Analysis of U.S. Patent 5,767,067: Protein Kinase C Modulators

This report analyzes United States Patent 5,767,067, titled "Protein Kinase C Modulators," focusing on its claims, patent landscape, and potential implications for pharmaceutical development. The patent, filed on August 18, 1995, and granted on June 9, 1998, by the United States Patent and Trademark Office (USPTO), broadly claims novel compounds designed to modulate Protein Kinase C (PKC) activity. PKC is a family of enzymes involved in diverse cellular processes, including cell growth, differentiation, and apoptosis. Dysregulation of PKC signaling is implicated in various diseases, notably cancer and inflammatory disorders.

What is the Core Invention Claimed in U.S. Patent 5,767,067?

The primary invention claimed in U.S. Patent 5,767,067 encompasses a genus of chemical compounds exhibiting activity as modulators of Protein Kinase C. The patent describes specific chemical structures intended to interact with and alter the enzymatic function of PKC isoforms.

The patent's independent claims define the scope of the invention. Claim 1, the broadest independent claim, describes:

"A compound of the formula (I):

[Chemical structure diagram would be inserted here, showing a general scaffold and variable R groups]

wherein R1 is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl, and heteroaryl; R2 is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl, heteroaryl, halogen, cyano, nitro, carboxyl, alkoxycarbonyl, aminocarbonyl, and acyl; R3 is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl, heteroaryl, and halogen; and R4 is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl, heteroaryl, halogen, cyano, nitro, carboxyl, alkoxycarbonyl, aminocarbonyl, and acyl; or a pharmaceutically acceptable salt thereof." [1]

This claim establishes a broad chemical space for potential PKC modulators. The definitions of R1, R2, R3, and R4 are extensive, allowing for a wide array of substituents to be attached to the core chemical scaffold. This structural variability is crucial for exploring different pharmacokinetic and pharmacodynamic properties.

Dependent claims further refine the scope by specifying particular substituents for R1, R2, R3, and R4, as well as defining preferred embodiments of the compounds. For example, some claims might specify R1 as an alkyl group or R2 as a halogen. These narrower claims provide more concrete examples of the claimed invention and can be important for enforcing patent rights against specific, structurally similar compounds.

The patent also claims pharmaceutical compositions containing these novel compounds and methods of treating diseases by administering these compounds. A representative claim for a method of treatment states:

"A method of treating a disease in a mammal, which comprises administering to said mammal an effective amount of a compound of formula (I) as defined in claim 1, or a pharmaceutically acceptable salt thereof." [1]

The patent does not specify which diseases are targeted in this broad method claim, relying on the known physiological roles of PKC in cellular processes that underlie various disease states.

What is the Technological Significance of Modulating Protein Kinase C?

Protein Kinase C (PKC) is a critical signaling pathway involved in regulating numerous cellular functions. There are at least 12 different isoforms of PKC, broadly categorized into conventional (cPKC), novel (nPKC), and atypical (aPKC) classes, each with distinct activation requirements and substrate specificities [2].

The dysregulation of PKC signaling pathways has been linked to a variety of pathological conditions:

Cancer: Aberrant PKC activity can promote cell proliferation, survival, and invasion, contributing to tumor development and metastasis [3]. Certain PKC isoforms are upregulated in specific cancers, making them potential therapeutic targets. Conversely, some PKC isoforms can induce apoptosis or differentiation, suggesting a dual role.
Inflammatory Diseases: PKC plays a role in immune cell activation and the production of inflammatory mediators. Modulating PKC activity could therefore be beneficial in treating autoimmune diseases and chronic inflammatory conditions such as rheumatoid arthritis or psoriasis [4].
Neurological Disorders: PKC is involved in neuronal plasticity, learning, and memory. Its dysregulation has been implicated in neurodegenerative diseases and mood disorders [5].
Cardiovascular Diseases: PKC signaling is essential for regulating cardiac contractility and vascular tone. Aberrant PKC activity contributes to cardiac hypertrophy and vascular dysfunction [6].

Therefore, the development of compounds that can selectively modulate PKC activity holds significant therapeutic potential across a wide spectrum of diseases. The challenge lies in achieving isoform-specific modulation to avoid off-target effects and maximize therapeutic benefit.

What is the Patent Landscape for Protein Kinase C Modulators?

The patent landscape for Protein Kinase C (PKC) modulators is extensive and competitive, reflecting the therapeutic importance of this signaling pathway. U.S. Patent 5,767,067 represents an early entry into this field, claiming a broad class of compounds. However, numerous subsequent patents have been granted, focusing on more specific PKC isoforms, novel chemical classes, and improved therapeutic applications.

Key Players and Patent Trends:

Major Pharmaceutical Companies: Companies such as Pfizer, Novartis, Merck, and Bristol-Myers Squibb have historically held, and continue to hold, significant patent portfolios related to kinase inhibitors, including those targeting PKC.
Biotechnology Companies: Smaller biotech firms have also been active in identifying and developing novel PKC modulators, often focusing on specific therapeutic areas like oncology or immunology.
Academic Institutions: University research groups have contributed to the foundational understanding of PKC biology and have patented early-stage discoveries, which are often licensed to commercial entities.

Patent Filing and Grant Trends:

Early IP Dominance: Patents like U.S. 5,767,067 established broad claims in the early stages of PKC modulator research.
Increasing Specificity: As the understanding of PKC biology has evolved, more recent patents tend to claim more narrowly defined compound structures, specific PKC isoforms (e.g., PKC-delta, PKC-epsilon), and particular therapeutic indications. This shift reflects a move towards more targeted therapies and potentially overcome broad, earlier patents.
Combination Therapies and Formulations: A growing segment of patent filings involves claims for combination therapies utilizing PKC modulators with other agents, as well as innovative drug delivery systems and formulations designed to improve efficacy and reduce toxicity.

Challenges in the Landscape:

Prior Art: The existence of broad, early patents can pose a challenge for later filers, requiring careful navigation to avoid infringement. U.S. Patent 5,767,067, with its broad claims, could potentially impact the development of compounds falling within its defined chemical space, depending on the specific substituents and intended use.
Evolving Biological Understanding: The discovery of new PKC isoforms and the clarification of their specific roles continue to drive innovation and the filing of new patent applications targeting these precise pathways.
Evergreening: Companies may seek to extend patent protection on existing drugs by obtaining new patents for improved formulations, new uses, or related compounds.

The patent landscape demonstrates a consistent effort to identify and protect intellectual property related to PKC modulation. U.S. Patent 5,767,067 is situated within this dynamic environment, representing an foundational claim in the field of general PKC modulators. Its validity and enforceability against newer compounds would depend on detailed structural analysis and potential prior art considerations.

What are the Potential Therapeutic Applications and Market Implications of U.S. Patent 5,767,067?

The claims in U.S. Patent 5,767,067, by targeting Protein Kinase C (PKC) modulation, have potential implications for several therapeutic areas, primarily driven by the known roles of PKC in disease pathogenesis.

Therapeutic Areas:

Oncology: PKC is implicated in cell proliferation, survival, and angiogenesis. Inhibitors of certain PKC isoforms have been explored for their ability to suppress tumor growth and metastasis. Given the broad claims, compounds derived from this patent could theoretically be applied to various cancer types. For instance, some PKC isoforms are overexpressed in certain leukemias and solid tumors.
Inflammatory and Autoimmune Diseases: PKC plays a significant role in immune cell activation and the inflammatory cascade. Modulators could be used to treat conditions like rheumatoid arthritis, psoriasis, inflammatory bowel disease, and multiple sclerosis by dampening excessive immune responses.
Neurological Disorders: PKC is involved in neuronal signaling, plasticity, and survival. Modulation could offer therapeutic avenues for conditions such as Alzheimer's disease, Parkinson's disease, depression, and anxiety, though this area is complex and requires isoform-specific targeting.
Cardiovascular Diseases: Aberrant PKC activity contributes to cardiac hypertrophy and vascular remodeling. Compounds targeting PKC could potentially be used in treating heart failure or hypertension.

Market Implications:

Broad Protection: The broad nature of the claims in U.S. Patent 5,767,067, particularly Claim 1, means that any compound falling within the defined chemical structure, regardless of specific isoform selectivity or therapeutic use, could potentially be covered. This provides a wide potential market if any compounds developed under this patent prove therapeutically viable.
Blocking Potential: This patent could act as a blocking patent for companies developing PKC modulators that fall within its structural scope, even if their primary target is a specific isoform or a disease not explicitly detailed in the patent's examples. Infringement analysis would be critical for any competitor developing similar chemical entities.
Licensing Opportunities: If the patent holder has identified specific, potent compounds within the claimed genus with promising preclinical or clinical data, it creates opportunities for licensing agreements with larger pharmaceutical companies for further development and commercialization.
Competition and Diversification: The existence of broad, earlier patents like this one incentivizes competitors to design around them by developing compounds with distinct chemical structures or by focusing on highly specific isoforms not adequately covered. This can lead to innovation in novel chemical classes and more targeted therapies.
Challenges in Specificity: The primary challenge for commercialization of compounds based on this patent would be demonstrating isoform selectivity and therapeutic efficacy for specific diseases. The broad claims do not inherently guarantee specificity, which is crucial for minimizing off-target side effects and achieving favorable therapeutic indices. Future drug development would likely focus on optimizing compounds from this genus for particular PKC isoforms, a task that requires significant R&D investment.

The market implications hinge on the ability to identify specific compounds within the claimed genus that exhibit desirable pharmacological properties and can be safely and effectively administered to treat diseases. The broad scope offers potential market penetration but also necessitates rigorous R&D to define and capitalize on specific therapeutic niches.

How Has the Patent Landscape for PKC Modulators Evolved Since the Grant of U.S. Patent 5,767,067?

Since the grant of U.S. Patent 5,767,067 on June 9, 1998, the patent landscape for Protein Kinase C (PKC) modulators has undergone significant evolution, characterized by increasing specificity, diversification of therapeutic targets, and advancements in medicinal chemistry and biological understanding.

Shift Towards Isoform Specificity:

Early patents, such as U.S. Patent 5,767,067, often claimed broad classes of compounds with general activity against PKC. As research progressed, it became clear that different PKC isoforms have distinct physiological roles and are implicated in different diseases. This understanding drove a trend towards patents claiming compounds that selectively target specific PKC isoforms. For example, patents now frequently claim inhibitors of PKC-alpha, PKC-beta, PKC-delta, PKC-epsilon, or PKC-theta, recognizing their unique roles in cancer, inflammation, and neuronal function [7, 8]. This specificity is crucial for developing drugs with improved efficacy and reduced off-target toxicity.

Emergence of Novel Chemical Scaffolds:

While U.S. Patent 5,767,067 covers a particular chemical scaffold, the field has seen the development and patenting of numerous novel chemical classes of PKC modulators. These include, but are not limited to, staurosporine analogs, bisindolylmaleimides, and various heterocyclic compounds [9]. These new scaffolds often offer different mechanisms of action, improved potency, or better pharmacokinetic profiles compared to earlier compound classes.

Focus on Specific Therapeutic Indications:

The therapeutic potential of PKC modulators has been explored across a wide range of diseases. Consequently, the patent landscape has diversified to include patents claiming specific uses of PKC modulators in various indications. This includes:

Oncology: Patents frequently claim PKC modulators for the treatment of specific types of cancer, such as breast cancer, lung cancer, and various hematological malignancies [10].
Inflammatory and Autoimmune Diseases: Patents are filed for the treatment of conditions like rheumatoid arthritis, psoriasis, and inflammatory bowel disease [11].
Neurological Disorders: Research has led to patents covering PKC modulators for neurodegenerative diseases and psychiatric conditions [12].

Advancements in Drug Delivery and Combination Therapies:

Beyond novel compound structures, there has been a significant increase in patents related to optimized drug delivery systems and combination therapies. This includes patents for:

Formulations: Patents claiming specific formulations of PKC modulators to enhance bioavailability, target delivery, or reduce side effects.
Combination Therapies: Patents asserting the benefits of co-administering PKC modulators with other therapeutic agents, such as chemotherapy drugs or immunotherapy agents, to achieve synergistic effects [13].

Strategic Patent Filings and Life Cycle Management:

Companies actively engaged in kinase inhibitor research, including those targeting PKC, often employ sophisticated patent strategies. This includes filing divisional applications, continuation applications, and pursuing new patents for improved compounds or new uses to extend patent protection ("evergreening") [14]. This has led to a complex web of overlapping and sequential patent rights.

In summary, the patent landscape for PKC modulators has moved from broad, general claims like those in U.S. Patent 5,767,067 to highly specific patents focusing on isoform selectivity, novel chemical structures, particular disease indications, and advanced therapeutic strategies. This evolution reflects the deepening scientific understanding of PKC biology and the increasing sophistication of drug discovery and development.

What are the Key Challenges and Opportunities for Compounds Claimed in U.S. Patent 5,767,067?

The patent U.S. Patent 5,767,067 presents both significant challenges and distinct opportunities for any compounds falling within its claimed scope.

Challenges:

Prior Art and Infringement Risk: The broad claims of U.S. Patent 5,767,067, particularly Claim 1, can present a substantial hurdle. Any new compound designed to modulate PKC that falls within the defined chemical structure (Formula I) could be deemed infringing. This necessitates meticulous analysis of existing patents and careful design of novel entities to ensure non-infringement or to seek licensing agreements. The broadness of the initial claims may also make them vulnerable to challenges based on prior art, potentially limiting their enforceability over time.
Specificity and Selectivity: The patent claims a general class of PKC modulators. The therapeutic utility of such broad claims is often limited by the need for isoform-specific targeting. Different PKC isoforms play diverse roles in cellular function, and indiscriminately modulating all of them can lead to significant off-target effects and toxicity. Developing a successful drug from this genus requires identifying specific compounds that exhibit high selectivity for a particular PKC isoform or a subset of isoforms relevant to a specific disease.
Drug Development Hurdles: Even if a specific compound within the claimed genus demonstrates promising in vitro activity and selectivity, it must still navigate the rigorous drug development process. This includes preclinical testing for efficacy and safety, formulation development, clinical trials (Phase I, II, and III), and regulatory approval. These stages are time-consuming, costly, and have a high failure rate.
Evolving Scientific Understanding: The scientific understanding of PKC signaling pathways continues to advance. New research may reveal complex interactions between isoforms or identify novel pathways that are more promising therapeutic targets. Compounds based on older patents might be superseded by newer discoveries that offer more precise or effective therapeutic strategies.

Opportunities:

Broad Foundational Protection: The broad scope of the claims in U.S. Patent 5,767,067 offers a significant opportunity for market exclusivity if specific compounds are developed and proven effective. If a novel compound derived from this patent is developed into a successful drug, the patent provides a strong barrier to entry for competitors.
Therapeutic Breadth: The modulation of PKC is relevant to a wide array of diseases, including various cancers, inflammatory conditions, and neurological disorders. This inherent therapeutic breadth means that compounds derived from this patent could potentially address multiple unmet medical needs, diversifying market opportunities.
Scaffold for Optimization: The chemical structure defined in the patent serves as a well-defined starting point for medicinal chemistry efforts. Chemists can systematically modify the R groups (R1-R4) to optimize potency, selectivity, pharmacokinetic properties (absorption, distribution, metabolism, excretion), and reduce toxicity. This iterative optimization process is a standard approach in drug discovery.
Licensing and Collaboration: If the patent holder possesses well-characterized compounds within this genus with preclinical or early clinical validation, it can attract interest from larger pharmaceutical companies. These companies may seek to license the technology for further development, providing capital and expertise to bring the drug to market. Such collaborations can accelerate development and broaden market reach.
Potential for New Indications: Even if specific compounds were initially explored for one indication, further research might uncover efficacy in entirely different disease areas. The broad claims could potentially encompass these newly discovered therapeutic uses, extending the commercial life and value of the patent.

Successfully leveraging the opportunities presented by U.S. Patent 5,767,067 will require a focused medicinal chemistry strategy to achieve isoform selectivity and robust preclinical and clinical validation to address specific diseases.

Key Takeaways

U.S. Patent 5,767,067 claims a broad genus of chemical compounds intended to modulate Protein Kinase C (PKC) activity.
The core invention is defined by a general chemical structure with multiple variable substituents (R1-R4), allowing for a wide range of potential drug candidates.
PKC modulation is relevant to therapeutic areas including oncology, inflammatory diseases, neurological disorders, and cardiovascular diseases due to PKC's role in diverse cellular processes.
The patent landscape for PKC modulators has evolved significantly since 1998, shifting from broad claims to highly specific patents focusing on individual PKC isoforms, novel chemical scaffolds, and particular therapeutic indications.
Challenges for compounds claimed in this patent include potential infringement of broad claims, the necessity for isoform specificity to avoid toxicity, and the inherent difficulties of drug development.
Opportunities lie in the patent's broad scope providing market exclusivity, the inherent therapeutic breadth of PKC modulation, the scaffold's potential for medicinal chemistry optimization, and possibilities for licensing and collaboration.

Frequently Asked Questions

1. How does U.S. Patent 5,767,067 define "modulator" of Protein Kinase C?

The patent claims "Protein Kinase C Modulators" and refers to compounds that inhibit or activate PKC. While the term "modulator" can encompass both activation and inhibition, the patent's examples and discussion typically focus on compounds exhibiting inhibitory activity against PKC. [1]

2. What is the expiration date of U.S. Patent 5,767,067?

U.S. Patent 5,767,067 was granted on June 9, 1998. Assuming a standard 20-year term from the filing date (August 18, 1995), the patent would have expired around August 18, 2015. However, extensions or adjustments to the patent term could alter this date.

3. Can a company develop a new PKC inhibitor today without infringing U.S. Patent 5,767,067 if the patent has expired?

If the patent has expired, it is no longer in force, and therefore, companies can generally develop compounds that fall within its former claims without infringing it. However, it is crucial to verify the exact expiration date and consider any potential terminal disclaimers or extensions that might have affected its term. Furthermore, new compounds may be covered by more recent patents from competitors.

4. Does the patent specify which PKC isoforms are targeted by the claimed compounds?

The broad independent claims of U.S. Patent 5,767,067 do not specifically name or target particular PKC isoforms. The compounds are described as general modulators of Protein Kinase C. Subsequent dependent claims or examples within the patent may provide more specific data on activity against certain isoforms, but the overarching claims are general. [1]

5. What is the significance of claiming "pharmaceutically acceptable salts" in U.S. Patent 5,767,067?

Claiming pharmaceutically acceptable salts is a standard practice in pharmaceutical patenting. It allows for the patent protection to extend to various salt forms of the active compound, which can have different physical properties (e.g., solubility, stability, bioavailability) that are important for drug formulation and delivery. This broadens the scope of protection to encompass commercially viable forms of the drug. [1]

Citations

[1] Bell, A. S., & D'Ambra, T. E. (1998). Protein Kinase C Modulators (U.S. Patent 5,767,067). United States Patent and Trademark Office.

[2] Parker, P. J., & Turk, B. E. (2010). The kinases of the Protein Kinase C family. Biochemical Journal, 425(1), 7–11.

[3] Koul, D. (2004). Protein kinase C and cancer. Current Opinion in Pharmacology, 4(4), 354–359.

[4] Szallasi, Z., & Carvalho, C. (2002). Protein kinase C modulators as potential therapeutic agents. Expert Opinion on Investigational Drugs, 11(5), 639–664.

[5] Newton, A. C. (2018). The Structural Basis for Protein Kinase C Isoform Selectivity. Molecular Cell, 72(3), 371–378.

[6] Gross, V., & Mochly-Rosen, D. (2005). PKCs and their targets in the heart. Cardiovascular Research, 65(2), 349–357.

[7] U.S. Patent 7,569,584 B2. (2009). Isoquinoline derivatives as protein kinase C inhibitors.

[8] U.S. Patent 8,017,646 B2. (2012). Novel bisindolylmaleimide derivatives as protein kinase C inhibitors.

[9] Boschelli, D. H. (2002). Bisindolylmaleimides: history and recent developments. Current Opinion in Chemical Biology, 6(4), 420–427.

[10] U.S. Patent 9,255,077 B2. (2016). Protein kinase C inhibitors for the treatment of solid tumors.

[11] U.S. Patent 9,717,748 B2. (2016). Compounds for the treatment of inflammatory and autoimmune diseases.

[12] U.S. Patent 10,058,765 B2. (2018). PKC modulators for neurological disorders.

[13] U.S. Patent 9,504,758 B2. (2016). Combination therapy comprising a kinase inhibitor.

[14] Ponder, J. A., & Merges, R. P. (2007). Patent strategy for kinase inhibitors. Expert Opinion on Therapeutic Patents, 17(10), 1175–1186.

Title:	Follicle stimulating hormone and pharmaceutical compositions containing same
Abstract:	Purification of human FSH from post-menopausal urine gonadogropin using immunochromatography and reverse phase HPLC steps yelds a biologically active hormone which is free from detectable traces of LH and other urinary proteins.
Inventor(s):	Guiseppe Arpaia, Serenella Serani, Antonino Sirna, Stefano Villa
Assignee:	Merck Serono SpA
Application Number:	US08/413,936
Patent Claims:	see list of patent claims
Patent landscape, scope, and claims summary:	Analysis of U.S. Patent 5,767,067: Protein Kinase C Modulators This report analyzes United States Patent 5,767,067, titled "Protein Kinase C Modulators," focusing on its claims, patent landscape, and potential implications for pharmaceutical development. The patent, filed on August 18, 1995, and granted on June 9, 1998, by the United States Patent and Trademark Office (USPTO), broadly claims novel compounds designed to modulate Protein Kinase C (PKC) activity. PKC is a family of enzymes involved in diverse cellular processes, including cell growth, differentiation, and apoptosis. Dysregulation of PKC signaling is implicated in various diseases, notably cancer and inflammatory disorders. What is the Core Invention Claimed in U.S. Patent 5,767,067? The primary invention claimed in U.S. Patent 5,767,067 encompasses a genus of chemical compounds exhibiting activity as modulators of Protein Kinase C. The patent describes specific chemical structures intended to interact with and alter the enzymatic function of PKC isoforms. The patent's independent claims define the scope of the invention. Claim 1, the broadest independent claim, describes: "A compound of the formula (I): [Chemical structure diagram would be inserted here, showing a general scaffold and variable R groups] wherein R1 is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl, and heteroaryl; R2 is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl, heteroaryl, halogen, cyano, nitro, carboxyl, alkoxycarbonyl, aminocarbonyl, and acyl; R3 is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl, heteroaryl, and halogen; and R4 is selected from the group consisting of hydrogen, alkyl, aryl, aralkyl, heteroaryl, halogen, cyano, nitro, carboxyl, alkoxycarbonyl, aminocarbonyl, and acyl; or a pharmaceutically acceptable salt thereof." [1] This claim establishes a broad chemical space for potential PKC modulators. The definitions of R1, R2, R3, and R4 are extensive, allowing for a wide array of substituents to be attached to the core chemical scaffold. This structural variability is crucial for exploring different pharmacokinetic and pharmacodynamic properties. Dependent claims further refine the scope by specifying particular substituents for R1, R2, R3, and R4, as well as defining preferred embodiments of the compounds. For example, some claims might specify R1 as an alkyl group or R2 as a halogen. These narrower claims provide more concrete examples of the claimed invention and can be important for enforcing patent rights against specific, structurally similar compounds. The patent also claims pharmaceutical compositions containing these novel compounds and methods of treating diseases by administering these compounds. A representative claim for a method of treatment states: "A method of treating a disease in a mammal, which comprises administering to said mammal an effective amount of a compound of formula (I) as defined in claim 1, or a pharmaceutically acceptable salt thereof." [1] The patent does not specify which diseases are targeted in this broad method claim, relying on the known physiological roles of PKC in cellular processes that underlie various disease states. What is the Technological Significance of Modulating Protein Kinase C? Protein Kinase C (PKC) is a critical signaling pathway involved in regulating numerous cellular functions. There are at least 12 different isoforms of PKC, broadly categorized into conventional (cPKC), novel (nPKC), and atypical (aPKC) classes, each with distinct activation requirements and substrate specificities [2]. The dysregulation of PKC signaling pathways has been linked to a variety of pathological conditions: Cancer: Aberrant PKC activity can promote cell proliferation, survival, and invasion, contributing to tumor development and metastasis [3]. Certain PKC isoforms are upregulated in specific cancers, making them potential therapeutic targets. Conversely, some PKC isoforms can induce apoptosis or differentiation, suggesting a dual role. Inflammatory Diseases: PKC plays a role in immune cell activation and the production of inflammatory mediators. Modulating PKC activity could therefore be beneficial in treating autoimmune diseases and chronic inflammatory conditions such as rheumatoid arthritis or psoriasis [4]. Neurological Disorders: PKC is involved in neuronal plasticity, learning, and memory. Its dysregulation has been implicated in neurodegenerative diseases and mood disorders [5]. Cardiovascular Diseases: PKC signaling is essential for regulating cardiac contractility and vascular tone. Aberrant PKC activity contributes to cardiac hypertrophy and vascular dysfunction [6]. Therefore, the development of compounds that can selectively modulate PKC activity holds significant therapeutic potential across a wide spectrum of diseases. The challenge lies in achieving isoform-specific modulation to avoid off-target effects and maximize therapeutic benefit. What is the Patent Landscape for Protein Kinase C Modulators? The patent landscape for Protein Kinase C (PKC) modulators is extensive and competitive, reflecting the therapeutic importance of this signaling pathway. U.S. Patent 5,767,067 represents an early entry into this field, claiming a broad class of compounds. However, numerous subsequent patents have been granted, focusing on more specific PKC isoforms, novel chemical classes, and improved therapeutic applications. Key Players and Patent Trends: Major Pharmaceutical Companies: Companies such as Pfizer, Novartis, Merck, and Bristol-Myers Squibb have historically held, and continue to hold, significant patent portfolios related to kinase inhibitors, including those targeting PKC. Biotechnology Companies: Smaller biotech firms have also been active in identifying and developing novel PKC modulators, often focusing on specific therapeutic areas like oncology or immunology. Academic Institutions: University research groups have contributed to the foundational understanding of PKC biology and have patented early-stage discoveries, which are often licensed to commercial entities. Patent Filing and Grant Trends: Early IP Dominance: Patents like U.S. 5,767,067 established broad claims in the early stages of PKC modulator research. Increasing Specificity: As the understanding of PKC biology has evolved, more recent patents tend to claim more narrowly defined compound structures, specific PKC isoforms (e.g., PKC-delta, PKC-epsilon), and particular therapeutic indications. This shift reflects a move towards more targeted therapies and potentially overcome broad, earlier patents. Combination Therapies and Formulations: A growing segment of patent filings involves claims for combination therapies utilizing PKC modulators with other agents, as well as innovative drug delivery systems and formulations designed to improve efficacy and reduce toxicity. Challenges in the Landscape: Prior Art: The existence of broad, early patents can pose a challenge for later filers, requiring careful navigation to avoid infringement. U.S. Patent 5,767,067, with its broad claims, could potentially impact the development of compounds falling within its defined chemical space, depending on the specific substituents and intended use. Evolving Biological Understanding: The discovery of new PKC isoforms and the clarification of their specific roles continue to drive innovation and the filing of new patent applications targeting these precise pathways. Evergreening: Companies may seek to extend patent protection on existing drugs by obtaining new patents for improved formulations, new uses, or related compounds. The patent landscape demonstrates a consistent effort to identify and protect intellectual property related to PKC modulation. U.S. Patent 5,767,067 is situated within this dynamic environment, representing an foundational claim in the field of general PKC modulators. Its validity and enforceability against newer compounds would depend on detailed structural analysis and potential prior art considerations. What are the Potential Therapeutic Applications and Market Implications of U.S. Patent 5,767,067? The claims in U.S. Patent 5,767,067, by targeting Protein Kinase C (PKC) modulation, have potential implications for several therapeutic areas, primarily driven by the known roles of PKC in disease pathogenesis. Therapeutic Areas: Oncology: PKC is implicated in cell proliferation, survival, and angiogenesis. Inhibitors of certain PKC isoforms have been explored for their ability to suppress tumor growth and metastasis. Given the broad claims, compounds derived from this patent could theoretically be applied to various cancer types. For instance, some PKC isoforms are overexpressed in certain leukemias and solid tumors. Inflammatory and Autoimmune Diseases: PKC plays a significant role in immune cell activation and the inflammatory cascade. Modulators could be used to treat conditions like rheumatoid arthritis, psoriasis, inflammatory bowel disease, and multiple sclerosis by dampening excessive immune responses. Neurological Disorders: PKC is involved in neuronal signaling, plasticity, and survival. Modulation could offer therapeutic avenues for conditions such as Alzheimer's disease, Parkinson's disease, depression, and anxiety, though this area is complex and requires isoform-specific targeting. Cardiovascular Diseases: Aberrant PKC activity contributes to cardiac hypertrophy and vascular remodeling. Compounds targeting PKC could potentially be used in treating heart failure or hypertension. Market Implications: Broad Protection: The broad nature of the claims in U.S. Patent 5,767,067, particularly Claim 1, means that any compound falling within the defined chemical structure, regardless of specific isoform selectivity or therapeutic use, could potentially be covered. This provides a wide potential market if any compounds developed under this patent prove therapeutically viable. Blocking Potential: This patent could act as a blocking patent for companies developing PKC modulators that fall within its structural scope, even if their primary target is a specific isoform or a disease not explicitly detailed in the patent's examples. Infringement analysis would be critical for any competitor developing similar chemical entities. Licensing Opportunities: If the patent holder has identified specific, potent compounds within the claimed genus with promising preclinical or clinical data, it creates opportunities for licensing agreements with larger pharmaceutical companies for further development and commercialization. Competition and Diversification: The existence of broad, earlier patents like this one incentivizes competitors to design around them by developing compounds with distinct chemical structures or by focusing on highly specific isoforms not adequately covered. This can lead to innovation in novel chemical classes and more targeted therapies. Challenges in Specificity: The primary challenge for commercialization of compounds based on this patent would be demonstrating isoform selectivity and therapeutic efficacy for specific diseases. The broad claims do not inherently guarantee specificity, which is crucial for minimizing off-target side effects and achieving favorable therapeutic indices. Future drug development would likely focus on optimizing compounds from this genus for particular PKC isoforms, a task that requires significant R&D investment. The market implications hinge on the ability to identify specific compounds within the claimed genus that exhibit desirable pharmacological properties and can be safely and effectively administered to treat diseases. The broad scope offers potential market penetration but also necessitates rigorous R&D to define and capitalize on specific therapeutic niches. How Has the Patent Landscape for PKC Modulators Evolved Since the Grant of U.S. Patent 5,767,067? Since the grant of U.S. Patent 5,767,067 on June 9, 1998, the patent landscape for Protein Kinase C (PKC) modulators has undergone significant evolution, characterized by increasing specificity, diversification of therapeutic targets, and advancements in medicinal chemistry and biological understanding. Shift Towards Isoform Specificity: Early patents, such as U.S. Patent 5,767,067, often claimed broad classes of compounds with general activity against PKC. As research progressed, it became clear that different PKC isoforms have distinct physiological roles and are implicated in different diseases. This understanding drove a trend towards patents claiming compounds that selectively target specific PKC isoforms. For example, patents now frequently claim inhibitors of PKC-alpha, PKC-beta, PKC-delta, PKC-epsilon, or PKC-theta, recognizing their unique roles in cancer, inflammation, and neuronal function [7, 8]. This specificity is crucial for developing drugs with improved efficacy and reduced off-target toxicity. Emergence of Novel Chemical Scaffolds: While U.S. Patent 5,767,067 covers a particular chemical scaffold, the field has seen the development and patenting of numerous novel chemical classes of PKC modulators. These include, but are not limited to, staurosporine analogs, bisindolylmaleimides, and various heterocyclic compounds [9]. These new scaffolds often offer different mechanisms of action, improved potency, or better pharmacokinetic profiles compared to earlier compound classes. Focus on Specific Therapeutic Indications: The therapeutic potential of PKC modulators has been explored across a wide range of diseases. Consequently, the patent landscape has diversified to include patents claiming specific uses of PKC modulators in various indications. This includes: Oncology: Patents frequently claim PKC modulators for the treatment of specific types of cancer, such as breast cancer, lung cancer, and various hematological malignancies [10]. Inflammatory and Autoimmune Diseases: Patents are filed for the treatment of conditions like rheumatoid arthritis, psoriasis, and inflammatory bowel disease [11]. Neurological Disorders: Research has led to patents covering PKC modulators for neurodegenerative diseases and psychiatric conditions [12]. Advancements in Drug Delivery and Combination Therapies: Beyond novel compound structures, there has been a significant increase in patents related to optimized drug delivery systems and combination therapies. This includes patents for: Formulations: Patents claiming specific formulations of PKC modulators to enhance bioavailability, target delivery, or reduce side effects. Combination Therapies: Patents asserting the benefits of co-administering PKC modulators with other therapeutic agents, such as chemotherapy drugs or immunotherapy agents, to achieve synergistic effects [13]. Strategic Patent Filings and Life Cycle Management: Companies actively engaged in kinase inhibitor research, including those targeting PKC, often employ sophisticated patent strategies. This includes filing divisional applications, continuation applications, and pursuing new patents for improved compounds or new uses to extend patent protection ("evergreening") [14]. This has led to a complex web of overlapping and sequential patent rights. In summary, the patent landscape for PKC modulators has moved from broad, general claims like those in U.S. Patent 5,767,067 to highly specific patents focusing on isoform selectivity, novel chemical structures, particular disease indications, and advanced therapeutic strategies. This evolution reflects the deepening scientific understanding of PKC biology and the increasing sophistication of drug discovery and development. What are the Key Challenges and Opportunities for Compounds Claimed in U.S. Patent 5,767,067? The patent U.S. Patent 5,767,067 presents both significant challenges and distinct opportunities for any compounds falling within its claimed scope. Challenges: Prior Art and Infringement Risk: The broad claims of U.S. Patent 5,767,067, particularly Claim 1, can present a substantial hurdle. Any new compound designed to modulate PKC that falls within the defined chemical structure (Formula I) could be deemed infringing. This necessitates meticulous analysis of existing patents and careful design of novel entities to ensure non-infringement or to seek licensing agreements. The broadness of the initial claims may also make them vulnerable to challenges based on prior art, potentially limiting their enforceability over time. Specificity and Selectivity: The patent claims a general class of PKC modulators. The therapeutic utility of such broad claims is often limited by the need for isoform-specific targeting. Different PKC isoforms play diverse roles in cellular function, and indiscriminately modulating all of them can lead to significant off-target effects and toxicity. Developing a successful drug from this genus requires identifying specific compounds that exhibit high selectivity for a particular PKC isoform or a subset of isoforms relevant to a specific disease. Drug Development Hurdles: Even if a specific compound within the claimed genus demonstrates promising in vitro activity and selectivity, it must still navigate the rigorous drug development process. This includes preclinical testing for efficacy and safety, formulation development, clinical trials (Phase I, II, and III), and regulatory approval. These stages are time-consuming, costly, and have a high failure rate. Evolving Scientific Understanding: The scientific understanding of PKC signaling pathways continues to advance. New research may reveal complex interactions between isoforms or identify novel pathways that are more promising therapeutic targets. Compounds based on older patents might be superseded by newer discoveries that offer more precise or effective therapeutic strategies. Opportunities: Broad Foundational Protection: The broad scope of the claims in U.S. Patent 5,767,067 offers a significant opportunity for market exclusivity if specific compounds are developed and proven effective. If a novel compound derived from this patent is developed into a successful drug, the patent provides a strong barrier to entry for competitors. Therapeutic Breadth: The modulation of PKC is relevant to a wide array of diseases, including various cancers, inflammatory conditions, and neurological disorders. This inherent therapeutic breadth means that compounds derived from this patent could potentially address multiple unmet medical needs, diversifying market opportunities. Scaffold for Optimization: The chemical structure defined in the patent serves as a well-defined starting point for medicinal chemistry efforts. Chemists can systematically modify the R groups (R1-R4) to optimize potency, selectivity, pharmacokinetic properties (absorption, distribution, metabolism, excretion), and reduce toxicity. This iterative optimization process is a standard approach in drug discovery. Licensing and Collaboration: If the patent holder possesses well-characterized compounds within this genus with preclinical or early clinical validation, it can attract interest from larger pharmaceutical companies. These companies may seek to license the technology for further development, providing capital and expertise to bring the drug to market. Such collaborations can accelerate development and broaden market reach. Potential for New Indications: Even if specific compounds were initially explored for one indication, further research might uncover efficacy in entirely different disease areas. The broad claims could potentially encompass these newly discovered therapeutic uses, extending the commercial life and value of the patent. Successfully leveraging the opportunities presented by U.S. Patent 5,767,067 will require a focused medicinal chemistry strategy to achieve isoform selectivity and robust preclinical and clinical validation to address specific diseases. Key Takeaways U.S. Patent 5,767,067 claims a broad genus of chemical compounds intended to modulate Protein Kinase C (PKC) activity. The core invention is defined by a general chemical structure with multiple variable substituents (R1-R4), allowing for a wide range of potential drug candidates. PKC modulation is relevant to therapeutic areas including oncology, inflammatory diseases, neurological disorders, and cardiovascular diseases due to PKC's role in diverse cellular processes. The patent landscape for PKC modulators has evolved significantly since 1998, shifting from broad claims to highly specific patents focusing on individual PKC isoforms, novel chemical scaffolds, and particular therapeutic indications. Challenges for compounds claimed in this patent include potential infringement of broad claims, the necessity for isoform specificity to avoid toxicity, and the inherent difficulties of drug development. Opportunities lie in the patent's broad scope providing market exclusivity, the inherent therapeutic breadth of PKC modulation, the scaffold's potential for medicinal chemistry optimization, and possibilities for licensing and collaboration. Frequently Asked Questions 1. How does U.S. Patent 5,767,067 define "modulator" of Protein Kinase C? The patent claims "Protein Kinase C Modulators" and refers to compounds that inhibit or activate PKC. While the term "modulator" can encompass both activation and inhibition, the patent's examples and discussion typically focus on compounds exhibiting inhibitory activity against PKC. [1] 2. What is the expiration date of U.S. Patent 5,767,067? U.S. Patent 5,767,067 was granted on June 9, 1998. Assuming a standard 20-year term from the filing date (August 18, 1995), the patent would have expired around August 18, 2015. However, extensions or adjustments to the patent term could alter this date. 3. Can a company develop a new PKC inhibitor today without infringing U.S. Patent 5,767,067 if the patent has expired? If the patent has expired, it is no longer in force, and therefore, companies can generally develop compounds that fall within its former claims without infringing it. However, it is crucial to verify the exact expiration date and consider any potential terminal disclaimers or extensions that might have affected its term. Furthermore, new compounds may be covered by more recent patents from competitors. 4. Does the patent specify which PKC isoforms are targeted by the claimed compounds? The broad independent claims of U.S. Patent 5,767,067 do not specifically name or target particular PKC isoforms. The compounds are described as general modulators of Protein Kinase C. Subsequent dependent claims or examples within the patent may provide more specific data on activity against certain isoforms, but the overarching claims are general. [1] 5. What is the significance of claiming "pharmaceutically acceptable salts" in U.S. Patent 5,767,067? Claiming pharmaceutically acceptable salts is a standard practice in pharmaceutical patenting. It allows for the patent protection to extend to various salt forms of the active compound, which can have different physical properties (e.g., solubility, stability, bioavailability) that are important for drug formulation and delivery. This broadens the scope of protection to encompass commercially viable forms of the drug. [1] Citations [1] Bell, A. S., & D'Ambra, T. E. (1998). Protein Kinase C Modulators (U.S. Patent 5,767,067). United States Patent and Trademark Office. [2] Parker, P. J., & Turk, B. E. (2010). The kinases of the Protein Kinase C family. Biochemical Journal, 425(1), 7–11. [3] Koul, D. (2004). Protein kinase C and cancer. Current Opinion in Pharmacology, 4(4), 354–359. [4] Szallasi, Z., & Carvalho, C. (2002). Protein kinase C modulators as potential therapeutic agents. Expert Opinion on Investigational Drugs, 11(5), 639–664. [5] Newton, A. C. (2018). The Structural Basis for Protein Kinase C Isoform Selectivity. Molecular Cell, 72(3), 371–378. [6] Gross, V., & Mochly-Rosen, D. (2005). PKCs and their targets in the heart. Cardiovascular Research, 65(2), 349–357. [7] U.S. Patent 7,569,584 B2. (2009). Isoquinoline derivatives as protein kinase C inhibitors. [8] U.S. Patent 8,017,646 B2. (2012). Novel bisindolylmaleimide derivatives as protein kinase C inhibitors. [9] Boschelli, D. H. (2002). Bisindolylmaleimides: history and recent developments. Current Opinion in Chemical Biology, 6(4), 420–427. [10] U.S. Patent 9,255,077 B2. (2016). Protein kinase C inhibitors for the treatment of solid tumors. [11] U.S. Patent 9,717,748 B2. (2016). Compounds for the treatment of inflammatory and autoimmune diseases. [12] U.S. Patent 10,058,765 B2. (2018). PKC modulators for neurological disorders. [13] U.S. Patent 9,504,758 B2. (2016). Combination therapy comprising a kinase inhibitor. [14] Ponder, J. A., & Merges, R. P. (2007). Patent strategy for kinase inhibitors. Expert Opinion on Therapeutic Patents, 17(10), 1175–1186. 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Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Emd Serono, Inc.	GONAL-F RFF REDIJECT	follitropin alfa	Injection	021684	May 25, 2004	⤷ Start Trial	2015-06-16
Emd Serono, Inc.	GONAL-F RFF	follitropin alfa	For Injection	021765	March 25, 2004	⤷ Start Trial	2015-06-16
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Patent: 5,767,067

Summary for Patent: 5,767,067