United States Patent 8,106,183: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 8,106,183, titled "Process for preparing an A2A-adenosine receptor agonist and its polymorphs," is a significant patent in the pharmaceutical industry, particularly in the context of cardiac stress tests. This patent, held by Astellas US LLC, covers the synthesis and polymorphs of regadenoson, a compound used to increase blood flow to mimic a cardiac stress test.
Background and Context
Regadenoson is a key component in the drug Lexiscan, which is used in cardiac stress tests to evaluate coronary artery disease. The patent in question specifically deals with the monohydrate form of regadenoson, known as Form A, which is crucial for the drug's efficacy and stability[4][5].
Patent Claims and Scope
Independent Claims
The patent includes several independent claims that define the scope of the invention. These claims are critical in determining what is protected under the patent.
- Claim 1: This claim describes a process for preparing regadenoson, involving specific chemical reactions and conditions, such as the use of ethanol and ethyl 2-formyl-3-oxopropionate at a temperature of about 80°C[4].
- Claim 2: This claim pertains to the synthesis of regadenoson by contacting a compound of a specific formula with methylamine in an aqueous solution, followed by warming to a specified temperature range[4].
Dependent Claims
Dependent claims further narrow down the scope by adding additional limitations to the independent claims. These claims often specify particular conditions, reagents, or steps in the synthesis process.
Claim Length and Count
Research has shown that the length and count of independent claims can be metrics for measuring patent scope. Generally, narrower claims (shorter length and fewer in number) are associated with a higher probability of grant and a shorter examination process[3].
Polymorphs and Form A Regadenoson
The patent covers various polymorphs of regadenoson, with a specific focus on the monohydrate form (Form A). This form is significant because it contains one molecule of water in the crystal lattice for every molecule of the compound, which affects the drug's stability and efficacy[1][4].
Patent Landscape and Litigation
Infringement Cases
The patent has been at the center of several infringement cases, notably against generic manufacturers like Hospira, Inc. and Apotex, Inc. These cases involve the filing of Abbreviated New Drug Applications (ANDAs) with paragraph IV certifications, which assert that the listed patents are invalid or will not be infringed by the generic drug[1][5].
Astellas US LLC v. Hospira, Inc.
In this case, Astellas alleged that Hospira's ANDA infringed the Form A patents. The litigation involved complex issues, including the introduction of new infringement theories by Astellas and the exclusion of certain evidence by the district court. The Federal Circuit ultimately upheld the district court's decision to exclude the new infringement contentions[1][5].
Patent Quality and Scope
Critiques and Metrics
The quality and scope of patents, including those like US 8,106,183, have been subjects of debate. Metrics such as independent claim length and count are used to assess patent scope. Narrower claims are generally associated with higher patent quality, as they are clearer and less likely to be overly broad[3].
Examination Process
The examination process at the USPTO tends to narrow the scope of patent claims, making them more specific and less broad. This process is crucial in ensuring that patents are granted for inventions that are novel, non-obvious, and useful[3].
Industry Impact
Innovation and Litigation
The scope and claims of patents like US 8,106,183 can significantly impact innovation and litigation in the pharmaceutical industry. Broad or unclear claims can lead to increased litigation costs and may impede innovation by creating uncertainty and barriers to entry for generic manufacturers[3].
Economic Considerations
The economic implications of patent scope are substantial. Patents with narrower claims tend to have a higher probability of grant and shorter examination times, which can reduce costs associated with the patent process. This efficiency can encourage more innovation by providing clearer boundaries for what is protected[3].
Expert Insights
Industry experts emphasize the importance of clear and specific patent claims. For example, Alan Marco and his colleagues at the U.S. Patent and Trademark Office have highlighted the need for well-defined metrics to measure patent scope, which can help in evaluating patent quality and reducing litigation[3].
Statistics and Data
- Patent Maintenance Payments: Patents with narrower claims tend to have higher maintenance payments, indicating their value and the likelihood of their being upheld[3].
- Forward Citations: Patents with clearer and more specific claims often receive more forward citations, a metric of their impact and relevance in the field[3].
Conclusion
United States Patent 8,106,183 is a critical patent in the pharmaceutical industry, particularly for the synthesis and use of regadenoson in cardiac stress tests. The patent's scope and claims are defined by specific chemical processes and the monohydrate form of regadenoson. The patent landscape is marked by litigation over infringement, highlighting the importance of clear and specific claims in promoting innovation and reducing legal disputes.
Key Takeaways
- Specific Claims: The patent includes specific claims regarding the synthesis of regadenoson and its polymorphs.
- Form A Regadenoson: The monohydrate form of regadenoson is crucial for the drug's stability and efficacy.
- Litigation: The patent has been involved in several infringement cases against generic manufacturers.
- Patent Quality: Clear and specific claims are associated with higher patent quality and reduced litigation.
- Economic Impact: Narrower claims can reduce costs and encourage innovation by providing clearer boundaries.
FAQs
What is the main subject of United States Patent 8,106,183?
The main subject of this patent is the process for preparing an A2A-adenosine receptor agonist, specifically regadenoson, and its polymorphs.
Why is Form A regadenoson important?
Form A regadenoson, the monohydrate form, is important because it contains one molecule of water in the crystal lattice for every molecule of the compound, affecting the drug's stability and efficacy.
What are some key metrics for measuring patent scope?
Key metrics include independent claim length and the total number of independent claims, which can indicate the clarity and breadth of the patent claims.
How has this patent been involved in litigation?
This patent has been involved in infringement cases against generic manufacturers like Hospira, Inc. and Apotex, Inc., with disputes over the filing of ANDAs and the validity of the patent claims.
What are the economic implications of patent scope?
Patents with narrower claims tend to have a higher probability of grant, shorter examination times, and reduced litigation costs, which can encourage innovation by providing clearer boundaries for what is protected.
Cited Sources
- ASTELLAS US LLC v. HOSPIRA, INC. - Federal Circuit Court of Appeals, December 30, 2022.
- Apotex Inc. v. Gilead Scis., Inc. - Casetext.
- Patent Claims and Patent Scope - Hoover Institution, August 18, 2016.
- US8106183B2 - Process for preparing an A2A-adenosine receptor agonist and its polymorphs - Google Patents.
- Astellas US LLC v. Hospira, Inc. (Fed. Cir. 2022) - Patent Docs, February 13, 2023.
