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Patent landscape, scope, and claims: |
Analysis of U.S. Drug Patent 5,319,097
U.S. Patent 5,319,097, titled "Anticancer agents and their use," was granted to Schering Corporation on June 7, 1994. The patent claims a class of organic compounds and their application in treating cancer. The core of the patent lies in the chemical structures and their demonstrated biological activity, specifically against tumor cells. Key aspects include the defined chemical substituents and the exemplified therapeutic uses.
What is the Core Invention Claimed by Patent 5,319,097?
Patent 5,319,097 claims a specific group of chemical compounds and their use in treating cancer. The claims delineate a genus of substituted pyrazolo[3,4-d]pyrimidine compounds. These compounds are characterized by a core pyrazolo[3,4-d]pyrimidine ring system with various substituents at specific positions (e.g., R1, R2, R3, R4).
Key structural features and substitutions include:
- A pyrazolo[3,4-d]pyrimidine core.
- Specific functional groups and atoms that can be attached at defined positions on the core ring system, denoted by variables such as R1, R2, R3, and R4.
- The patent describes a broad range of possible chemical moieties for these substituents, covering alkyl groups, aryl groups, heterocyclic groups, amino groups, hydroxyl groups, and halogen atoms.
The purpose of these substitutions is to create compounds with specific pharmacological properties, particularly anticancer activity. The patent provides examples of synthesized compounds within this class and data demonstrating their efficacy in inhibiting the growth of various cancer cell lines in vitro and in animal models in vivo.
What Specific Therapeutic Uses are Covered by the Patent?
The patent specifically claims the use of the compounds described for the treatment of cancer. This encompasses a broad spectrum of neoplastic diseases.
The patent indicates efficacy against:
- Solid tumors: Examples suggest activity against various types of solid tumors.
- Hematological malignancies: While not explicitly detailed in every claim, the general description of anticancer agents implies potential application.
- Specific cancer cell lines: The patent references in vitro testing against a range of human cancer cell lines, indicating a broad spectrum of potential applicability.
The therapeutic method involves administering a therapeutically effective amount of one of the claimed compounds or a pharmaceutically acceptable salt thereof to a subject in need of such treatment. The patent does not specify particular dosages or administration routes beyond general pharmaceutical practices.
What is the Intellectual Property Landscape Surrounding Patent 5,319,097?
The patent landscape for anticancer agents is highly competitive, with numerous patents covering chemical entities, formulations, and methods of use. Understanding this landscape is crucial for assessing freedom to operate and potential infringement risks.
Key aspects of the landscape include:
- Core Compound Patents: Patents claiming novel chemical structures with demonstrated therapeutic utility, similar to 5,319,097.
- Formulation Patents: Patents covering specific drug delivery systems, formulations (e.g., extended-release, injectable), or combinations of active ingredients.
- Method of Use Patents: Patents claiming the use of a known compound for treating a new disease or a new patient population, or through a novel administration regimen.
- Polymorph and Salt Patents: Patents covering specific crystalline forms (polymorphs) or pharmaceutically acceptable salts of active pharmaceutical ingredients, which can extend market exclusivity.
- Manufacturing Process Patents: Patents protecting specific methods of synthesizing the active pharmaceutical ingredient.
For Patent 5,319,097 specifically:
- Prior Art: The novelty and inventiveness of the claimed compounds would have been assessed against existing knowledge at the time of filing. This includes other pyrazolo[3,4-d]pyrimidine derivatives with different substitution patterns or reported biological activities.
- Cited Patents: A review of patents cited by the U.S. Patent and Trademark Office (USPTO) during the examination of 5,319,097 provides insight into the closest prior art considered by the examiner.
- Citing Patents: Patents that cite 5,319,097 in their own applications indicate subsequent research and development that built upon or distinguished from the invention claimed. This is a critical indicator of the patent's influence.
A detailed patentability search and freedom-to-operate analysis would be necessary to identify specific competing patents that may overlap with the claims of 5,319,097, particularly for any drug products developed based on its claims.
What is the Status and Prosecution History of U.S. Patent 5,319,097?
Understanding the prosecution history of a patent provides insight into the scope of the claims as allowed and any limitations or disclaimers made during examination.
Key elements of patent prosecution include:
- Filing Date: October 5, 1993.
- Grant Date: June 7, 1994.
- Patent Term: The patent term for applications filed before June 8, 1995, was 17 years from the grant date. Therefore, the original expiration date would have been June 7, 2011. However, extensions to patent terms, such as Patent Term Adjustment (PTA) and Patent Term Extension (PTE) for regulatory delays, could have altered this.
- Examination Process: The USPTO examiner reviewed the application against prior art, assessing novelty, non-obviousness, and enablement. Office Actions were issued, to which the applicant responded by amending claims or providing arguments.
The claims in Patent 5,319,097 include:
- Independent Claims: These are broad claims that define the core invention without reference to other claims.
- Dependent Claims: These claims narrow the scope of an independent claim by adding specific limitations or embodiments.
The prosecution history documents any arguments made by the applicant to overcome rejections, which can help in interpreting the intended scope of the claims. For instance, if the examiner initially rejected claims based on a specific prior art reference, the applicant's arguments for distinguishing their invention might shed light on the precise boundaries of the claimed subject matter.
What are the Key Examples and Disclosures within the Patent?
Patent 5,319,097 provides specific examples of synthesized compounds and experimental data to support the claimed invention. These examples are crucial for understanding the practical embodiments of the patent and the basis for its enablement.
Disclosures typically include:
- Synthesis Procedures: Detailed step-by-step instructions for preparing the claimed compounds, allowing a person skilled in the art to reproduce them. This includes specific reagents, reaction conditions, and purification methods.
- Characterization Data: Spectroscopic data (e.g., NMR, MS) and physical properties (e.g., melting point) to confirm the identity and purity of the synthesized compounds.
- Biological Testing Data: In vitro and in vivo data demonstrating the anticancer activity of the compounds. This often includes:
- IC50 values (the concentration of a compound that inhibits a biological function by 50%) against various cancer cell lines.
- Results from animal xenograft models, showing tumor growth inhibition.
- Mechanism of action studies, if performed.
The examples in Patent 5,319,097 illustrate specific compounds that fall within the broader claimed genus. These specific examples can be important in infringement analysis, as a compound that matches an exemplified structure is clearly covered by the patent. The breadth of the generic claims, however, extends beyond these specific examples.
What is the Significance of the Pyrazolo[3,4-d]pyrimidine Scaffold?
The pyrazolo[3,4-d]pyrimidine scaffold is a bicyclic heterocyclic aromatic organic compound. It is a purine analog and has been a subject of significant research in medicinal chemistry due to its potential for diverse biological activities.
Significance of the scaffold:
- Bioisosterism with Purines: Its structural similarity to purines allows pyrazolo[3,4-d]pyrimidines to interact with biological targets that normally bind purines, such as enzymes involved in nucleic acid metabolism or signaling pathways.
- Drug Development Potential: This scaffold has been explored for a wide range of therapeutic applications, including anticancer, antiviral, anti-inflammatory, and cardiovascular agents.
- Modulable Structure: The scaffold offers multiple positions for chemical modification, allowing for fine-tuning of pharmacological properties, including potency, selectivity, and pharmacokinetic profiles.
In the context of Patent 5,319,097, the choice of the pyrazolo[3,4-d]pyrimidine scaffold signifies an effort to design molecules that can interfere with cancer cell proliferation, survival, or growth by targeting specific biochemical pathways. The patent claims a particular set of substitutions on this scaffold that were found to confer the desired anticancer properties.
Key Takeaways
U.S. Patent 5,319,097 claims a class of substituted pyrazolo[3,4-d]pyrimidine compounds and their use in cancer treatment. The patent was granted in 1994 and originally expired in 2011, though extensions may have applied. The invention is based on the chemical structure of these compounds and their demonstrated ability to inhibit cancer cell growth. The pyrazolo[3,4-d]pyrimidine scaffold is recognized for its purine-like structure, enabling interaction with biological targets relevant to cancer. The prosecution history and exemplified compounds are critical for defining the exact scope of protection.
FAQs
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What is the expiration date of U.S. Patent 5,319,097?
The original expiration date of U.S. Patent 5,319,097 was June 7, 2011, as it was granted prior to the changes in patent term calculation for applications filed on or after June 8, 1995. Any applicable Patent Term Adjustment or Patent Term Extension for regulatory delays would have adjusted this date.
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Can I still develop and sell compounds claimed by Patent 5,319,097?
As the original patent term has expired, compounds covered by the expired claims are generally available for development and sale, assuming no other patents with later expiration dates (e.g., covering specific formulations, polymorphs, or methods of use) are in force and are being infringed.
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Does the patent claim a specific drug that is currently on the market?
Patent 5,319,097 claims a genus of compounds. To determine if a specific drug on the market is covered, a detailed comparison of the drug's chemical structure and claimed uses against the patent's claims would be necessary. The patent expired in 2011, suggesting any associated drug would likely be off-patent, or rely on later-expiring patents for exclusivity.
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What is the significance of "pharmaceutically acceptable salts" in the claims?
The inclusion of "pharmaceutically acceptable salts" means the patent protection extends not only to the free base or acid form of the claimed compounds but also to their salt forms. These salts are often created to improve a compound's solubility, stability, or bioavailability, and are common in drug development.
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Where can I find the prosecution history and full text of Patent 5,319,097?
The full text of the patent and its prosecution history (including Office Actions and responses) are publicly available through the United States Patent and Trademark Office (USPTO) Patent Center (formerly PAIR) and the Google Patents database.
Citations
[1] Schering Corporation. (1994). Anticancer agents and their use (U.S. Patent No. 5,319,097). Washington, DC: U.S. Patent and Trademark Office.
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