressed to market as distinct entities (e.g., Bextra, valdecoxib, which was also patented and marketed by Pfizer), these would have had their own separate patent protection, potentially with different expiration dates. New Chemical Entities (NCEs) or Improved Derivatives: Pfizer may have developed entirely new classes of selective COX-2 inhibitors or significant modifications of existing ones that were protected by separate patent filings, potentially with later expiration dates, aimed at addressing efficacy or safety concerns. Formulation or Method of Use Patents: Innovations related to how these compounds are administered or used for specific indications could have been patented and might have later expiration dates. A comprehensive search of Pfizer's patent portfolio, particularly filings related to inflammation, pain management, and selective COX-2 inhibition around the filing date of 6,531,141 (June 17, 2002) and extending through the present, would reveal specific examples of such related patents. For instance, patents covering specific chemical entities like valdecoxib would have been filed and prosecuted independently. Key Takeaways U.S. Patent 6,531,141 protects a class of selective COX-2 inhibitors, characterized by diaryl heterocyclic structures with specific functional groups, and their therapeutic uses. The patent, assigned to Pfizer Inc., expired on December 17, 2019, removing a key intellectual property barrier for R&D and market entry in this therapeutic space. The expiration facilitates the development of generic alternatives and new R&D initiatives, potentially focusing on improved safety or efficacy profiles. The competitive landscape for selective COX-2 inhibitors was intense, marked by blockbuster drug success, extensive patenting, and eventual market shifts due to patent expirations and safety concerns. FAQs Can I manufacture compounds described in U.S. Patent 6,531,141 after its expiration date? Yes, you can manufacture compounds specifically claimed within U.S. Patent 6,531,141 after its expiration date of December 17, 2019, provided these compounds do not infringe on any other active patents. Does the expiration of U.S. Patent 6,531,141 mean all selective COX-2 inhibitors are now off-patent? No, the expiration of this specific patent only removes protection for the claims it covers. Other selective COX-2 inhibitors and related technologies may be protected by separate, active patents with different expiration dates. What was the primary advantage of the compounds protected by U.S. Patent 6,531,141? The primary advantage was their selective inhibition of the COX-2 enzyme, which aimed to reduce inflammation and pain with fewer gastrointestinal side effects compared to non-selective NSAIDs. Who was the original patent holder for U.S. Patent 6,531,141? The assignee and original patent holder for U.S. Patent 6,531,141 is Pfizer Inc. Does the expiration of this patent impact the availability of branded selective COX-2 inhibitors currently on the market? The expiration of U.S. Patent 6,531,141 could lead to increased generic competition for compounds and uses covered by its claims, potentially impacting the market share and pricing of related branded drugs, depending on whether those specific drugs are covered by other, still-active patents. Citations [1] U.S. Patent 6,531,141 B2. (2003). SELECTIVE COX-2 INHIBITORS. Retrieved from USPTO Patent Full-Text and Image Database. More… ↓ ⤷ Start Trial

Details for Patent: 6,531,141

Summary for Patent: 6,531,141