Analysis of United States Drug Patent 7,351,701

United States Patent 7,351,701, titled "Substituted heterocyclic compounds and their use as inhibitors of phosphodiesterase type 4," was granted to Glaxo Group Limited on April 8, 2008. The patent covers a class of small molecules designed to inhibit phosphodiesterase type 4 (PDE4) enzymes. PDE4 enzymes are involved in the breakdown of cyclic adenosine monophosphate (cAMP), a key intracellular signaling molecule. Inhibition of PDE4 leads to increased intracellular cAMP levels, which can modulate inflammatory responses. The primary therapeutic target for such inhibitors is inflammatory diseases, particularly respiratory conditions like asthma and chronic obstructive pulmonary disease (COPD).

What is the Core Invention of Patent 7,351,701?

The central invention of Patent 7,351,701 resides in a specific set of substituted heterocyclic compounds and their application in treating diseases mediated by PDE4. The patent defines a genus of chemical structures with claims designed to encompass a broad range of compounds sharing a common structural motif.

The patent's claims are structured to protect not only specific chemical entities but also the method of using these compounds for therapeutic purposes. This dual protection is critical for establishing market exclusivity and preventing competitors from developing or marketing similar PDE4 inhibitors.

The patent also discloses specific examples of synthesized compounds, providing concrete evidence of the invention’s realization and enabling further characterization and testing. These examples are crucial for defining the practical scope of the patent and demonstrating its utility.

What are the Key Chemical Structures Claimed?

Patent 7,351,701 primarily claims compounds of a general formula, which represents a broad class of chemical structures. The formula, as detailed in the patent, defines specific positions on a core heterocyclic ring system where various substituents can be attached. These substituents are critical for determining the compound's pharmacological properties, including its potency, selectivity for PDE4 over other PDE isoforms, and pharmacokinetic profile.

The generic formula described in the patent is a composite of various structural elements and variable groups (R groups) attached to a core heterocyclic scaffold. The patent defines the R groups and the heterocyclic core with specific chemical limitations, such as being alkyl, alkoxy, halo, or substituted aryl groups, among others [1].

The claims delineate specific ranges for these substituents and their potential modifications, aiming to cover a wide array of potential drug candidates that fit the overall structural and functional criteria of the invention. This broad claim scope is a strategic element in patent protection, anticipating future chemical modifications that could retain the desired therapeutic activity.

What is the Therapeutic Utility and Target Indication?

The therapeutic utility of the compounds claimed in Patent 7,351,701 is centered on their ability to inhibit PDE4 enzymes. This inhibition leads to elevated intracellular cAMP levels, which are known to exert anti-inflammatory effects.

The primary target indications mentioned in the patent are inflammatory diseases. This includes, but is not limited to, respiratory conditions such as:

Asthma: A chronic inflammatory disease of the airways characterized by reversible bronchoconstriction and inflammation.
Chronic Obstructive Pulmonary Disease (COPD): A progressive lung disease that includes emphysema and chronic bronchitis, characterized by airflow limitation and inflammation.
Allergic rhinitis: Inflammation of the nasal passages triggered by allergens.

The patent also suggests potential utility in other inflammatory conditions where PDE4 plays a significant role in the pathological process. The mechanism of action—PDE4 inhibition—allows for a broad application across various inflammatory pathways.

What is the Patent Landscape for PDE4 Inhibitors?

The patent landscape for PDE4 inhibitors is extensive and competitive, reflecting the significant therapeutic potential of this drug class. Numerous pharmaceutical companies have pursued patents covering novel PDE4 inhibitors, their synthetic routes, and their therapeutic applications.

Key players in the PDE4 inhibitor space include:

GlaxoSmithKline (GSK): As the assignee of Patent 7,351,701, GSK is a major historical developer of PDE4 inhibitors. Roflumilast (Daliresp/Daxas), although not directly covered by this specific patent number, is a notable PDE4 inhibitor developed by AstraZeneca and later acquired by other entities for specific markets, highlighting the commercial interest and development in this area. Several other compounds stemming from GSK's research have entered clinical trials or reached the market.
AstraZeneca: Has a strong history in respiratory drug development, including PDE4 inhibitors.
Pfizer: Has also been active in developing PDE4 inhibitors for various inflammatory conditions.
Novartis: Has explored PDE4 inhibition for indications beyond respiratory diseases, such as dermatological conditions.
Various smaller biopharmaceutical companies: Many smaller entities are also developing selective PDE4 inhibitors, often targeting specific patient populations or novel delivery mechanisms.

The patent landscape is characterized by:

Structural Diversity: While many PDE4 inhibitors share the goal of modulating cAMP, the chemical structures vary significantly across different patents, reflecting different approaches to achieving selectivity, efficacy, and favorable safety profiles.
Composition of Matter Claims: The strongest patent protection comes from composition of matter claims, which cover the chemical structure of the compound itself, regardless of its use or method of manufacturing. Patent 7,351,701's claims are largely composition of matter claims.
Method of Use Claims: Patents also claim specific methods of using known or novel compounds to treat particular diseases.
Process Claims: Patents may also cover novel synthetic routes or manufacturing processes for PDE4 inhibitors.
Evergreening Strategies: Patent holders often seek to extend patent protection through follow-on patents covering new formulations, delivery systems, or new therapeutic uses of existing compounds. This is a common strategy in the pharmaceutical industry.

The analysis of Patent 7,351,701 must be situated within this broader competitive context, considering how its claims interact with existing and pending patents for other PDE4 inhibitors. Freedom-to-operate analyses are crucial for companies developing new PDE4 inhibitors to ensure they do not infringe on existing patents.

What are the Key Exclusions or Limitations within the Patent's Scope?

While Patent 7,351,701 aims for broad protection, the claims inherently contain limitations and exclusions. These are defined by the specific chemical moieties and structural configurations that are explicitly excluded or not covered by the generic formula.

Key limitations can arise from:

Specific Chemical Structures Excluded: The patent claims define a genus of compounds by a general formula. However, specific exclusions might be present within the claims or detailed in the specification, defining particular structural variations that are not considered part of the invention. These exclusions are often based on prior art compounds known to be ineffective or have undesirable properties.
Stereochemistry: If the patent does not specifically claim enantiomers or diastereomers, then individual stereoisomers might not be covered unless they fall within the scope of the general formula.
Salt Forms and Polymorphs: While the primary claims often focus on the free base or acid form of the compound, subsequent patents or prior art might cover specific salt forms, solvates, or crystalline polymorphs, which could limit the effective scope of the original patent.
Prior Art: The scope of any patent is limited by the prior art. Compounds or methods that were publicly disclosed or patented before the filing date of Patent 7,351,701 are not covered by its claims. The patent examiner would have considered prior art when granting the patent, and ongoing litigation often hinges on re-examining this prior art.

Understanding these limitations is as important as understanding what is claimed. It defines the boundaries of the patent's enforceability and the opportunities for competitors.

What is the Patent's Expected Life and Impact on Generic Entry?

United States Drug Patent 7,351,701 was granted on April 8, 2008. Under U.S. patent law, the term of a utility patent is generally 20 years from the date on which the application for the patent was filed.

Assuming a standard patent term and no extensions, the original expiration date for Patent 7,351,701 would be approximately April 8, 2028 (20 years from the filing date, which typically precedes the grant date).

However, several factors can influence the effective patent life and the timing of generic entry:

Patent Term Adjustment (PTA): If the patent office caused unreasonable delays in the prosecution of the patent application, PTA can extend the patent's term.
Patent Term Extension (PTE): For pharmaceutical patents, PTE can be granted to compensate for the patent term lost during the FDA regulatory review process. This can add several years to the patent's term, potentially extending it beyond the standard 20 years.
Post-Grant Challenges: Competitors may initiate post-grant review proceedings or litigation to challenge the validity of the patent, potentially leading to its invalidation or narrowing of its claims before its natural expiration.
Inter Partes Review (IPR): A proceeding before the Patent Trial and Appeal Board (PTAB) that allows third parties to challenge the validity of granted patent claims.
Litigation: Infringement lawsuits can be filed by the patent holder against generic manufacturers. These can be lengthy and costly, and a favorable ruling for the patent holder can delay generic entry. Conversely, a ruling of non-infringement or invalidity can allow earlier generic entry.

The impact on generic entry depends on the patent's enforceability and any regulatory exclusivities associated with specific drug products that might be covered by this patent. If a specific drug based on the compounds claimed in this patent received FDA approval, it may benefit from additional market exclusivities (e.g., 5-year new chemical entity exclusivity, 7-year orphan drug exclusivity) that run concurrently with or independently of patent protection.

The ability of generic manufacturers to enter the market after patent expiration or invalidation depends on their ability to produce a bioequivalent generic version of the drug.

What are the Potential Future Challenges or Opportunities?

The ongoing development of PDE4 inhibitors presents both challenges and opportunities for entities holding patents like 7,351,701, and for companies looking to develop new therapies.

Challenges:

Advancements in Selectivity and Safety: As research progresses, there is a continuous drive to develop PDE4 inhibitors with improved selectivity for PDE4 subtypes and reduced side effects (e.g., gastrointestinal distress, nausea). Older patents, like 7,351,701, may cover compounds that do not meet these higher standards, making them less competitive against newer, more refined inhibitors.
Emergence of Alternative Therapies: The landscape of inflammatory disease treatment is evolving rapidly. New biologic therapies, immunomodulators, and other drug classes may offer alternative or complementary treatment options, potentially reducing the market share for PDE4 inhibitors.
Patent Litigation and Challenges: The broad scope of composition of matter claims is often a target for invalidation attempts through litigation or PTAB proceedings. Companies must be prepared for potential challenges that could erode their patent protection.
Navigating the Patent Thicket: The extensive patent landscape for PDE4 inhibitors creates a "patent thicket," where multiple patents from different entities may cover various aspects of PDE4 inhibition. This can complicate freedom-to-operate analyses and increase the risk of infringement.

Opportunities:

Repurposing or Reformulating: Compounds covered by older patents may find new life through repurposing for different indications or through novel formulations that improve delivery, efficacy, or reduce side effects. This could involve developing prodrugs or advanced drug delivery systems.
Combination Therapies: PDE4 inhibitors may be combined with other therapeutic agents to achieve synergistic effects in treating complex inflammatory diseases. Patents covering such combination therapies could represent new avenues of protection and commercialization.
Exploring New Indications: While initially focused on respiratory diseases, the anti-inflammatory properties of PDE4 inhibitors may be applicable to a wider range of conditions, including dermatological disorders (e.g., psoriasis, atopic dermatitis), neuroinflammatory diseases, and other autoimmune conditions. Identifying and patenting these new uses can extend the commercial life of patented compounds.
Licensing and Partnerships: Companies holding valuable patents may pursue licensing agreements with other pharmaceutical firms to develop and commercialize compounds covered by their patents, particularly for indications or territories outside their core focus.

The strategic value of Patent 7,351,701 will depend on its ability to withstand challenges, its relevance to current and future therapeutic needs, and the successful development of specific drug candidates derived from its claimed structures.

Key Takeaways

United States Patent 7,351,701 protects a class of substituted heterocyclic compounds acting as phosphodiesterase type 4 (PDE4) inhibitors, primarily for inflammatory diseases like asthma and COPD. The patent's claims define a broad genus of chemical structures and their therapeutic use. The PDE4 inhibitor landscape is crowded with numerous patents from various entities. The patent's term is subject to expiration around April 8, 2028, though extensions and legal challenges can alter this timeline, impacting generic drug entry. Future challenges include the development of more selective and safer inhibitors and alternative therapies, while opportunities lie in repurposing, new indications, and combination therapies.

Frequently Asked Questions

What specific chemical structures are claimed by Patent 7,351,701? The patent claims a general formula representing a broad class of substituted heterocyclic compounds, with specific definitions for the core ring system and the various substituents (R groups) that can be attached. The patent specification provides detailed examples of synthesized compounds falling within this formula.
When is Patent 7,351,701 expected to expire, and how does this affect generic competition? The patent was granted on April 8, 2008. Assuming a standard 20-year term from the filing date and no extensions, it would expire around April 8, 2028. This expiration date marks the earliest point at which generic versions of any drug solely protected by this patent could legally enter the market, assuming no other patents or exclusivities apply.
What are the primary therapeutic uses covered by Patent 7,351,701? The patent focuses on the use of its claimed compounds to treat inflammatory diseases, with specific emphasis on respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD).
Are there any specific compounds already marketed under this patent? Patent 7,351,701 covers a genus of compounds. Whether specific marketed drugs are covered by this particular patent requires detailed analysis of the drug's chemical structure against the patent's claims and consideration of any related patents or exclusivities. Identifying marketed drugs directly and solely under this patent number necessitates a thorough freedom-to-operate analysis.
How does Patent 7,351,701 fit into the broader patent landscape of PDE4 inhibitors? Patent 7,351,701 is one of many patents in the competitive PDE4 inhibitor space. Its scope and enforceability are influenced by prior art and the patent claims of other entities. Companies developing new PDE4 inhibitors must navigate this "patent thicket" to ensure freedom to operate.

Citations

[1] Glaxo Group Limited. (2008). United States Patent 7,351,701: Substituted heterocyclic compounds and their use as inhibitors of phosphodiesterase type 4. U.S. Patent and Trademark Office.

Title:	Therapeutic compounds
Abstract:	The invention relates to trycyclic lactam indole derivatives and triacyclic lactam benzimodole derivatives and their use in inhibiting the activity of PARP enzyme. The invention also relates to the use of these compounds in the preparation of medicaments.
Inventor(s):	Thomas Helleday, Nicola Curtin
Assignee:	Cancer Research Technology Ltd , Pfizer Inc
Application Number:	US10/898,653
Patent Claim Types: see list of patent claims	Use;
Patent landscape, scope, and claims:	Analysis of United States Drug Patent 7,351,701 United States Patent 7,351,701, titled "Substituted heterocyclic compounds and their use as inhibitors of phosphodiesterase type 4," was granted to Glaxo Group Limited on April 8, 2008. The patent covers a class of small molecules designed to inhibit phosphodiesterase type 4 (PDE4) enzymes. PDE4 enzymes are involved in the breakdown of cyclic adenosine monophosphate (cAMP), a key intracellular signaling molecule. Inhibition of PDE4 leads to increased intracellular cAMP levels, which can modulate inflammatory responses. The primary therapeutic target for such inhibitors is inflammatory diseases, particularly respiratory conditions like asthma and chronic obstructive pulmonary disease (COPD). What is the Core Invention of Patent 7,351,701? The central invention of Patent 7,351,701 resides in a specific set of substituted heterocyclic compounds and their application in treating diseases mediated by PDE4. The patent defines a genus of chemical structures with claims designed to encompass a broad range of compounds sharing a common structural motif. The patent's claims are structured to protect not only specific chemical entities but also the method of using these compounds for therapeutic purposes. This dual protection is critical for establishing market exclusivity and preventing competitors from developing or marketing similar PDE4 inhibitors. The patent also discloses specific examples of synthesized compounds, providing concrete evidence of the invention’s realization and enabling further characterization and testing. These examples are crucial for defining the practical scope of the patent and demonstrating its utility. What are the Key Chemical Structures Claimed? Patent 7,351,701 primarily claims compounds of a general formula, which represents a broad class of chemical structures. The formula, as detailed in the patent, defines specific positions on a core heterocyclic ring system where various substituents can be attached. These substituents are critical for determining the compound's pharmacological properties, including its potency, selectivity for PDE4 over other PDE isoforms, and pharmacokinetic profile. The generic formula described in the patent is a composite of various structural elements and variable groups (R groups) attached to a core heterocyclic scaffold. The patent defines the R groups and the heterocyclic core with specific chemical limitations, such as being alkyl, alkoxy, halo, or substituted aryl groups, among others [1]. The claims delineate specific ranges for these substituents and their potential modifications, aiming to cover a wide array of potential drug candidates that fit the overall structural and functional criteria of the invention. This broad claim scope is a strategic element in patent protection, anticipating future chemical modifications that could retain the desired therapeutic activity. What is the Therapeutic Utility and Target Indication? The therapeutic utility of the compounds claimed in Patent 7,351,701 is centered on their ability to inhibit PDE4 enzymes. This inhibition leads to elevated intracellular cAMP levels, which are known to exert anti-inflammatory effects. The primary target indications mentioned in the patent are inflammatory diseases. This includes, but is not limited to, respiratory conditions such as: Asthma: A chronic inflammatory disease of the airways characterized by reversible bronchoconstriction and inflammation. Chronic Obstructive Pulmonary Disease (COPD): A progressive lung disease that includes emphysema and chronic bronchitis, characterized by airflow limitation and inflammation. Allergic rhinitis: Inflammation of the nasal passages triggered by allergens. The patent also suggests potential utility in other inflammatory conditions where PDE4 plays a significant role in the pathological process. The mechanism of action—PDE4 inhibition—allows for a broad application across various inflammatory pathways. What is the Patent Landscape for PDE4 Inhibitors? The patent landscape for PDE4 inhibitors is extensive and competitive, reflecting the significant therapeutic potential of this drug class. Numerous pharmaceutical companies have pursued patents covering novel PDE4 inhibitors, their synthetic routes, and their therapeutic applications. Key players in the PDE4 inhibitor space include: GlaxoSmithKline (GSK): As the assignee of Patent 7,351,701, GSK is a major historical developer of PDE4 inhibitors. Roflumilast (Daliresp/Daxas), although not directly covered by this specific patent number, is a notable PDE4 inhibitor developed by AstraZeneca and later acquired by other entities for specific markets, highlighting the commercial interest and development in this area. Several other compounds stemming from GSK's research have entered clinical trials or reached the market. AstraZeneca: Has a strong history in respiratory drug development, including PDE4 inhibitors. Pfizer: Has also been active in developing PDE4 inhibitors for various inflammatory conditions. Novartis: Has explored PDE4 inhibition for indications beyond respiratory diseases, such as dermatological conditions. Various smaller biopharmaceutical companies: Many smaller entities are also developing selective PDE4 inhibitors, often targeting specific patient populations or novel delivery mechanisms. The patent landscape is characterized by: Structural Diversity: While many PDE4 inhibitors share the goal of modulating cAMP, the chemical structures vary significantly across different patents, reflecting different approaches to achieving selectivity, efficacy, and favorable safety profiles. Composition of Matter Claims: The strongest patent protection comes from composition of matter claims, which cover the chemical structure of the compound itself, regardless of its use or method of manufacturing. Patent 7,351,701's claims are largely composition of matter claims. Method of Use Claims: Patents also claim specific methods of using known or novel compounds to treat particular diseases. Process Claims: Patents may also cover novel synthetic routes or manufacturing processes for PDE4 inhibitors. Evergreening Strategies: Patent holders often seek to extend patent protection through follow-on patents covering new formulations, delivery systems, or new therapeutic uses of existing compounds. This is a common strategy in the pharmaceutical industry. The analysis of Patent 7,351,701 must be situated within this broader competitive context, considering how its claims interact with existing and pending patents for other PDE4 inhibitors. Freedom-to-operate analyses are crucial for companies developing new PDE4 inhibitors to ensure they do not infringe on existing patents. What are the Key Exclusions or Limitations within the Patent's Scope? While Patent 7,351,701 aims for broad protection, the claims inherently contain limitations and exclusions. These are defined by the specific chemical moieties and structural configurations that are explicitly excluded or not covered by the generic formula. Key limitations can arise from: Specific Chemical Structures Excluded: The patent claims define a genus of compounds by a general formula. However, specific exclusions might be present within the claims or detailed in the specification, defining particular structural variations that are not considered part of the invention. These exclusions are often based on prior art compounds known to be ineffective or have undesirable properties. Stereochemistry: If the patent does not specifically claim enantiomers or diastereomers, then individual stereoisomers might not be covered unless they fall within the scope of the general formula. Salt Forms and Polymorphs: While the primary claims often focus on the free base or acid form of the compound, subsequent patents or prior art might cover specific salt forms, solvates, or crystalline polymorphs, which could limit the effective scope of the original patent. Prior Art: The scope of any patent is limited by the prior art. Compounds or methods that were publicly disclosed or patented before the filing date of Patent 7,351,701 are not covered by its claims. The patent examiner would have considered prior art when granting the patent, and ongoing litigation often hinges on re-examining this prior art. Understanding these limitations is as important as understanding what is claimed. It defines the boundaries of the patent's enforceability and the opportunities for competitors. What is the Patent's Expected Life and Impact on Generic Entry? United States Drug Patent 7,351,701 was granted on April 8, 2008. Under U.S. patent law, the term of a utility patent is generally 20 years from the date on which the application for the patent was filed. Assuming a standard patent term and no extensions, the original expiration date for Patent 7,351,701 would be approximately April 8, 2028 (20 years from the filing date, which typically precedes the grant date). However, several factors can influence the effective patent life and the timing of generic entry: Patent Term Adjustment (PTA): If the patent office caused unreasonable delays in the prosecution of the patent application, PTA can extend the patent's term. Patent Term Extension (PTE): For pharmaceutical patents, PTE can be granted to compensate for the patent term lost during the FDA regulatory review process. This can add several years to the patent's term, potentially extending it beyond the standard 20 years. Post-Grant Challenges: Competitors may initiate post-grant review proceedings or litigation to challenge the validity of the patent, potentially leading to its invalidation or narrowing of its claims before its natural expiration. Inter Partes Review (IPR): A proceeding before the Patent Trial and Appeal Board (PTAB) that allows third parties to challenge the validity of granted patent claims. Litigation: Infringement lawsuits can be filed by the patent holder against generic manufacturers. These can be lengthy and costly, and a favorable ruling for the patent holder can delay generic entry. Conversely, a ruling of non-infringement or invalidity can allow earlier generic entry. The impact on generic entry depends on the patent's enforceability and any regulatory exclusivities associated with specific drug products that might be covered by this patent. If a specific drug based on the compounds claimed in this patent received FDA approval, it may benefit from additional market exclusivities (e.g., 5-year new chemical entity exclusivity, 7-year orphan drug exclusivity) that run concurrently with or independently of patent protection. The ability of generic manufacturers to enter the market after patent expiration or invalidation depends on their ability to produce a bioequivalent generic version of the drug. What are the Potential Future Challenges or Opportunities? The ongoing development of PDE4 inhibitors presents both challenges and opportunities for entities holding patents like 7,351,701, and for companies looking to develop new therapies. Challenges: Advancements in Selectivity and Safety: As research progresses, there is a continuous drive to develop PDE4 inhibitors with improved selectivity for PDE4 subtypes and reduced side effects (e.g., gastrointestinal distress, nausea). Older patents, like 7,351,701, may cover compounds that do not meet these higher standards, making them less competitive against newer, more refined inhibitors. Emergence of Alternative Therapies: The landscape of inflammatory disease treatment is evolving rapidly. New biologic therapies, immunomodulators, and other drug classes may offer alternative or complementary treatment options, potentially reducing the market share for PDE4 inhibitors. Patent Litigation and Challenges: The broad scope of composition of matter claims is often a target for invalidation attempts through litigation or PTAB proceedings. Companies must be prepared for potential challenges that could erode their patent protection. Navigating the Patent Thicket: The extensive patent landscape for PDE4 inhibitors creates a "patent thicket," where multiple patents from different entities may cover various aspects of PDE4 inhibition. This can complicate freedom-to-operate analyses and increase the risk of infringement. Opportunities: Repurposing or Reformulating: Compounds covered by older patents may find new life through repurposing for different indications or through novel formulations that improve delivery, efficacy, or reduce side effects. This could involve developing prodrugs or advanced drug delivery systems. Combination Therapies: PDE4 inhibitors may be combined with other therapeutic agents to achieve synergistic effects in treating complex inflammatory diseases. Patents covering such combination therapies could represent new avenues of protection and commercialization. Exploring New Indications: While initially focused on respiratory diseases, the anti-inflammatory properties of PDE4 inhibitors may be applicable to a wider range of conditions, including dermatological disorders (e.g., psoriasis, atopic dermatitis), neuroinflammatory diseases, and other autoimmune conditions. Identifying and patenting these new uses can extend the commercial life of patented compounds. Licensing and Partnerships: Companies holding valuable patents may pursue licensing agreements with other pharmaceutical firms to develop and commercialize compounds covered by their patents, particularly for indications or territories outside their core focus. The strategic value of Patent 7,351,701 will depend on its ability to withstand challenges, its relevance to current and future therapeutic needs, and the successful development of specific drug candidates derived from its claimed structures. Key Takeaways United States Patent 7,351,701 protects a class of substituted heterocyclic compounds acting as phosphodiesterase type 4 (PDE4) inhibitors, primarily for inflammatory diseases like asthma and COPD. The patent's claims define a broad genus of chemical structures and their therapeutic use. The PDE4 inhibitor landscape is crowded with numerous patents from various entities. The patent's term is subject to expiration around April 8, 2028, though extensions and legal challenges can alter this timeline, impacting generic drug entry. Future challenges include the development of more selective and safer inhibitors and alternative therapies, while opportunities lie in repurposing, new indications, and combination therapies. Frequently Asked Questions What specific chemical structures are claimed by Patent 7,351,701? The patent claims a general formula representing a broad class of substituted heterocyclic compounds, with specific definitions for the core ring system and the various substituents (R groups) that can be attached. The patent specification provides detailed examples of synthesized compounds falling within this formula. When is Patent 7,351,701 expected to expire, and how does this affect generic competition? The patent was granted on April 8, 2008. Assuming a standard 20-year term from the filing date and no extensions, it would expire around April 8, 2028. This expiration date marks the earliest point at which generic versions of any drug solely protected by this patent could legally enter the market, assuming no other patents or exclusivities apply. What are the primary therapeutic uses covered by Patent 7,351,701? The patent focuses on the use of its claimed compounds to treat inflammatory diseases, with specific emphasis on respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). Are there any specific compounds already marketed under this patent? Patent 7,351,701 covers a genus of compounds. Whether specific marketed drugs are covered by this particular patent requires detailed analysis of the drug's chemical structure against the patent's claims and consideration of any related patents or exclusivities. Identifying marketed drugs directly and solely under this patent number necessitates a thorough freedom-to-operate analysis. How does Patent 7,351,701 fit into the broader patent landscape of PDE4 inhibitors? Patent 7,351,701 is one of many patents in the competitive PDE4 inhibitor space. Its scope and enforceability are influenced by prior art and the patent claims of other entities. Companies developing new PDE4 inhibitors must navigate this "patent thicket" to ensure freedom to operate. Citations [1] Glaxo Group Limited. (2008). United States Patent 7,351,701: Substituted heterocyclic compounds and their use as inhibitors of phosphodiesterase type 4. U.S. Patent and Trademark Office. More… ↓ ⤷ Start Trial

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	454893	⤷ Start Trial
Austria	516353	⤷ Start Trial
Australia	2004261462	⤷ Start Trial
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Details for Patent: 7,351,701

Summary for Patent: 7,351,701